Domain‐specific development of face memory but not face perception

How does the remarkable human ability for face recognition arise over development? Competing theories have proposed either late maturity (beyond 10 years) or early maturity (before 5 years), but have not distinguished between perceptual and memory aspects of face recognition. Here, we demonstrate a perception–memory dissociation. We compare rate of development for (adult, human) faces versus other social stimuli (bodies), other discrete objects (cars), and other categories processed in discrete brain regions (scenes, bodies), from 5 years to adulthood. For perceptual discrimination, performance improved with age at the same rate for faces and all other categories, indicating no domain‐specific development. In contrast, face memory increased more strongly than non‐face memory, indicating domain‐specific development. The results imply that each theory is partly true: the late maturity theory holds for face memory, and the early maturity theory for face perception.     

Reduced willingness to approach genuine smilers in social anxiety explained by potential for social evaluation,not misperception of smile authenticity

ABSTRACT

We investigate perception of, and responses to, facial expression authenticity for the first time in social anxiety, testing genuine and polite smiles. Experiment 1 (N?=?141) found perception of smile authenticity was unaffected, but that approach ratings, which are known to be reduced in social anxiety for happy faces, are more strongly reduced for genuine than polite smiles. Moreover, we found an independent contribution of social anxiety to approach ratings, over and above general negative affect (state/trait anxiety, depression), only for genuine smiles, and not for polite ones. We argue this pattern of results can be explained by genuine smilers signalling greater potential for interaction – and thus greater potential for the scrutiny that is feared in social anxiety – than polite smiles. Experiment 2 established that, relative to polite smilers, genuine smilers are indeed perceived as friendlier and likely to want to talk for longer if approached. Critically, the degree to which individual face items were perceived as wanting to interact correlated strongly with the amount that social anxiety reduced willingness to approach in Experiment 1. We conclude it is the potential for social evaluation and scrutiny signalled by happy expressions, rather than their positive valence, that is important in social anxiety.     

The decay of short-term implicit memory: Unpacking lag

McKone (1995) reported a short-lived repetition priming effect, superimposed on long-lived priming. This short-term implicit memory survived a few intervening items and several seconds for words but decayed precipitously for nonwords, producing a lag 3 lexicality interaction. Here, mechanisms of decay are studied by disconfounding the time delay and interference components of lag. In Experiment 1, time delay was varied while number of intervening items was held constant, and vice versa. In Experiment 2, priming was plotted as a function of time delay, with and without intervening items. Using a lexical decision task, both experiments found independent contributions of time and interference to the decay of short-term priming. Further, Experiment 2 attributed the lag 3 lexicality interaction to a particular sensitivity of nonword traces to interference. An illustration of how these effects might arise in the word recognition system is provided.     

Short-term implicit memory: Visual, auditory, and cross-modality priming

Short-term implicit memory was examined for mixed auditory (A) and visual (V) stimuli. In lexical decision, words and nonwords were repeated at lags of 0, 1, 3, and 6 intervening trials, in four prime-target combinations (VV, VA, AV, AA). Same-modality repetition priming showed a lag x lexicality interaction for visual stimuli (nonwords decayed faster), but not for auditory stimuli (longer lasting smooth decay for both words and nonwords). These modality differences suggest that short-term priming has a perceptual locus, with the phonological lexicon maintaining stimuli active longer than the orthographic lexicon and treating pseudowords as potential words. We interpret these differences in terms of the different memory needs of speech recognition and text reading. Weak cross-modality short-term priming was present for words and nonwords, indicating recoding between perceptual forms.     

Sensitivity of 4-year-olds to featural and second-order relational changes in face distinctiveness

Sensitivity to adult ratings of facial distinctiveness (how much an individual stands out in a crowd) has been demonstrated previously in children age 5 years or older. Experiment 1 extended this result to 4-year-olds using a "choose the more distinctive face" task. Children's patterns of choice across item pairs also correlated well with those of adults. In Experiment 2, original faces were made more distinctive via local feature changes (e.g., bushier eyebrows) or via relational changes (spacing changes, e.g., eyes closer together). Some previous findings suggest that children's sensitivity develops more slowly to relational changes than to featural changes. However, when we matched featural and relational changes for effects on distinctiveness in adult participants, 4-year-olds were equally sensitive to both. Our results suggest that (a) 4-year-olds' face space has important aspects of structure in common with that of adults and that (b) there is no specific developmental delay for a second-order relational component of configural/holistic processing.     

