No full-text available
To read the full-text of this research,
you can request a copy directly from the authors.
Capacity limits of information processing in the brain. Trends in Cognitive Sciences, 9, 296-305
Abstract
Despite the impressive complexity and processing power of the human brain, it is severely capacity limited. Behavioral research has highlighted three major bottlenecks of information processing that can cripple our ability to consciously perceive, hold in mind, and act upon the visual world, illustrated by the attentional blink (AB), visual short-term memory (VSTM), and psychological refractory period (PRP) phenomena, respectively. A review of the neurobiological literature suggests that the capacity limit of VSTM storage is primarily localized to the posterior parietal and occipital cortex, whereas the AB and PRP are associated with partly overlapping fronto-parietal networks. The convergence of these two networks in the lateral frontal cortex points to this brain region as a putative neural locus of a common processing bottleneck for perception and action.
... Evidence that the brain likes large amounts of information includes a dislike of too little complexity in sensory signals [5][6][7] and addiction to tools designed to provide a lot of data to our senses [8][9][10]. However, the brain has limited resources, and thus, it cannot deal with too much information [11][12][13]. The brain, therefore, dislikes incoming sensory signals with too much complexity [14][15][16]. ...
... In all these Logit-Losev results, we saw the inverted-U-shape behavior. The optimal complexity of this behavior is shown in mathematical form in Equation (11). Interestingly, this optimum depended only on parameter . ...
... In all these Logit-Losev results, we saw the inverted-U-shape behavior. The optimal complexity of this behavior is shown in mathematical form in Equation (11). Interestingly, this optimum depended only on parameter µ. ...
When evaluating sensory stimuli, people tend to prefer those with not too little or not too much complexity. A recent theoretical proposal for this phenomenon is that preference has a direct link to the Observed Fisher Information that a stimulus carries about the environment. To make this theory complete, one must specify the model that the brain has about complexities in the world. Here, we develop this model by first obtaining the distributions of three indices of complexity measured as normalized Shannon Entropy in real-world images from seven environments. We then search for a parametric model that accounts for these distributions. Finally, we measure the Observed Fisher Information that each image has about the parameters of this model. The results show that with few exceptions, the distributions of image complexities are unimodal, have negative skewness, and are leptokurtotic. Moreover, the sign and magnitude of the skewness varies systematically with the location of the mode. After investigating tens of models for these distributions, we show that the Logit-Losev function, a generalization of the hyperbolic-secant distribution, fits them well. The Observed Fisher Information for this model shows the inverted-U-shape behavior of complexity preference. Finally, we discuss ways to test our Fisher-Information theory.
... A greater panel of faces should therefore improve the signal-to-noise ratio of the selected noisy faces and thus accelerate the convergence towards a higher quality and more robust CI, both at the individual and at the average levels. Surely, the improvement in signal-to-noise ratio due to the increase in face stimuli per trial should reach a plateau because the visual processing capacity of the human brain is limited (e.g., participants should perform poorly with 100 faces per trial; Marois & Ivanoff, 2005;Palmer, 1990). Still, providing more faces per trial should deliver (a) clearer CIs for a given number of trials and (b) high-quality CIs with fewer trials and a shorter completion time. ...
... This was not the case here with our participants. A possible reason may stem from the limitations of the human brain when it comes to processing visual information, suggesting that adding more faces per trial should not help improve the method (Marois & Ivanoff, 2005;Palmer, 1990). Considering the present findings, the Brief-RC12 ...
The reverse correlation is an innovative method to capture visual representations (i.e., classification images, CIs) of social targets. However, this method necessitates many trials to compute high-quality CIs, which poses important practical and economic challenges. We introduce a new version of the reverse correlation method, namely, the Brief-RC. By increasing the number of stimuli (i.e., noisy faces) presented at each trial, the Brief-RC improves the quality of individual (and average) CIs and lowers the overall task length. In two experiments, assessments by external judges confirmed that the new method delivers equally good (Experiment 1) or higher-quality (Experiment 2) outcomes than the traditional method for the same number of trials, time length and number of stimuli. The informational values of CIs were also compared using a more objective metric (infoVal). Because the Brief-RC facilitates the production of higher-quality individual CIs, social psychology researchers may more easily address a series of relevant research questions. K E Y W O R D S Brief-RC, classification images, infoVal, rcirc package, reverse correlation, visual representations
... On a daily basis, our environment inundates us with an immense quantity of information. However, the human brain cannot process all of this data at once [1]. In order to maintain the effectiveness and functionality of our behavior, a selection process becomes imperative [2]. ...
... The exclusion of datasets was based on a set of criteria already established in previous ERP studies [23,24] and necessary to ensure the reliability of our findings. These criteria included the following: First of all, [1] insufficient target detection in the zero-distractor condition (less than 60% accuracy). It is highly probable that individuals showing strongly impaired target detection in the zero-distractor condition may not have understood the task correctly or are unable to perceive the stimuli adequately, which would introduce confounding factors to our experiment. ...
Distractor-induced blindness (DIB) describes a reduced access to a cued visual target–if multiple target-like distractors have been presented beforehand. Previous ERP data suggest a cumulative frontal inhibition triggered by distractors, which affects the updating process of the upcoming target. In the present study, we examine whether the modality of the cue—formerly defined in the visual domain–affects the expression of these neural signatures. 27 subjects were tested in a cross-modal DIB task: Distractors and targets were defined by a transient change of stimuli shape in a random-dot kinematogram. The onset of the target was announced by a rise in amplitude of a sinusoidal tone. Behavioral results confirmed that detection of the target relies on the number of preceding distractor episodes. Replicating previous unimodal results, ERP responses to distractors were characterized by a frontal negativity starting at 100 ms, which increases with an increasing number of distractor episodes. However, the processing–and detection–of the target was not characterized by a more-expressed P3 response, but by an occipital negativity. The current data confirm that the neural signatures of target awareness depend on the experimental setup used: In case of the DIB, the cross-modal setting might lead to a reduction of attentional resources in the visual domain.
... Behavioral data from this study also suggest that both low-load and high-load scenarios remain within participants' manageable levels of cognitive load, thus facilitating the observation of the time advancement effect under high load. However, the brain's capacity to mobilize additional resources and optimize resource allocation for enhanced efficiency under high load is restricted under extreme conditions 53 . For instance, cognitive overload resulting from a load increase beyond individual processing capacity may impede cognitive task performance efficiency 52 , potentially counteracting the time advancement effect or even eliciting a time delay effect. ...
... Second, the time-shift effect proposed in this study may have specific limitations, particularly in scenarios involving moderate increases in cognitive load. If cognitive load is significantly heightened, the brain's ability to mobilize additional resources and optimize resource allocation to enhance efficiency may be constrained 52,53 . Future research should distinguish between varying levels of cognitive load intensity to further elucidate the mechanisms underlying cognitive load regulation. ...
Data-driven decision making (DDDM) is becoming an indispensable component of work across various fields, and the perception of aberrant data (PAD) has emerged as an essential skill. Nonetheless, the neural processing mechanisms underpinning PAD remain incompletely elucidated. Direct evidence linking neural oscillations to PAD is currently lacking, and the impact of cognitive load remains ambiguous. We address this issue using EEG time-frequency analysis. Data were collected from 21 healthy participants. The experiment employed a 2 (low vs. high cognitive load) × 2 [PAD+ (aberrant data accurately identified as aberrant) vs. PAD- (non-aberrant data correctly recognized as normal)] within-subject laboratory design. Results indicate that upper β band oscillations (26–30 Hz) were significantly enhanced in the PAD + condition compared to PAD-, with consistent activity observed in the frontal (p < 0.001, = 0.41) and parietal lobes (p = 0.028, = 0.22) within the 300–350 ms time window. Additionally, as cognitive load increased, the time window of β oscillations for distinguishing PAD+ from PAD- shifted earlier. This study enriches our understanding of the PAD neural basis by exploring the distribution of neural oscillation frequencies, decision-making neural circuits, and the windowing effect induced by cognitive load. These findings have significant implications for elucidating the pathological mechanisms of neurodegenerative disorders, as well as in the initial screening, intervention, and treatment of diseases.
... Whereas the above-mentioned studies on algorithmic aversion/appreciation directly compared the human willingness to offload tasks to another human vs. an artificial system, other studies have focused on the conditions under which humans are generally willing to offload cognition to artificial systems (Wahn et al., 2023;Weis & Wiese, 2019a, 2019bWiese et al., 2022). Such cognitive offloading, broadly defined as "the use of physical action to alter the information processing requirements of a task so as to reduce cognitive demand" (Risko & Gilbert, 2016, p. 676), can help humans to overcome cognitive capacity limitations (Marois & Ivanoff, 2005;Wahn & König, 2017) and thereby enable them to attain goals they could not have attained (as quickly, easily, or efficiently) otherwise. Cognitive offloading is omnipresent in daily life. ...
... Moreover, future research could tap more directly into the limitations of attention (Marois & Ivanoff, 2005;Wahn & König, 2017) by instructing participants to track a number of targets that goes beyond their individual maximum tracking load and thereby create an attentional overload. With this manipulation, participants might be willing to offload to a larger extent (compared to the present study) as they would likely feel overwhelmed with the task in the Solo condition. ...
With the increased sophistication of technology, humans have the possibility to offload a variety of tasks to algorithms. Here, we investigated whether the extent to which people are willing to offload an attentionally demanding task to an algorithm is modulated by the availability of a bonus task and by the knowledge about the algorithm’s capacity. Participants performed a multiple object tracking (MOT) task which required them to visually track targets on a screen. Participants could offload an unlimited number of targets to a “computer partner”. If participants decided to offload the entire task to the computer, they could instead perform a bonus task which resulted in additional financial gain—however, this gain was conditional on a high performance accuracy in the MOT task. Thus, participants should only offload the entire task if they trusted the computer to perform accurately. We found that participants were significantly more willing to completely offload the task if they were informed beforehand that the computer’s accuracy was flawless (Experiment 1 vs. 2). Participants’ offloading behavior was not significantly affected by whether the bonus task was incentivized or not (Experiment 2 vs. 3). These results combined with those from our previous study (Wahn et al. in PLoS ONE 18:e0286102, 2023), which did not include a bonus task but was identical otherwise, show that the human willingness to offload an attentionally demanding task to an algorithm is considerably boosted by the availability of a bonus task—even if not incentivized—and by the knowledge about the algorithm’s capacity.
... Research in cognitive neurosciences highlights a number of bottlenecks impinging upon the flow of information from sensation to action (Anderson 2009, 63). These bottlenecks are human limits in perceiving all the relevant information in the environment, in holding it in mind and in acting upon the visual world (Marois and Ivanoff 2005). For example, human short-term memory is limited, the average adult being able to store approximately seven meaningful units (plus or minus two) at a time (Miller 1956). ...
... For example, human short-term memory is limited, the average adult being able to store approximately seven meaningful units (plus or minus two) at a time (Miller 1956). But it is not just short-term memory; all our cognitive subsystems have some upper limit in information processing (Marois and Ivanoff 2005), meaning that human brains have a limited processing capacity or bandwidth. ...
The Internet allows humans to effortlessly communicate with each other in novel ways and delivers instantaneous access to vast amounts of information and accumulated knowledge. Recently, several scholars have made the case that the Internet can enhance human cognition, while others are skeptical or disagree. Within the context of the wider debate around human enhancement, to what extent can it be argued that the Internet enhances human cognition? In an effort to resolve this question, we examine three critical assumptions: (1) the Internet fosters an active learning environment characterized by deep and constructive learning, (2) the current design of the Internet benefits users and promotes adaptive behaviors, and (3) the Internet improves cognitive function. Our analysis systematizes the evidence presented in recent scholarship that points to either an optimistic or pessimistic view on whether the Internet can function as a cognitive enhancement—with some evidence, such as the “Google effect,” being cited by either side of the debate. Moreover, we find a clash of differing ideological views, which risks polarizing both the academic and the public debate on the topic. In the effort to advance this debate toward a conclusion based on the available objective facts and evidence, we argue for a nuanced approach: to designate the Internet as a technologically enabled environment, not as a single technological intervention that can be reliably expected to enhance or decrease cognition.
