Eliot Hazeltine

University of Iowa | UI · Department of Psychological and Brain Sciences

Task knowledge is encoded hierarchically such that complex tasks are composed of simpler tasks. This compositional organization also supports generalization to facilitate learning of related but novel complex tasks. To study how the brain implements composition and generalization in hierarchical task learning, we trained human participants on two c...

The congruency sequence effect (CSE) refers to a reduction in the congruency effect after incongruent trials compared to congruent trials in a conflict-inducing task. There is an ongoing debate about the mechanisms underlying the CSE. To help inform this debate, we conducted a meta-analysis of the relevant CSE studies published in the past 31 years...

Objectives Older adult executive function varies widely due to brain and cognitive aging. Variance in older adult executive function is linked to increased response conflict from cognitive and brain aging. Cognitive Reserve (CR) is a theoretical protective mechanism that lessens brain aging’s impact on cognition and is associated with greater educa...

Binding theories claim that features of an episode are bound to each other and can be retrieved once these features are re-encountered. Binding effects have been shown in task-switching studies with a strong focus on bindings of observable features such as responses. In this study, we aimed to investigate whether task rules, translating stimulus in...

Responses are slower in two-choice tasks when either a previous stimulus feature or the previous response repeats than when all features repeat or all features change. Current views of action control posit that such partial repetition costs (PRCs) index the time to update a prior “binding” between a stimulus feature and the response or to resolve p...

Executive Function (EF) is a complex higher order cognitive process that involves integrating sub-processes of attention, working memory, inhibition, and task switching and known to be one of the first cognitive functions to be affected by age related declines. Global Functional Connectivity (GFC), a measure of whole brain connectivity in brain net...

Task-switch costs are affected by the pairings of stimulus and response modalities. For example, switch costs are reduced when switching between visual-manual and auditory-vocal tasks compared to switching between visual-vocal and auditory-manual tasks. These modality pairing effects are generally interpreted as reflecting increased crosstalk betwe...

Response repetitions aid performance when a task repeats but impair performance when a task switches. Although this interaction is robust, theoretical accounts remain controversial. Here, we used an un-cued, predictable task-switching paradigm with univalent targets to explore whether a simple bias to switch the response when the task switches can...

Teacher judgments of students’ reading abilities in the elementary grades have been researched extensively, but less is known about how middle school teachers judge their students’ word reading, fluency, vocabulary, and comprehension skills. Such information could be useful when determining which students and reading components would be reasonable...

Dual-task costs are thought to reflect the architecture of the cognitive processes that guide voluntary action. Thus, manipulations that affect dual-task costs can provide insight into how we represent and select behavior as well as allow us to better design machines and controls for safer, more efficient performance. This line of research has reve...

There has been an increasing interest in uncovering the mechanisms underpinning how people decide which task to perform at a given time. Many studies suggest that task representations are crucial in guiding such voluntary task selection behavior, which is primarily reflected in a bias to select task repetitions over task switches. However, it is no...

During goal-directed behavior, humans purportedly form and retrieve so-called event files, conjunctive representations that link context-specific information about stimuli, their associated actions, and the expected action outcomes. The automatic formation, and later retrieval, of such conjunctive representations can substantially facilitate effici...

The burgeoning interest in how voluntary actions are organized into goal-based behaviors has produced a rich body of data showing that task representations are complex, integrating not only stimulus and response information but also internal (e.g., goals and relationships among actions) and external (e.g., task-irrelevant stimuli) context. The domi...

People respond more slowly in two-choice tasks when either a previous stimulus feature or the previous response repeats in partial repetition trials than when (a) both repeat in complete repetition trials or (b) both alternate in complete alternation trials. The binding account posits that such partial repetition costs index a memory-retrieval conf...

Repeating a response from the previous trial typically leads to performance benefits. However, these benefits are eliminated, and usually reversed, when switching to a new task (i.e., response-repetition costs). Here, we test the proposal that response-repetition costs reflect changes in the representation of an action. To investigate this, we desi...

