Marie L Smith

Birkbeck, University of London · Department of Psychological Sciences

Perceptual decisions are derived from the combination of priors and sensorial input. While priors are broadly understood to reflect experience/expertise developed over one’s lifetime, the role of perceptual expertise at the individual level has seldom been directly explored. Here, we manipulate probabilistic information associated with a high and l...

Mental imagery (MI) is the ability to generate visual phenomena in the absence of sensory input. MI is often likened to visual working memory (VWM): the ability to maintain and manipulate visual representations. How MI is recruited during VWM is yet to be established. In a modified orientation change-discrimination task, we examined how behavioral...

Although humans are considered to be face experts, there is a well-established reliable variation in the degree to which neurotypical individuals are able to learn and recognise faces. While many behavioural studies have characterised these differences, studies that seek to relate the neuronal response to standardised behavioural measures of abilit...

It is considerably harder to generalize identity across different pictures of unfamiliar faces, compared with familiar faces. This finding hints strongly at qualitatively distinct processing of unfamiliar face stimuli—for which we have less expertise. Yet, the extent to which face selective versus generic visual processes drive outcomes during this...

Face recognition ability is often reported to be a relative strength in Williams syndrome (WS). Yet methodological issues associated with the supporting research, and evidence that atypical face processing mechanisms may drive outcomes ‘in the typical range’, challenge these simplistic characterisations of this important social ability. Detailed in...

Rapidly and accurately processing information from faces is a critical human function that is known to improve with developmental age. Understanding the underlying drivers of this improvement remains a contentious question, with debate continuing as to the presence of early vs. late maturation of face-processing mechanisms. Recent behavioural evide...

Faces transmit a wealth of important social signals. While previous studies have elucidated the network of cortical regions important for perception of facial expression, and the associated temporal components such as the P100, N170 and EPN, it is still unclear how task constraints may shape the representation of facial expression (or other face ca...

Rapidly and accurately processing information from faces is a critical human function that is known to improve with developmental age. Understanding the underlying drivers of this improvement remains a contentious question, with debate continuing as to the presence of early vs. late maturation of face processing mechanisms. Recent behavioural evide...

Older adults tend to perform more poorly than younger adults on emotional expression identification tasks. The goal of the present study was to test a processing mechanism that might explain these differences in emotion recognition-specifically, age-related variation in the utilization of specific visual cues. Seventeen younger and 17 older adults...

Older adults tend to perform more poorly than younger adults on emotional expression identification tasks. The goal of the present study was to test a processing mechanism that might explain these differences in emotion recognition – specifically, age-related variation in the utilization of specific visual cues. Seventeen younger and 17 older adult...

Unusual patterns of fixation behavior in individuals with autism spectrum disorder during face tasks hint at atypical processing strategies that could contribute to diminished face expertise in this group. Here, we use the Bubbles reverse correlation technique to directly examine face-processing strategies during identity judgments in children with...

Direct gaze is a powerful social cue signalling the attention of another person toward oneself. Here we investigated the relevance of low spatial frequency (LSF) and high spatial frequency (HSF) in facial cues for direct gaze processing. We identified two distinct peaks in the ERP response, the N170 and N240 components. These two components were re...

Unusual patterns of fixation behaviour in individuals with autism spectrum disorder during face tasks hint at atypical processing strategies that could contribute to diminished face expertise in this group. Here, we use the Bubbles reverse correlation technique to directly examine face-processing strategies during identity judgments in children wit...

Face processing abilities vary across the lifespan: increasing across childhood and adolescence, peaking around 30 years of age, and then declining. Despite extensive investigation, researchers have yet to identify qualitative changes in face processing during development that can account for the observed improvements on laboratory tests. The curre...

Detailed analysis of expression judgments in Williams syndrome reveals that successful emotion categorization need not reflect ‘classic’ information processing strategies. These individuals draw upon a distinct set of featural details to identify happy and fearful faces that differ from those used by typically developing comparison groups: children...