... Cortical columns of the brain gray matter are characterized by highly sophisticated connections for both the intra and inter layers. This complexity is largely based on the large number of neurons with over 125 trillions of synapses in the cortex alone [30]. There is an immeasurable effort from the neuroscience community in modelling cortex connections, and one proposal is a discrete-time Markov chain with |L| states, each representing one layer of the cortical column. ...
In recent years, numerous research efforts have been dedicated towards developing efficient implantable devices for brain stimulation. However, there are limitations and challenges with the current technologies. Firstly, the stimulation of neurons currently is possible through implantable electrodes but limited to a population of neurons. Secondly, a major hurdle lies in developing miniature devices that can last for a lifetime in the patient's brain. In parallel, Optogenetics has emerged proposing the stimulation of neurons using light by means of optical fibers inserted through the skull. Many challenges are thus introduced in terms of suitability to patient's lifestyle and biocompatibility. We have recently proposed the concept of wireless optogenetic nanonetworking devices (WiOptND), addressing these long-term deployment problems, and at the same time targeting single neuron stimulation [1]. The WiOptND is equipped with a miniature LED that is able to stimulate a genetically engineered neuron while harvesting energy from ultrasonic vibrations. This paper investigates how light propagates in the brain tissue, and based on the power required to emit sufficient intensity for stimulation, an energy harvesting circuitry is designed. A number of charging protocols are also proposed to maximize energy efficiency while ensuring minimum number of neural spike misfirings. These protocols include the Charge and Fire, the Predictive Sliding Detection Window, and its variant Markov-Chain based Time-Delay Patterns. Simulation results show the drop of stimulation ratio for 25% and more stable trend in its efficiency ratio are exhibited on Markov-Chain based Time-Delay Patterns compared to Change and Fire. The results show the feasibility of utilizing WiOptND for long-term implants, and a new direction towards precise stimulation of neurons in the cortical columns of the brain.
... The brain is an intricately connected dynamic system that supports substantial information processing capacity underlying human thought (Marois & Ivanoff, 2005). How complex cognitive processes are executed in the brain remains a deeply challenging and unsolved question. ...
Traditional approaches to understanding the brain's resilience to neuropathology have identified neurophysiological variables, often described as brain or cognitive 'reserve,' associated with better outcomes. However, mechanisms of function and resilience in large-scale brain networks remain poorly understood. Dynamic network theory may provide a basis for substantive advances in understanding functional resilience in the human brain. In this perspective, we describe recent theoretical approaches from network control theory as a framework for investigating network level mechanisms underlying cognitive function and the dynamics of neuroplasticity in the human brain. We describe the theoretical opportunities offered by the application of network control theory at the level of the human connectome to understand cognitive resilience and inform translational intervention.
... Neuroscience studies found individual differences in working memory and other cognitive activities in the human brain [34]. However, it remains unclear from a physiological standpoint whether capacity to process or produce information varies from person to person [25]. Online performance deterioration may also depend on acquired experience (as a form of cognitive dexterity) with a system. ...
This article presents evidence of performance deterioration in online user sessions quantified by studying a massive dataset containing over 55 million comments posted on Reddit in April 2015. After segmenting the sessions (i.e., periods of activity without a prolonged break) depending on their intensity (i.e., how many posts users produced during sessions), we observe a general decrease in the quality of comments produced by users over the course of sessions. We propose mixed-effects models that capture the impact of session intensity on comments, including their length, quality, and the responses they generate from the community. Our findings suggest performance deterioration: Sessions of increasing intensity are associated with the production of shorter, progressively less complex comments, which receive declining quality scores (as rated by other users), and are less and less engaging (i.e., they attract fewer responses). Our contribution evokes a connection between cognitive and attention dynamics and the usage of online social peer production platforms, specifically the effects of deterioration of user performance.
... That the brain's biology is to blame for all kinds of cognitive and/or behavioral flaws is not a novel idea (Buschman et al., 2011;Marois and Ivanoff, 2005;Miller and Buschman, 2015;Ramsey et al., 2004). However, providing neuroscientific evidence that a hard-wired biological constraint shapes and/or distorts the way the brain processes information is not an easy task. ...
Is irrational behavior the incidental outcome of biological constraints imposed on neural information processing? In this work, we consider the paradigmatic case of gamble decisions, where gamble values integrate prospective gains and losses. Under the assumption that neurons have a limited firing response range, we show that mitigating the ensuing information loss within artificial neural networks that synthetize value involves a specific form of self-organized plasticity. We demonstrate that the ensuing efficient value synthesis mechanism induces value range adaptation. We also reveal how the ranges of prospective gains and/or losses eventually determine both the behavioral sensitivity to gains and losses and the information content of the network. We test these predictions on two fMRI datasets from the OpenNeuro.org initiative that probe gamble decision-making but differ in terms of the range of gain prospects. First, we show that peoples' loss aversion eventually adapts to the range of gain prospects they are exposed to. Second, we show that the strength with which the orbitofrontal cortex (in particular: Brodmann area 11) encodes gains and expected value also depends upon the range of gain prospects. Third, we show that, when fitted to participant’s gambling choices, self-organizing artificial neural networks generalize across gain range contexts and predict the geometry of information content within the orbitofrontal cortex. Our results demonstrate how self-organizing plasticity aiming at mitigating information loss induced by neurons’ limited response range may result in value range adaptation, eventually yielding irrational behavior.
... When m = n, this explanation is fully faithful to the actual prediction. However, if n is very large, showing all m = n of these training examples to explain the prediction may induce cognitive overload, often also referred to as information overload (Marois and Ivanoff, 2005;Abdul et al., 2020). ...
... What do these findings offer in terms of understanding the role of selective attention in implicit learning? Attentional or selective mechanisms are essential to our cognitive system, in the visual system alone, we are bombarded with information of about 10 8 bits per second (Itti & Koch, 2000;Marois & Ivanoff, 2005). This requires mechanisms of selection, chunking, and binding (Fiser & Aslin, 2005;Wheeler & Treisman, 2002). ...
With attentional mechanisms, humans select and de-select information from the environment. But does selective attention modulate implicit learning? We tested whether the implicit acquisition of contingencies between features are modulated by the task-relevance of those features. We implemented the contingencies in a novel variant of the contextual cueing paradigm. In such a visual search task, participants could use non-spatial cues to predict target location, and then had to discriminate target shapes. In Experiment 1, the predictive feature for target location was the shape of the distractors (task-relevant). In Experiment 2, the color feature of distractors (task-irrelevant) cued target location. Results showed that participants learned to predict the target location from both the task-relevant and the task-irrelevant feature. Subsequent testing did not suggest explicit knowledge of the contingencies. For the purpose of further testing the significance of task-relevance in a cue competition situation, in Experiment 3, we provided two redundantly predictive cues, shape (task-relevant) and color (task-irrelevant) simultaneously, and subsequently tested them separately. There were no observed costs of single predictive cues when compared to compound cues. The results were not indicative of overshadowing effects, on the group and individual level, or of reciprocal overshadowing. We conclude that the acquisition of contingencies occurs independently of task-relevance and discuss this finding in the framework of the event coding literature.
... /fcogn. . attention allocation and its implications for cognitive performance in multitasking situations (Marois and Ivanoff, 2005). Visuospatial or spatial attention involves distributing processing power across specific points or regions in space to locate target objects. ...
Environmental hypoxia, resulting from reduced oxygen supply, poses a significant risk of dysfunctioning and damaging the neurocognitive system, particularly in relation to anxiety and stress. Inadequate oxygenation can lead to acute and chronic brain damage. Scholars used behavioral, hemodynamic, and electromagnetic neurofunctional techniques to investigate the effects of normobaric and hypobaric hypoxia on neurocognitive systems. They found a correlation between hypoxia, altered psychomotor responses, and changes
in EEG alpha, theta, beta, and gamma rhythms, which affect spatial attention and memory. Hypoxia affects event related potential (ERP) components differently depending on latency. Perceptual responses N1 and P2 remain largely unaffected, while the amplitudes of preattentive MMN, vMMN, and P3a are significantly altered. Late latency components related to attention, particularly P3b, are also altered. These changes illustrate the spectrum from sensory detection to more complex cognitive processing, highlighting the
brain's efficiency in managing information. Interestingly, the amplitudes of P3b, ADAN and CNV can increase with increased cognitive demands in hypoxia. This suggests a compensatory response. Prolonged exposure exacerbates these effects, resulting in compensatory delayed behavioral responses and alterations in behavioral monitoring and conflict inhibitory control, as reflected by reduced amplitudes in some attention related ERP components, including N2, N2pc, and ERN. Thus, neurocognitive function and integrity are under stress. ERP sources and hemodynamic images reveal that vulnerable brain regions include the frontal prefrontal cortices, hippocampus, basal ganglia, and parietal and visual cortices, which are essential for attention related processes like decision making and spatial memory. The auditory system appears less affected.
[Keywords]: normobaric and hypobaric hypoxia, high altitude, working memory, attention, alertness, brain and behavior, EEG/ERPs, neuroimaging
[Critical Description]
This review, which is part of the research topic "Detrimental Effects of Hypoxia on Brain and Cognitive Functions" of Frontiers in Cognition, contributes to the literature by elucidating the complex relationship between environmental hypoxia and its detrimental effects on neurocognitive function. By employing a range of neurofunctional techniques, including behavioral assessments, electrophysiological measurements (such as EEG and ERPs), and hemodynamic imaging, the authors provide a comprehensive examination of how both normobaric and hypobaric hypoxia impact cognitive processes.
Key findings indicate that hypoxia is associated with altered psychomotor responses and significant changes in EEG rhythms that are crucial for spatial attention and memory. The differential effects of hypoxia on several ERP components highlight the nuanced impact of hypoxia on cognitive processing - while early perceptual responses such as N1 and P2 remain stable, cognitive components such as ADAN, LDAP and P3b, as well as preattentive components P3a, MMN and vMMN show marked changes. Moreover, the identification of specific brain regions—like the frontal prefrontal cortices, hippocampus, and basal ganglia—as vulnerable to hypoxia enhances our understanding of the neuroanatomical correlates of cognitive impairments observed under low-oxygen conditions.
... This indicates a disruption in the ability to manage and segregate different cognitive processes effectively, potentially due to cognitive interference or the blending of task elements (Monsell, 2003). This aspect of our findings highlights the neural competition theory, which posits that concurrent tasks compete for shared cognitive resources, often leading to errors or slower task execution (Marois & Ivanoff, 2005). To further our understanding, a longitudinal study following individuals' cognitive changes with continued exposure to multitasking environments could illuminate whether cognitive declines are transient or if individuals develop compensatory mechanisms over time. ...
This study investigates the cognitive impacts of video game immersion and task interference on immediate and delayed recall as well as recognition tasks. We enrolled 160 subjects aged 18 to 29, who were regular players of "shoot-em-up" video games for at least 3 years. Participants were assigned to one of three experimental groups or a control group. The experimental conditions varied in the timing and type of tasks: the first group performed a video game session between recall tasks, the second group multitasked with video games and recall tasks simultaneously, and the third group engaged in task switching from video games to recall tasks. Using the Rey Auditory Verbal Learning Test, we measured the effects of these conditions on cognitive performance, focusing on error types and recall accuracy. Results indicated that multitasking and task switching significantly affected the subjects' performance, with notable decrements in recall and recognition accuracy in conditions of high task interference. The study highlights the cognitive costs associated with multitasking in immersive digital games and provides insights into how task similarity and interference might increase error rates and affect memory performance.
... To summarise, although its ability to penetrate the deeper levels of the mind and ultimately consciousness is limited, cognitive psychology has captured and described important aspects of perception and cognition. Unsurprisingly, some of its most important findings concern the limited ability of the mind (Cowan, 2001;Miller, 1956;Posner et al., 1980;Sternberg, 1966) or the brain (e.g., Marois & Ivanoff, 2005) to encode, attend to, and store information. ...
