Why faces are and are not special: an effect of expertise

Recognition memory for faces is hampered much more by inverted presentation than is memory for any other material so far examined. The present study demonstrates that faces are not unique with regard to this vulnerability to inversion. The experiments also attempt to isolate the source of the inversion effect. In one experiment, use of stimuli (landscapes) in which spatial relations among elements are potentially important distinguishing features is shown not to guarantee a large inversion effect. Two additional experiments show that for dog experts sufficiently knowledgeable to individuate dogs of the same breed, memory for photographs of dogs of that breed is as disrupted by inversion as is face recognition. A final experiment indicates that the effect of orientation on memory for faces does not depend on inability to identify single features of these stimuli upside down. These experiments are consistent with the view that experts represent items in memory in terms of distinguishing features of a different kind than do novices. Speculations as to the type of feature used and neuropsychological and developmental implications of this accomplishment are offered.     

真实记忆与虚假记忆中的生命性效应研究

本研究采用DRM范式,探讨了生命性对真实和虚假记忆的影响。实验1使用类别呈现词语强化类别加工,实验2伪随机呈现词语弱化类别加工并进行即时及延时探测。结果发现：（1）当强化类别加工时,生命性和类别对击中率有相类似的促进效应;（2）当弱化类别加工并进行即时探测时,生命性对击中率的促进作用最强;（3）类别效应促进真实记忆和虚假记忆,但生命性效应仅促进了真实记忆,而不影响虚假记忆的产生;（4）在即时与延时探测中均发现类别效应和生命性效应。本研究证明了：（1）生命性效应的作用机制不同于类别效应;（2）生命性效应对真实和虚假记忆的作用机制不同;（3）类别效应和生命性效应的存在时效长达24小时,但是生命性效应的衰退速度较快。     

The inversion effect reveals species differences in face processing

Face recognition is a complex skill that requires the integration of facial features across the whole face, e.g., holistic processing. It is unclear whether, and to what extent, other species process faces in a manner that is similar to humans. Previous studies on the inversion effect, a marker of holistic processing, in nonhuman primates have revealed mixed results in part because many studies have failed to include alternative image categories necessary to understand whether the effects are truly face-specific. The present study re-examined the inversion effect in rhesus monkeys and chimpanzees using comparable testing methods and a variety of high quality stimuli including faces and nonfaces. The data support an inversion effect in chimpanzees only for conspecifics' faces (expert category), suggesting face-specific holistic processing similar to humans. Rhesus monkeys showed inversion effects for conspecifics, but also for heterospecifics' faces (chimpanzees), and nonfaces images (houses), supporting important species differences in this simple test of holistic face processing.     

Investigating the effects of inversion on configural processing with an audiovisual temporal-order judgment task

Research has shown that inversion is more detrimental to the perception of faces than to the perception of other types of visual stimuli. Inverting a face results in an impairment of configural information processing that leads to slowed early face processing and reduced accuracy when performance is tested in face recognition tasks. We investigated the effects of inverting speech and non-speech stimuli on audiovisual temporal perception. Upright and inverted audiovisual video clips of a person uttering syllables (experiments 1 and 2), playing musical notes on a piano (experiment 3), or a rhesus monkey producing vocalisations (experiment 4) were presented. Participants made unspeeded temporal-order judgments regarding which modality stream (auditory or visual) appeared to have been presented first. Inverting the visual stream did not have any effect on the sensitivity of temporal discrimination responses in any of the four experiments, thus implying that audiovisual temporal integration is resilient to the effects of orientation in the picture plane. By contrast, the point of subjective simultaneity differed significantly as a function of orientation only for the audiovisual speech stimuli but not for the non-speech stimuli or monkey calls. That is, smaller auditory leads were required for the inverted than for the upright-visual speech stimuli. These results are consistent with the longer processing latencies reported previously when human faces are inverted and demonstrates that the temporal perception of dynamic audiovisual speech can be modulated by changes in the physical properties of the visual speech (ie by changes in orientation).     

