Fast saccades to faces during the feedforward sweep.

Saccadic choice tasks use eye movements as a response method, typically in a task where observers are asked to saccade as quickly as possible to an image of a prespecified target category. Using this approach, face-selective saccades have been observed within 100 ms poststimulus. When taking into account oculomotor processing, this suggests that faces can be detected in as little as 70 to 80 ms. It has therefore been suggested that face detection must occur during the initial feedforward sweep, since this latency leaves little time for feedback processing. In the current experiment, we tested this hypothesis using backward masking-a technique shown to primarily disrupt feedback processing while leaving feedforward activation relatively intact. Based on minimum saccadic reaction time, we found that face detection benefited from ultra-fast, accurate saccades within 110 to 160 ms and that these eye movements are obtainable even under extreme masking conditions that limit perceptual awareness. However, masking did significantly increase the median SRT for faces. In the manual responses, we found remarkable detection accuracy for faces and houses, even when participants indicated having no visual experience of the test images. These results provide evidence for the view that the saccadic bias to faces is initiated by coarse information used to categorize faces in the feedforward sweep but that, in most cases, additional processing is required to quickly reach the threshold for saccade initiation.

Effects of age on face perception: Reduced eye region discrimination ability but intact holistic processing.

While age-related decline in face recognition memory is well-established, the degree of decline in face perceptual abilities across the lifespan and the underlying mechanisms are incompletely characterized. In the present study, we used the part-whole task to examine lifespan changes in holistic and featural processing. After studying an intact face, participants are tested for memory of a face part (eyes, nose, mouth) with the target and foil part presented either in isolation or in the context of the whole face. To the extent that parts are encoded into a holistic face representation, an advantage is expected for part recognition when tested in the whole face condition. The task therefore provides measures of holistic processing (whole-over-isolated-part trial advantage) and featural processing for each part when tested in isolation. Using a large sample of 3,341 online participants aged 18-69 years, we found that while discrimination of the eye region decreased beginning in the 50s, both mouth discrimination accuracy and the holistic advantage of whole versus part trial discrimination were stable with age. In separate analyses by gender, we found that age-related declines in eye region accuracy were more pronounced in males than females. We discuss potential mechanistic explanations for this eye region-specific decline with age, including age-related hearing loss directing attention toward the mouth. Further, we discuss how this could be related to the age-related positivity effect, which is associated with reduced sensitivity to eye-related emotions (e.g., anger) but preserved mouth-related emotion sensitivity (e.g., happiness). (PsycInfo Database Record (c) 2023 APA, all rights reserved).

A perceptual field test in object experts using gaze-contingent eye tracking.

A hallmark of expert object recognition is rapid and accurate subordinate-category recognition of visually homogenous objects. However, the perceptual strategies by which expert recognition is achieved is less known. The current study investigated whether visual expertise changes observers' perceptual field (e.g., their ability to use information away from fixation for recognition) for objects in their domain of expertise, using a gaze-contingent eye-tracking paradigm. In the current study, bird experts and novices were presented with two bird images sequentially, and their task was to determine whether the two images were of the same species (e.g., two different song sparrows) or different species (e.g., song sparrow and chipping sparrow). The first study bird image was presented in full view. The second test bird image was presented fully visible (full-view), restricted to a circular window centered on gaze position (central-view), or restricted to image regions beyond a circular mask centered on gaze position (peripheral-view). While experts and novices did not differ in their eye-movement behavior, experts' performance on the discrimination task for the fastest responses was less impaired than novices in the peripheral-view condition. Thus, the experts used peripheral information to a greater extent than novices, indicating that the experts have a wider perceptual field to support their speeded subordinate recognition.

The culture of perceptual expertise and the other-race effect.

In our commentary, we propose that the ORE can be viewed as a form of perceptual expertise. Like experts, we recognize own-race faces at the subordinate level as individuals and novices when recognize other-race faces at the basic level of race. Applying a perceptual expertise account, we explain the ORE in terms of its cognitive, neural, and motivational factors. We suggest that by creating a culture of "other-race" expertise, improvements in other-race face recognition can be achieved.

Hidden in Plain Sight: Overlooked Results and Other Errors in Evaluating Online Laboratory Results.

People are increasingly accessing their own laboratory (lab) results online. However, Canadians may be expected to use different systems to access their results, depending upon where they are tested (e.g., community lab vs. hospital), and these results may be displayed differently. This study examined the extent to which participants without medical expertise (N = 25) made errors identifying lab results (i.e., missing or mis-identifying abnormal results) in a mock report. Six participants overlooked each of the flagged values, 20 participants missed an abnormal result that was not flagged, and 2 participants mis-identified a normal value as out of range. We describe potential causes of these errors and the implications for the design of consumer-facing lab results.

