The preferred level of face categorization depends on discriminability

People usually categorize objects more quickly at the basic level (e.g., “dog”) than at the subordinate (e.g., “collie”) or superordinate (e.g., “animal”) levels. Notable exceptions to this rule include objects of expertise, faces, or atypical objects (e.g., “penguin,” “poodle”), all of which show faster than normal subordinate-level categorization. We hypothesize that the subordinate-level reaction time advantage for faces is influenced by their discriminability relative to other faces in the stimulus set. First, we replicated the subordinate-level advantage for faces (Experiment 1) and then showed that a basic-level advantage for faces can be elicited by increasing the perceptual similarity of the face stimuli, making discrimination more difficult (Experiment 2). Finally, we repeated both effects within subjects, showing that individual faces were slower to be categorized in the context of similar faces and more quickly categorized among diverse faces (Experiment 3).     

Training experts: individuation without naming is worth it

There is growing evidence that individuation experience is necessary for development of expert object discrimination that transfers to new exemplars. Individuation training in human studies has primarily used label association tasks where labels are learned at both the individual and more abstract (basic) level, and expertise criterion requires that individual-level judgments become as fast as basic-level judgments. However, there are training situations when the use of labels is not practical (e.g., with animals or some clinical populations). Moreover, labeling itself can facilitate object discrimination, thus it is unclear what role labels play in the acquisition of expertise in such training paradigms. Here, participants completed an online game that did not require labels in which they interacted with novel objects (Greebles) or control objects (Yufos). Games either required individuation or categorization. We then assessed the impact of this exposure on an abridged Greeble training paradigm. As expected, participants who played Yufo games or Greeble categorization games showed a significant basic-level advantage for Greebles in the abridged training paradigm, typical of novices. However, participants who played the Greeble identity game showed a reduced basic-level advantage, suggesting that individuation without labels may be sufficient to acquire perceptual expertise.     

Object categorization: reversals and explanations of the basic-level advantage

People are generally faster and more accurate to name or categorize objects at the basic level (e.g., dog) relative to more general (animal) or specific (collie) levels, an effect replicated in Experiment 1 for categorization of object pictures. To some, this pattern suggests a dual-process mechanism, in which objects first activate basic-level categories directly and later engage more general or specific categories through the spread of activation in a processing hierarchy. This account is, however, challenged by data from Experiment 2 showing that neuropsychological patients with impairments of conceptual knowledge categorize more accurately at superordinate levels than at the basic level--suggesting that knowledge about an object's general nature does not depend on prior basic-level categorization. The authors consider how a parallel distributed processing theory of conceptual knowledge can reconcile the apparent discrepancy. This theory predicts that if healthy individuals are encouraged to make rapid categorization responses, the usual basic > general advantage should also reverse, a prediction tested and confirmed in Experiment 3. Implications for theories of visual object recognition are discussed.     

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.     

The neural plasticity of other-race face recognition

Although it is well established that people are better at recognizing own-race faces than at recognizing other-race faces, the neural mechanisms mediating this advantage are not well understood. In this study, Caucasian participants were trained to differentiate African American (or Hispanic) faces at the individual level (e.g., Joe, Bob) and to categorize Hispanic (or African American) faces at the basic level of race (e.g., Hispanic, African American). Behaviorally, subordinate-level individuation training led to improved performance on a posttraining recognition test, relative to basic-level training. As measured by event-related potentials, subordinate- and basic-level training had relatively little effect on the face N170 component. However, as compared with basic-level training, subordinate-level training elicited an increased response in the posterior expert N250 component. These results demonstrate that learning to discriminate other-race faces at the subordinate level of the individual leads to improved recognition and enhanced activation of the expert N250 component.     