Instead of bringing intellectual closure, the philosophical debate surrounding the nature of consciousness has found itself at an impasse. Extreme positions, from those denying the existence of consciousness to those who wish to imbue the entire universe with it, testify to the lack of common understanding of what consciousness is and how best it could be described and studied. In this paper, reality has its source in a subjective conscious field called the human information field, which is the only source of experience and whose centre is unknowable. Objective reality equals a consensus between individual fields, which underpins the stability and durability of social organisation. The conceptual importance of matter is due to its easy distinguishability from the self. The concept of the human information field offers answers to the hard and the “hardest” problems of consciousness, that is the explanatory gap between consciousness and its material apparatus and the ability of science to understand its own source, respectively. Its limitations constrain our ability to understand the world but are also the prime movers of exploration, development, and learning.
... A arquitetura da cognição humana possui gargalos importantes que contribuem para estabelecer limites de velocidade e de processamento paralelo. Dentre esses gargalos destacamos: o tempo de identificação consciente e de consolidação de um estímulo visual na memória visual de curto prazo, o número restrito de estímulos que podem permanecer na memória visual de curto prazo e o efeito da seleção de resposta para cada estímulo, que atrasa subsequentes seleções [15]. ...
O risco em um processo de tomada de decisão é a variável que representa o que é desconhecido ou não controlado. Para modelá-lo, é comum o uso de probabilidades para representar relações de causalidade que, no escopo da decisão, produzem uma estimativa das consequências de determinada linha de ação. No presente trabalho demonstramos que o risco é inerente à construção da consciência situacional. Concluímos assim que as informações disponíveis para o processo decisório também são sujeitas ao risco, corroborando para a tese de que o risco deve ser formalmente considerado um fator de decisão.
... Next, it is well known that attention faces critical bottlenecks and capacity limitations (Lang, 2009;Marois and Ivanoff, 2005). For example, focusing intensely on achieving a goal (e.g., counting certain signs) takes people's attention away from accomplishing other tasks (e.g., remembering the content of non-target ads). ...
In contemporary urban environments, advertisements are ubiquitous, capturing the attention of individuals navigating through cityscapes. This study simulates this situation by using VR as an advertising research tool and combining it with eye-tracking to rigorously assess attention to and retention of visual advertisements. Specifically, participants drove through a virtual city with 40 AI-generated, experimentally manipulated, and randomly assigned advertisements (20 commercial, 20 health) distributed throughout. Our results confirm theoretical predictions about the link between exposure, visual attention, and incidental memory. Specifically, we found that attended ads are likely to be recalled and recognized, and concurrent task demands (counting sales signs) decreased visual attention and subsequent recall and recognition of the ads. Finally, we identify the influence of ad placement in the city as a very important but previously hard-to-study factor influencing advertising effects. This paradigm offers great flexibility for biometric advertising research and can be adapted to varying contexts, including highways, airports, and subway stations, and theoretically manipulate other variables. Moreover, considering the metaverse as a next-generation advertising environment, our work demonstrates how causal mechanisms can be identified in ways that are of equally high interest to both theoretical as well as applied advertising research.
... Sensory inputs are filtered to reduce cognitive efforts-the mind can only consciously reflect on so much information (Schwitzgebel, 2021). With constrained attention and processing capacity, human cognition faces various limitations (Marois & Ivanoff, 2005). The mind is bombarded with an overwhelming amount of information daily, making it impractical to evaluate every piece of encountered information comprehensively. ...
Beliefs are fundamental to an individual’s behavior and identity, yet they cannot be picked and chosen by an individual. This paper reviews the role of the individual’s voluntary choice and control in the formation of beliefs. It is concluded that the formation of beliefs, consisting of five main stages (Connors & Halligan 2017), is involuntary. Cognitive biases and heuristics and external influences are innate features of the human mind and the nature of beliefs, rendering extensive control over beliefs impossible. Moreover, conscious awareness of involuntary influences is not thorough and does not induce will or control over changing and interfering with the process of belief formation. Though the limitations of the mind and the inability for control seems unfavorable and undesirable, developing an open and adaptive mindset proves to be even more significant. Acknowledging the involuntary nature of beliefs cultivates a perspective that allows for effective examination upon the execution and application of beliefs.
... When assessing horse-rider combinations in competition, judges are currently required to take all of these elements into account and assess them in relation to a set pattern of increasingly advanced movements [27,28]. However, the complexity of such judging tasks has been argued to exceed human cognitive capacity [32][33][34], resulting in the development of cognitive heuristics, commonly referred to as short-cuts, in order to cope with high cognitive load, executed under time pressure [15,[35][36][37]. Some of these cognitive short cuts have been shown to result in systematic errors and biases, such as nationalistic bias [35], patriotism by proxy, home bias, reputation, and order bias [15]. ...
This study investigated the visual search behavior of equestrian dressage judges at different expertise levels during the assessment of Grand Prix horse-rider combinations. Twenty judges (11 foundational level, 9 advanced level) participated in the study, with their eye movements recorded using Tobii Fusion Eyetracker as they evaluated video recordings of dressage tests. Fixation metrics, namely Total Duration of Fixation (TDF), Average Duration of Fixation (ADF), and Total Number of Fixations (TNF), were analyzed across four Areas of Interest (AOIs): front, back, rider, and horse’s feet. Statistical analysis utilized linear mixed-effects models. Results demonstrated that judges consistently focused more on the front of the horse, with additional differences in fixation duration and frequency based on judge experience and specific movements. Advanced judges focused more on the horses’ feet, suggesting they draw meaning from specific areas indicative of performance quality. Conversely, foundational level judges focused more on the rider, reflecting different evaluative priorities at lower levels of the sport. These findings suggest that judges focus on a limited number of highly relevant areas, differing across movements and expertise levels. The study underscores the necessity of understanding both gaze behavior and subsequent interpretations of visual information to increase judging transparency, fairness, and equine welfare.
... Human cognition is highly complex and notably involves around 100 billion neurons and an estimated storage capacity of 1.25 × 10 12 bytes, leading to very high processing abilities. Nonetheless, the brain is made of biological matter and is therefore limited in its capacities [37], including storage size and the speed and accuracy of processing. This idea is captured in the term bounded rationality [38], which relates such cognitive limits to the ensuing need to rely on less demanding cognitive processes such as biases and heuristics. ...
Ignorance, or the lack of knowledge, appears to be steadily spreading, despite the increasing availability of information. The notion of informed ignorance herein proposed to describe the widespread position of being exposed to an abundance of information yet lacking relevant knowledge, which is tied to the exponential growth in misinformation driven by technological developments and social media. Linked to many of societies’ most looming catastrophes, from political polarization to the climate crisis, practices related to knowledge and information are deemed some of the most imminent and daunting modern threats, evidenced by the latest report of the World Economic Forum, which has named misinformation the most severe short-term global risk. This paper’s epistemic perspective links the properties of today’s information culture and the ways in which it interacts with individual capacities and limitations in current technological and socio-political contexts. Such a position is analyzed through the lens of epistemic principles as a contemporary epistemic phenotype that emerges from an environment of ill-adapted and excessive information inputs and leads to a distinctive type of social injustice that is primarily epistemic in nature. While equity and accessibility are widely discussed as important contributing factors to epistemic discrepancies, other overlooked but fundamental issues underlying epistemic injustices are considered, such as information manipulation, cognitive limitations, and epistemic degradation. To effectively face this elusive threat, we propose an inclusive viewpoint that harnesses knowledge from cognitive science, science and technology studies, and social epistemology to inform a unifying theory of its main impacts and driving forces. By adjusting a modern epistemic framework to the described phenomena, we intend to contextually outline its trajectory and possible means of containment based on a shared responsibility to maintain ethical epistemic standards. In a time of international unrest and mounting civil acts of violence, it is pertinent to emphasize the ethical principles of knowledge systems and authorities and suggest policy adaptations to maintain a social contract based on the shared values of truth and freedom.
... Cognitive and physical constraints limit the rate at which people can convey or receive information. This basic experience of all people is grounded in the structure of the brain [27]. Nonetheless, this limitation is sometimes overlooked in models of digital communication. ...
We propose a set of metrics, based upon the four flows theory of the communicative constitution of organizations, to evaluate the emergence of organization in a social network. Using an agent-based model (ABM), we validate that our metrics chart the evolution of partial organizations as the population progresses from complete dissociation to unified allegiance. Our metrics allow the evaluation of organizational strength much more efficiently than previous, context-specific methods. The simulation produces other results consistent with human society, such as stable heterogeneity of structures and organizational figureheads, further validating our results. The ABM of emergent organization incorporates only widely-observed cognitive behaviors and the recognition by agents of group membership, without any cooperation among the agents. The four flows are produced solely by agents biasing their limited communication resources in favor of allies. While reaffirming the centrality of communication patterns to organization, we thus also challenge the minimal conditions required to produce organizing behavior and complex social structures.
... [47] In the biological system, VSTM allows temporary storage of visual information in the service of ongoing cognitive tasks, representing the visual storage component of the working memory system. [48,49] A proof of concept demonstration of VSTM in a 2D memitter enabling both image sensing and preservation of relevant information after removing the stimuli, i.e., memory, is conceptually schematized in Figure 4a. For this purpose, an optical input pattern of 3 × 3 pixels is applied to a 3 × 3 μm 2 area of the 2D memitter (Figure 4b), where red pixels represent stimulation with a 2 mW μm −2 power density while black pixels represent no stimulation (details of optical pattern stimulation in Experimental Section and Figure S5, Supporting Information). ...
Neuromorphic computing aims to leverage physical phenomena of adaptive materials for emulating information processing capabilities and effectiveness of biological neuronal circuits. In this framework, memristors (resistors with memory) based on 2D materials are demonstrated for the hardware implementation of highly integrated artificial neural networks. All the works reported thus far exploited electrical properties of 2D materials to emulate neuromorphic functionalities. Here, a 2D memitter (emitter with memory) is reported on that exploits the stimuli‐responsive photoluminescence of a monolayer WS2 for neuromorphic‐type of data processing. A combined experimental and modeling approach reveals that photoluminescent dynamics triggered by optical stimulation emulates Short‐Term synaptic Plasticity and Visual Short‐Term Memory typical of biological systems. While spatio‐temporal processing capabilities of input signals can be used for information processing in the context of reservoir computing, the capability of the 2D memitter of sensing, processing, and memorizing‐forgetting optical inputs in the same physical substrate can be utilized for in‐sensor computing.
... Training improves task specific performance 570 We contrasted the single-task RSVP training with a single/dual multitask training paradigm 571 due to their divergent cognitive demands: while they both tap information processing limits 572 the former is predominately perceptual whereas the latter recruits more executive 573 operations (Marois and Ivanoff, 2005). Given that specific training typically augments task 574 performance, we expected that individuals in the rapid serial visual presentation (RSVP) 575 control training group (who did not train on the multitask) would exhibit poorer multitask 576 performance after training relative to their multitask training counterparts. ...
Methods of cognitive enhancement for humans are most impactful when they generalize across tasks. However, the extent to which such “transfer” is possible via interventions is widely debated. In addition, the contribution of excitatory and inhibitory processes to such transfer is unknown. Here, in a large-scale neuroimaging individual differences study with humans (both sexes), we paired multitasking training and noninvasive brain stimulation (transcranial direct current stimulation, tDCS) over multiple days and assessed performance across a range of paradigms. In addition, we varied tDCS dosage (1.0 and 2.0 mA), electrode montage (left or right prefrontal regions), and training task (multitasking vs a control task) and assessed GABA and glutamate concentrations via ultrahigh field 7T magnetic resonance spectroscopy. Generalized benefits were observed in spatial attention, indexed by visual search performance, when multitasking training was combined with 1.0 mA stimulation targeting either the left or right prefrontal cortex (PFC). This transfer effect persisted for ∼30 d post intervention. Critically, the transferred benefits associated with right prefrontal tDCS were predicted by pretraining concentrations of glutamate in the PFC. Thus, the effects of this combined stimulation and training protocol appear to be linked predominantly to excitatory brain processes.