Effects of geometric distortions on face-recognition performance

The importance of 'configural' processing for face recognition is now well established, but it remains unclear precisely what it entails. Through four experiments we attempted to clarify the nature of configural processing by investigating the effects of various affine transformations on the recognition of familiar faces. Experiment 1 showed that recognition was markedly impaired by inversion of faces, somewhat impaired by shearing or horizontally stretching them, but unaffected by vertical stretching of faces to twice their normal height. In experiment 2 we investigated vertical and horizontal stretching in more detail, and found no effects of either transformation. Two further experiments were performed to determine whether participants were recognising stretched faces by using configural information. Experiment 3 showed that nonglobal vertical stretching of faces (stretching either the top or the bottom half while leaving the remainder undistorted) impaired recognition, implying that configural information from the stretched part of the face was influencing the process of recognition--ie that configural processing involves global facial properties. In experiment 4 we examined the effects of Gaussian blurring on recognition of undistorted and vertically stretched faces. Faces remained recognisable even when they were both stretched and blurred, implying that participants were basing their judgments on configural information from these stimuli, rather than resorting to some strategy based on local featural details. The tolerance of spatial distortions in human face recognition suggests that the configural information used as a basis for face recognition is unlikely to involve information about the absolute position of facial features relative to each other, at least not in any simple way.     

Learning the moves: the effect of familiarity and facial motion on person recognition across large changes in viewing format

Familiarity with a face or person can support recognition in tasks that require generalization to novel viewing contexts. Using naturalistic viewing conditions requiring recognition of people from face or whole body gait stimuli, we investigated the effects of familiarity, facial motion, and direction of learning/test transfer on person recognition. Participants were familiarized with previously unknown people from gait videos and were tested on faces (experiment 1a) or were familiarized with faces and were tested with gait videos (experiment 1b). Recognition was more accurate when learning from the face and testing with the gait videos, than when learning from the gait videos and testing with the face. The repetition of a single stimulus, either the face or gait, produced strong recognition gains across transfer conditions. Also, the presentation of moving faces resulted in better performance than that of static faces. In experiment 2, we investigated the role of facial motion further by testing recognition with static profile images. Motion provided no benefit for recognition, indicating that structure-from-motion is an unlikely source of the motion advantage found in the first set of experiments.     

Mental rotation of faces

The effect of orientation upon face recognition was explored in two experiments, which used a procedure adapted from the mental rotation literature. In the first experiment, a linear increase in the RT of same-different judgments was found as the second of a pair of sequentially presented faces was rotated away from the vertical. Also, it was found that the effect of changing facial expression did not interact with orientation. In the second experiment, a linear relationship between RT and orientation was found in a task involving the recognition of famous faces. This recognition task was found to be more affected by inversion than was an expression classification task. These results are interpreted as evidence against the view that inverted faces are processed in a qualitatively different manner from upright faces, and are also inconsistent with the hypothesis that inversion makes faces difficult to recognize because facial expression cannot be extracted from an inverted face.     

Recognizing rotated faces and Greebles: What properties drive the face inversion effect?

The fact that faces are strongly affected by picture-plane inversion has often been cited as evidence for face-specific mechanisms. It is unclear, however, whether this “face inversion effect” is driven by properties shared by faces or whether the effect is specific to faces as a category. To address this issue, we compared the recognition of faces and novel Greebles, which were specifically matched to faces along various stimulus dimensions. In two experiments, participants were required to name individual faces or Greebles following training at either single or multiple orientations. We found that performance systematically decreased with increasing misorientation from either the upright (Experiment 1) or nearest trained orientation (Experiment 2). Importantly, the magnitude of this orientation effect was similar for both faces and Greebles. Taken together, these results suggest that the face inversion effect may be a consequence of the visual homogeneity of the stimulus category, regardless of the category.     

Seeing faces as objects: no face inversion effect with geometrical discrimination

Inversion dramatically impairs face perception, recognition, and discrimination. Yet it does not interfere with the ability to make precise estimates of facial feature distances. To investigate this discontinuity between facial feature distance estimation and general perception and recognition, we assessed the effect of inversion on the discrimination of differences in facial compression and elongation or expansion using geometrically distorted faces. The results clearly showed that geometrical face discrimination is not subject to the traditional face inversion effect and did not show a benefit for natural faces. Although discrimination thresholds were not affected by inversion, response times to the distance judgments were faster with inversion, especially when the inverted faces contained natural configurations. Based on these counterintuitive results, we suggest that participants used analytical processing to do the discrimination task. Moreover, we suggest that the depth with which a face is holistically encoded depends on the nature of the task, face orientation, and similarity between a face and the prototypical face template.     

The effects of inversion and familiarity on face versus body cues to person recognition

Extensive research has focused on face recognition, and much is known about this topic. However, much of this work seems to be based on an assumption that faces are the most important aspect of person recognition. Here we test this assumption in two experiments. We show that when viewers are forced to choose, they do use the face more than the body, both for familiar (trained) person recognition and for unfamiliar person matching. However, we also show that headless bodies are recognized and matched with very high accuracy. We further show that processing style may be similar for faces and bodies, with inversion effects found in all cases (bodies with heads, faces alone and bodies alone), and evidence that mismatching bodies and heads causes interference. We suggest that recent findings of no inversion effect when stimuli are headless bodies may have been obtained because the stimuli led viewers to focus on nonbody aspects (e.g., clothes) or because pose and identity tasks led to somewhat different processing. Our results are consistent with holistic processing for bodies as well as faces. (PsycINFO Database Record (c) 2012 APA, all rights reserved).     

