Detecting objects is easier than categorizing them

Two experiments compared performance in an object detection task, in which participants categorized photographs as objects and nonobject textures, and an object categorization task, in which photographs were categorized into basic-level categories. The basic-level categorization task was either easy (e.g., dogs vs. buses) or difficult (e.g., dogs vs. cats). Participants performed similarly in the detection and the easy-categorization tasks, but response times to the difficult-categorization task were slower. This latter finding is difficult to reconcile with the conclusions of Grill-Spector and Kanwisher (2005) who reported equivalent performance on detection and basic-level categorization tasks and took this as evidence that figure-ground segregation and basic-level categorization are mediated by the same mechanism.     

Detecting objects is easier than categorizing them

Two experiments compared performance in an object detection task, in which participants categorized photographs as objects and nonobject textures, and an object categorization task, in which photographs were categorized into basic-level categories. The basic-level categorization task was either easy (e.g., dogs vs. buses) or difficult (e.g., dogs vs. cats). Participants performed similarly in the detection and the easy-categorization tasks, but response times to the difficult-categorization task were slower. This latter finding is difficult to reconcile with the conclusions of Grill-Spector and Kanwisher (2005) Grill-Spector, G. and Kanwisher, N. 2005. Visual recognition: As soon as you know it is there, you know what it is. Psychological Science, 16: 152–160. [Crossref], [PubMed], [Web of Science ®] , [Google Scholar] who reported equivalent performance on detection and basic-level categorization tasks and took this as evidence that figure–ground segregation and basic-level categorization are mediated by the same mechanism.     

Effects of stimulus duration and choice delay on visual categorization in pigeons

We [Lazareva, O. F., Freiburger, K. L., & Wasserman, E. A. (2004). Pigeons concurrently categorize photographs at both basic and superordinate levels. Psychonomic Bulletin and Review, 11, 1111-1117] previously trained four pigeons to classify color photographs into their basic-level categories (cars, chairs, flowers, or people) or into their superordinate-level categories (natural or artificial). Here, we found that brief stimulus durations had the most detrimental effect on the basic-level discrimination of natural stimuli by the same pigeons. Increasing the delay between stimulus presentation and choice responding had greater detrimental effect on the basic-level discrimination than the superordinate-level discrimination. These results suggest that basic-level discriminations required longer stimulus durations and were more subject to forgetting than were superordinate-level discriminations. Additionally, categorization of natural stimuli required longer stimulus durations than categorization of artificial stimuli, but only at the basic level. Together, these findings suggest that basic-level categorization may not always be superior to superordinate-level categorization and provide additional evidence of a dissociation between natural and artificial stimuli in pigeons’ categorization.     

Subtle activation of a social categorization triggers group-level emotions

Previous research [Smith, E. R., Seger, C. R., & Mackie, D. M. (2007). Can emotions be truly group-level? Evidence regarding four conceptual criteria. Journal of Personality and Social Psychology, 93, 431-446] has demonstrated that when people are explicitly asked about the emotions they experience as members of a particular group, their reported emotions converge toward a profile typical for that group. Two studies demonstrate that the same type of convergence occurs when a group identity is made situationally salient through priming, without an explicit request to report group-level emotions. People who identify more strongly with the group converge more, and show more similarity between their group-primed emotions and explicitly reported group-level emotions. This research confirms that activating a social identity produces convergence for emotions as well as for attitudes and behaviors. It also suggests that some previous emotion research may have tapped group rather than individual-level emotions, potentially requiring some reconceptualization.     