Dissociations between performance and visual fixations after subordinate- and basic-level training with novel objects.

Previous work suggests that subordinate-level object training improves exemplar-level perceptual discrimination over basic-level training. However, the extent to which visual fixation strategies and the use of visual features, such as color and spatial frequency (SF), change with improved discrimination was not previously known. In the current study, adults (n = 24) completed 6 days of training with 2 families of computer-generated novel objects. Participants were trained to identify one object family at the subordinate level and the other object family at the basic level. Before and after training, discrimination accuracy and visual fixations were measured for trained and untrained exemplars. To examine the impact of training on visual feature use, image color and SF were manipulated and tested before and after training. Discrimination accuracy increased for the object family trained at the subordinate-level, but not for the family trained at the basic level. This increase was seen for all image manipulations (color, SF) and generalized to untrained exemplars within the trained family. Both subordinate- and basic-level training increased average fixation duration and saccadic amplitude and decreased the number of total fixations. Collectively, these results suggest a dissociation between discrimination accuracy, indicative of recognition, and the associated pattern of changes present for visual fixations.

Bird expertise does not increase motion sensitivity to bird flight motion.

While motion information is important for the early stages of vision, it also contributes to later stages of object recognition. For example, human observers can detect the presence of a human, judge its actions, and judge its gender and identity simply based on motion cues conveyed in a point-light display. Here we examined whether object expertise enhances the observer's sensitivity to its characteristic movement. Bird experts and novices were shown point-light displays of upright and inverted birds in flight, or upright and inverted human walkers, and asked to discriminate them from spatially scrambled point-light displays of the same stimuli. While the spatially scrambled stimuli retained the local motion of each dot of the moving objects, it disrupted the global percept of the object in motion. To estimate a detection threshold in each object domain, we systematically varied the number of noise dots in which the stimuli were embedded using an adaptive staircase approach. Contrary to our predictions, the experts did not show disproportionately higher sensitivity to bird motion, and both groups showed no inversion cost. However, consistent with previous work showing a robust inversion effect for human motion, both groups were more sensitive to upright human walkers than their inverted counterparts. Thus, the result suggests that real-world experience in the bird domain has little to no influence on the sensitivity to bird motion and that birds do not show the typical inversion effect seen with humans and other terrestrial movement.

Emotional gist: the rapid perception of facial expressions.

While it has been established that expression perception is rapid, it is unclear whether early appraisal mechanisms invoke holistic perception. In the current study, we defined gist perception as the appraisal of a stimulus within a single glance (<125 ms). We employed the expression composite task used previously by Tanaka and colleagues in a 2012 study, with several critical modifications: (i) we developed stimuli that eliminated contrast artifacts, (ii) we employed a masking technique to abolish low-level cues, and (iii) all the face stimuli were composite stimuli compared to mix of natural and composite stimuli previously used. Participants were shown a congruent (e.g. top: angry/ bottom: angry) or incongruent (e.g. top: angry/ bottom: happy) expression for 17, 50 or 250 ms and instructed to selectively attend to the cued expression depicted in the top (or bottom) half of the composite face and ignore the uncued portion. Compared to the isolated condition, a facilitation effect was found for congruent angry expressions, as well as an interference effect for incongruent happy and angry expressions at the shortest exposure duration of 17. Together these results provide evidence that the holistic gist perception of expression cannot be overridden by selective attention.

Identity-specific neural responses to three categories of face familiarity (own, friend, stranger) using fast periodic visual stimulation.

Previous studies have focused on the modulatory effects of face familiarity on different components of an event-related potential (ERP), but there is controversy in the literature regarding the precise component that reflects the process of identity recognition. This may be partly explained by limits to this waveform analysis approach, as waveforms elicited by the presentation of a face are likely to reflect a variety of different cognitive processes that overlap in time. Using fast periodic visual stimulation and EEG (FPVS-EEG), we directly measured the electrophysiological response reflecting identity-specific recognition after isolating it from responses attributable to low-level visual processing and face-selective processes that are not identity-specific. The observed response therefore provides a robust and objective measure of the recognition of a personally familiar face generated bilaterally in the occipito-temporal region. We tested the magnitude of this identity-specific response to three categories of familiarity: the own-face (high familiarity), a friend's face (moderate familiarity), and a stranger's face (no familiarity). We found the largest response to the participant's own-face, followed by an intermediate response to a highly personally familiar face, and the smallest response to an unfamiliar face. An additional response was observed over the posterior cortical midline for familiar faces only, consistent with theories that familiar identity recognition also triggers post-perceptual semantic processing.