... One issue that should be considered when incorporating music into LKM is whether practitioners may be influenced by music, thereby not being able to focus on the practice of meditation. The existence of this concern is because listening to music is likely to take up limited attentional resources that could be used for LKM [34]. However, according to the arousal-mood theory [35,36], the level of arousal of practitioners can be affected by background music, and the positive emotions triggered by music may help them to concentrate. ...
Loving-kindness meditation (LKM) has been widely used in promoting mental health, with positive emotions as an important mechanism. The current study explored the impact of background music on the effects and difficulties of LKM practice. Two hundred participants were randomly divided into six groups, wherein LKM plus music with harmony only, LKM plus music with harmony and melody, and LKM without music were presented in a different order during the intermediate three days of a five-day LKM intervention. Participants reported three types of positive emotions (pro-social, low-arousal, and medium-arousal positive emotions) and the difficulties during meditation (lack of concentration and lack of pro-social attitudes) after each of three sessions. The results of MANOVA indicated that compared to the session without music, incorporating music could evoke more low-arousal positive emotions and pro-social positive emotions without altering the difficulties. However, the results did not reveal significant differences in the effects of music with harmony and music with harmony and melody on both emotions and difficulties. Additionally, practice effects may have influenced the generation of medium-arousal positive emotions and the difficulty of concentration, but the results were inconsistent across groups. Our findings suggest potential benefits for practitioners of LKM in incorporating music during the meditation process, and the directions for future research were further discussed.
... One critical limitation of the human visual system is its confined resources for representing multiple objects at once (16)(17)(18). On the neural level, simultaneous objects compete for these confined resources, leading to marked reductions in neural activity when multiple individual objects are presented (19)(20)(21). ...
Previous research shows that the beauty of natural images is already determined during perceptual analysis. However , it is unclear which perceptual computations give rise to the perception of beauty. Here, we tested whether perceived beauty is predicted by spatial integration across an image, a perceptual computation that reduces processing demands by aggregating image parts into more efficient representations of the whole. We quantified integrative processing in an artificial deep neural network model, where the degree of integration was determined by the amount of deviation between activations for the whole image and its constituent parts. This quantification of integration predicted beauty ratings for natural images across four studies with different stimuli and designs. In a complementary functional magnetic resonance imaging study, we show that integrative processing in human visual cortex similarly predicts perceived beauty. Together, our results establish integration as a computational principle that facilitates perceptual analysis and thereby mediates the perception of beauty.
... Instead, daily living activities often involve performing two tasks simultaneously, such as walking and talking or climbing stairs while thinking about something, a concept known as dual-task (DT) [20,21]. When attention is distributed between two simultaneous activities, a decrease in performance on both tasks may be experienced, in contrast to when they are performed individually [22], and healthy nervous systems have been shown to have limitations in information processing, which affects the ability to multitask [23]. In individuals with neurodegenerative diseases, these limitations may manifest themselves more markedly and significantly affect the performance of their daily tasks [24]. ...
Previous research has established good test–retest reliability for isokinetic dynamometry in fibromyalgia. However, the reliability of this test under dual-task conditions has not been investigated in fibromyalgia. Methods: A total of 10 women with fibromyalgia participated in this study. Participants completed the concentric/concentric test. The dual-task condition involved subtracting two by two while performing the test. Results: Reliability analysis under the single condition showed “poor” to “excellent” values for maximum peak torque in knee extension and “moderate” to “excellent” values for average. “Poor” to “excellent” reliability values were found in knee flexion for the maximum and average. Dual-task condition in knee extension ranged from “moderate” to “excellent” for maximum and average values, and in knee flexion, it ranged from “poor” to “excellent” for maximum value and from “moderate” to “excellent” for average value. Conclusions: Isokinetic dynamometry demonstrated sufficient reliability for measuring strength in knee extension maximum and average during single-task and dual-task conditions, along with knee flexion dual-task average in fibromyalgia. For knee flexion single-task maximum and average and knee flexion dual-task maximum, we did not obtain sufficiently reliable measurements. Only the concentric/concentric test has been studied, and future studies with a larger sample size are needed in order to generalize the results.
... Indeed, mental load refers to the demands that tasks place on a person's limited information-processing resources (Park et al., 2020). Due to this limitation in brain processing capacity (Marois and Ivanoff, 2005;Moray, 1967) or distractor interference (Lavie, 2005), concurrent tasks can reduce performance (Pongpipat et al., 2021). ...
Introduction: The mental load caused by simultaneous multitasking can affect visual information processing and reduce its ability. This study investigated the effect of mental load caused by cognitive tasks simultaneously with visual task on the number of active voxels in the visual cortex.
Methods: This study recruited 22 individuals with a mean age of 24.72 ± 5.47 years. 3-Tesla functional magnetic resonance imaging (fMRI) was used to examine the functions of the visual cortex and amygdala region during three different task conditions: visual task alone, visual task with an auditory n-back task, and visual task with an arithmetic task. The visual stimuli consisted of Gabor patches with a contrast of 55% at spatial frequencies of 0.25, 4, and 9 cycles per degree (cpd). These were presented in three trials of eight blocks with a stimulation time of 12 sec and a rest time of 14 sec.
Results: Activated brain voxels in the primary, secondary, and associated visual cortex areas were reduced in response to the mental load imposed by the n-back and arithmetic tasks. This reduction was greater for a spatial frequency of 0.25 cpd in the n-back task condition and spatial frequency of 9 cpd in the arithmetic task condition. In addition, the amygdala was stimulated in 2-back task and arithmetic task conditions.
Conclusions: This study revealed a decline in the number of activated voxels of the visual cortex due to the mental load caused by simultaneous cognitive tasks, confirming the findings of previous psychophysical studies.
... A. Miller, 1994;Sweller et al., 2011), potentially leading to heuristic processing of sensory information and an increased likelihood of inaccuracies in conclusions or reflections during information processing (Chaiken & Ledgerwood, 2012;Fayol et al., 1994;Yun et al., 2010). This processing capacity restricted by biological limits (Marois & Ivanoff, 2005;Yun et al., 2010) creates bottlenecks that could discard relevant information contributing to a decrease in the accuracy of executive functions, especially in decision making (Schumacher et al., 2001;Tombu et al., 2011). The use of AI chatbots could help overcome this human limitation (Dorneich et al., 2003) as they possess the ability to rapidly process vast amounts of information (Narayanan et al., 2021;OpenAI, 2023a), although intriguingly, when ChatGPT performs human cognitive tasks such as working memory, it exhibits similar limitations to those observed in humans (Gong et al., 2023). ...
Background: Chat generative retrained transformer (ChatGPT) represents a groundbreaking advancement in Artificial Intelligence (AI-chatbot) technology, utilizing transformer algorithms to enhance natural language processing and facilitating their use for addressing specific tasks. These AI chatbots can respond to questions by generating verbal instructions similar to those a person would provide during the problem-solving process. Aim: ChatGPT has become the fastest growing software in terms of user adoption in history, leading to an anticipated widespread use of this technology in the general population. Current literature is predominantly focused on the functional aspects of these technologies, but the field has not yet explored hypotheses on how these AI chatbots could impact the evolutionary aspects of human cognitive development. Thesis: The “neuronal recycling hypothesis” posits that the brain undergoes structural transformation by incorporating new cultural tools into “neural niches,” consequently altering individual cognition. In the case of technological tools, it has been established that they reduce the cognitive demand needed to solve tasks through a process called “cognitive offloading.” In this theoretical article, three hypotheses were proposed via forward inference about how algorithms such as ChatGPT and similar models may influence the cognitive processes and structures of upcoming generations. Conclusions: By forecasting the neurocognitive effects of these technologies, educational and political communities can anticipate future scenarios and formulate strategic plans to either mitigate or enhance the cognitive influence that these factors may have on the general population.
... The beneficial effect of compression on performance in Figure 2D can thus be explained by the recruitment of greater processing resources, resulting in an overall steeper weighting curve (Figure 2A), which counteracts the effects of decision noise . It is commonly assumed that neural gain is a finite resource (Cowan, 2001;Lennie, 2003;Marois & Ivanoff, 2005;Tombu et al., 2011). Thus, in some task contexts (e.g., when sample processing is computationally demanding), giving a higher decision weight to one sample may come at the cost of other samples. ...
People routinely make decisions based on samples of numerical values. A common conclusion from the literature in psychophysics and behavioral economics is that observers subjectively compress magnitudes, such that extreme values have less sway over people’s decisions than prescribed by a normative model (underweighting). However, recent studies have reported evidence for anti-compression, that is, the relative overweighting of extreme values. Here, we investigate potential reasons for this discrepancy in findings and propose that it might reflect adaptive responses to different task requirements. We performed a large-scale study (n = 586) of sequential numerical integration, manipulating (a) the task requirement (averaging a single stream or comparing two interleaved streams of numbers), (b) the distribution of sample values (uniform or Gaussian), and (c) their range (1–9 or 100–900). The data showed compression of subjective values in the averaging task, but anticompression in the comparison task. This pattern held for both distribution types and for both ranges. In model simulations, we show that either compression or anticompression can be beneficial for noisy observers, depending on the sample-level processing demands imposed by the task. This suggests that the empirically observed patterns of over- and underweighting might reflect adaptive responses.
Background:
Dual-task activities, which involve performing two separate tasks simultaneously, often result in reduced motor function and daily activity performance among individuals with knee osteoarthritis (OA).
Objective:
This study aimed to investigate the impact of single- and dual-task conditions on muscle strength and performance in individuals with knee OA and examine how cognitive load influences physical task performance in this population.
Methods:
Sixty patients with knee OA were included. Baseline data included demographic characteristics, pain (Visual Analog Scale), and physical function (Western Ontario and McMaster Universities Osteoarthritis Index (WOMAC)). Muscle strength and performance were assessed using isokinetic and sit-to-stand tests, initially under single-task conditions, and then under dual-task conditions three days later. Dual-tasking involved physical tasks with varying cognitive exercises (changed between sessions) and familiarization sessions to minimize learning effects.
Results:
The investigation revealed that individuals with knee OA showed reduced muscle strength and impaired sit-to-stand performance during dual-task activities, with lower peak torque (p = .0025), total work (p = .026), and longer time to peak torque (p = .011). Decreased muscle performance correlated with worse WOMAC scores (p ≤ .01, r = -0.506), particularly in dual-task conditions. Regression analysis identified extension total work and the sit-to-stand test as key predictors of dual-task performance, explaining 32.2% of the variance.
Conclusion:
Dual-task performance impairs muscle strength and physical function in individuals with knee OA, demonstrated by reduced peak torque, total work, and sit-to-stand performance. Extension total work and sit-to-stand test emerged as key predictors of dual-task performance, emphasizing the need to address cognitive load in rehabilitation strategies.
Mindfulness meditation is a form of mental training rooted in ancient wisdom traditions and is focused on cultivating a non-judgmental stance toward present-moment awareness. Here, we synthesize cognitive-behavioral effects in long-term meditators (LTMs) resulting from diverse and prolonged meditation practices. Preliminary evidence suggests that LTMs exhibit increased cognitive-sensory integration and decoupling of affective processes, as demonstrated in enhanced interoceptive awareness, reduced negative affective pain perception, and more rational decision-making. Additionally, LTMs may experience more emotional neutrality, self-boundary dissolution, and less normative self-awareness. Neuroimaging findings include increased bottom-up activation, particularly within the salience network (interoception, pain, affect), and reduced connectivity between the executive (dorsolateral prefrontal cortex) and salience (dorsal anterior cingulate cortex) networks (reduced pain). Research also displayed reduced amygdala activation to fear (reduced negative affect), increased temporoparietal junction activation (pre-reflective experiential processes, empathy), and altered midline default-mode network activation, which is associated with emotional neutrality and pre-reflective experiential processes, such as non-ordinary states of consciousness. Methodological limitations, specifically heterogeneous predictor variables, restrict the interpretation of trait effects, temporal dynamics in cognitive processing, and the unique influences of meditative activities. These limitations indicate the need for a unified research framework and a systematic neurophenomenological investigation of advanced meditation—through the study of unfolding states, stages, and endpoints in meditative development. In summary, LTMs display a distinct neurophenomenological gestalt of mindfulness, wherein meditative expertise is reflected in altered general brain processing, potentially enhanced cognitive integration, increased cognitive flexibility and self-regulation, and heightened non-dual awareness—signifying a potentially important form of embodied cognition.
