Alyson Saville

N170 face specificity and face memory depend on hometown size.

Face recognition depends on visual experience in a number of different ways. Infrequent exposure to faces belonging to categories defined by species, age, or race can lead to diminished memory for and discrimination between members of those categories relative to faces belonging to categories that dominate an observers environment. Early visual impairment can also have long-lasting and broad effects on face discrimination - just a few months of visual impairment due to congenital cataracts can lead to diminished discrimination between faces that differ in their configuration, for example (Le Grand et al., 2001). Presently, we consider a novel aspect of visual experience that may impact face recognition: The approximate amount of different faces observers encountered during their childhood. We recruited undergraduate observers from small (500-1000 individuals) and large communities (30,000-100,000 individuals) and asked them to complete a standard face memory test and a basic ERP paradigm designed to elicit a robust N170 response, including the classic face inversion effect. We predicted that growing up in a small community might lead to diminished face memory and an N170 response that was less specific to faces. These predictions were confirmed, suggesting that the sheer number of faces one can interact with during their upbringing shapes their behavioral abilities and the functional architecture of face processing in the brain.

The emotional blink: adult age differences in visual attention to emotional information.

To assess age differences in attention-emotion interactions, the authors asked young adults (ages 18-33 years) and older adults (ages 60-80 years) to identify target words in a rapid serial visual presentation (RSVP) task. The second of two target words was neutral or emotional in content (positive in Experiment 1, negative in Experiment 2). In general, the ability to identify targets from a word stream declined with age. Age differences specific to the attentional blink were greatly reduced when baseline detection accuracy was equated between groups. With regard to emotion effects, older adults showed enhanced identification of both positive and negative words relative to neutral words, whereas young adults showed enhanced identification of positive words and reduced identification of negative words. Together these findings suggest that the nature of attention-emotion interactions changes with age, but there was little support for a motivational shift consistent with emotional regulation goals at an early stage of cognitive processing.

A face detection bias for horizontal orientations develops in middle childhood

Faces are complex stimuli that can be described via intuitive facial features like the eyes, nose, and mouth, “configural” features like the distances between facial landmarks, and features that correspond to computations performed in the early visual system (e.g., oriented edges). With regard to this latter category of descriptors, adult face recognition relies disproportionately on information in specific spatial frequency and orientation bands: many recognition tasks are performed more accurately when adults have access to mid-range spatial frequencies (8–16 cycles/face) and horizontal orientations (Dakin and Watt, 2009). In the current study, we examined how this information bias develops in middle childhood. We recruited children between the ages of 5–10 years-old to participate in a simple categorization task that required them to label images according to whether they depicted a face or a house. Critically, children were presented with face and house images comprised either of primarily horizontal orientation energy, primarily vertical orientation energy, or both horizontal and vertical orientation energy. We predicted that any bias favoring horizontal information over vertical should be more evident in faces than in houses, and also that older children would be more likely to show such a bias than younger children. We designed our categorization task to be sufficiently easy that children would perform at near-ceiling accuracy levels, but with variation in response times that would reflect how they rely on different orientations as a function of age and object category. We found that horizontal bias for face detection (but not house detection) correlated significantly with age, suggesting an emergent category-specific bias for horizontal orientation energy that develops during middle childhood. These results thus suggest that the tuning of high-level recognition to specific low-level visual features takes place over several years of visual development.

Adult Age Differences in Attention to Semantic Context

ABSTRACT In three experiments age differences in attention to semantic context were examined. The performance of younger adults (ages 18–29 years) and older adults (ages 60–79 years) on a semantic priming task indicated that both age groups could use information regarding the probability that a prime and target would be related to flexibly anticipate the target category given the prime word (Experiment 1). The timing by which target expectancies were reflected in reaction time performance was delayed for older adults as compared to younger adults, but only when the target was expected to be semantically unrelated to the prime word (Experiment 2). When the target and prime were expected to be semantically related, the time course of priming effects was similar for younger and older adults (Experiment 3). Together the findings indicate that older adults are able to use semantic context and the probability of stimulus relatedness to anticipate target information. Although aging may be associated with a delay in the timing by which controlled expectancies are expressed, these findings argue against an age-related decline in the ability to represent contextual information.

