Speech-associated gestures, Broca's area, and the human mirror system

Speech-associated gestures are hand and arm movements that not only convey semantic information to listeners but are themselves actions. Broca's area has been assumed to play an important role both in semantic retrieval or selection (as part of a language comprehension system) and in action recognition (as part of a "mirror" or "observation-execution matching" system). We asked whether the role that Broca's area plays in processing speech-associated gestures is consistent with the semantic retrieval/selection account (predicting relatively weak interactions between Broca's area and other cortical areas because the meaningful information that speech-associated gestures convey reduces semantic ambiguity and thus reduces the need for semantic retrieval/selection) or the action recognition account (predicting strong interactions between Broca's area and other cortical areas because speech-associated gestures are goal-direct actions that are "mirrored"). We compared the functional connectivity of Broca's area with other cortical areas when participants listened to stories while watching meaningful speech-associated gestures, speech-irrelevant self-grooming hand movements, or no hand movements. A network analysis of neuroimaging data showed that interactions involving Broca's area and other cortical areas were weakest when spoken language was accompanied by meaningful speech-associated gestures, and strongest when spoken language was accompanied by self-grooming hand movements or by no hand movements at all. Results are discussed with respect to the role that the human mirror system plays in processing speech-associated movements.     

Self-monitoring and mimicry of positive and negative social behaviors

This study examined the role that self-monitoring plays in behavioral mimicry. Participants were exposed to videotaped targets who were laughing, yawning, frowning, or neutral in their expression. Participants’ behavioral mimicry while viewing the targets was recorded. It was hypothesized that higher self-monitors would show greater mimicry than lower self-monitors. It was also hypothesized that participants would respond differently to positive and negative target expressions. Participants who scored higher in self-monitoring did mimic the targets’ behaviors more often, and participants showed less mimicry of frowns than of laughs or yawns.     

Walking patterns change rapidly following asymmetrical lower extremity loading

The purpose of this study was to determine the amount of time needed for individuals to become well accommodated to asymmetrical changes in lower extremity inertial properties. Participants walked at 1.57 m s(-1) during four separate data collection sessions over the period of eight days. On days 1 and 7, participants completed a 60 min treadmill protocol consisting of both overground (motion and ground reaction force recorded) and treadmill (vertical ground reaction force recorded) walking. On day 1, 1.95 kg was attached distally to one shank prior to the start of the 60 min treadmill protocol and was not removed until day 7. On day 7, the load was permanently removed prior to the 60 min treadmill protocol. On days 2 and 8 participants completed three overground walking trials and walked on the treadmill for approximately 5 min. Stance and swing time asymmetries appeared immediately and were complete following initial assessment after the load was attached. Net joint moments at the knee and hip were altered and continued to change beyond initial exposure to the load, but these changes were complete within 5 min. Overall, results suggest that changes in walking symmetry due to asymmetrical lower extremity loading are immediate and complete within 5 min of exposure to the load. We recommend that at least 5 min of walking or other normal activity be used to accommodate individuals to novel asymmetrical lower extremity loading.     

Tracking unique objects

Is content addressable in the representation that subserves performance in multiple-object-tracking (MOT) experiments? We devised an MOT variant that featured unique, nameable objects (cartoon animals) as stimuli. There were two possible response modes: standard, in which observers were asked to report the locations of all target items, and specific, in which observers had to report the location of a particular object (e.g., "Where is the zebra?"). A measure of capacity derived from accuracy allowed for comparisons of the results between conditions. We found that capacity in the specific condition (1.4 to 2.6 items across several experiments) was always reliably lower than capacity in the standard condition (2.3 to 3.4 items). Observers could locate specific objects, indicating a content-addressable representation. However, capacity differences between conditions, as well as differing responses to the experimental manipulations, suggest that there may be two separate systems involved in tracking, one carrying only positional information, and one carrying identity information as well.     

Trait expectancies and stereotype expectancies have the same effect on person memory

Two studies examined whether trait expectancies and stereotype expectancies similarly affected memory for expectancy-relevant behaviors. The results of both studies showed that, when activated in identical ways, trait expectancies and stereotype expectancies had similar effects on recall. Better recall was obtained for expectancy-incongruent items when expectancies were activated in relatively overt ways, while better recall for expectancy-congruent items was obtained when expectancies were activated in less overt ways. Additional analyses examining the order of events that emerged in the recall protocols provided little evidence that participants attempted to reconcile the items, as would be predicted by some earlier models of person memory (e.g., Srull, 1981). The implications of these findings for how social expectancies guide social information processing are discussed.     

Family income and its relation to preschool children's adjustment for families in the NICHD Study of Early Child Care

The current study examines relations of mean-level estimates, linear changes, and instability in income and family processes to child outcomes and addresses whether income, through its impact on family functioning, matters more for children living in poverty. Temporal changes and instability in family processes, but not income, predicted children's adjustment. Cross-sectional mediational analyses indicated that for families living at the poverty threshold, family processes fully mediated the effect of average income over the study period on social behavior but only partially mediated its effect on cognitive-linguistic development. The strength of these associations diminished as average income exceeded the poverty threshold. That is, income had a greater impact on the family functioning and development of poor children than of nonpoor children.     

Constructing an understanding of mind: the development of children's social understanding within social interaction

Theories of children's developing understanding of mind tend to emphasize either individualistic processes of theory formation, maturation, or introspection, or the process of enculturation. However, such theories must be able to account for the accumulating evidence of the role of social interaction in the development of social understanding. We propose an alternative account, according to which the development of children's social understanding occurs within triadic interaction involving the child's experience of the world as well as communicative interaction with others about their experience and beliefs (Chapman 1991; 1999). It is through such triadic interaction that children gradually construct knowledge of the world as well as knowledge of other people. We contend that the extent and nature of the social interaction children experience will influence the development of children's social understanding. Increased opportunity to engage in cooperative social interaction and exposure to talk about mental states should facilitate the development of social understanding. We review evidence suggesting that children's understanding of mind develops gradually in the context of social interaction. Therefore, we need a theory of development in this area that accords a fundamental role to social interaction, yet does not assume that children simply adopt socially available knowledge but rather that children construct an understanding of mind within social interaction.     

The limitations of "vulnerability" as a protection for human research participants

Vulnerability is one of the least examined concepts in research ethics. Vulnerability was linked in the Belmont Report to questions of justice in the selection of subjects. Regulations and policy documents regarding the ethical conduct of research have focused on vulnerability in terms of limitations of the capacity to provide informed consent. Other interpretations of vulnerability have emphasized unequal power relationships between politically and economically disadvantaged groups and investigators or sponsors. So many groups are now considered to be vulnerable in the context of research, particularly international research, that the concept has lost force. In addition, classifying groups as vulnerable not only stereotypes them, but also may not reliably protect many individuals from harm. Certain individuals require ongoing protections of the kind already established in law and regulation, but attention must also be focused on characteristics of the research protocol and environment that present ethical challenges.     

Affective and attributional features of acculturative stress among ethnic minority college students

Little is known about the affective features of acculturative stress or its relation to attributional styles for negative events. The authors examined associations among acculturative stress, attributional style, and positive and negative affect among 96 ethnic minority college students. They hypothesized that acculturative stress would be characterized by elevated negative affect and global and stable attributions for negative events. Consistent with prediction, acculturative stress was significantly associated with negative affect and global attributions, even when controlling for other relevant predictors. Attributional style did not account for the association between negative affect and acculturative stress. Positive affect and stable and internal attributional styles were not related to acculturative stress. The authors discuss implications for reducing stress associated with acculturation.