This chapter is about reflecting on what it psychologically means for a person to be a client and what psychotherapeutic implications are associated with it, which must be taken into account in psychotherapy.
AI faces a trifecta of grand challenges: the Energy Wall, the Align- ment Problem and the Leap from Narrow AI to AGI. Contemporary AI solutions consume unsustainable amounts of energy during model training and daily operations. Making things worse, the amount of computation required to train each new AI model has been doubling every 2 months since 2020, directly translating to unprecedented increases in energy consumption.
The leap from AI to AGI requires multiple functional subsystems operating in a balanced manner, which requires a system architec- ture. However, the current approach to artificial intelligence lacks system design; even though system characteristics play a key role in the human brain; from the way it processes information to how it makes decisions. System design is the key to alignment, one of the most challenging goals in AI. This difficulty stems from the fact that the complexity of human moral system requires a similarly so- phisticated system for alignment. Without accurately reflecting the complexity of these core moral subsystems and systems, aligning AI with human values becomes significantly more challenging.
In this paper, we posit that system design is the missing piece in overcoming the grand challenges. We present a Systematic Ap- proach to AGI that utilizes system design principles to AGI, while providing ways to overcome the energy wall and the alignment challenges. This paper asserts that artificial intelligence can be real- ized through a multiplicity of design-specific pathways, rather than a singular, overarching AGI architecture. AGI systems may exhibit diverse architectural configurations and capabilities, contingent upon their intended use cases. It advocates for a focus on employing system design principles as a guiding framework, rather than solely concentrating on a universal AGI architecture.
Background. Jumping and landing tests are frequently used as a tool to assess muscle function. However, they are performed in a controlled and predictable environment. The physical tests commonly used as part of the criteria for return to sport after injury are often performed with little or no cognitive load and low coordinative demand compared to game-specific actions. The aim of this systematic review was to examine the influence of performing a dual task (DT) or sport-specific task constrains during jump-landing tests on biomechanical variables related to lower limb injury risk in team sports.
Methods. This systematic review followed the specific methodological guidelines of the Preferred Reporting Items for Systematic Reviews and Meta-Analyses (PRISMA). The search was conducted in the databases Medline (PubMed), Web of Science, Cochrane Plus, and SportDiscus for studies published from 2013 until June 30, 2023. To be eligible, studies had to include: (1) kinematic and/or kinetic assessment of injury risk factors in the lower extremity; (2) a comparison between a simple jump or landing test and a DT jump or landing test which included cognitive information. The risk of bias in the selected articles was analyzed using the recommendations of the Cochrane Collaboration.
Results. Of the 656 records identified, 13 met the established criteria. Additionally, two more articles were manually included after screening references from the included articles and previous related systematic reviews. Regarding the Risk of bias assessment, 12 studies did not surpass a score of 3 points (out of a total of 7). Only three studies exceeded a score of 3 points, with one article achieving a total score of 6. From the included studies, comparative conditions included actions influenced by the inclusion of a sports ball (n D 6), performing tasks in virtual environments or with virtual feedback (n D 2), participation in cognitive tasks (n D 6), and tasks involving dual processes (nD7). The execution of decision-making (DM) during the jump-landing action resulted in biomechanical changes such as lower peak angles of hip flexion and knee flexion, along with increased vertical ground reaction force, knee abduction, and tibial internal rotation. Regarding limitations, discrepancies arise in defining what constitutes DT. As a result, it is possible that not all studies included in this review fit all conceptual definitions of DT. The inclusion of DT or constraints in jump-landing tests significantly alters biomechanical variables related to lower extremity injury risk in team sports. In future research, it would be beneficial to incorporate tasks into jumping tests that simulate the specific cognitive demands of team sports. This systematic review was registered in PROSPERO (registration number: CRD42023462102) and this research received no external funding.
Purpose
This study was designed to compare the effects of mental load, caused by concurrent auditory tasks, on attended and non‐attended visual stimuli in older and younger adults.
Methods
Participants performed a visual orientation discrimination task involving two spatially separated Gabor patches of 4 cycles/degree and 55% contrast. Participants received either a valid‐cue, invalid‐cue or a neutral‐cue for the patch whose orientation they were required to determine. An auditory n‐back task was performed simultaneously to impose mental load. Repeated‐measures ANOVA was used for investigation of main effects and interactions of ageing, mental load and attention condition on orientation discrimination.
Results
A total of 27 younger (mean age ± SD, 22.6 ± 1.3 years) and 23 older adults (54.7 ± 4.3 years) participated in the study. There was a significant effect of age ( p = 0.01) and mental load ( p < 0.001) on the proportion of correct orientation discrimination responses. Attentional condition significantly affected the proportion of correct responses ( p = 0.02), but there was no significant interaction between attention, mental load and age group ( p = 0.85). There was no overall difference in the proportion of no responses (the proportion of trials in which the participants failed to respond) between the two age groups ( p = 0.53) nor on the overall effect of attention on the proportion of no responses ( p = 0.25). There was, however, a significant effect of mental load on the proportion of no responses ( p = 0.002).
Conclusion
Although mental load reduced performance equally for both age groups and for all attentional conditions, older adults had poorer overall performance. Therefore, a given mental load is more likely to drive older observers to unacceptable levels of task performance.
In major‐minor tonality, V implies I, and rising fourths, falling thirds and rising seconds between successive chord roots are more common than falling fourths, rising thirds and falling seconds respectively. Possible explanations involve history (in two‐part medieval counterpoint, harmonic major sixths resolved to octaves – maintained in V–I); the rising leading note (V–I includes it, IV–I does not); acoustic speculation (in V–I, the third harmonic of resolves to the second); voice leading (in V ⁷ –I, a tritone resolves to a third by contrary step); melodic closure (a rising melodic leap implies subsequent falling steps, and melodies often end with –, harmonised V–I); root newness (chords ‘progress’ if the second chord's root is not part of the first); and tonal stability (V is less stable than IV, giving it a stronger ‘urge’ to resolve). An additional possibility combines the ‘virtual‐pitch’ theory of Ernst Terhardt with the ‘implication‐realisation’ theory of Leonard B. Meyer and Eugene Narmour. Major and minor triads imply subsidiary virtual pitches (missing fundamentals; see Rameau's ‘fundamental bass’) at third and fifth intervals below the root. These weakly perceived pitches are realised in the next chord if the root falls by a third or rises a fourth or major second, creating a feeling of forward progression – while also facilitating intonation for singers and melodic instrumentalists. The theory correctly predicts that successive harmonic complex (but not pure) tones an octave apart sound more similar if rising, and rising octaves are more common than falling in melody. It also explains why Classical modulations are asymmetrical in the opposite direction, major keys tending to modulate to V (not IV) and minor to III (not VI): accidental flats tend to be more perceptually salient or stable than sharps.
Introduction
Cognitive models have proposed that behavioral tasks can be categorized along at least three dimensions: the sensory-motor modality of the information, its representational format (e.g., location vs. identity), and the cognitive processes that transform it (e.g., response selection). Moreover, we can quickly and flexibly encode, represent, or manipulate information along any of these dimensions. How is this flexibility in encoding such information implemented in the cerebral cortex?
Methods
To address this question, we devised a series of functional magnetic resonance imaging (fMRI) experiments in each of which participants performed two distinct tasks that differed along one of the three dimensions.
Results
Using multivariate pattern analysis of the fMRI data, we were able to decode between tasks along at least one task dimension within each of the cortical regions activated by these tasks. Moreover, the multiple demand network, a system of brain regions previously associated with flexible task encoding, was largely composed of closely juxtaposed sets of voxels that were specialized along each of the three tested task dimensions.
Discussion
These results suggest that flexible task encoding is primarily achieved by the juxtaposition of specialized representations processing each task dimension in the multiple demand network.
Brain injuries can significantly impact mental processes and lead to hidden disabilities not easily detectable. Traditional methods for assessing these impacts are imprecise, leading to unreliable prevalence estimates and treatments with uncertain effectiveness. Immersive virtual reality has shown promise for assessment, but its use as a standalone tool is rare. Our research focused on developing and validating a standalone immersive virtual reality classification system for unilateral spatial neglect, a condition common following brain injury characterized by inattention to one side of space. Our study involved 51 brain injury inpatients and 30 controls, all engaging with ‘The Attention Atlas’, an immersive virtual reality game for testing visual search skills. Our classification system aimed to identify patients with neglect, ‘minor atypicality’ (indicative of inattention not consistent enough to be labelled as neglect) or non-neglect. This categorization was based on a simple mathematical definition, utilizing gameplay to describe spatial orientation (to the left or right side) and attentional challenge (indicative of search inefficiency). These metrics were benchmarked against a normative model to detect atypical visual search, which refers to gameplay beyond the usual bounds. The combination of neglected side, orientation and challenge factors was used to categorize neglect. We discovered a strong correlation between atypical visual search patterns and neglect risk factors, such as middle cerebral artery stroke, parietal injuries and existing neglect diagnoses (Poisson regression incidence rate ratio = 7.18, 95% confidence interval = 4.41–11.90). In our study, immersive virtual reality-identified neglect in one-fourth of the patients (n = 13, 25.5%), minor atypicality in 17.6% (n = 9) and non-neglect in the majority, 56.9% (n = 29). This contrasts with standard assessments, which detected neglect in 17.6% (n = 9) of cases and had no intermediate category. Our analysis determined six categories of neglect, the most common being left hemispace neglect with above-median orientation and challenge scores. Traditional assessments were not significantly more accurate (accuracy = 84.3%, P = 0.06) than a blanket assumption of non-neglect. Traditional assessments were also relatively insensitive in detecting immersive virtual reality-identified neglect (53.8%), particularly in less severe cases and those involving right-side inattention. Our findings underline the effectiveness of immersive virtual reality in revealing various dimensions of neglect, surpassing traditional methods in sensitivity and detail and operating independently from them. To integrate immersive virtual reality into real-world clinical settings, collaboration with healthcare professionals, patients and other stakeholders is crucial to ensure practical applicability and accessibility.
A recent hypothesis characterizes difficulties in multitasking as being the price humans pay for our ability to generalize learning across tasks. The mitigation of these costs through training has been associated with reduced overlap of constituent task representations within frontal, parietal, and subcortical regions. Transcranial direct current stimulation, which can modulate functional brain activity, has shown promise in generalizing performance gains when combined with multitasking training. However, the relationship between combined transcranial direct current stimulation and training protocols with task-associated representational overlap in the brain remains unexplored. Here, we paired prefrontal cortex transcranial direct current stimulation with multitasking training in 178 individuals and collected functional magnetic resonance imaging data pre- and post-training. We found that 1 mA transcranial direct current stimulation applied to the prefrontal cortex paired with multitasking training enhanced training transfer to spatial attention, as assessed via a visual search task. Using machine learning to assess the overlap of neural activity related to the training task in task-relevant brain regions, we found that visual search gains were predicted by changes in classification accuracy in frontal, parietal, and cerebellar regions for participants that received left prefrontal cortex stimulation. These findings demonstrate that prefrontal cortex transcranial direct current stimulation may interact with training-related changes to task representations, facilitating the generalization of learning.
