Facilitation and interference are asymmetric in holistic face processing.

A hallmark of face specificity is holistic processing. It is typically measured by paradigms such as the part-whole and composite tasks. However, these tasks show little evidence for common variance, so a comprehensive account of holistic processing remains elusive. One aspect that varies between tasks is whether they measure facilitation or interference from holistic processing. In this study, we examined facilitation and interference in a single paradigm to determine the way in which they manifest during a face perception task. Using congruent and incongruent trials in the complete composite face task, we found that these two aspects are asymmetrically influenced by the location and cueing probabilities of the target facial half, suggesting that they may operate somewhat independently. We argue that distinguishing facilitation and interference has the potential to disentangle mixed findings from different popular paradigms measuring holistic processing in one unified framework.

Effects of masculinity vs. femininity on competence judgement of politician faces and election outcome prediction.

First impressions of politician faces can be effective in predicting election outcomes, based on perceived competence from candidate photographs. However, it remains unclear whether such effects arose from facial features or other non-facial information present in the photographs (e.g. hairstyles, clothes, or poses). In four pre-registered studies, participants completed two tasks in a counter-balanced order: rating competence of individually presented faces and predicting election outcome of each pair of winner and runner-up faces. We examined competence judgment and election outcome prediction on faces from male politicians depicted on original portraits (Experiment 1), or on computer-generated faces with facial features extracted from the portraits (Experiment 2). The faces were then either masculinized or feminized (Experiments 3 and 4). We found that competence ratings were significantly higher for winners than runners-up and that winners were more likely predicted to win the elections than runners-up in all but Experiment 4, where faces of the winners were feminized and faces of the runners-up were masculinized. Regardless of facial feature changes, correlations were found between competence ratings and election outcome prediction. These findings suggest that facial features are critical for evaluating competence and predicting election outcome, and that masculine features may enhance stereotypical leadership impressions.

The role of implicit social bias on holistic processing of out-group faces.

Although faces of in-group members are generally thought to be processed holistically, there are mixed findings on whether holistic processing remains robust for faces of out-group members and what factors contribute to holistic processing of out-group faces. This study examined how implicit social bias, experience with out-group members, and ability to process in-group faces holistically might predict the magnitude of holistic processing for faces of two out-groups: other-race and other-age groups. In Experiment 1, Caucasian participants viewed Caucasian (own-race) and East Asian (other-race) faces. In Experiment 2, young adult participants viewed young adult (own-age) and baby (other-age) faces. Each participant completed a composite task with in-group and out-group faces, an implicit association test, and questionnaires about their experience with in-group and out-group members. We found that while the participants had relatively extensive experience with the other-race group, they had limited experience with the other-age group. Nonetheless, implicit social bias was found to positively predict the magnitude of holistic processing for both other-race and other-age faces. Exploratory analyses on the interactions among the predictors suggest that the effect of implicit social bias was primarily observed in participants with strong holistic processing ability of in-group faces but with low level of experience with members of the out-groups. These findings suggest that observers utilize different kinds of information when processing out-group faces, and that social features, such as race or age, are incorporated to influence how out-group faces are processed efficiently.

Preference at First Sight: Effects of Shape and Font Qualities on Evaluation of Object-Word Pairs.

Subjective preferences for visual qualities of shapes and fonts have been separately reported. Such preferences are often similarly attributed to factors such as aesthetic impressions, attributed meaning from the visual properties, or processing fluency. Because shapes and fonts were rarely studied together, we investigated whether these qualities had a similar impact on preference judgment of object-word pairs. Each pair consisted of an abstract object with either preferred or disliked shape qualities and a pseudoword with either preferred or disliked font qualities. We found that only shape qualities, but not font qualities, influenced preference ratings of the object-word pairs, with higher preferences for pairs with preferred than disliked shapes. Moreover, eye movement results indicated that while participants fixated the word before the object, their prolonged fixation on the object when first attending to it might have contributed to the preference ratings. Nonetheless, other measures, including response times, total fixation numbers, and total dwell time, showed different patterns for shape and font qualities, revealing that participants attended more to objects with preferred than disliked shapes, and to words with disliked than preferred fonts. Taken together, these results suggest that shape and font qualities have differential influences on preferences and processing of objects and words.