The structure of task representations is widely studied with task-switching procedures in which the experimenter compares performance across predetermined categories of trial transitions (viz., switch costs). This approach has been productive, but relies on experimental assumptions about the relationships among stimulus-response mappings that defin...

During goal-directed behavior, humans purportedly form and retrieve so called 'event files' - conjunctive representations that link context-specific information about stimuli, their associated actions, and the expected action-outcomes. The automatic formation - and later retrieval - of such conjunctive 'event file' representations can substantially...

Flexibly shifting attention between stimulus dimensions (e.g., shape and color) is a central component of regulating cognition for goal-based behavior. In the present report, we examine the functional roles of different cortical regions by manipulating two demands on task switching that have been confounded in previous studies—shifting attention be...

Two related accounts of dual-task costs—multiple resource competition and crosstalk—explain why costs can be reduced when there is less overlap between the two tasks. However, distinguishing between competition for limited resources and crosstalk between concurrently performed operations has proven difficult. In the present study, we compared these...

Many middle-school students struggle with basic reading skills. One reason for this might be a lack of automaticity in word-level lexical processes. To investigate this, we used a novel backward masking paradigm, in which a written word is either covered with a mask or not. Participants (N = 444 [after exclusions]; nfemale = 264, nmale = 180) were...

Does cognitive control operate globally (across task sets) or locally (within a task set)? Recently, two of the current co-authors (Hazeltine and Schumacher 2016; Schumacher and Hazeltine 2016) proposed that humans represent tasks as task files: hierarchically structured, compartmentalized subsets of our current goals and motivations, task instruct...

The pairings of tasks' stimulus and response modalities affect the magnitude of dual-task costs. For example, dual-task costs are larger when a visual-vocal task is paired with an auditory-manual task compared with when a visual-manual task is paired with an auditory-vocal task. These results are often interpreted as reflecting increased crosstalk...

Researchers have recognized the role that task representation plays in our behavior for many years. However, the specific influence that the structure of one’s task representation has on executive functioning has only recently been investigated. Prior research suggests that adjustments of cognitive control are affected by subtle manipulations of as...

The stop signal task (SST) is the gold standard experimental model of inhibitory control. However, neither SST condition–contrast (stop vs. go, successful vs. failed stop) purely operationalizes inhibition. Because stop trials include a second, infrequent signal, the stop versus go contrast confounds inhibition with attentional and stimulus process...

Declining episodic memory is common among otherwise healthy older adults, in part due to negative effects of aging on hippocampal circuits. However, there is significant variability between individuals in severity of aging effects on the hippocampus and subsequent memory decline. Importantly, variability may be influenced by modifiable protective p...

Manipulating the pairings of stimulus and response modalities has been shown to affect how response selection processes for distinct tasks interact. For example, Stephan and Koch (Psychol Res 75(6):491–498, 2011) found smaller performance costs when participants switched between visual–manual (VM) and auditory–vocal (AV) tasks (modality compatible;...

To inform the development of gamified assessments, this study explored how students with or at risk for reading difficulties in Grades 6–8 (N = 202) perceived and interacted with a decoding assessment designed with gamification characteristics. Three data sources enhanced the methodological triangulation: observations and scores from testing, surve...

Declining episodic memory is common among otherwise healthy older adults, in part due to negative effects of aging on hippocampal circuits. However, there is significant variability between individuals in severity of aging effects on the hippocampus and subsequent memory decline. Importantly, variability may be influenced by modifiable protective p...

Dual-task costs are often significantly reduced or eliminated when both tasks use compatible stimulus-response (S-R) pairs. Either by design or unintentionally, S-R pairs used in dual-task experiments that produce small dual-task costs typically have two properties that may reduce dual-task interference. One property is that they are easy to keep s...

Cognitive control is the term applied to the set of processes that allow us to adapt our behavior to a changing environment and evolving goals. Much of the research on cognitive control is conducted using relatively simple experimental tasks. In this review, we propose an integrative account of cognitive control to more complex task situations. Spe...