Relational cognition—the ability to infer relationships that generalize to novel combinations of objects—is fundamental to human and animal intelligence. Despite this importance, it remains unclear how relational cognition is implemented in the brain due in part to a lack of hypotheses and predictions at the levels of collective neural activity and behavior. Here we discovered, analyzed, and experimentally tested neural networks (NNs) that perform transitive inference (TI), a classic relational task (if A > B and B > C, then A > C). We found NNs that (i) generalized perfectly, despite lacking overt transitive structure prior to training, (ii) generalized when the task required working memory (WM), a capacity thought to be essential to inference in the brain, (iii) emergently expressed behaviors long observed in living subjects, in addition to a novel order-dependent behavior, and (iv) expressed different task solutions yielding alternative behavioral and neural predictions. Further, in a large-scale experiment, we found that human subjects performing WM-based TI showed behavior inconsistent with a class of NNs that characteristically expressed an intuitive task solution. These findings provide neural insights into a classical relational ability, with wider implications for how the brain realizes relational cognition.
This scholarly inquiry initiates a nuanced exploration into the Islamic conceptualization of _Allah_ as ‘_Al-Aleem_’ (the All-Knowing) and ‘_Al-Khabir_’ (the All-Aware), postulating a reconciliation wherein Allah is identified as the quintessential Intelligence and truth. _Allah_’s attributes of divine omniscience and ubiquitous awareness underscore a divine understanding enveloping all of existence, positioning Him as the epitome of All-Information. This paper delves into the intersection of Islamic theological constructs and modern information theory, proposing a novel interpretation that aligns _Allah_’s divine omniscience with the theory's principles. Information theory posits that the foundation of all information is inherently probabilistic, mirroring the probabilistic outcomes observed in quantum mechanics. This seemingly contradicts ‘_Al-Qadar_’, an All-Knowing Allah's predetermined will or predestination. However, we can bridge this gap by considering _Allah _as the embodiment of all information. This paper facilitates a richer understanding of _Allah_’s predetermined will in Islam and builds bridges with the randomness and unpredictable nature witnessed in the quantum world. This research aims to augment _Allah_ as the Infinite Information through an interdisciplinary lens, bridging quantum indeterminacy and Islamic Omnipotence. This quantum-religious interface reconciles quantum information theory with Islamic theological constructs.
Dual tasks (DTs) combining walking with a cognitive task can cause various levels of cognitive–motor interference, depending on which brain resources are recruited in each case. However, the brain activation and functional connectivity underlying cognitive–motor interferences remain to be elucidated. Therefore, this study investigated the neural correlation during different DT conditions in 40 healthy young adults (mean age: 27.53 years, 28 women). The DTs included walking during subtraction or N‐Back tasks. Cognitive–motor interference was calculated, and brain activation and functional connectivity were analysed. Portable functional near‐infrared spectroscopy was utilized to monitor haemodynamics in the prefrontal cortex (PFC), motor cortex and parietal cortex during each task. Walking interference (decrease in walking speed during DT) was greater than cognitive interference (decrease in cognitive performance during DT), regardless of the type of task. Brain activation in the bilateral PFC and parietal cortex was greater for walking during subtraction than for standing subtraction. Furthermore, brain activation was higher in the bilateral motor and parietal and PFCs for walking during subtraction than for walking alone, but only increased in the PFC for walking during N‐Back. Coherence between the bilateral lateral PFC and between the left lateral PFC and left motor cortex was significantly greater for walking during 2‐Back than for walking. The PFC, a critical brain region for organizing cognitive and motor functions, played a crucial role in integrating information coming from multiple brain networks required for completing DTs. Therefore, the PFC could be a potential target for the modulation and improvement of cognitive–motor functions during neurorehabilitation.
Értekezésemben a főemlős agykéreg pályajelöléssel feltérképezett anatómiaia hálózatának elméleten és kísérleten alapuló kutatásával kapcsolatos eredményeimet foglalom össze. Célom volt a nagy léptékű integráció, a populációk összeköttetési mintázatainak és az elemi építőegységek, az axonok és axonvégződések szerepének megértése a hálózat szerveződésében. Kimutattam, hogy a kompartmentalizált hálózatban az elsődleges érzőkérgi áreák szintjén a heteromodális integráció a magasabb hierarchia szintek multimodális struktúráinak híd szerepével magyarázható. A konvergenciafok bevezetésével a csúcsok és élek tulajdonságain keresztül meghatároztam az agykérgi jelfolyam egyedi jellemzőit. Így a prefrontális kéregben (PFC) kimutattam az áreák topológián alapuló hierarchiáját. Szintén kimutattam, hogy egyes PFC-áreák globális konvergencia régiók, emiatt hálózati szűk keresztmetszetként limitálhatják a munkamemória kapacitását. Rámutattam, hogy a PFC funkciója a magas szintű áreákkal interakcióban valósul meg a „globális munkatérben”. A kolumnák hálózatában área 3b és 1 oldalirányú összeköttetésein bizonyítottam, hogy az interakciók áreán belül az eltérő, áreák között elsődlegesen a hasonló funkciót reprezentáló populációk között alakulnak ki. Ugyanitt meghatároztam a köztes szintű hálózati motívumot és szerepét a populációs válaszban. Kimutattam a kérgi hálózat éleinek heterogén struktúráját és szerepét az összeköttetésekben mind a vezetőképességet befolyásoló axonmorfológiában és a szinaptikus boutonok jelátvitel hatékonyságát jellemző morfológiájában. Bizonyítékot szolgáltattam a nem-szövetspecifikus alkalikus foszfatáz (TNAP) réteg-specifikus lokalizációjára a szinaptikus résben. Feltártam, hogy a molekuláris hálózatban a TNAP többféle módon képes szabályozni a jelátvitelt.
Drawing on Brashers’ (2001) theory of communication and uncertainty management, the study reported in this chapter examines the role of transformational leadership (TFL) in employees’ uncertainty management process in the context of DX and its impact on their appraisal of DX, self-efficacy, and job performance. The study examined the hypotheses regarding the complex interplay between these factors with the data collected over four waves from 873 employee–supervisor dyads in Japan. Structural equation modeling analyses have revealed that: (a) uncertainty is negatively associated with employees’ appraisal of DX, self-efficacy, and job performance; (b) TFL is positively associated with these factors; and, moreover, (c) TFL moderates the impact of uncertainty on appraisal and self-efficacy. Simple-slope analyses indicate that, when one’s direct supervisor exhibits low TFL behaviors, uncertainty is significantly negatively associated with their appraisal and self-efficacy; conversely, in the high-TFL condition, the adverse impact of uncertainty diminishes. These findings highlight the pivotal role of transformational leadership in shaping positive appraisals and self-efficacy among organizational members, thereby enhancing their job performance in the face of DX-driven uncertainty. Theoretical and practical implications of the obtained findings are discussed with reference to the relevant literature.
The topic of information overload is analysed pragmatically and phenomenologically, providing insight into the causes of the phenomenon, possible remedies, and broader implications. The discussion on the broader context touches on more abstract issues that include a discussion on infosphere, the ramifications of the replacement of offline (physical) experience with the reading experience, and the discussion on the relevance of modes of information delivery viewed through the prism of different forms of orality employed on the Internet. Special attention is given to the analysis of information fatigue syndrome. The requirement to educate users in the areas of reading literacy and information literacy is emphasized.
Keywords: information overload, information fatigue syndrome, infosphere, information literacy, reading literacy
A callosotomy patient was tested in 2 dual-task experiments requiring successive speeded responses to lateralized stimuli. The patient showed a robust psychological refractory period (PRP) effect. Three aspects of the data indicate that, unlike for the control participants, the PRP effect for the split-brain patient should not be attributed to a response selection bottleneck. First, the patient did not show an increase in reaction time (RT) when the 2 tasks required responses from a common output system compared with when different output systems were used. Second, inconsistent stimulus–response mappings for the 2 tasks increased RTs for the control participants but had minimal effect on the performance of the split-brain patient. Third, the consistency manipulation was underadditive with stimulus onset asynchrony but was additive or overadditive for the normal participants. These results suggest that the persistent PRP effect following callosotomy should be attributed to a bottleneck associated with response initiation, a strategy adopted to comply with the task demands, or a combination of these factors.
A theory of executive control is presented that proposes that executive processes control subordinate processes by manipulating their parameters, reconfiguring them to respond in accord with the current task set. It adopts C. Bundesen's (1990) theory of visual attention (TVA) and R. M. Nosofsky and T. J. Palmeri's (1997) exemplar-based random walk (EBRW) as the theory of subordinate processes. It assumes that a task set is a set of TVA and EBRW parameters sufficient to perform a task and that set switching involves changing those parameters. The theory solves 2 computational problems that emerge in dual-task situations: the binding problem and the serial order problem. It can perform dual tasks in series or in parallel but prefers the serial strategy because it is faster and it solves the binding problem naturally. The theory accounts for concurrence cost, set-switching cost, crosstalk between tasks, and the modulation of crosstalk by task set.
Further simulations of human multiple-task performance have been conducted with computational models that are based on the executive-process interactive control (EPIC) architecture introduced by D. E. Meyer and D. E. Kieras (see record 84-14604). These models account well for patterns of reaction times and psychological refractory-period phenomena (delays of overt responses after short stimulus onset asynchronies) observed in a variety of laboratory paradigms and realistic situations. This supports the claim of the present theoretical framework that multiple-task performance relies on adaptive executive control, which enables substantial amounts of temporal overlap among stimulus identification, response selection, and movement-production processes for concurrent tasks. Such overlap is achieved through optimized task scheduling by flexible executive processes that satisfy prevailing instructions about task priorities and allocate limited-capacity perceptual-motor resources efficiently. (PsycINFO Database Record (c) 2012 APA, all rights reserved)
We sought to measure separately the motor potentials for each of 2 concurrent tasks and to use these measurements to identify the locus of dual-task interference. Lateralized readiness potentials (LRPs) were measured in the psychological refractory period paradigm, in which a separate response is required to each of 2 successive signals. As the interval between the signals decreased, the 2 reaction time (RT) tasks increasingly overlapped and the 2nd RT was prolonged. The LRP for the 2nd task was also delayed but maintained a constant temporal relation with the 2nd RT and sometimes preceded the 1st-task RT. The results indicate that (a) independent measures of the LRP can be obtained for each of 2 concurrent tasks, (b) slowing of the 2nd task was caused by a delay in processes that precede LRP onset, and (c) the 1st task may cease to interfere with the 2nd considerably before producing an overt response.
Further simulations of human multiple-task performance have been conducted with computational models that are based on the executive-process interactive control (EPIC) architecture introduced by D. E. Meyer and D. E. Kieras (1997a). These models account well for patterns of reaction times and psychological refractory-period phenomena (delays of overt responses after short stimulus onset asynchronies) observed in a variety of laboratory paradigms and realistic situations. This supports the claim of the present theoretical framework that multiple-task performance relies on adaptive executive control, which enables substantial amounts of temporal overlap among stimulus identification, response selection, and movement-production processes for concurrent tasks. Such overlap is achieved through optimized task scheduling by flexible executive processes that satisfy prevailing instructions about task priorities and allocate limited-capacity perceptual–motor resources efficiently.