Rapid category selectivity for animals versus man-made objects: An N2pc study.

Visual recognition occurs rapidly at multiple categorization levels, including the superordinate level (e.g., animal), basic level (e.g., cat), or exemplar level (e.g., my cat). Visual search for animals is faster than for man-made objects, even when the images from those categories have comparable gist statistics (i.e., low- or mid-level visual information), which suggests that higher-level, conceptual influences may support this search advantage for animals. However, it remains unclear whether the search advantage can be explained in part by early visual search processes via the N2pc ERP component, which emerges earlier than behavioral responses, across different categorization levels. Participants searched for 1) an exact image (e.g., a specific squirrel image, Exemplar-level Search), 2) any images of an item (e.g., any squirrels, Basic-level Search), or 3) any items in a category (e.g., any animals, Superordinate-level Search). In addition to Target Present trials, Foil trials measured involuntary attentional selection of task-irrelevant images related to the targets (e.g., other squirrel images when searching for a specific squirrel image, or other animals when searching for squirrels). ERP results revealed 1) a larger N2pc amplitude during Foil trials in Exemplar-level Search for animals than man-made objects, and 2) faster onset latencies for animal search than man-made object search across all categorization levels. These results suggest that the search advantage for animals over man-made objects emerges early, and that attentional selection is more biased toward the basic-level (e.g., squirrel) for animals than for man-made objects during visual search.

The effect of implicit racial bias on recognition of other-race faces.

Previous research has established a possible link between recognition performance, individuation experience, and implicit racial bias of other-race faces. However, it remains unclear how implicit racial bias might influence other-race face processing in observers with relatively extensive experience with the other race. Here we examined how recognition of other-race faces might be modulated by observers' implicit racial bias, in addition to the effects of experience and face recognition ability. Caucasian participants in a culturally diverse city completed a memory task for Asian and Caucasian faces, an implicit association test, a questionnaire assessing experience with Asians and Caucasians, and a face recognition ability test. As expected, recognition performance for Asian faces was positively predicted by increased face recognition ability, and experience with Asians. More importantly, it was also negatively predicted by increased positive bias towards Asians, which was modulated by an interaction between face recognition ability and implicit bias, with the effect of implicit bias observed predominantly in observers with high face recognition ability. Moreover, the positions of the first two fixations when participants learned the other-race faces were affected by different factors, with the first fixation modulated by the effect of experience and the second fixation modulated by the interaction between implicit bias and face recognition ability. Taken together, these findings suggest the complexity in understanding the perceptual and socio-cognitive influences on the other-race effect, and that observers with high face recognition ability may more likely evaluate racial features involuntarily when recognizing other-race faces.

Flexible face processing: Holistic processing of facial identity is modulated by task-irrelevant facial expression.

Holistic processing is a hallmark of face perception and has been observed separately for facial identity and expression. While the identity of a face remains constant regardless of any changes in facial expressions, to what extent is holistic processing of facial identity affected by task-irrelevant facial expressions? If holistic processing is flexible and integrates both identity and expression information, the magnitude of holistic processing of facial identity may be systematically modulated by different facial expressions, due to either visual or emotional differences among the expressions. In Experiment 1, participants matched the identities of target halves of two sequentially presented face composites, with both composites showing either positive (happy) or negative (angry) expressions. The presentation duration for the test composite was either short (200 ms) or long (until a response). With a short presentation duration, the magnitude of holistic processing of identity for happy and angry composites was comparable. In contrast, with a long presentation duration, holistic processing of identity was reduced for angry compared with happy face composites. Experiment 2 replicated the results and showed reduced holistic processing of identity for face composites with either angry or neutral expressions, compared with happy expressions, given a long presentation duration. Because the modulation of facial expressions on holistic processing of facial identity was observed with long, but not short, presentation durations, these results suggest that such influence is unlikely solely due to visual differences, but may instead arise from cognitive evaluation of the emotions conveyed by facial expressions.

Roles of Category, Shape, and Spatial Frequency in Shaping Animal and Tool Selectivity in the Occipitotemporal Cortex.

