How we interact with objects: learning from brain lesions

Motor deficits are the most common outcome of brain damage. Although a large part of such disturbances arises from loss of elementary sensorimotor functions, several syndromes cannot be explained purely on these bases. In this article, we briefly describe higher-order motor impairments, with specific attention to the characteristic ability of the human hand to interact with objects and tools. Disruption of this motor skill at several independent levels is used to outline a comprehensive model, in which various current proposals for a modular organization of hand-object interactions can be integrated. In this model, cortical mechanisms related to object interaction are independent from representations of the semantic features of objects.     

Cultural differences in neural function associated with object processing

Behavioral research suggests that Westerners focus more on objects, whereas East Asians attend more to relationships and contexts. We evaluated the neural basis for these cultural differences in an event-related fMRI study. East Asian and American participants incidentally encoded pictures of (1) a target object alone, (2) a background scene with no discernable target object, and (3) a distinct target object against a meaningful background. Americans, relative to East Asians, activated more regions implicated in object processing, including bilateral middle temporal gyrus, left superior parietal/angular gyrus, and right superior temporal/supramarginal gyrus. In contrast to the cultural differences in object-processing areas, few differences emerged in background-processing regions. These results suggest that cultural experiences subtly direct neural activity, particularly for focal objects, at an early stage of scene encoding.     

Effects of exposure to muscular and hypermuscular media images on young men's muscularity dissatisfaction and body dissatisfaction

This study examined the effects of exposure to muscular and hypermuscular media images on young men's body images, and the moderating roles of baseline body dissatisfaction (BD) and muscularity dissatisfaction (MD). Men (M age = 21.9, SD = 2.8) were exposed to pictures of muscular (n = 34) or hypermuscular (n = 29) male physiques throughout a 30-min health seminar. In support of the study hypotheses, higher levels of baseline BD and MD were associated with greater post-seminar BD and MD. In addition, MD moderated the effects of the exposure conditions on BD; greater baseline MD was associated with greater post-seminar BD, but only among men who viewed the muscular images. These results speak to the importance of pre-existing muscularity concerns in determining men's reactions to muscular physique images, and suggest that exposure to the media ideal of muscularity, and not muscularity per se, elicits body dissatisfaction in men with pre-existing muscularity concerns.     

A dual-process account of digit invariance learning

Performance in the McGeorge and Burton (1990) digit invariance task was originally thought to be mediated by unconscious abstraction of a “rule” that identified the invariant feature across all study items. Subsequent explanations have suggested explicit strategy use or similarity-to-exemplar matching rather than abstraction. This paper presents data that suggest that both similarity and abstraction can be used under different task demands. Delay between study and test afforded abstraction of the invariant knowledge whereas reducing the pool of study exemplars enhanced responding based on specific similarity. These results parallel effects found in the categorization literature. Rule abstraction in this sense may be due to statistical learning of feature frequency rather than abstraction of a central tendency or a complex/conceptual rule. Categorizing responses into subjective memory states (remember/know/guess) demonstrates that neither the similarity matching nor the abstraction mechanism uses information from episodic memory. Confidence measures show that participants are more confident of responses when the prototypical representation is used but not specific similarity. Taken together, these data suggest that abstracted knowledge is not held consciously but that participants have meta-awareness of when they are using the abstracted representation.     

Life-span development of visual working memory: when is feature binding difficult?

We asked whether the ability to keep in working memory the binding between a visual object and its spatial location changes with development across the life span more than memory for item information. Paired arrays of colored squares were identical or differed in the color of one square, and in the latter case, the changed color was unique on that trial (item change) or was duplicated elsewhere in the array (color-location binding change). Children (8-10 and 11-12 years old) and older adults (65-85 years old) showed deficits relative to young adults. These were only partly simulated by dividing attention in young adults. The older adults had an additional deficiency, specifically in binding information, which was evident only when item- and binding-change trials were mixed together. In that situation, the older adults often overlooked the more subtle, binding-type changes. Some working memory processes related to binding undergo life-span development in an inverted-U shape, whereas other, bias- and salience-related processes that influence the use of binding information seem to develop monotonically.     

Stereotype Directionality and Attractiveness Stereotyping: Is Beauty Good or is Ugly Bad?

Dion, Berscheid, and Walster (1972), in their seminal article, labeled the attribution of positive characteristics to attractive people the "beauty-is-good" stereotype. The stereotyping literature since then provides extensive evidence for the differential judgment and treatment of attractive versus unattractive people, but does not indicate whether it is an advantage to be attractive or a disadvantage to be unattractive. Two studies investigated the direction of attractiveness stereotyping by comparing judgments of positive and negative attributes for medium vs. low and medium vs. high attractive faces. Taken together, results for adults (Experiment 1) and children (Experiment 2) suggest that most often, unattractiveness is a disadvantage, consistent with negativity bias (e.g., Rozin & Royzman, 2001) but contrary to the "beauty-is-good" aphorism.     

Between ignorance and truth: Partition dependence and learning in judgment under uncertainty

In 3 studies, participants viewed sequences of multiattribute objects (e.g., colored shapes) appearing with varying frequencies and judged the likelihood of the attributes of those objects. Judged probabilities reflected a compromise between (a) the frequency with which each attribute appeared and (b) the ignorance prior probability cued by the number of distinct values that the focal attribute could take on. Thus, judged probabilities were partition dependent, varying with the number of events into which the state space was subjectively divided. This bias was diminished among participants more confident in what they learned, was strong and insensitive to level of confidence when ignorance priors were especially salient, and required ignorance priors to be salient only when probabilities were elicited (not during encoding).