The number of stimulus and response alternatives was varied in the 1st task of an attentional blink (AB) experiment (both tasks unspeeded) and in a speeded AB paradigm (SAB; speeded immediate response in Task₁). Accuracy in Task₂ did not depend on the number of alternatives in the AB paradigm (Experiment 1); however, accuracy in Task₂ decreased as alternatives increased in the SAB paradigm (Experiments 2–3). Longer response times in Task₁ were associated with lower accuracy in Task₂. The results suggest that the duration of central processing in Task₁ modulates the AB phenomenon. The results are discussed in the context of the central interference theory. The theory provides a unified theoretical framework within which the AB and SAB paradigms, the probe signal paradigm, and the psychological refractory period paradigm can be analyzed and understood. (PsycINFO Database Record (c) 2012 APA, all rights reserved)
Investigated the locus of interference effects and the nature of the retrieval process in secondary memory and compared RT performance on the same materials as W. James's (1980) primary memory (PM) and secondary memory (SM) conditions in the S. Sternberg (1969) paradigm. 90 undergraduates participated in 2 experiments. Identical materials were used in a PM and SM Sternberg situation, the SM process being produced by introducing a distractor task between the termination of the memory set and the probe. As in a release from the proactive interference (PI) paradigm, 3 consecutive trials from 1 taxonomic category were given, and a shift was made to another category for 24 consecutive categories. The 1st trial on a category was defined as low in interference, and the 3rd was defined as high. Overall, results strongly support a response-set, list-differentiation, and an interference at retrieval interpretation of PI, in contrast to an encoding (perceptual) one, and stress the view that the initial retrieval act is retrieval of the address of the set and not of individual items. (47 ref) (PsycINFO Database Record (c) 2012 APA, all rights reserved)
A callosotomy patient was tested in 2 dual-task experiments requiring successive speeded responses to lateralized stimuli. The patient showed a robust psychological refractory period (PRP) effect. Three aspects of the data indicate that, unlike for the control participants, the PRP effect for the split-brain patient should not be attributed to a response selection bottleneck. First, the patient did not show an increase in reaction time (RT) when the 2 tasks required responses from a common output system compared with when different output systems were used. Second, inconsistent stimulus-response mappings for the 2 tasks increased RTs for the control participants but had minimal effect on the performance of the split-brain patient. Third, the consistency manipulation was underadditive with stimulus onset asynchrony but was additive or overadditive for the normal participants. These results suggest that the persistent PRP effect following callosotomy should be attributed to a bottleneck associated with response initiation, a strategy adopted to comply with the task demands, or a combination of these factors.
The authors present the central capacity sharing (CCS) model and derive equations describing its behaviors to explain results from dual-task situations. The predictions of the CCS model are contrasted with those of the central bottleneck model. The CCS model predicts all of the hallmark effects of the psychological refractory period (PRP) paradigm: -1 slope of the PRP effect at short stimulus onset asynchronies (SOAs), underadditivity of precentral Task 2 manipulations, additivity of central or postcentral Task 2 manipulations with SOA, and carry forward to Task 2 of Task 1 precentral or central manipulations at short SOAs. The CCS model also predicts that Task 1 response times increase with decreasing SOA. The model is a viable alternative to the central bottleneck model.
Through rapid serial visual presentation (RSVP), we asked Ss to identify a partially specified letter (target) and then to detect the presence or absence of a fully specified letter (probe). Whereas targets are accurately identified, probes are poorly detected when they are presented during a 270-ms interval beginning 180 ms after the target. Probes presented immediately after the target or later in the RSVP stream are accurately detected. This temporary reduction in probe detection was not found in conditions in which a brief blank interval followed the target or Ss were not required to identify the target. The data suggest that the presentation of stimuli after the target but before target-identification processes are complete produces interference at a letter-recognition stage. This interference may cause the temporary suppression of visual attention mechanisms observed in the present study.
Neurophysiologists have documented the existence of multiple cortical areas responsive to different visual features. This modular organization has sparked theoretical interest in how the "binding problem" is solved. Recent data from a neurological patient (R.M.) with bilateral parietal-occipital lesions demonstrates that the binding problem is not just a hypothetical construct; it can be a practical problem, as rare as the selective inability to perceive motion or color. R.M. miscombines colors and shapes even under free viewing conditions and is unable to judge either relative or absolute visual locations. The evidence suggests that a single explanation--an inadequate spatial representation--can account for R.M.'s spatial judgment and feature-binding deficits.
When 2 targets are presented among distractors in rapid serial visual presentation, correct identification of the 1st target results in a deficit for a 2nd target appearing within 200-500 ms. This attentional blink (AB; J.E. Raymond, K.L. Shapiro, & K.M. Arnell, 1992) was examined for categorically defined targets (letters among nonletters) in 7 experiments. AB was obtained for the 2nd letter target among digit distractors (Experiment 1) and also for a 3rd target (Experiment 2). Results of Experiments 3-5 confirmed that AB is triggered by local interference from immediate posttarget stimulation (Raymond et al., 1992) and showed that AB is modulated by the discriminability between the 1st target and the immediately following distractor. Experiments 5-7 further examined the effects of both local interference and global discriminability. A 2-stage model is proposed to account for the AB results.
In vision, attentional limitations are reflected in interference or reduced accuracy when two objects must be identified at once in a brief display. In our experiments a brief temporal separation was introduced between the two objects to be identified. We measured how long the object continued to interfere with the second, and hence the time course of the first object's attentional demand. According to conventional serial models, attention is assigned rapidly to one object after another, with a dwell time of only a few dozen milliseconds per item. But we report here that interference lasts for several hundred milliseconds--an order of magnitude more than the prediction of conventional models. We suggest that visual attention is not a high-speed switching mechanism, but a sustained state during which relevant objects become available to influence behaviour. This conclusion is consistent with recent physiological results in the monkey.
A functional dissociation of the spatial and object visual systems was produced by selective interference in intact young adults. Subjects were instructed to remember the location of a dot in a spatial memory test, and the form of an object memory test. As predicted by current notions of dissociable visual systems in the primate, spatial memory was selectively impaired by a movement discrimination spatial task, whereas object memory was selectively impaired by a color discrimination object task.
After the detection of a target item in a rapid stream of visual stimuli, there is a period of 400-600 ms during which subsequent targets are missed. This impairment has been labelled the 'attentional blink'. It has been suggested that, unlike an eye blink, the additional blink does not reflect a suppression of perceptual processing, but instead reflects a loss of information at a postperceptual stage, such as visual short-term memory. Here we provide electrophysiological evidence that words presented during the attentional blink period are analysed to the point of meaning extraction, even though these extracted meanings cannot be reported 1-2s later. This shows that the attentional blink does indeed reflect a loss of information at a postperceptual stage of processing, and provides a demonstration of the modularity of human brain function.
When we identify a visual object such as a word or letter, our ability to detect a second object is impaired if it appears within 400ms of the first. This phenomenon has been termed the attentional blink or dwell time and is a measure of our ability to allocate attention over time (temporal attention). Patients with unilateral visual neglect are unaware of people or objects contralateral to their lesion. They are considered to have a disorder of attending to a particular location in space (spatial attention). Here we examined the non-spatial temporal dynamics of attention in patients, using a protocol for assessing the attentional blink. Neglect patients with right parietal, frontal or basal ganglia strokes had an abnormally severe and protracted attentional blink When they identified a letter, their awareness of a subsequent letter was significantly diminished for a length of time that was three times as long as for individuals without neglect. Our results demonstrate for the first time that visual neglect is a disorder of directing attention in time, as well as space.
Working memory involves the short-term maintenance of an active representation of information so that it is available for further processing. Visual working memory tasks, in which subjects retain the memory of a stimulus over brief delays, require both the perceptual encoding of the stimulus and the subsequent maintenance of its representation after the stimulus is removed from view. Such tasks activate multiple areas in visual and prefrontal cortices. To delineate the roles these areas play in perception and working memory maintenance, we used functional magnetic resonance imaging (fMRI) to obtain dynamic measures of neural activity related to different components of a face working memory task-non-selective transient responses to visual stimuli, selective transient responses to faces, and sustained responses over memory delays. Three occipitotemporal areas in the ventral object vision pathway had mostly transient responses to stimuli, indicating their predominant role in perceptual processing, whereas three prefrontal areas demonstrated sustained activity over memory delays, indicating their predominant role in working memory. This distinction, however, was not absolute. Additionally, the visual areas demonstrated different degrees of selectivity, and the prefrontal areas demonstrated different strengths of sustained activity, revealing a continuum of functional specialization, from occipital through multiple prefrontal areas, regarding each area's relative contribution to perceptual and mnemonic processing.
Restrictions to attentional capacity are revealed by the interference that commonly results when two sensory inputs must be identified at the same time. To investigate this phenomenon within and between modalities, we presented streams of visual and/or auditory inputs, containing occasional targets to be identified and recalled. For two visual or two auditory streams, identification of one target produced a sustained reduction in the ability to identify a second, the period of interference lasting for several hundred milliseconds. Subjectively, when attention was assigned to one target it was temporarily unavailable for another. In contrast, there was no such time-locked interference between targets in different modalities. The results suggest a modality-specific restriction to concurrent attention and awareness; visual attention to one simple target does not restrict concurrent auditory attention to another.
When an observer detects a target in a rapid stream of visual stimuli, there is a brief period of time during which the detection of subsequent targets is impaired. In this study, event-related potentials (ERPs) were recorded from normal adult observers to determine whether this "attentional blink" reflects a suppression of perceptual processes or an impairment in postperceptual processes. No suppression was observed during the attentional blink interval for ERP components corresponding to sensory processing (the P1 and N1 components) or semantic analysis (the N400 component). However, complete suppression was observed for an ERP component that has been hypothesized to reflect the updating of working memory (the P3 component). Results indicate that the attentional blink reflects an impairment in a postperceptual stage of processing.
The prefrontal cortex has long been suspected to play an important role in cognitive control, in the ability to orchestrate thought and action in accordance with internal goals. Its neural basis, however, has remained a mystery. Here, we propose that cognitive control stems from the active maintenance of patterns of activity in the prefrontal cortex that represent goals and the means to achieve them. They provide bias signals to other brain structures whose net effect is to guide the flow of activity along neural pathways that establish the proper mappings between inputs, internal states, and outputs needed to perform a given task. We review neurophysiological, neurobiological, neuroimaging, and computational studies that support this theory and discuss its implications as well as further issues to be addressed
A fundamental issue for psychological science concerns the extent to which people can simultaneously perform two perceptual-motor tasks. Some theorists have hypothesized that such dual-task performance is severely and persistently constrained by a central cognitive "bottle-neck," whereas others have hypothesized that skilled procedural decision making and response selection for two or more tasks can proceed at the same time under adaptive executive control. The three experiments reported here support this latter hypothesis. Their results show that after relatively modest amounts of practice, at least some participants achieve virtually perfect time sharing in the dual-task performance of basic choice reaction tasks. The results also show that observed interference between tasks can be modulated by instructions about differential task priorities and personal preferences for daring (concurrent) or cautious (successive) scheduling of tasks. Given this outcome, future research should investigate exactly when and how such sophisticated skills in dual-task performance are acquired.
Functional magnetic resonance imaging (fMRI) of subjects attempting to detect a visual change occurring during a screen flicker was used to distinguish the neural correlates of change detection from those of change blindness. Change detection resulted in enhanced activity in the parietal and right dorsolateral prefrontal cortex as well as category-selective regions of the extrastriate visual cortex (for example, fusiform gyrus for changing faces). Although change blindness resulted in some extrastriate activity, the dorsal activations were clearly absent. These results demonstrate the importance of parietal and dorsolateral frontal activations for conscious detection of changes in properties coded in the ventral visual pathway, and thus suggest a key involvement of dorsal-ventral interactions in visual awareness.
We used functional magnetic resonance imaging (fMRI) and event-related potentials (ERPs) to visualize the cerebral processing of unseen masked words. Within the areas associated with conscious reading, masked words activated left extrastriate, fusiform and precentral areas. Furthermore, masked words reduced the amount of activation evoked by a subsequent conscious presentation of the same word. In the left fusiform gyrus, this repetition suppression phenomenon was independent of whether the prime and target shared the same case, indicating that case-independent information about letter strings was extracted unconsciously. In comparison to an unmasked situation, however, the activation evoked by masked words was drastically reduced and was undetectable in prefrontal and parietal areas, correlating with participants' inability to report the masked words.