A unified account of the effects of distinctiveness, inversion, and race in face recognition

A framework is outlined in which individual faces are assumed to be encoded as a point in a multidimensional space, defined by dimensions that serve to discriminate faces. It is proposed that such a framework can account for the effects of distinctiveness, inversion, and race on recognition of faces. Two specific models within this framework are identified: a norm-based coding model, in which faces are encoded as vectors from a population norm or prototype; and a purely exemplar-based model. Both models make similar predictions, albeit in different ways, concerning the interactions between the effects of distinctiveness, inversion and race. These predictions were supported in five experiments in which photographs of faces served as stimuli. The norm-based coding version and the exemplar-based version of the framework cannot be distinguished on the basis of the experiments reported, but it is argued that a multidimensional space provides a useful heuristic framework to investigate recognition of faces. Finally, the relationship between the specific models is considered and an implementation in terms of parallel distributed processing is briefly discussed.     

Towards an exemplar model of face processing: the effects of race and distinctiveness.

Valentine (1991a, 1991b) described a theoretical framework for face recognition in which faces are encoded as locations in a multidimensional space. It was argued that this approach could provide a unified account of the effects of distinctiveness, inversion, and race on face recognition. In this paper we evaluate the ability of this theoretical framework to account for the effects of distinctiveness and race in four experiments in which white British and Japanese faces served as stimuli and both white British and Japanese students acted as subjects. In a recognition memory experiment the expected "own-race bias" was observed as a Race of Subject x Race of Face interaction. Distinctive faces were recognized more accurately than typical faces, but the effect of distinctiveness did not interact with the race of face or the race of subject. Typical faces were classified faster than distinctive faces in a task in which intact faces had to be distinguished from jumbled faces, as found in earlier work, and the effect of distinctiveness did not interact with the race of face or race of subject. In contrast, a task in which subjects classified faces according to their race did show a greater effect of distinctiveness for own-race faces. The results are discussed in relation to the two specific models within the multidimensional space framework identified by Valentine (1991a): a purely exemplar-based model and a norm-based coding model. It is argued that these results are more easily accommodated in terms of a purely exemplar-based model. Some conceptual problems in applying the norm-based coding model to the effect of race are discussed.     

Discrimination of faces and houses by rhesus monkeys: the role of stimulus expertise and rotation angle

The face inversion effect, or impaired recognition of upside down compared to upright faces, is used as a marker for the configural processing of faces in primates. The inversion effect in humans and chimpanzees is strongest for categories of stimuli for which subjects have considerable expertise, primarily conspecifics’ faces. Moreover, discrimination performance decreases linearly as faces are incrementally rotated from upright to inverted. This suggests that rotated faces must be transformed, or normalized back into their most typical viewpoint before configural processing can ensue, and the greater the required normalization, the greater the likelihood of errors resulting. Previous studies in our lab have demonstrated a general face inversion effect in rhesus monkeys that was not influenced by expertise. Therefore, the present study examined the influence of rotation angle on the visual perception of face and nonface stimuli that varied in their level of expertise to further delineate the processes underlying the inversion effect in rhesus monkeys. Five subjects discriminated images in five orientation angles. Results showed significant linear impairments for all stimulus categories, including houses. However, compared to the upright images, only rhesus faces resulted in worse performance at rotation angles greater than 45°, suggesting stronger configural processing for stimuli for which subjects had the greatest expertise.     

The body-inversion effect

Researchers argue that faces are recognized via the configuration of their parts. An important behavioral finding supporting this claim is the face-inversion effect, in which inversion impairs recognition of faces more than nonface objects. Until recently, faces were the only class of objects producing the inversion effect for untrained individuals. This study investigated whether the inversion effect extends to human body positions, a class of objects whose exemplars are structurally similar to each other. Three experiments compared the recognition of upright and inverted faces, houses, and body positions using a forced-choice, same/different paradigm. For both reaction time and error data, the recognition of possible human body postures was more affected by inversion than the recognition of houses. Further, the recognition of possible human body postures and recognition of faces showed similar effects of inversion. The inversion effect was diminished for impossible body positions that violated the biomechanical constraints of human bodies. These data suggest that human body positions, like faces, may be processed configurally by untrained viewers.     