Neural and behavioral effects of subordinate-level training of novel objects across manipulations of color and spatial frequency.

Perceptual expertise is marked by subordinate-level recognition of objects in the expert domain. In this study, participants learned one family of full-color, artificial objects at the subordinate (species) level and another family at the basic (family) level. Discrimination of trained and untrained exemplars was tested before and after training across several image manipulations [full-color, grayscale, low spatial frequency (LSF) and high spatial frequency (HSF)] while event-related potentials (ERPs) were recorded. Regardless of image manipulation, discrimination (indexed by d') of trained and of untrained exemplars was enhanced after subordinate-level training, but not after basic-level training. Enhanced discrimination after subordinate-level training generalized to untrained exemplars and to grayscale images and images in which LSF or HSF information was removed. After training, the N170 and N250, recorded over occipital and occipitotemporal brain regions, were both more enhanced after subordinate-level training than after basic-level training. However, the topographic distribution of enhanced responses differed across components. The N170 latency predicted reaction time after both basic-level training and subordinate-level training, highlighting an association between behavioral and neural responses. These findings further elucidate the role of the N170 and N250 as ERP indices of subordinate-level expert object processing and demonstrate how low-level manipulations of color and spatial frequency impact behavior and the N170 and N250 components independent of training or expertise.

Part and whole face representations in immediate and long-term memory.

Although there is empricial support for the old adage that "we never forget a face" (Journal of Experimental Psychology: General 104 (1975) 54-75), the cognitive processes responsible for our long-term face memories are not well understood. By manipulating the upright and inverted orientation of faces during encoding and retrieval, we investigated the influence of holistic processing on our ability to recognize faces stored in long-term memory. In Experiment 1, participants were trained to identify 12 novel upright faces (six male, six female) by name (e.g., "Joe," "Sue") to a criterion of 100% accuracy. Following learning, holistic memory for the upright and inverted faces was tested using the parts/wholes face recognition task. Different groups of participants were tested either immediately, one week, or two weeks after learning. A significant holistic effect was found for faces tested in their original upright orientation that was stable over the immediate, one-week, and two-week testing periods. In contrast, recognition of the same faces when shown inverted was poor and showed no evidence of holistic processing. In Experiment 2, faces were learned in their inverted orientations with 100% accuracy and tested in their upright and inverted orientations. At the immediate, one-week, or two-week intervals, recognition of inverted faces was relatively poor and there was no evidence of holistic processing for faces tested either in inverted or upright orientations. Collectively, these results indicate holistic processing provides an efficient means for the encoding and retrieval of faces in long-term memory that are relatively stable with the passage of time.

Examining the neural correlates of within-category discrimination in face and non-face expert recognition.

While expert face discrimination develops naturally in humans, expert discrimination in non-face object categories, such as birds, cars and dogs, is acquired through years of experience and explicit practice. The current study used an implicit visual discrimination paradigm and electroencephalography (EEG) - Fast Periodic Visual Stimulation - to examine whether within-category discrimination of faces and non-face objects of expertise rely on shared mechanisms despite their distinct learning histories. Electroencephalogram was recorded while bird experts and bird novices viewed 60 s sequences of bird images or face images presented at a periodic rate of six images per second (i.e., 6.0 Hz). In the sequence, an adapting base image of a family-level bird (e.g., robin), a species-level bird (e.g., purple finch) or a face (e.g., Face A) was presented repeatedly for four consecutive cycles, followed by a different within-category "oddball" image at every fifth cycle (e.g., warbler, house finch, Face B). A differential response between the adapting base and the oddball images (6.0 Hz/fifth cycle = 1.20 Hz) provided an index of within-category discriminability. The results showed that both experts and novices demonstrated a robust EEG signal of equal magnitudes to the 6.00 Hz base face and bird images at medial-occipital channels and to the oddball 1.20 Hz face and bird images at the more anterior occipito-temporal channels. To examine whether the responses to faces and birds were generated by shared neural mechanisms, we correlated the responses to birds and faces at the participant-level. For the base signal at medial-occipital channels, all object categories positively correlated in both the experts and the novices, as expected given that the base signal indexes visual responses that are shared by all object categories (e.g., low-level). In contrast, for the discrimination signal at the more anterior occipito-temporal channels, the response to family- and species-level birds positively correlated with faces for the experts, but no face-bird association was found for the novices. These findings indicate the existence of partially shared neural mechanisms for within-category discrimination of faces and birds in the experts, but not in the novices.