Miller (1956) summarized evidence that people can remember about seven chunks in short-term memory (STM) tasks. However, that number was meant more as a rough estimate and a rhetorical device than as a real capacity limit. Others have since suggested that there is a more precise capacity limit, but that it is only three to five chunks. The present target article brings together a wide variety of data on capacity limits suggesting that the smaller capacity limit is real. Capacity limits will be useful in analyses of information processing only if the boundary conditions for observing them can be carefully described. Four basic conditions in which chunks can be identified and capacity limits can accordingly be observed are: (1) when information overload limits chunks to individual stimulus items, (2) when other steps are taken specifically to block the recording of stimulus items into larger chunks, (3) in performance discontinuities caused by the capacity limit, and (4) in various indirect effects of the capacity limit. Under these conditions, rehearsal and long-term memory cannot be used to combine stimulus items into chunks of an unknown size; nor can storage mechanisms that are not capacity-limited, such as sensory memory, allow the capacity-limited storage mechanism to be refilled during recall. A single, central capacity limit averaging about four chunks is implicated along with other, noncapacity-limited sources. The pure STM capacity limit expressed in chunks is distinguished from compound STM limits obtained when the number of separately held chunks is unclear. Reasons why pure capacity estimates fall within a narrow range are discussed and a capacity limit for the focus of attention is proposed.
The term attention is used to describe the focusing of cognitive processes onto a subset of the information that is currently available. This focusing is useful whenever a given cognitive process is faced with multiple sources of input, and attention is therefore important across a wide variety of tasks. Attention plays several distinct computational roles, including binding together the features of an object, minimizing interference in working memory, and mitigating the deleterious effects of noise. Recent research also indicates that attention can operate on a variety of different representational formats, including spatial representations and abstract object‐based representations. Most theories of attention have assumed that attention is a unitary process that operates at a single stage of processing, but it is now clear that it operates within different cognitive systems under different conditions. Thus, attentional focusing does not appear to be achieved by a unitary attentional process; instead, focusing appears to be implemented by a collection of partially independent attentional processes that are embedded within other cognitive processes. However, these attentional processes must work together to produce unified behavioral output, and recent research has focused extensively on the control systems that coordinate the allocation of attention.
When an individual attempts to perform two tasks at the same time, the tasks often interfere with each other. This interference has been studied for several decades with the psychological refractory period paradigm, in which two targets that require independent responses are presented on each trial, separated by a variable delay period; interference typically takes the form of increased response times for the second target at short interstimulus delays. The present study used electrophysiological recordings to determine whether a specific index of perception and categorization (the P3 wave) is delayed in the same manner as response times. Although response times for the second target were found to be greatly delayed at short interstimulus intervals, the P3 wave was not substantially delayed. This finding indicates that there was minimal interference during target identification and categorization and that the prolongation of response times in this paradigm primarily reflects a delay in a relatively late process, such as response selection.
Humans often experience difficulty when asked to perform multiple tasks at the same time. Two of the better-known forms of dual-task interference are the attentional blink (AB) effect and the Psychological Refractory Period (PRP) effect. These phenomena have traditionally been studied independently, using divergent methodologies and different dependent measures. This chapter aims to explore the possibility that these dual-task phenomena might reflect the same underlying processing limitation — a central bottleneck. It also discusses how AB and PRP effects are related to other phenomena such as repetition blindness and movements of spatial attention across visual space.
Evidence suggesting that the attentional blink (AB) phenomenon is caused by a central processing bottleneck is reviewed. A bottleneck model of the psychological refractory period paradigm is used to motivate four major predictions concerning the patterns of results expected in dual-task experiments. This model, which was designed to explain results from experiments in which both tasks are speeded, is modified to make predictions for experiments in which one task or the other is not speeded. This extention of the bottleneck model allows the authors to test four major predictions in the context of the AB paradigm. The bulk of the evidence is consistent with these predictions, and so the authors conclude that the AB phenomenon is caused by a processing bottleneck. The evidence also provides some constraints on the possible locus of the bottleneck in the information-processing stream. (PsycINFO Database Record (c) 2012 APA, all rights reserved)
Detection of change when one display of familiar objects replaces another display might be based purely upon visual codes,
or also on identity information (i.e., knowingwhat was presentwhere in the initial display). Displays of 10 alphanumeric characters were presented and, after a brief offset, were presented
again in the same position, with or without a change in a single character. Subjects’ accuracy in change detection did not
suggest preservation of any more information than is usually available in whole report, except with the briefest of offsets
(under 50 msec). Stimulus duration had only modest effects. The interaction of masking with offset duration followed the pattern
previously observed with unfamiliar visual stimuli (Phillips, 1974). Accuracy was not reduced by reflection of the characters
about a horizontal axis, suggesting that categorical information contributed negligibly. Detection of change appears to depend
upon capacity-limited visual memory; (putative) knowledge of what identities are present in different display locations does
not seem to contribute.
The study of divided attention has produced many apparent demonstrations of “capacity limitation.” Possible ambiguities in such demonstrations are considered for three major types of experimental situation: simultaneous inputs with separate responses; choice; and classification. Two issues emerge. First, demonstrations always rest on assumptions about process set, i.e., the set of internal processes by which the task actually is performed. Alternative process sets are considered for situations of each type. Second, a demonstration of capacity limitation is made either by increasing the number of simultaneous processes, or by changing the bias between them. In either case effects unrelated to capacity limitation may influence the results. If several processes contribute to a single response, some performance decrement must accompany an increase in their number, simply through the increased overall chance for error. If the subject is biased toward one alternative in a choice or classification situation, the benefits enjoyed by this alternative may reflect not a preferential allocation of attentional capacity, but simply a willingness to decide in favor of this alternative with relatively little evidence.
The storage of visual short-term memory (VSTM) capacity for objects defined by features from the same dimension (colour) and from separate dimensions (texture and shape) was assessed in four experiments. In agreement with the framework proposed by Wheeler and Treisman (2002) concerning binding in VSTM, it is shown that features from the same dimension compete for storage capacity while features from separate dimensions are relatively stored in parallel. Furthermore, evidence is offered that integration between object features can be stored in VSTM, just as well as single features, provided that features from that object are encoded as the components of a single unitary object. When features are processed as properties of separate objects, integration of these features is poorly stored in VSTM.
There is considerable evidence that visual attention is concentrated at a single locus in the visual field, and that this locus can be moved independent of eye movements. Two studies are reported which suggest that, while certain aspects of attention require that locations be scanned serially, at least one operation may be carried out in parallel across several independent loci in the visual field. That is the operation of indexing features and tracking their identity. The studies show that: (a) subjects are able to track a subset of up to 5 objects in a field of 10 identical randomly-moving objects in order to distinguish a change in a target from a change in a distractor; and (b) when the speed and distance parameters of the display are designed so that, on the basis of some very conservative assumptions about the speed of attention movement and encoding times, the predicted performance of a serial scanning and updating algorithm would not exceed about 40% accuracy, subjects still manage to do the task with 87% accuracy. These findings are discussed in relation to an earlier, and independently motivated model of feature-binding--called the FINST model--which posits a primitive identity maintenance mechanism that indexes and tracks a limited number of visual objects in parallel. These indexes are hypothesized to serve the function of binding visual features prior to subsequent pattern recognition.
Working memory refers to a system for temporary storage and manipulation of information in the brain, a function critical for a wide range of cognitive operations. It has been proposed that working memory includes a central executive system (CES) to control attention and information flow to and from verbal and spatial short-term memory buffers. Although the prefrontal cortex is activated during both verbal and spatial passive working memory tasks, the brain regions involved in the CES component of working memory have not been identified. We have used functional magnetic resonance imaging (fMRI) to examine brain activation during the concurrent performance of two tasks, which is expected to engage the CES. Activation of the prefrontal cortex was observed when both tasks are performed together, but not when they are performed separately. These results support the view that the prefrontal cortex is involved in human working memory.
When two concurrent sensorimotor tasks require separate responses, selection of the first response generally delays selection of the second. Dual-task performance was examined in four patients who had undergone surgical transection of the forebrain commissures including the corpus callosum. One light flash was presented to each visual field in succession, and patients made a choice response to each stimulus with the ipsilateral hand, thereby confining the tasks to separate hemispheres. All four showed dual-task interference very similar to that found with normal individuals. Therefore, still-intact subcortical structures must play a critical role in sequencing response selection processes (the 'dual-task bottleneck'), confirming the distinction between the attentional limitations involved in planning actions and those involved in perceptual analysis.
People often have trouble performing 2 relatively simple tasks concurrently. The causes of this interference and its implications for the nature of attentional limitations have been controversial for 40 years, but recent experimental findings are beginning to provide some answers. Studies of the psychological refractory period effect indicate a stubborn bottleneck encompassing the process of choosing actions and probably memory retrieval generally, together with certain other cognitive operations. Other limitations associated with task preparation, sensory-perceptual processes, and timing can generate additional and distinct forms of interference. These conclusions challenge widely accepted ideas about attentional resources and probe reaction time methodologies. They also suggest new ways of thinking about continuous dual-task performance, effects of extraneous stimulation (e.g., stop signals), and automaticity. Implications for higher mental processes are discussed.
Research suggests that dual-task interference is caused by a central bottleneck (together with response grouping and impaired preparation). The emphasis placed on the 1st response in these experiments, however, may have discouraged the sharing of processing resources between tasks. In the present experiment, instructions placed equal emphasis on 2 choice reaction-time tasks in which stimuli were presented simultaneously on 20% of the trials. In contrast to a graded trade-off of resources, a bottleneck predicts bimodality in the distribution of interresponse intervals for the 2 tasks, reflecting the 2 possible orders in which their respective central stages might be performed. Most subjects showed such a bimodality, along with other signs of a bottleneck; the remainder showed evidence of response grouping. The data suggest that the bottleneck is structural rather than strategic and make the graded sharing of resources less plausible.
We sought to measure separately the motor potentials for each of 2 concurrent tasks and to use these measurements to identify the locus of dual-task interference. Lateralized readiness potentials (LRPs) were measured in the psychological refractory period paradigm, in which a separate response is required to each of 2 successive signals. As the interval between the signals decreased, the 2 reaction time (RT) tasks increasingly overlapped and the 2nd RT was prolonged. The LRP for the 2nd task was also delayed but maintained a constant temporal relation with the 2nd RT and sometimes preceded the 1st-task RT. The results indicate that (a) independent measures of the LRP can be obtained for each of 2 concurrent tasks, (b) slowing of the 2nd task was caused by a delay in processes that precede LRP onset, and (c) the 1st task may cease to interfere with the 2nd considerably before producing an overt response.
Short-term memory storage can be divided into separate subsystems for verbal information and visual information, and recent studies have begun to delineate the neural substrates of these working-memory systems. Although the verbal storage system has been well characterized, the storage capacity of visual working memory has not yet been established for simple, suprathreshold features or for conjunctions of features. Here we demonstrate that it is possible to retain information about only four colours or orientations in visual working memory at one time. However, it is also possible to retain both the colour and the orientation of four objects, indicating that visual working memory stores integrated objects rather than individual features. Indeed, objects defined by a conjunction of four features can be retained in working memory just as well as single-feature objects, allowing sixteen individual features to be retained when distributed across four objects. Thus, the capacity of visual working memory must be understood in terms of integrated objects rather than individual features, which places significant constraints on cognitive and neurobiological models of the temporary storage of visual information.
Two critical target stimuli (T1 and T2) were embedded in a stream of white letters shown on a black background, using a rapid serial visual presentation paradigm (RSVP, 100 msec/item). T1 was a red H or S; T2 was an X or a Y. Performance in a two-alternative discrimination on T2 was impaired when processing of T1 was required--a result often called an attentional blink (AB). In previous work, the response in Task1 has been an unspeeded and delayed response at the end of the trial. Three experiments compared performances in Task2 that depended on whether Task1 required an unspeeded delayed response or a speeded immediate response. A larger AB was found when a speeded response was required. Furthermore, in the speeded conditions, faster responses in Task1 were associated with a smaller and shorter AB effect than were slower responses. The results show that manipulations affecting a relatively late stage of processing--response selection--affect the magnitude and duration of the AB phenomenon. A new central inhibition theory is proposed to account for these results. According to this theory, the AB is similar to the psychological refractory period effect and is caused by central postponement of short-term consolidation of T2.