Few would argue that the unique insights brought by studying the typical and atypical development of psychological processes are essential to building a comprehensive understanding of the brain. Often, however, the associated challenges of working with non-standard adult populations results in the more complex psychophysical paradigms being rejecte...

Facial expression recognition skills are known to improve across childhood and adolescence, but the mechanisms driving the development of these important social abilities remain unclear. This study investigates directly whether there are qualitative differences in child and adult processing strategies for these emotional stimuli. With a novel adapt...

Direct gaze is a crucial signal in human social communication, which is known to attract visual attention and modulate a wide range of behaviours. The present study investigated whether direct gaze facilitates rapid orienting to faces, which is important for adaptive on-line communication, and its neural correlates. Fifteen participants performed a...

Accurately determining the familiarity of another and correctly establishing their identity are vital social skills. A considerable body of work has explored their perceptual and neural underpinnings and debate remains regarding whether they are dissociable, that is, separable parts of a dual process, or different aspects of a common retrieval proc...

Children are widely accepted to process faces differently from adults, with aspects of adult-like processing and neural specialization continuing to develop into early adulthood. Critically, however, little is known about the specific information processing strategies employed as children mature. Here, we investigate the development of face process...

Direct gaze is a powerful social cue used to indicate the attention of another on oneself and is of such importance to typical everyday social interaction that it is preferentially attended from birth (Farroni et al., 2002). Previous research has indicated better face encoding and retrieval of faces displaying direct as opposed to averted gaze with...

The ability to accurately determine the emotional state of others is critical for successful social functioning. However older adults can demonstrate selective difficulties in identifying negative emotions from faces while the ability to identify positive emotional faces is preserved. In younger adults the categorization of facial expressions of em...

The modulating effect of emotional expression on the rewarding nature of attractive and nonattractive female faces in heterosexual men was explored in a motivated viewing paradigm. This paradigm, which is an indicator of neural reward, requires the viewer to expend effort to maintain or reduce image-viewing times. Males worked to extend the viewing...

Accurate classification of the emotional state of others is of vital importance to human social functioning and is a process that relies heavily upon the extraction and processing of specific visual cues from faces. Although the successful identification of a given facial expression has been shown to rely on the processing of specific visual featur...

What constitutes normal cortical dynamics in healthy human subjects is a major question in systems neuroscience. Numerous in vitro and in vivo animal studies have shown that ongoing or resting cortical dynamics are characterized by cascades of activity across many spatial scales, termed neuronal avalanches. In experiment and theory, avalanche dynam...

Previous research indicates that, under explicit instructions to listen to spoken stimuli or in speech-oriented behavioural tasks, the brain's responses to senseless pseudowords are larger than those to meaningful words; the reverse is true in non-attended conditions. These differential responses could be used as a tool to trace linguistic processe...

The study of internal knowledge representations is a cornerstone of the research agenda in the interdisciplinary study of cognition. An influential proposal assumes that the brain uses its internal knowledge of the external world to constrain, in a top-down manner, high-dimensional sensory data into a lower-dimensional representation that enables p...

How do human brain networks react to dynamic changes in the sensory environment? We measured rapid changes in brain network organization in response to brief, discrete, salient auditory stimuli. We estimated network topology and distance parameters in the immediate central response period, <1 s following auditory presentation of standard tones inte...

To identify tasks that were sensitive to a temporary decline in cognitive performance after sleep deprivation and to investigate the ability of the acetylcholinesterase inhibitor donepezil to reverse any sleep deprivation-induced impairment. Thirty healthy volunteers were administered either a 5-mg daily dose of donepezil or placebo for 14-17 days,...

Rapid accurate categorization of the emotional state of our peers is of critical importance and as such many have proposed that facial expressions of emotion can be processed without conscious awareness. Typically, studies focus selectively on fearful expressions due to their evolutionary significance, leaving the subliminal processing of other fac...

Effortful cognitive performance is theoretically expected to depend on the formation of a global neuronal workspace. We tested specific predictions of workspace theory, using graph theoretical measures of network topology and physical distance of synchronization, in magnetoencephalographic data recorded from healthy adult volunteers (N = 13) during...