The stop-signal task (SST) is used to study action-stopping in the laboratory. In SSTs, the P3 event-related potential following stop-signals is considered to be a neural index of motor inhibition. However, a similar P3 deflection is often observed following infrequent events in non-inhibition tasks. Moreover, within SSTs, stop-signals are indeed i...

Abstract: The stop-signal task (SST) is a gold standard for assessing motor inhibition in the laboratory. In the classic SST, participants respond to “go” signals on every trial and attempt to withhold responses when presented with “stop” signals that sometimes follow the go signal. The action-stopping literature conceptualizes the interaction bet...

Many details in reading curricula (e.g., the order of materials) have analogs in laboratory studies of learning (e.g., blocking/interleaving). Principles of learning from cognitive science could be used to structure these materials to optimize learning, but they are not commonly applied. Recent work bridges this gap by “field testing” such principl...

An important component of learning to read is the acquisition of letter-to-sound- mappings. The sheer quantity of mappings and many exceptions suggests that children may use a form of statistical learning to acquire them. However, while statistical models of reading are item-based, reading instruction typically focuses on rule-based approaches invo...

Limitations in our ability to produce two responses at the same time – that is, dual-task interference – are typically measured by comparing performance when two stimuli are presented and two responses are made in close temporal proximity to when a single stimulus is presented and a single response is made. While straightforward, this approach leav...

Automaticity in word recognition has been hypothesized to be important in reading development (LaBerge & Samuels, 1974; Perfetti, 1985). However, when predicting educational outcomes, it is difficult to isolate the influence of automatic word recognition from factors such as processing speed or knowledge of grapheme-phoneme correspondences. Cogniti...

Compared with young adults, older adults demonstrate difficulty forming and retrieving episodic memories. One proposed mechanism is that older adults are impaired at binding information into nonoverlapping representations, which is a key function of the hippocampus. The current experiments evaluate age differences in acquiring new memories using a...

This commentary explores the relationships between the construct of successful aging and the experimental psychology of human aging—cognitive gerontology. What can or should cognitive gerontology contribute to understanding, defining, and assessing successful aging? Standards for successful aging reflect value judgments that are culturally and hist...

Evidence from tasks that primarily tap either hippocampal- or striatal-based memory systems suggests that although these systems often compete for control of behavior, aging is associated with greater cooperation between them. This may stem from altered prefrontal cortex function. Here, we use a configural response task designed to engage both memo...

Parkinson’s disease (PD) is associated with procedural learning deficits. Nonetheless, studies have demonstrated that reward-related learning is comparable between patients with PD and controls (Bódi et al., Brain, 132(9), 2385–2395, 2009; Frank, Seeberger, & O’Reilly, Science, 306(5703), 1940–1943, 2004; Palminteri et al., Proceedings of the Natio...

To behave adaptively in complex and dynamic environments, one must link perception and action to satisfy internal states, a process known as response selection (RS). A largely unexplored topic in the study of RS is how interstimulus and interresponse similarity affect performance. To examine this issue, we manipulated stimulus similarity by using c...

The act of choosing an action based on stimulus information and a set of arbitrary rules is termed response selection. It embodies the core of voluntary behavior and plays a critical role in most experimental tasks, yet the processes supporting it are poorly understood. Often, response selection is assumed to arise through the activation of stimulu...

Human behavior is remarkably complex—even during the performance of relatively simple tasks—yet it is often assumed that learned associations between stimuli and responses provide the representational substrate for action selection. Here, we introduce an alternative framework, called a task file, that includes hierarchical associations between stim...

Stimulus-driven attention can improve working memory (WM) when drawn to behaviorally relevant information, but the neural mechanisms underlying this effect are unclear. The present study used functional magnetic resonance imaging (fMRI) to test competing hypotheses regarding the nature of the benefits of stimulus-driven attention to WM: that stimul...