Does the nature of representation in the category-selective regions in the occipitotemporal cortex reflect visual or conceptual properties? Previous research showed that natural variability in visual features across categories, quantified by image gist statistics, is highly correlated with the different neural responses observed in the occipitotemporal cortex. Using fMRI, we examined whether category selectivity for animals and tools would remain, when image gist statistics were comparable across categories. Critically, we investigated how category, shape, and spatial frequency may contribute to the category selectivity in the animal- and tool-selective regions. Female and male human observers viewed low- or high-passed images of round or elongated animals and tools that shared comparable gist statistics in the main experiment, and animal and tool images of naturally varied gist statistics in a separate localizer. Univariate analysis revealed robust category-selective responses for images with comparable gist statistics across categories. Successful classification for category (animals/tools), shape (round/elongated), and spatial frequency (low/high) was also observed, with highest classification accuracy for category. Representational similarity analyses further revealed that the activation patterns in the animal-selective regions were most correlated with a model that represents only animal information, whereas the activation patterns in the tool-selective regions were most correlated with a model that represents only tool information, suggesting that these regions selectively represent information of only animals or tools. Together, in addition to visual features, the distinction between animal and tool representations in the occipitotemporal cortex is likely shaped by higher-level conceptual influences such as categorization or interpretation of visual inputs.SIGNIFICANCE STATEMENT Since different categories often vary systematically in both visual and conceptual features, it remains unclear what kinds of information determine category-selective responses in the occipitotemporal cortex. To minimize the influences of low- and mid-level visual features, here we used a diverse image set of animals and tools that shared comparable gist statistics. We manipulated category (animals/tools), shape (round/elongated), and spatial frequency (low/high), and found that the representational content of the animal- and tool-selective regions is primarily determined by their preferred categories only, regardless of shape or spatial frequency. Our results show that category-selective responses in the occipitotemporal cortex are influenced by higher-level processing such as categorization or interpretation of visual inputs, and highlight the specificity in these category-selective regions.

Category selectivity for animals and man-made objects: Beyond low- and mid-level visual features.

Distinct concepts, such as animate and inanimate entities, comprise vast and systematic differences in visual features. While observers search for animals faster than man-made objects, it remains unclear to what extent visual or conceptual information contributes to such differences in visual search performance. Previous studies demonstrated that visual features are likely sufficient for distinguishing animals from man-made objects. Across four experiments, we examined whether low- or mid-level visual features solely contribute to the search advantage for animals by using images of comparable visual shape and gist statistics across the categories. Participants searched for either animal or man-made object targets on a multiple-item display with fruit/vegetable distractors. We consistently observed faster search performance for animal than man-made object targets. Such advantage for animals was unlikely affected by differences in low- or mid-level visual properties or whether observers were either explicitly told about the specific targets or not explicitly told to search for either animals or man-made objects. Instead, the efficiency in categorizing animals over man-made objects appeared to contribute to the search advantage. We suggest that apart from low- or mid-level visual differences among categories, higher-order processes, such as categorization via interpreting visual inputs and mapping them onto distinct concepts, may be critical in shaping category-selective effects.

Emergence of the benefits and costs of grouping for visual search.

The present study investigated how grouping related items leads to the emergence of benefits (facilitation when related items are search targets) and costs (interference when related items are distractors) in visual search. Participants integrated different views (related items) of a novel Lego object via (a) assembling the object, (b) disassembling the object, or (c) sitting quietly without explicit instructions. An omnibus ANOVA revealed that neural responses (N2pc ERP) for attentional selection increased between pretest to posttest regardless of the training condition when a specific target view appeared (benefit) and when a nontarget view from the same object as the target view appeared (cost). Bonferroni-corrected planned comparisons revealed that assembling the object (but not disassembling the object or no training) had a significant impact from pretest to posttest, although the ANOVA did not reveal any interaction effects, suggesting that the effects might not differ across training conditions. This study is one of the first to demonstrate the emergence of the costs and benefits of grouping novel targets on visual search efficiency.

Increased experience amplifies the activation of task-irrelevant category representations.