Continuous dynamics in the real-time perception of race

Although the outcomes of race categorization have been studied in detail, the temporal dynamics of real-time processing of race remain elusive. We measured participants’ hand movements en route to one of two race-category alternatives by recording the streaming x, y coordinates of the computer mouse. Study 1 showed that, when categorizing White and Black computer-generated faces that featurally overlapped with the opposite race, mouse trajectories showed a continuous spatial attraction toward the opposite category. Moreover, these race-atypical White and Black targets induced spatial attraction effects that had different temporal signatures. Study 2 showed that, when categorizing real faces that varied along a continuum of racial ambiguity, graded increases in ambiguity led to corresponding increases in trajectories’ attraction to the opposite category and trajectories’ movement complexity. These studies provide evidence for temporally dynamic competition across perceptions of race, where simultaneously and partially-active race categories continuously evolve into single categorical outcomes over time. Moreover, the findings show how different social category cues may exert different dynamic patterns of influence over the real-time processing that culminates in categorizations of others.     

Salient Color Terms in Four Languages

Elicited lists of color terms were used to investigate the relative salience of basic and nonbasic color terms in four languages. Salience was operationalized in terms of frequency of mention and mean rank sequence of appearance on the lists. Primary basic terms were generally found to be the most salient, followed by derived basic and nonbasic terms, in that order. However, in some of the group lists the nonbasic terms beige, turquoise, navy blue and sky blue were found to have higher frequencies of mention and/or higher mean sequence ranks than some derived basic terms. The possible basicness of these terms is discussed.     

Do Humans and Deep Convolutional Neural Networks Use Visual Information Similarly for the Categorization of Natural Scenes?

The investigation of visual categorization has recently been aided by the introduction of deep convolutional neural networks (CNNs), which achieve unprecedented accuracy in picture classification after extensive training. Even if the architecture of CNNs is inspired by the organization of the visual brain, the similarity between CNN and human visual processing remains unclear. Here, we investigated this issue by engaging humans and CNNs in a two-class visual categorization task. To this end, pictures containing animals or vehicles were modified to contain only low/high spatial frequency (HSF) information, or were scrambled in the phase of the spatial frequency spectrum. For all types of degradation, accuracy increased as degradation was reduced for both humans and CNNs; however, the thresholds for accurate categorization varied between humans and CNNs. More remarkable differences were observed for HSF information compared to the other two types of degradation, both in terms of overall accuracy and image-level agreement between humans and CNNs. The difficulty with which the CNNs were shown to categorize high-passed natural scenes was reduced by picture whitening, a procedure which is inspired by how visual systems process natural images. The results are discussed concerning the adaptation to regularities in the visual environment (scene statistics); if the visual characteristics of the environment are not learned by CNNs, their visual categorization may depend only on a subset of the visual information on which humans rely, for example, on low spatial frequency information.     

Familiarity increases the accuracy of categorizing male sexual orientation

Although individual differences are known to influence numerous aspects of social perception, such as person memory and individuation, little is known about how such variations may affect social categorization. Extending prior research, the present study tested one potential moderator: familiarity with group members. Specifically, straight participants (n = 84) reported their real-life experiences with gay men and categorized faces as gay or straight. Results showed that participants who reported greater familiarity with gay men were significantly more sensitive, or accurate, in judging the sexual orientations of men from their faces. These results are discussed in terms of their theoretical implications for social perception and future research directions are outlined.     

Is social inhibition of return due to action co-representation?

When two individuals alternate reaching responses to visual targets presented on a shared workspace, one individual is slower to respond to targets occupying the same position as their partner’s previous response. This phenomenon is thought to be due to processes that inhibit the initiation of a movement to a location recently acted upon. However, two distinct forms of the inhibition account have been posited, one based on inhibition of an action, the other based on inhibition of an action and location. Furthermore, an additional recent explanation suggests the phenomenon is due to mechanisms that give rise to action congruency effects. Thus the three different theories differ in the degree to which action co-representation plays a role in the effect. The aim of the present work was to examine these competing accounts. Three experiments demonstrated that when identical actions are made, the effect is modulated by the configuration of the visual stimuli acted upon and the perceptual demands of the task. In addition, when the co-actors perform different actions to the same target, the effect is still observed. These findings support the hypothesis that this particular joint action phenomenon is generated via social cues that induce location-based inhibition of return rather than being due to shared motor co-representations.     