A powerful methodology is required to resolve what is still one of the greatest methodological challenges in the cognitive neuroscience of vision: When dealing with complex visual stimuli, how can a brain response be attributed to a specific object category (e.g. a face), a specific feature (e.g. the eye) or a specific function (detecting an eye de...

A fundamental problem in vision is to understand which visual information correlates with the perception of a stimulus and how the brain extracts and aggregates this information to arrive at a conscious perception. We examined this problem in a case study involving the perceptual reversal of an ambiguous image (here, Dali's painting the Slave Marke...

Human beings are natural experts at processing faces, with the exception of other-race faces. Despite numerous studies it is still unclear whether the so-called other-race effect results from changes of visual information processing depending on the race of input faces. We first investigated this question with hybrid faces (Schyns & Oliva, 1999) th...

For the first time, we reveal the time course of integration of Spatial Frequency (SF) facial features from the brain activity of observers who categorized Eckman's six basic expressions of emotions (i.e. happy, surprised, fearful, angry, disgusted, sad). In the experiment, three observers saw 21,000 sparse versions of expressive faces. Their task...

The categorization of facial expressions has been shown to be associated with a lateral-occipital negativity in the ERP record at around 170 ms following stimulus onset (N170). It has been suggested that this negativity reflects processing in a region of the lateral-occipital cortex known as the Fusiform Face Area (FFA). Using both source reconstru...

Accurate and efficient interpretation of facial expressions of emotion is essential for humans to socially interact with others. Facial expressions communicate information from which we can quickly infer the state of mind of our peers and adjust our behavior accordingly. Considering the face as a transmitter of emotion signals and the brain as a de...

- Introduction: In this study we demonstrate that the uncertainty of a categorization task modulates the information that the observer encodes from the stimulus. We demonstrate this in the context of a face categorization task and show that task uncertainty causes a greater extraction of information. - Methods: Two observers completed 8000 trials...

Graph theory provides many metrics of complex network organization that can be applied to analysis of brain networks derived from neuroimaging data. Here we investigated the test-retest reliability of graph metrics of functional networks derived from magnetoencephalography (MEG) data recorded in two sessions from 16 healthy volunteers who were stud...

Analysis of the EEG Data: Time Course of the Sensitivity to Combinations of Spatial Frequency Bands (Observer LF, “fear”). Every 4 ms, on electrode OTL and OTR, we represent the combination of the five spatial frequency bands with a binary number (in decimal between 1 and 31) and color code it between white (1) and red (31), see Figure 4 for detail...

Analysis of the EEG Data: Time Course of the Sensitivity to Combinations of Spatial Frequency Bands (Observer UM, “fear”). (1.65 MB TIF)

Analysis of the EEG Data: Time Course of the Sensitivity to Combinations of Spatial Frequency Bands (Observer LF, “disgust”). (1.70 MB TIF)

Analysis of the EEG Data: Decorrelation of Facial Expressions Between 140 and 200 ms Following Stimulus Onset. A. Backus-Spread Measure of Decorrelation of Facial Expressions (Observers LF). At each time point, for each expression, we transform the classification image (OTR+OTL) into a single high-dimensional vector (of 38×24 image pixels×5 spatial...

Analysis of the EEG Data: Time Course of the Sensitivity to Combinations of Spatial Frequency Bands (Observer UM, “disgust”). (1.65 MB TIF)

Analysis of the EEG Data: Time Course of the Sensitivity to Combinations of Spatial Frequency Bands (Observer LF, collapsed across all seven expressions). For each electrode, we collapsed the time course of sensitivity to the combinations of spatial frequency bands across the seven expressions. OTR+OTL. To depict the respective contributions of the...