In what sense is implicit memory "episodic"? The effect of reinstating environmental context

We consider three aspects of the term episodic. Previous literature shows implicit memory does not make conscious autobiographical reference but does code an item's intrinsic context (e.g., perceptual detail). Here, we consider extrinsic context--namely, that not directly processed as part of item identification and not overtly relevant to the task. Study-test mismatch in environmental context (outdoors vs. indoors) reduced memory in an explicit stem-cued recall task but had no effect on repetition priming in an implicit stem completion task. This was true even for very low frequency words. We support the view that implicit memory reflects traces within perceptual (or semantic) knowledge-based systems that are instance specific but do not code the full spatiotemporal context information necessary to support conscious recollection. We also interpret our results as consistent with differences in environmental context specificity between free recall and recognition.     

Categorical perception of face identity in noise isolates configural processing.

Neuropsychological evidence suggests that face recognition based on configural (holistic) information can occur in isolation from recognition based on local feature cues. The present study shows that configural processing can be isolated experimentally in normal subjects. A phenomenon is reported that exists only for upright whole faces, namely categorical perception (CP) of face identity in noise. Three discrimination tasks (ABX, better likeness, and similarity ratings) were used to test for perceptual distortion across the category boundary predicted from binary classification of face morphs. Noise was added such that any single local region provided unreliable cues to identity. Under these conditions, CP was found for upright faces but not for inverted faces or single features, even with more than 10,000 trials. The CP-in-noise signature phenomenon was then used to show that configural processing survives image plane rotations of 45 degrees-90 degrees.     

Aftereffects for face attributes with different natural variability: adapter position effects and neural models

Adaptation to distorted faces is commonly interpreted as a shift in the face-space norm for the adapted attribute. This article shows that the size of the aftereffect varies as a function of the distortion level of the adapter. The pattern differed for different facial attributes, increasing with distortion level for symmetric deviations of eye height and decreasing for asymmetric deviations. These results are interpreted in terms of different coding ranges for the 2 facial attributes, arising from differences in eye-height variability in natural face images (large for symmetric, small for asymmetric). Neural models developed in low-level vision also are applied to facial attributes, contrasting a 2-pool (norm-based) and a multichannel (exemplar-based) model. The adapter position effects generally support a norm-based model, as did a finding that perception of stimuli further from the norm than the adapter was shifted in the direction of the norm, rather than repulsed away from the adapter.     

No face-like processing for objects-of-expertise in three behavioural tasks

In the debate between expertise and domain-specific explanations of "special" processing for faces, a common belief is that behavioural studies support the expertise hypothesis. The present article refutes this view, via a combination of new data and review. We tested dog experts with confirmed good individuation of exemplars of their breed-of-expertise. In all experiments, standard results were confirmed for faces. However, dog experts showed no face-like processing for dogs on three behavioural tasks (inversion; the composite paradigm; and sensitivity to contrast reversal). The lack of holistic/configural processing, indicated in the first two of these tests, is shown by review to be consistent rather than inconsistent with previous studies of objects-of-expertise.     

Familiar other-race faces show normal holistic processing and are robust to perceptual stress

Other-race individuals are remembered more poorly and receive less holistic/configural processing than same-race individuals, at least when faces are novel. Here, we examine the amelioration of these effects with familiarity, using distinctiveness-matched Caucasian and Asian stimulus sets. We confirmed a cross-race deficit for upright faces following a single encoding trial, which disappeared rapidly with practice on a small set of other-race 'friends' and did not re-emerge when perceptual processing was put under stress (presentation in the periphery). We also examined holistic/configural processing for familiarised faces using the peripheral inversion effect (McKone, 2004 Journal of Experimental Psychology: Learning, Memory, and Cognition 30 181 - 197). A test for faces and nonface objects (dogs) confirmed the validity of this technique as providing a direct measure of holistic processing; we then showed that, after 1 h of training, holistic processing was as strong for other-race as same-race faces. We conclude that practice with other-race individuals can rapidly engage normal face-processing mechanisms.