Investigating the perception of face identity in adults on the autism spectrum using behavioural and electrophysiological measures.

In the present study, we investigated face processing in individuals with self-reported Autism Spectrum Disorder (ASD, n = 16) and typically developing control participants (n = 16) using behavioural and electrophysiological measures. As a measure of their face memory, we administered the Cambridge Face Memory Test to participants in the ASD group. The results showed that the scores of the ASD participants were reliably below the age- and gender-matched norms of neurotypical individuals. To measure brain responses to faces, we used the fast periodic visual stimulation method, presenting photographs of a same-identity face (i.e., base face) at a constant frequency of 6 Hz (F) interleaved with different-identity faces (i.e., the oddball faces) presented at 1.2 Hz. The 6 Hz presentation of the base face and 1.2 Hz presentation of the oddball face elicited periodic brain responses corresponding to face detection and face individuation processes, respectively. Participants viewed four blocks of upright faces and four blocks of inverted faces. The results showed an enhanced EEG response to upright base faces at 6 Hz frequency and its harmonics compared to inverted faces, and the response was most focal over medial occipital channels. An enhanced response was found to upright oddball faces at 1.2 Hz and its harmonics compared to the inverted faces, and the response was centred over occipito-temporal channels in the right hemisphere. Critically, no differences or interactions were found between the ASD and typically developing groups in the responses to either the 6 Hz base faces or the 1.2 oddball faces. These results suggest that in individuals with ASD, the earlier stage of face perception, as measured by the fast periodic visual stimulation paradigm, can be dissociated from the later memory stage of face processing, as assessed by the Cambridge Face Memory Test.

A regional composite-face effect for species-specific recognition: Upper and lower halves play different roles in holistic processing of monkey faces.

Using a composite-face paradigm, we examined the holistic processing induced by Asian faces, Caucasian faces, and monkey faces with human Asian participants in two experiments. In Experiment 1, participants were asked to judge whether the upper halves of two faces successively presented were the same or different. A composite-face effect was found for Asian faces and Caucasian faces, but not for monkey faces. In Experiment 2, participants were asked to judge whether the lower halves of the two faces successively presented were the same or different. A composite-face effect was found for monkey faces as well as for Asian faces and Caucasian faces. Collectively, these results reveal that own-species (i.e., own-race and other-race) faces engage holistic processing in both upper and lower halves of the face, but other-species (i.e., monkey) faces engage holistic processing only when participants are asked to match the lower halves of the face. The findings are discussed in the context of a region-based holistic processing account for the species-specific effect in face recognition.

Color and spatial frequency differentially impact early stages of perceptual expertise training.

The current study examined the role of color and spatial frequency on the early acquisition of perceptual expertise after one week of laboratory training with bird stimuli. Participants learned to categorize finches (or warblers) at the subordinate species level (e.g., purple finch) and categorize warblers (or finches) at the more general family level. Training images were presented in their natural colors across 6 sessions. Participants completed a subordinate level species matching task prior to training, one day after training and one week after training while event-related potentials (ERPs) were recorded. Bird images were presented in either their natural congruent color, incongruent color, grayscale, low spatial frequency (LSF < 8 cycles per image) or high spatial frequency (HSF > 8 cycles per image). Replicating previous training studies, performance benefited more from subordinate- than basic-level training. Before training, any color helped performance, but color congruence effects (congruent > incongruent) only emerged after subordinate-level training. Spatial frequency manipulations did not interact with training. The N170 ERP component was sensitive to spatial frequency manipulations, but not color. N170 spatial frequency effects did not interact with training, and training effects generalized to all manipulations except the LSF images. Like performance, color congruence effects on the N250 were only observed after subordinate level training. These results are consistent with previous reports suggesting that effects of perceptual expertise training on performance are more clearly indexed by N250 than N170 effects. Taken together, our behavioral and ERP results show that color plays an important role in both low- and high- level visual processing, supporting surface-plus-edge-based theories for object processing and recognition.

The easy-to-hard training advantage with real-world medical images.

