What’s in the name? Categorical perception for unfamiliar faces can occur through labeling (original) (raw)
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What's in the name? Categorical Perception of unfamiliar faces can occur through labelling.
Psychonomic Bulletin & Review, 15, 787-794, 2008
The conditions under which categorical perception (CP) occurs for unfamiliar faces are unclear. Although CP is generally found only for familiar faces, it has been reported for unfamiliar faces after brief training (Levin& Beale, 2000) or even without any learning of the original faces (Campanella, Hanoteau, Seron, Joassin, & Bruyer, 2003). Three experiments investigated whether CP can be observed for an unfamiliar morphed face continuum without preexposure to the endpoints of the continuum (Experiment 1); with brief exposure to the endpoints (Experiment 2); or with exposure to named endpoints (Experiment 3). CP was always observed for matched pairs of famous faces. However, CP for unfamiliar faces was induced only when participants observed names paired with the endpoint faces before the start of the experiment. The results suggest that CP effects for unfamiliar faces can be observed extremely rapidly when clear category labels are presented.
Categorical perception of newly learned faces
Visual Cognition, 2007
Five experiments investigated identification and discrimination of faces. Stimuli were blends of two faces generated with a morphing algorithm. Two same-gender and two different-gender pairs of faces were tested. Experiment 1 (identification) estimated the point of indifference along the morphing sequence, and the associated differential threshold. Experiment 2 (discrimination, ABX) demonstrated that novel faces are perceived categorically. Identity was a more important factor than gender in generating the perceptual categories. Experiment 3 and 4 (identification) demonstrated that categories are generated progressively in the course of the experiment and depend on the range of morphs tested in any one condition. Confidence ratings (Experiment 5) showed that the multidimensional space where faces are represented can be collapsed onto a single dimension. Response probabilities and response times for Experiments 1 Á4 were predicted simultaneously by a counting model postulating that quanta of discriminal information are
Adaptation aftereffects reveal how categorization training changes the encoding of face identity
2020
Previous research suggests that learning to categorize faces along a novel dimension changes the perceptual representation of such dimension, increasing its discriminability, its invariance, and the information used to identify faces varying along the dimension. A common interpretation of these results is that categorization training promotes the creation of novel dimensions, rather than simply the enhancement of already-existing representations. Here, we trained a group of participants to categorize faces that varied along two morphing dimensions, one of them relevant to the categorization task and the other irrelevant to the task. An untrained group did not receive such categorization training. In three experiments, we used face adaptation aftereffects to explore how categorization training changes the encoding of face identities at the extremes of the category-relevant dimension, and whether such training produces encoding of the category-relevant dimension as a preferred directi...
European Journal of Neuroscience, 2010
Neuroimaging studies of humans have provided inconsistent evidence with respect to the response properties of the fusiform face area (FFA). It has been claimed that neural populations within this region are sensitive to subtle differences between individual faces only when they are perceived as distinct identities [P. Rotshtein et al. (2005) Nature Neuroscience, 8, 107-113]. However, sensitivity to subtle changes of identity was found in previous studies using unfamiliar faces, for which categorical perception is less pronounced. Using functional magnetic resonance adaptation and morph continua of personally familiar faces, we investigated sensitivity to subtle changes between faces that were located either on the same or opposite sides of a categorical perceptual boundary. We found no evidence for categorical perception within the FFA, which exhibited reliable sensitivity to subtle changes of face identity whether these were perceived as distinct identities, or not. On the contrary, both the posterior superior temporal sulcus and prefrontal cortex exhibited categorical perception, as subtle changes between faces perceived as different identities yielded larger release from adaptation than those perceived as the same identity. These observations suggest that, whereas the FFA discriminates subtle physical changes of personally familiar faces, other regions encode faces in a categorical fashion.
Language-induced categorical perception of faces?