Prior research has demonstrated the benefits (i.e., task-relevant attentional selection) and costs (i.e., task-irrelevant attentional capture) of prior knowledge on search for an individual target or multiple targets from a category. This study investigated whether the level of experience with particular categories predicts the degree of task-relevant and task-irrelevant activation of item and category representations. Adults with varying levels of dieting experience (measured via 3 subscales of Disinhibition, Restraint, Hunger; Stunkard & Messick, Journal of Psychosomatic Research, 29(1), 71-83, 1985) searched for targets defined as either a specific food item (e.g., carrots), or a category (i.e., any healthy or unhealthy food item). Apart from the target-present trials, in the target-absent "foil" trials, when searching for a specific item (e.g., carrots), irrelevant items from the target's category (e.g., squash) were presented. The ERP (N2pc) results revealed that the activation of task-relevant representations (measured via Exemplar and Category N2pc amplitudes) did not differ based on the degree of experience. Critically, however, increased dieting experience, as revealed by lower Disinhibition scores, predicted activation of task-irrelevant representations (i.e., attentional capture of foils from the target item category). Our results suggest that increased experience with particular categories encourages the rapid activation of category representations even when category information is task irrelevant, and that the N2pc in foil trials could potentially serve as an indication of experience level in future studies on categorization.

Visual appearance interacts with conceptual knowledge in object recognition.

Objects contain rich visual and conceptual information, but do these two types of information interact? Here, we examine whether visual and conceptual information interact when observers see novel objects for the first time. We then address how this interaction influences the acquisition of perceptual expertise. We used two types of novel objects (Greebles), designed to resemble either animals or tools, and two lists of words, which described non-visual attributes of people or man-made objects. Participants first judged if a word was more suitable for describing people or objects while ignoring a task-irrelevant image, and showed faster responses if the words and the unfamiliar objects were congruent in terms of animacy (e.g., animal-like objects with words that described human). Participants then learned to associate objects and words that were either congruent or not in animacy, before receiving expertise training to rapidly individuate the objects. Congruent pairing of visual and conceptual information facilitated observers' ability to become a perceptual expert, as revealed in a matching task that required visual identification at the basic or subordinate levels. Taken together, these findings show that visual and conceptual information interact at multiple levels in object recognition.

The resilience of object predictions: early recognition across viewpoints and exemplars.

Recognition of everyday objects can be facilitated by top-down predictions. We have proposed that these predictions are derived from rudimentary image information, or gist, extracted rapidly from the low spatial frequencies (LSFs) (Bar Journal of Cognitive Neuroscience 15: 600­609, 2003). Because of the coarse nature of LSF representations, we hypothesized here that such predictions can accommodate changes in viewpoint as well as facilitate the recognition of visually similar objects. In a repetition-priming task, we indeed observed significant facilitation of target recognition that was primed by LSF objects across moderate viewpoint changes, as well as across visually similar exemplars. These results suggest that the LSF representations are specific enough to activate accurate predictions, yet flexible enough to overcome small changes in visual appearance. Such gist representations facilitate object recognition by accommodating changes in visual appearance due to viewing conditions, and help generalize from familiar to novel exemplars.

Visual prediction and perceptual expertise.

Making accurate predictions about what may happen in the environment requires analogies between perceptual input and associations in memory. These elements of predictions are based on cortical representations, but little is known about how these processes can be enhanced by experience and training. On the other hand, studies on perceptual expertise have revealed that the acquisition of expertise leads to strengthened associative processing among features or objects, suggesting that predictions and expertise may be tightly connected. Here we review the behavioral and neural findings regarding the mechanisms involving prediction and expert processing, and highlight important possible overlaps between them. Future investigation should examine the relations among perception, memory and prediction skills as a function of expertise. The knowledge gained by this line of research will have implications for visual cognition research, and will advance our understanding of how the human brain can improve its ability to predict by learning from experience.

Predictive feedback and conscious visual experience.

The human brain continuously generates predictions about the environment based on learned regularities in the world. These predictions actively and efficiently facilitate the interpretation of incoming sensory information. We review evidence that, as a result of this facilitation, predictions directly influence conscious experience. Specifically, we propose that predictions enable rapid generation of conscious percepts and bias the contents of awareness in situations of uncertainty. The possible neural mechanisms underlying this facilitation are discussed.