At face value: Categorization goals modulate vigilance for angry faces

The present research demonstrates that the attention bias to angry faces is modulated by how people categorize these faces. Since facial expressions contain psychologically meaningful information for social categorizations (i.e., gender, personality) but not for non-social categorizations (i.e., eye-color), angry facial expression should especially capture attention during social categorization tasks. Indeed, in three studies, participants were slower to name the gender of angry compared to happy or neutral faces, but not their color (blue or green; Study 1) or eye-color (blue or brown; Study 2). Furthermore, when different eye-colors were linked to a personality trait (introversion, extraversion) versus sensitivity to light frequencies (high, low), angry faces only slowed down categorizations when eye-color was indicative of a social characteristic (Study 3). Thus, vigilance for angry facial expressions is contingent on people's categorization goals, supporting the perspective that even basic attentional processes are moderated by social influences.     

Interracial contexts debilitate same-race face recognition

Social cognitive research has documented the integral role of social categories (e.g., race) in face processing. Activating a social category can lead perception and memory of faces to be biased in a category-consistent direction. The current research extends this past work, to test the hypothesis that making a social category salient can reduce subsequent face recognition. In two experiments, the current research finds that the typically superior same-race recognition is debilitated by making the same-race category salient. We find that when White-Americans self-categorize as ‘White,’ subsequent perceptual and memorial biases reduce the typically strong same-race recognition.     

Visual categorization of natural stimuli by domestic dogs

One of the fundamental issues in the study of animal cognition concerns categorization. Although domestic dogs (Canis familiaris) are on the brink to become one of the model animals in animal psychology, their categorization abilities are unknown. This is probably largely due to the absence of an adequate method for testing dogs’ ability to discriminate between large sets of pictures in the absence of human cueing. Here we present a computer-automated touch-screen testing procedure, which enabled us to test visual discrimination in dogs while social cueing was ruled out. Using a simultaneous discrimination procedure, we first trained dogs (N = 4) to differentiate between a set of dog pictures (N = 40) and an equally large set of landscape pictures. All subjects learned to discriminate between the two sets and showed successful transfer to novel pictures. Interestingly, presentation of pictures providing contradictive information (novel dog pictures mounted on familiar landscape pictures) did not disrupt performance, which suggests that the dogs made use of a category-based response rule with classification being coupled to category-relevant features (of the dog) rather than to item-specific features (of the background). We conclude that dogs are able to classify photographs of natural stimuli by means of a perceptual response rule using a newly established touch-screen procedure. Electronic supplementary material The online version of this article (doi:) contains supplementary material, which is available to authorized users.     

On the existence of prelinguistic categories: A case study

The purpose of this study was to investigate whether infants spontaneously form categories during the prelinguistic period and whether these categories are based on the same principles as adult basic-level categories. A new methodology, using a functional use measure as the determinant of category composition, was employed in a case study of one infant's horn category. Results indicated that this category met Schlesinger's (1982) criteria for a prelinguistic category and that the category was based on similarity relationships, as adult categories are.     

When surface and deep-level diversity collide: The effects on dissenting group members

Diversity researchers have distinguished between surface-level (e.g., social categories) and deep-level (e.g., attitudes, opinions, information, and values) diversity, but have not fully explored the complexities of their simultaneous existence in groups. We examined how the relationship between surface-level and deep-level diversity impacts the emotional and behavioral reactions of dissenting group members and the effectiveness of decision-making groups. We conducted two studies focusing on dissenting social majority members (individuals who hold dissenting deep-level task perspectives yet belong to the surface-level majority) in three-person groups. The results show that surface-level diverse groups (with two similar and one dissimilar individuals) were perceived as more positive and accepting, fostered more persistent and confident voicing of dissenting perspectives, and displayed greater task engagement than surface-level homogeneous groups (containing all similar individuals). Surface-level diversity (both task-relevant and irrelevant) may be beneficial for groups even when the group member who is different on the surface does not have a different deep-level task perspective to share. We discuss implications for understanding how surface-level diversity affects organizational work groups.