Detecting personal familiarity depends on static frames in "thin slices" of behavior.

Brief glimpses of nonverbal behavior (or “thin slices”) offer ample visual information to make reliable judgments about individuals. Previous work has largely focused on the personality characteristics and traits of individuals; however, the nature of dyadic relationships (strangers, lovers, or friends) can also be determined (Ambady & Gray, Journal of Personality and Social Psychology, 83, 947–961 2002). Judgments from thin slices are known to be accurate, but the motion features supporting accurate performance are unknown. We explored whether personal familiarity was detectable within the context of “thin slices” of genuine interaction, as well as the invariant properties of thin-slice recognition. In two experiments, participants sequentially viewed two 6-s silent videos on each trial of an individual interacting with an unfamiliar partner; the other depicted the same person interacting with a personally familiar partner. All sequences were cropped so that only the target individual was visible. In Experiment 1, participants viewed either the original sequences, reversed sequences, a static-image “slideshow” of the sequence, or a static-image slideshow with blank frames separating the images. In Experiment 2, all participants viewed the original sequences and clips played at either double speed or half speed. Participants’ performance was above chance in the forward and reverse conditions, but was significantly better in both the static-image slideshow conditions. When task speed was manipulated, we found a larger performance cost for fast than for slow videos. Detecting personal familiarity via spontaneous natural gestures depends on information in static images more than on face or body movement. Although static images are typically less important for recognizing nonverbal behavior, we argue they may be valuable for making familiarity judgments from thin slices.

The Impact of Face Inversion on Animacy Categorization

Face animacy perception is categorical: Gradual changes in the real/artificial appearance of a face lead to nonlinear behavioral responses. Neural markers of face processing are also sensitive to face animacy, further suggesting that these are meaningful perceptual categories. Artificial faces also appear to be an “out-group” relative to real faces such that behavioral markers of expert-level processing are less evident with artificial faces than real ones. In the current study, we examined how categorical processing of real versus doll faces was impacted by the face inversion effect, which is one of the most robust markers of expert face processing. We examined how explicit categorization of faces drawn from a real/doll morph continuum was affected by face inversion (Experiment 1) and also how the response properties of the N170 were impacted by face animacy and inversion. We found that inversion does not change the position or steepness of the category boundary measured behaviorally. Further, neural markers of face processing are equally impacted by inversion regardless of whether they are elicited by real faces or doll faces. On balance, our results indicate that inversion has a limited impact on the categorical perception of face animacy.

School‐age children's neural sensitivity to horizontal orientation energy in faces

Face processing mechanisms are tuned to specific low-level features including mid-range spatial frequencies and horizontal orientation energy. Behaviorally, adult observers are more effective at face recognition tasks when these information channels are available. Neural responses to face images also reflect these information biases: Face-sensitive ERP components respond preferentially to face images that contain horizontal orientation energy. How does neural tuning of face representations to horizontal information develop? Behavioral results show that this information bias increases over time such that younger children have a reduced bias favoring horizontally-filtered faces that increases with age. In the present study, we chose to investigate how neural sensitivity to these low-level features develops in the same age range, using ERP as a means of studying children and adults. Specifically, we examined how both face-sensitive ERP components (the P100 and N170) changed their responses to faces and non-faces as a function of age and orientation energy. Briefly, we found that the latency of the P100 and N170 component across age groups was consistent with the gradual emergence of a bias favoring horizontal orientation energy during middle childhood. The amplitude of the N170 component, however, exhibited a more complicated developmental profile that does not easily map onto previous behavioral results obtained from children in the same age ranges.

Aging and inhibitory tagging during visual search

Search Task: • Figure 1 illustrates the sequence of events in a sample trial. • Participants completed two different visual search tasks in separate blocks: an efficient task (Q among O’s) and an inefficient task (O among Q’s). • The items were randomly placed at 20 locations in the array with either 6 or 10 items presented in each array. Display size was manipulated to assess search efficiency. The target was displayed on half the trials. • Participants responded with a ‘Yes’ or ‘No’ if the target was in the display. Speed was emphasized but not over accuracy.