Beliefs alter holistic face processing ... if response bias is not taken into account.

The composite paradigm is widely used to quantify holistic processing (HP) of faces, but there is debate regarding the appropriate design (partial vs. complete) and measures in this task. Here, we argue that some operational definitions of HP are problematic because they are sensitive to top-down influences, even though the underlying concept is assumed to be cognitively impenetrable. In Experiment 1, we told one group of participants that the target face half would remain the same on 75% of trials and another group that it would change on 75% of trials. The true proportion of same/different trials was 50%-groups only differed in their beliefs about the target halves. In Experiment 2, we manipulated the actual proportion of same/different trials in the experiment (75% of trials were the same for one group; 75% of trials were different for another group) but did not give explicit instructions about proportions. In both experiments, these manipulations influenced response biases that altered partial design measures of HP while the complete design measure was unaffected. We argue that the partial design should be abandoned because it has poor construct validity.

Holistic processing predicts face recognition.

The concept of holistic processing is a cornerstone of face-recognition research. In the study reported here, we demonstrated that holistic processing predicts face-recognition abilities on the Cambridge Face Memory Test and on a perceptual face-identification task. Our findings validate a large body of work that relies on the assumption that holistic processing is related to face recognition. These findings also reconcile the study of face recognition with the perceptual-expertise work it inspired; such work links holistic processing of objects with people's ability to individuate them. Our results differ from those of a recent study showing no link between holistic processing and face recognition. This discrepancy can be attributed to the use in prior research of a popular but flawed measure of holistic processing. Our findings salvage the central role of holistic processing in face recognition and cast doubt on a subset of the face-perception literature that relies on a problematic measure of holistic processing.

Does temporal integration of face parts reflect holistic processing?

We examined whether temporal integration of face parts reflects holistic processing or response interference. Participants learned to name two faces "Fred" and two "Bob." At test, the top and bottom halves of different faces formed composites and were presented briefly separated in time. Replicating prior findings (Singer & Sheinberg, Vision Research, 46, 1838-1847, 2006), naming of the target half for aligned composites was slowed when the irrelevant half was from a face with a different name rather than from the original face. However, no interference was observed when the irrelevant half had a name identical to the name of the target half but came from a different learned face, arguing against a true holistic effect. Instead, response interference was obtained when the target half briefly preceded the irrelevant half. Experiment 2 confirmed a double dissociation of holistic processing versus response interference for intact faces versus temporally separated face halves, suggesting that simultaneous presentation of facial information is critical for holistic processing.

Selective interference on the holistic processing of faces in working memory.

Faces and objects of expertise compete for early perceptual processes and holistic processing resources (Gauthier, Curran, Curby, & Collins, 2003). Here, we examined the nature of interference on holistic face processing in working memory by comparing how various types of loads affect selective attention to parts of face composites. In dual tasks, all loads impaired overall performance on face judgment compared with no load. However, a face load reduced holistic face processing (Experiment 1) whereas an object load did not, regardless of expertise (Experiments 2 and 3). Also, 2 types of faces produced asymmetrical interference on each other (Experiment 4), refuting the hypothesis that any faces would produce equal interference. Thus, the interference on holistic face processing in working memory does not depend on overlap in expertise or face processing, but may be modulated by limitations in encoding or maintenance of highly similar representations.

Dissociating the effects of angular disparity and image similarity in mental rotation and object recognition.

Performance is often impaired linearly with increasing angular disparity between two objects in tasks that measure mental rotation or object recognition. But increased angular disparity is often accompanied by changes in the similarity between views of an object, confounding the impact of the two factors in these tasks. We examined separately the effects of angular disparity and image similarity on handedness (to test mental rotation) and identity (to test object recognition) judgments with 3-D novel objects. When similarity was approximately equated, an effect of angular disparity was only found for handedness but not identity judgments. With a fixed angular disparity, performance was better for similar than dissimilar image pairs in both tasks, with a larger effect for identity than handedness judgments. Our results suggest that mental rotation involves mental transformation procedures that depend on angular disparity, but that object recognition is predominately dependent on the similarity of image features.