The effect of categorisation on sensitivity to second-order relations in novel objects

Adults appear to be more sensitive to configural information, including second-order relations (the spacing of features), in faces than in other objects. Superior processing of second-order relations in faces may arise from our experience of identifying faces at the individual level of categorisation (eg Bob versus John) but other objects at the basic level of categorisation (eg table versus chair; Gauthier and Tarr, 1997 Vision Research 37 1673- 1682). We simulated this learning difference with novel stimuli (comprised of blobs) by having two groups view the same stimuli but learn to identify the objects only at the basic level (based on the number of constituent blobs) or at both the basic level and individual level (based on the spacing, or second-order relations, of the blobs) of categorisation. Results from two experiments showed that, after training, observers in the individual-level training group were more sensitive to the second-order relations in novel exemplars of the learned category than observers in the basic-level training group. This is the first demonstration of specific improvement in sensitivity to second-order relations after training with non-face stimuli. The findings are consistent with the hypothesis that adults are more sensitive to second-order relations in faces than in other objects, at least in part, because they have more experience identifying faces at the individual level of categorisation.     

The entry point of face recognition: evidence for face expertise.

Previous studies have shown that experts (e.g., birdwatchers) are as fast to recognize objects at subordinate levels of abstraction (e.g., robin) as they are to recognize the same object at the basic level (e.g., bird). As a test of face expertise, the current study found that adults identify faces more frequently (Experiment 1) and as quickly (Experiment 2) at the subordinate level (e.g., Bill Clinton) as at the basic level (e.g., human). Whereas brief presentation (75 ms) impaired subordinate-level recognition of nonface objects, it did not impair the subordinate level recognition of faces (Experiment 3). Finally, in an identity-matching task, subordinate-level primes facilitated the matching responses of faces but not nonface objects (Experiment 4). Collectively, these results indicate that face expertise, like expert object expertise, promotes a downward shift in recognition to more subordinate levels of abstraction.     

Perceptual expertise and the plasticity of other-race face recognition

In this paper, we argue that our ability to recognize own-race faces can be treated as a form of perceptual expertise. Similar to object experts (e.g., birdwatchers), people differentiate own-race faces at the subordinate level of categorization. In contrast, like novices, we tend to classify other-race faces at the basic level of race. We demonstrate that, as a form of perceptual expertise, other-race face recognition can be systematically taught in the lab through subordinate-level training. When participants learn to quickly and accurately differentiate other-race faces at the subordinate level of the individual, the individuating training transfers to improved recognition of untrained other-race faces, produces changes in event-related brain components, and reduces implicit racial bias. Subsequent work has shown that other-race learning can be optimized by directing participants to the diagnostic features of a racial group. The benefits of other-race training are fairly long-lived and are evident even 2 weeks after training. Collectively, the training studies demonstrate the plasticity of other-race face recognition. Rather than a process that is fixed by early developmental events, other-race face recognition is malleable and dynamic, continually being reshaped by the perceptual experiences of the observer.     

The basic-level convergence effect in memory distortions

Abstract— Whereas most previous findings suggest that memory may become more abstract over time, so that memory for gist outlasts verbatim memory, there are findings suggesting that abstract information may sometimes be instantiated in more specific terms. In this study, we examined the hypothesis that retained information tends to converge at an intermediate level of abstractness—the basic level. In two experiments, we found bidirectional, symmetrical shifts in the memory for story material: Participants presented with either subordinate terms (e.g., sports car) or superordinate terms (e.g., vehicle) tended to falsely report basic-level terms (e.g., car) instead. This pattern emerged for both recall and recognition memory tests, at both immediate and delayed testing, and under free and forced reporting. The results suggest that the basic level, which has been considered cognitively optimal for perception, categorization, and communication, is also the preferred level for retaining episodic information in memory.     