The effects of facial expressions and tears on the speed of sex recognition

The goal of this research was to examine the effects of facial expressions on the speed of sex recognition. Prior research revealed that sex recognition of female angry faces was slower compared with male angry faces and that female happy faces are recognized faster than male happy faces. We aimed to replicate and extend the previous research by using different set of facial stimuli, different methodological approach and also by examining the effects of some other previously unexplored expressions (such as crying) on the speed of sex recognition. In the first experiment, we presented facial stimuli of men and women displaying anger, fear, happiness, sadness, crying and three control conditions expressing no emotion. Results showed that sex recognition of angry females was significantly slower compared with sex recognition in any other condition, while sad, crying, happy, frightened and neutral expressions did not impact the speed of sex recognition. In the second experiment, we presented angry, neutral and crying expressions in blocks and again only sex recognition of female angry expressions was slower compared with all other expressions. The results are discussed in a context of perceptive features of male and female facial configuration, evolutionary theory and social learning context.     

A look at how we look at others: Orientation inversion and photographic negation disrupt the perception of human bodies

Although disproportionate inversion effects have often been considered manifestations of the special processes recruited by upright faces, several papers using sequential matching tasks have reported that body postures also produce sizeable inversion effects. However, comparison of inversion effects observed with transient body postures and effects elicited by judgements of facial structure is complicated by qualitative differences between the stimuli and the tasks. Here we report a series of experiments that use attractiveness judgements to provide a better comparison of the effect of inversion as well as contrast negation on face and body perception. Significant effects of inversion and negation were observed for both face and body stimuli. While the magnitude of the inversion effects was broadly comparable, the negation effect was considerably larger for faces. These effects converge with evidence from cognitive neuroscience to suggest that both faces and bodies recruit similar orientation-specific processes distinct from processes used for generic objects.     

Discrimination of human and dog faces and inversion responses in domestic dogs (Canis familiaris)

Although domestic dogs can respond to many facial cues displayed by other dogs and humans, it remains unclear whether they can differentiate individual dogs or humans based on facial cues alone and, if so, whether they would demonstrate the face inversion effect, a behavioural hallmark commonly used in primates to differentiate face processing from object processing. In this study, we first established the applicability of the visual paired comparison (VPC or preferential looking) procedure for dogs using a simple object discrimination task with 2D pictures. The animals demonstrated a clear looking preference for novel objects when simultaneously presented with prior-exposed familiar objects. We then adopted this VPC procedure to assess their face discrimination and inversion responses. Dogs showed a deviation from random behaviour, indicating discrimination capability when inspecting upright dog faces, human faces and object images; but the pattern of viewing preference was dependent upon image category. They directed longer viewing time at novel (vs. familiar) human faces and objects, but not at dog faces, instead, a longer viewing time at familiar (vs. novel) dog faces was observed. No significant looking preference was detected for inverted images regardless of image category. Our results indicate that domestic dogs can use facial cues alone to differentiate individual dogs and humans and that they exhibit a non-specific inversion response. In addition, the discrimination response by dogs of human and dog faces appears to differ with the type of face involved.     

Local contrast and Pavlovian induction

Two experiments examined the effects of number and similarity of stimuli on local contrast. In the first experiment, local contrast effects differed in magnitude as a function of the similarity among stimuli; greater positive local contrast appeared when stimuli were less similar, though this effect sometimes reversed for very dissimilar stimuli. In the second experiment, both positive and negative local contrast appeared transiently during the course of training a discrimination including two quite dissimilar stimuli. When two new stimuli were added, both effects reappeared in several cases. The effects remained when the discrimination was rendered more difficult by substituting a new stimulus very similar to one of the original pair. These and other data suggest that local contrast depends on the same factors that produce Pavlovian induction; in the absence of an alternative account, Pavlov's interpretation may be useful in suggesting further research that will help identify the mechanisms involved in both classical and operant discrimination learning.     

Attention misplaced: the role of diagnostic features in the face-inversion effect

Inversion disproportionately impairs recognition of face stimuli compared to nonface stimuli arguably due to the holistic manner in which faces are processed. A qualification is put forward in which the first point fixated on is different for upright and inverted faces and this carries some of the face-inversion effect. Three experiments explored this possibility by using fixation crosses to guide attention to the eye or mouth region of the to-be-presented faces in different orientations. Recognition was better when the fixation cross appeared at the eye region than at the mouth region. The face-inversion effect was smaller when the eyes were cued than when the mouth was cued or when there was no cueing. The results suggest that the first facial feature attended to is important for accurate face recognition and this may carry some of the effects of inversion.