Categorical perception (CP) facilitates the discrimination of stimuli belonging to different categories relative to those from the same category. Effects of CP on the discrimination of color and shape have been attributed to the top-down modulation of visual perception by the left-lateralized language processes. We used a divided visual field (DVF) search paradigm to investigate the prospective effects of CP on face identity and gender processing. Consistent with visual processing of face identity in the right hemisphere, we found CP facilitated perception only in the left visual field (LVF). In contrast, and consistent with language-induced CP, we observed a between-category advantage for processing face gender only in the right visual field (RVF). Taken together, our results suggest that language-induced CP plays a role in the category-based visual processing of faces by the left hemisphere, but face familiarity processing might be dependent on different, identity-specialized netw...
Arbitrary category labels can change similarity judgments of human faces
2012
In two experiments, participants were presented with a triad of morphed White and Hispanic faces paired with pseudoword labels. The meanings of these labels were manipulated to represent categorical information about the face. Labels were said to represent either the person's belief, the food s/he ate, the disease s/he had, or the person's last name. The results indicated that categorical information affects our judgments of faces. Information categories such as belief, food, and diseases were particularly strong in modifying the participants' similarity judgment of faces, whereas information characterized with last names of faces were least powerful. Previous research focuses on race face perception being affected primarily by racial indicators or racial information. Our results provide that how we perceptually analyze faces is not confined to obvious racial cues, but by non-racial semantic information as well, suggesting that category-relevant information by itself provides a strong basis for inductive generalization.
Familiarity effects on categorization levels of faces and objects
Cognition, 2009
It is well established that faces, in contrast to objects, are categorized as fast or faster at the individual level (e.g., Bill Clinton) than at the basic-level (e.g., human face). This subordinate-shift from basiclevel categorization has been considered an outcome of visual expertise with processing faces. However, in the present study we found that, similar to familiar faces, categorization of individuallyknown familiar towers is also faster at the individual level than at the basic-level in naïve participants. In addition, category-verification of familiar stimuli, at basic and superordinate levels, was slower and less accurate compared to unfamiliar stimuli. Thus, the existence of detailed semantic information, regardless of expertise, can induce a shift in the default level of object categorization from basic to individual level. Moreover, the individually-specific knowledge is not only more easilyretrieved from memory but it might also interfere with accessing more general category information.
Recognition of Facial Prototypes: The Importance of Categorical Structure and Degree of Learning
Journal of Memory and Language, 2001
The importance of categorical structure in the recognition and classification of realistic face prototypes, following a variable number of learning trials, was investigated in four experiments. Subjects either classified or observed well-defined (Experiments 1-3) or ill-defined (Experiment 4) faces belonging to three categories for one or nine trial blocks, followed by a transfer test. Recognition performance following classification (Experiment 1) and observational (Experiments 2 and 3) training was virtually the same: Oldness judgments were highest for the category prototypes and old instances and were least for new and random instances, with these tendencies increased following nine learning trials. When features were made ill defined (Experiment 4), oldness judgments decreased for the category prototype following nine learning trials. Multidimensional scaling (Experiment 5) revealed that the category structure for the well-defined and ill-defined faces was globally similar, and therefore, the disparate recognition of the category prototype was not due to a radical reorganization of the stimulus space. These results suggest that false recognition of the category prototype is at least partially based on type of category structure, and that prior studies using false recognition of the category prototype as evidence of an earlier abstraction process are probably misguided. Rather, false recognition is more likely due to erroneous combinations of features, with category influences playing less of a role.
Emergence of categorical face perception after extended early-onset blindness
Proceedings of the National Academy of Sciences of the United States of America, 2017
It is unknown whether the ability to visually distinguish between faces and nonfaces is subject to a critical period during development. Would a congenitally blind child who gains sight several years after birth be able to acquire this skill? This question has remained unanswered because of the rarity of cases of late sight onset. We had the opportunity to work with five early-blind individuals who gained sight late in childhood after treatment for dense bilateral cataracts. We tested their ability to categorize patterns as faces, using natural images that spanned a spectrum of face semblance. The results show that newly sighted individuals are unable to distinguish between faces and nonfaces immediately after sight onset, but improve markedly in the following months. These results demonstrate preserved plasticity for acquiring face/nonface categorization ability even late in life, and set the stage for investigating the informational and neural basis of this skill acquisition.