Do separate processes identify objects as exemplars versus members of basic-level categories? Evidence from hemispheric specialization

When an object is identified as a specific exemplar, is it analyzed differently than when it is identified at the basic level? On the basis of a previous theory, we predicted that the left hemisphere (LH) is specialized for classifying objects at the basic level and the right hemisphere (RH) is specialized for classifying objects as specific exemplars. To test this prediction, participants were asked to view lateralized pictures of animals, artifacts, and faces of famous people; immediately after each picture was presented, a label was read aloud by the computer, and the participants decided whether the label was correct for that picture. A label could name the object at either the basic level (e.g., bird) or as an exemplar (e.g., robin). As predicted, we found that basic-level labels were matched faster when pictures were presented in the right visual field (and hence encoded initially in the LH), whereas exemplar labels were matched faster when pictures were presented in the left visual field (and hence encoded initially in the RH).     

Familiarity and person construal: Individuating knowledge moderates the automaticity of category activation

In this experiment, we examined how perceivers' familiarity with targets moderates person construal. Based on evidence from object categorization that level of construal varies with expertise in a manner that maximizes cue validity, we reasoned that although social (i.e., group‐level) categorization is functional for construing unfamiliar others (about whom little or no individuating information is available), it is less functional for familiar others (about whom a great deal of individuating information is available). Results from an automatic priming paradigm provided evidence for our reasoning: Participants categorized unfamiliar faces according to the most salient categorical dimension available in the visual information (in this case, sex), but did not do so for familiar faces. Implications for models of person perception are discussed. Copyright © 2009 John Wiley & Sons, Ltd.     

Holistic processing is tuned for in-group faces

Past research has found that mere in-group/out-group categorizations are sufficient to elicit biases in face memory. The current research yields novel evidence that mere social categorization is also sufficient to modulate processes underlying face perception, even for faces for which we have strong perceptual expertise: same-race (SR) faces. Using the composite face paradigm, we find that SR faces categorized as in-group members (i.e., fellow university students) are processed more holistically than are SR faces categorized as out-group members (i.e., students at another university). Hence, holding perceptual expertise with faces constant, categorizing an SR target as an out-group member debilitates the strong holistic processing typically observed for SR faces.     

Naming very familiar people: When retrieving names is faster than retrieving semantic biographical information

One of the most reliable findings in the literature on person indentification is that semantic categorization of a face occurs more quickly than naming a face. Here we present two experiments in which participants are shown the faces of their colleagues, i.e., personally familiar people, encountered with high frequency. In each experiment, naming was faster than making a semantic classification, despite the fact that the semantic classifications were highly salient to the participants (Experiment 1: highest degree obtained; Experiment 2: nationality). The finding is consistent with models that allow or parallel access from faces to semantic information and to names, and demonstrates the need for the frequency of exposure to names to be taken into account in models of proper name processing e.g. Burke, Mackay, Worthley and Wade (1991) .     

On facial expertise: processing strategies of twins' parents

Parents of monozygotic twins typically learn to recognise their own children and also to tell them apart on photographs. However, it is unknown whether such exemplar expertise can be generalised to unfamiliar faces of equal similarity (ie other twins). In the present study, parents of monozygotic twins were compared to 'control' parents whose children were non-twin siblings. In a same/different task with familiar and unfamiliar twin faces as stimuli, twins' parents were faster than control parents in distinguishing their own children, but slower when distinguishing unfamiliar twin faces. These unexpected findings can be interpreted as a generalisation of a habitual perceptual strategy that is efficient only with familiar face exemplars. When pictures of the twins' faces were inverted by 180degrees, the typical inversion costs for familiar faces were observed, but the twins' parents recognised unfamiliar twins' faces better when these were inverted than when upright. This inverted inversion effect could be caused by the high similarity of the face pairs as well as by experience with familiar faces of equally high similarity. We conclude that the facial expertise of twins' parents is idiosyncratic to their own children and not based on an enhanced general facial expertise.     