Analysis of the EEG Data: Time Course of the Sensitivity to Combinations of Spatial Frequency Bands (Observer UM, collapsed across all seven expressions). (1.72 MB TIF)

Analysis of the EEG Data: Decorrelation of Facial Expressions Between 140 and 200 ms Following Stimulus Onset. A. Backus-Spread Measure of Decorrelation of Facial Expressions (Observers UM). (1.81 MB TIF)

Self-organized criticality is an attractive model for human brain dynamics, but there has been little direct evidence for its existence in large-scale systems measured by neuroimaging. In general, critical systems are associated with fractal or power law scaling, long-range correlations in space and time, and rapid reconfiguration in response to ex...

Face perception is a complex process involving a network of brain structures, dynamically processing information to enable judgments about a face to be made (e.g., familiarity, identity, and expression). Here we introduce an analysis methodology that makes it possible to directly study this information processing in the brain from spatially and tem...

Competent social organisms will read the social signals of their peers. In primates, the face has evolved to transmit the organism's internal emotional state. Adaptive action suggests that the brain of the receiver has co-evolved to efficiently decode expression signals. Here, we review and integrate the evidence for this hypothesis. With a computa...

If the brain is a machine that processes information, then its cognitive activity can be interpreted as a set of information processing states linking stimulus to response (i.e. as a mechanism or an algorithm). The cornerstone of this research agenda is the existence of a method to translate the measurable states of brain activity into the informat...

The brain computations that underlie our ability to recognize facial expressions involve the extraction of relevant information from the faces of our peers, and allow us to readily respond in an appropriate manner to the displayed emotion. Here we present recent advances in understanding the brain processes underlying the categorization of facial e...

Reverse correlation methods have been widely used in neuroscience for many years and have recently been applied to study the sensitivity of human brain signals (EEG, MEG) to complex visual stimuli. Here we employ one such method, Bubbles (Gosselin, F., Schyns, P.G., 2001. Bubbles: A technique to reveal the use of information in recognition tasks. V...

A key to understanding visual cognition is to determine when, how, and with what information the human brain distinguishes between visual categories. So far, the dynamics of information processing for categorization of visual stimuli has not been elucidated. By using an ecologically important categorization task (seven expressions of emotion), we d...

Cognitive neuroscience assumes a correspondence between specific spatio-temporal patterns of neural activity and the states of a mechanism that processes cognitive information. Mechanistic explanations of cognition should therefore translate patterns of neural activity into the components of a formal mechanism: a set of information processing state...

Transient periods of synchronized oscillating neuronal discharges in the brain have been proposed to support the discrete perceptual moments underlying conscious visual experience. However, the information content of these perceptual moments remains a critical challenge to the understanding of consciousness. We uncovered this information content in...

One of the most impressive disorders following brain damage to the ventral occipitotemporal cortex is prosopagnosia, or the inability to recognize faces. Although acquired prosopagnosia with preserved general visual and memory functions is rare, several cases have been described in the neuropsychological literature and studied at the functional and...

The subjectively seamless nature of visual experience would intuitively suggest that the underlying representations of the visual world evolve continuously. There is, however, a controversial alternative suggesting that these visual representations are in fact discrete, built up in the brain over a number of discrete processing epochs. In order to...

In 1994, Schyns & Oliva presented the concept of hybrids, images generated by combining the low spatial frequency (LSF) content of one image and the high spatial frequency (HSF) content of a second image. They were used to analyse the flexible nature of the human visual system for the categorization of scenes [?] and of faces [?].

This article examines the human face as a transmitter of expression signals and the brain as a decoder of these expression signals. If the face has evolved to optimize transmission of such signals, the basic facial expressions should have minimal overlap in their information. If the brain has evolved to optimize categorization of expressions, it sh...

Abstract-Examining the receptive fields of brain signals can elucidate how information impinging on the former modulates the latter. We applied this time-honored approach in early vision to the higher-level brain processes underlying face categorizations. Electroencephalograms in response to face-information samples were recorded while observers re...

Ph. D. thesis submitted to the Department of Physics and Astronomy, University of Glasgow, 2003. Thesis (Ph. D.)--University of Glasgow, 2003. Includes bibliographical references.