Many medical professions require practitioners to perform visual categorizations in domains such as radiology, dermatology, and neurology. However, acquiring visual expertise is tedious and time-consuming and the perceptual strategies mediating visual categorization skills are poorly understood. In this paper, the Ease algorithm was developed to predict an item's categorization difficulty (Ease value) based on the item's perceptual similarity to all within-category items versus between-category items in the dataset. In this study, Ease values were used to construct an easy-to-hard and hard-to-easy training schedule for teaching melanoma diagnosis. Whereas previous visual training studies suggest that an easy-to-hard schedule benefits learning outcomes, no studies to date have demonstrated the easy-to-hard advantage with complex, real-world images. In our study, 237 melanoma and benign images were collected for training and testing purposes. The diagnostic accuracy of images was verified by an expert dermatologist. Based on their Ease values, the items were grouped into easy, medium, and hard categories, each containing an equal number of melanoma and benign lesions. During training, participants categorized images of skin lesions as either benign or melanoma and were given corrective feedback after each trial. In the easy-to-hard training condition, participants learned to categorize all the easy items first, followed by the medium items, and finally the hard items. Participants in the hard-to-easy training condition learned items in the reverse order. Post-training results showed that training in both conditions transferred to the classification of new melanoma and benign images. Participants in the easy-to-hard condition showed modest advantages both in the acquisition and retention of the melanoma diagnosis skills, but neither scheduling condition exhibited a gross advantage. The Ease values of the items predicted categorization accuracy after, but not before training, suggesting that the Ease algorithm is a promising tool for optimizing medical training in visual categorization.

Inversion effects in the expert classification of mammograms and faces.

A hallmark of a perceptual expert is the ability to detect and categorize stimuli in their domain of expertise after brief exposure. For example, expert radiologists can differentiate between "abnormal" and "normal" mammograms after a 250 ms exposure. It has been speculated that rapid detection depends on a global analysis referred to as holistic perception. Holistic processing in radiology seems similar to holistic perception in which a stimulus like a face is perceived as an integrated whole, not in terms of its individual features. Holistic processing is typically subject to inversion effects in which the inverted image is harder to process/recognize. Is radiological perception similarly subject to inversion effects? Eleven experienced radiologists (> 5 years of radiological experience) and ten resident radiologists (< 5 years of radiological experience) judged upright and inverted bilateral mammograms as "normal" or "abnormal". For comparison, the same participants judged whether upright and inverted faces were "happy" or "neutral". We obtained the expected inversion effect for faces. Expression discrimination was superior for upright faces. For mammograms, experienced radiologists exhibited a similar inversion effect, showing higher accuracy for upright than for inverted mammograms. Less experienced radiology residents performed more poorly than experienced radiologists and demonstrated no inversion effect with mammograms. These results suggest that the ability to discriminate normal from abnormal mammograms is a form of learned, holistic processing.

Inversion Impairs Expert Budgerigar Identity Recognition: A Face-Like Effect for a Nonface Object of Expertise.

The face-inversion effect is the finding that picture-plane inversion disproportionately impairs face recognition compared to object recognition and is now attributed to greater orientation-sensitivity of holistic processing for faces but not common objects. Yet, expert dog judges have showed similar recognition deficits for inverted dogs and inverted faces, suggesting that holistic processing is not specific to faces but to the expert recognition of perceptually similar objects. Although processing changes in expert object recognition have since been extensively documented, no other studies have observed the distinct recognition deficits for inverted objects-of-expertise that people as face experts show for faces. However, few studies have examined experts who recognize individual objects similar to how people recognize individual faces. Here we tested experts who recognize individual budgerigar birds. The effect of inversion on viewpoint-invariant budgerigar and face recognition was compared for experts and novices. Consistent with the face-inversion effect, novices showed recognition deficits for inverted faces but not for inverted budgerigars. By contrast, experts showed equal recognition deficits for inverted faces and budgerigars. The results are consistent with the hypothesis that processes underlying the face-inversion effect are specific to the expert individuation of perceptually similar objects.

The "parts and wholes" of face recognition: A review of the literature.

It has been claimed that faces are recognized as a "whole" rather than by the recognition of individual parts. In a paper published in the Quarterly Journal of Experimental Psychology in 1993, Martha Farah and I attempted to operationalize the holistic claim using the part/whole task. In this task, participants studied a face and then their memory presented in isolation and in the whole face. Consistent with the holistic view, recognition of the part was superior when tested in the whole-face condition compared to when it was tested in isolation. The "whole face" or holistic advantage was not found for faces that were inverted, or scrambled, nor for non-face objects, suggesting that holistic encoding was specific to normal, intact faces. In this paper, we reflect on the part/whole paradigm and how it has contributed to our understanding of what it means to recognize a face as a "whole" stimulus. We describe the value of part/whole task for developing theories of holistic and non-holistic recognition of faces and objects. We discuss the research that has probed the neural substrates of holistic processing in healthy adults and people with prosopagnosia and autism. Finally, we examine how experience shapes holistic face recognition in children and recognition of own- and other-race faces in adults. The goal of this article is to summarize the research on the part/whole task and speculate on how it has informed our understanding of holistic face processing.