归类优势与基本水平效应的再探讨

类别特异性分数是预测归类优势的有效指标。实验1考察该分数能否预测基本水平归类优势, 结果：分数较高的表现归类优势。实验2检验有归类优势的下位类别的分数, 结果：它们都有较高分数, 同时发现下位类别的特异性可以影响分数。实验3探讨相同的基本水平与特异性不同的下位组合的归类表现, 结果：下位特异性低就表现基本水平归类优势, 高则相反。据此提出“经验说”, 分数高低与人们在经验中对各层次类别形成的表征特异性程度相关。     

Identification and categorization in visual search

Seven experiments were addressed to the general question of whether the identification of letters and numbers is a more rapid process than the categorization of such stimuli. Subjects were required to make a single response if a target stimulus specified by name (e.g., “A,” “2”) or designated by category class alone (e.g., “letter,” “number”) was presented in a trial. The principal findings were: (1) identification reaction times (RTs) were faster than categorization RTs: (2) RTs for targets shown without a context were faster than RTs for targets shown in the context of other stimuli; (3) identification RTs for targets shown in the context of stimuli from a different conceptual-taxonomic category were faster than RTs for targets shown in the context of stimuli from the same category only when target-context stimulus discriminability differencet were optimized. The results were interpreted in terms of a two-stage processing model in which context face,ors affect the duration of an initial encoding-scanning stage and search instruction (effective memory size) factors affect the duration of the memory comparison stage.     

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.     

The Effects of Prior Processing Episodes on Basic level Superiority

Four experiments were conducted to investigate the effects of prior processing episodes on people's preference for categorizing objects at the basic level (e.g. dog) relative to their preference for categorizing at the superordinate (e.g. animal) and the subordinate (e.g. Dalmation) levels. The prior processing episode in Experiment 1 was designed to induce subjects to activate representations at the superordinate level, and those in the remaining experiments were designed to induce subjects to differentiate objects at the subordinate level. After the prior processing episodes, subjects performed either a free naming or a picture categorization task that required them to decide whether an illustrated object belonged to a specified category. Results showed that prior processing episodes modestly reduced the superiority of basic level to superordinate level and subordinate level in categorization but not in free naming. The results suggest that the basic-level advantage is subject to the effects of context, but the effects are not as strong as the context effects on other aspects of categorization behaviour (e.g. rating typicality of a category member). Hence, the preference for the basic level is a somewhat more stable, invariant aspect of conceptual representation. Possible determinations of this stability are discussed.     

Crowded and sparse domains in object recognition: consequences for categorization and naming

Some models of object recognition propose that items from structurally crowded categories (e.g., living things) permit faster access to superordinate semantic information than structurally dissimilar categories (e.g., nonliving things), but slower access to individual object information when naming items. We present four experiments that utilize the same matched stimuli: two examine superordinate categorization and two examine picture naming. Experiments 1 and 2 required participants to sort pictures into their appropriate superordinate categories and both revealed faster categorization for living than nonliving things. Nonetheless, the living thing superiority disappeared when the atypical categories of body parts and musical instruments were excluded. Experiment 3 examined naming latency and found no difference between living and nonliving things. This finding was replicated in Experiment 4 where the same items were presented in different formats (e.g., color and line-drawn versions). Taken as a whole, these experiments show that the ease with which people categorize items maps strongly onto the ease with which they name them.     

I Recognize Your Face, But I Can't Remember Your Name: A Grown up Explanation

Contemporary models of face recognition explain everyday difficulties in name retrieval by proposing that name information can only be accessed after semantic information (e.g. Bruce & Young, 1986) or by proposing an architecture which puts name retrieval at a disadvantage (e.g. Burton& Bruce,1992). Experiments reportedhere examined the time requiredto access name and semantic details by adult and child subjects. In Experiment 1 adult subjects took more time to match familiar faces to names than to other semantic details (e.g. occupation), a finding consistent with all the previous literature on name retrieval. Experiment 2, however, showed that the youngest subjects were significantly faster in matching familiar faces to names than to semantic details. Experiment 3 also showed that children were faster at accessing names than occupations when giving vocal responses to presentations of familiar faces. These findings are not predicted by rigidly sequential models of face recognition and are discussed with specific reference to the ontogenesis of models based on a more flexible connectionist architecture.