The present study aimed to characterize the mechanism by which working memory is enhanced for items that capture attention because of their novelty or saliency-that is, via bottom-up attention. The first experiment replicated previous research by corroborating that bottom-up attention directed to an item is sufficient for enhancing working memory a...

A partially informative cue presented before a stimulus can facilitate the production of the response. Prior information about an upcoming target can increase brain activity in both stimulus (c.f., Desimone & Duncan, 1995) and response (c.f., Leuthold et al., 1996) processing regions; however, it is unclear how the representation of the task might...

Categorical learning is dependent on feedback. Here, we compare how positive and negative feedback affect information-integration (II) category learning. Ashby and O’Brien (2007) demonstrated that both positive and negative feedback are required to solve II category problems when feedback was not guaranteed on each trial, and reported no difference...

Does semantic overlap between two tasks influence the difficulties encountered when learning to perform two tasks at the same? Are older adults more affected when there is a more and more semantic overlap between the tasks, that is when the central representations are more semantically related?

Reward has been shown to change behavior as a result of incentive learning (by motivating the individual to increase their effort) and instrumental learning (by increasing the frequency of a particular behavior). However, Palminteri et al. (2011) demonstrated that reward can also improve the incidental learning of a motor skill even when participan...

Age is often associated with a decline in cognitive abilities that are important for maintaining functional independence, such as learning new skills. Many forms of motor learning appear to be relatively well preserved with age, while learning tasks that involve associative binding tend to be negatively affected. The current study aimed to determin...

Recent evidence has sparked debate about the neural bases of response selection and inhibition. In the current study, we employed two reactive inhibition tasks, the Go/Nogo (GnG) and Simon tasks, to examine questions central to these debates. First, we investigated whether a fronto-cortical-striatal system was sensitive to the need for inhibition p...

Hick/Hyman Law describes one of the core phenomena in the study of human information processing: mean response time is a linear function of average uncertainty. In the original work of Hick, (1952) and Hyman, (1953), along with many follow-up studies, uncertainty regarding the stimulus and uncertainty regarding the response were confounded such tha...

Dual-task costs can be greatly reduced or even eliminated when both tasks use highly-compatible S-R associations. According to Greenwald (Journal of Experimental Psychology: Human Perception and Performance, 30, 632-636, 2003), this occurs because the appropriate response can be accessed without engaging performance-limiting response selection proc...

The magnitude of congruency effects depends on, among other things, the specifics of previous trials. To explain these modulating effects, a host of mechanisms by which previous trials affect the processing of relevant and irrelevant information on the present trial have been proposed, including feature repetition advantages, negative priming, item...

For skill learning processes to be effective, they must encode associations that are inherent to the current task and avoid those that are spurious or particular to training conditions so that learning can transfer to novel situations. Some everyday contexts even require grouped responding to simultaneously presented stimuli. Here we test whether l...

People are typically slower when executing two tasks than when only performing a single task. These dual-task costs are initially robust but are reduced with practice. Dux et al. (2009) explored the neural basis of dual-task costs and learning using fMRI. Inferior frontal junction (IFJ) showed a larger hemodynamic response on dual-task trials compa...

Implicit learning in the serial reaction time (SRT) task is sometimes disrupted by the presence of a secondary distractor task (e.g., Schumacher & Schwarb Journal of Experimental Psychology: General 138:270-290, 2009) and at other times is not (e.g., Cohen, Ivry, & Keele Journal of Experimental Psychology: Learning, Memory, and Cognition 16:17-30,...

What role does item similarity play in motor skill acquisition? To examine this question, we used a modified version of the chord learning task (Seibel, 1963) that entails producing simultaneous finger key presses, similar to playing a chord on a piano. In Experiment 1, difficulty, as indexed by response time (RT) to a particular chord on the first...

Early reading abilities are widely considered to derive in part from statistical learning of regularities between letters and sounds. Although there is substantial evidence from laboratory work to support this, how it occurs in the classroom setting has not been extensively explored; there are few investigations of how statistics among letters and...

Why are dual-task costs reduced with ideomotor (IM) compatible tasks (Greenwald & Shulman, 1973; Lien, Proctor & Allen, 2002)? In the present experiments, we first examine three different measures of single-task performance (pure single-task blocks, mixed blocks, and long stimulus onset asynchrony [SOA] trials in dual-task blocks) and two measures...

The neurocognitive architecture for response selection is uncertain. Some theorists suggest that it is mediated by an amodal central mechanism, whereas others propose a set of independent control mechanisms. In a functional neuroimaging experiment, we investigated the nature of response selection by examining how its underlying brain mechanisms are...

We examined the sequential modulation of congruency effects using a task in which the irrelevant information shares the same stimulus dimensions as the relevant information but is presented at an earlier time. In Experiment 1, sequential modulations were observed within a stimulus modality but not between stimulus modalities. In Experiment 2, seque...

Dual-task costs depend on the specific pairings of stimulus and response modalities. Such findings are analogous to domain-specific effects in the working memory (WM) literature, in which items compete for limited capacity when they involve related types of information. The present study explicitly examines the relationship between modality-pairing...

An influential account of how cognitive control deals with conflicting sources of information holds that conflict is monitored by a module that automatically recruits attention to resolve the conflict. This leads to reduced effects of conflict on the subsequent trial, a phenomenon termed conflict adaptation. A prominent question is whether control...

The present study examined performance across three two-choice tasks that used the same two stimuli, the same two stimulus locations, and the same two responses to determine how task demands can alter the Simon Effect, its distribution across reaction time, and its sequential modulation. In two of the tasks, repetitions of stimulus features were no...

The effects of spatial compatibility and spatial congruence have both been explained in terms of a dual-route model under which spatial information about the stimulus, regardless of task relevance, is directly passed from perception to action. Recently, however, some alternatives to the dual-route model of the Simon Effect have been proposed (or re...

Patients with damage to the left temporoparietal junction (TPJ) have a low verbal span without concomitant deficits in speech perception. This pattern of cognitive impairment is taken as evidence for a dedicated phonological buffer that plays little role in perception (storage-specific account). In contrast, other research suggests that items are m...

Structural equation modeling (SEM) and fMRI were used to test whether changes in the regional activity are accompanied by changes in the inter-regional connectivity as motor practice progresses. Ten healthy subjects were trained to perform finger movement task daily for 4 weeks. Three sessions of fMRI images were acquired within 4 weeks. The change...

The neural systems engaged by intrinsic positive or negative feedback were defined in an associative learning task. Through trial and error, participants learned the arbitrary assignments of a set of stimuli to one of two response categories. Informative feedback was provided on less than 25% of the trials. During positive feedback blocks, half of...

The dependence of the Simon effect on the correspondence of the previous trial can be explained by the conflict-monitoring theory, which holds that a control system adjusts automatic activation from irrelevant stimulus information (conflict adaptation) on the basis of the congruency of the previous trial. The authors report on 4 experiments showing...

Do voluntary (endogenous) and involuntary (exogenous) attention have the same perceptual consequences? Here we used fMRI to examine activity in the fusiform face area (FFA--a region in ventral visual cortex responsive to faces) and frontal-parietal areas (dorsal regions involved in spatial attention) under voluntary and involuntary spatial cueing c...

Two studies [Ivry, R. B., Franz, E. A., Kingstone, A., & Johnston, J. C. The psychological refractory period effect following callosotomy: Uncoupling of lateralized response codes. Journal of Experimental Psychology: Human Perception and Performance, 24, 463–480, 1998; Pashler, H., Luck, S., Hillyard, S. A., Mangun, G. R., O'Brien, S., & Gazzaniga,...

This study examined the representational nature of configural response learning using a task that required simultaneous keypresses with 2 or 3 fingers, similar to the production of chords on the piano. If the benefits of learning are related to the retrieval of individual stimulus-response mappings, performance should depend on the frequencies of t...