Computing the COM from the COP in postural sway movements

A method is described for computing the centre of mass (COM) from empirical estimates of the centre of pressure (COP) obtained by means of a force platform. The method is based on a biomechanical model of sway movements in quiet standing, according to which the horizontal acceleration of the COM is approximately proportional to the COM–COP difference. The equations are solved by approximating the solution with best fitting spline functions. The implications for movement control are discussed.     

Perceived infant temperament,locus of control,and maternal physiological response to infant gaze

Maternal physiologic response was used as an index of maternal attention to infant eye contact. Thirty-six women, each of whom had a 3-month-old infant, were shown 10-sec silent images of a 3-month-old infant on a videotape monitor. In one condition the en face position offered eye contact, in the other condition eye contact was not possible. Each woman viewed a sequence of six identical episodes of one condition followed by six episodes of the other condition. Heart rate and skin conductance were recorded continuously during the session. Skin conductance response did not differentiate between reciprocated and unreciprocated gaze. Cardiac response elicited by reciprocated gaze viewed first shifted from a predominately orienting response on early trials to an acceleratory response on Trial 6. The acceleratory response was most pronounced in those women identified as Externals by the Locus of Control Inventory (Rotter, J. B. Psychological Monographs, 1966, 80, [No. 609]). Initial viewing of the infant looking away elicited a predominantly deceleratory heart-rate response that did not habituate. Mothers who described their infants as being difficult as assessed by the questionnaire method (Carey, W. B. Journal of Pediatrics, 1970, 77, 188–194) were physiologically less sensitive to the change from the infant's averted gaze to its direct gaze. Results are discussed in terms of the role of direct and averted gaze during social transactions.     

On the development of communicative understandings: An early strategy for interpreting and responding to messages

Young children's apparently sophisticated understanding of language is explained by a simple heuristic which produces responses fortuitously appropriate to many of the messages directed to them. Specifically, the strategy recruits action responses to language unless some element, either linguistic or nonlinguistic, indicates otherwise. Two experiments tested for the existence of the heuristic by examining the responses of children, 19–34 months of age, to sentences susceptible of more than one interpretation. In the first experiment such sentences were spoken in as neutral a context as possible. In the second, the same sorts of sentences were presented in contexts supporting either action or informing responses. The results of both experiments indicate that young children interpret and respond to language in terms of an action-based strategy. Moreover, the observed effects of context show that even young children engage in a continuous, context-sensitive process of interpretation. The data are discussed with regard to speech act theory and its role in a developmental theory of understanding.     

The extra credit effect in interpersonal attraction

An experiment was conducted in which three levels of personal evaluation (positive, mixed, or negative) were crossed with two levels of dependence of the evaluator (high or low) and two levels of accuracy of the evaluation (high or low). Liking for the evaluator was expected to increase linearly with the favorableness of the evaluation, with two possible exceptions: When a positive evaluation from a dependent evaluator was inaccurate, and when a negative evaluation from a dependent evaluator was accurate. In the former case, the obvious inaccuracy of the positive evaluation in the face of the temptation to ingratiate was expected to elicit a decrement in liking (an “ingratiation effect”) by the person being evaluated. In the latter case, the honesty of the evaluator in the face of the temptation to ingratiate was expected to elicit an increment of linking (an “extra credit effect”) by the person being evaluated. Only the second of these two possibilities was supported.     

Changes with age in two components of visual search speed

Subjects aged 8, 10, 12, and 18 years participated in two visual search tasks. In one task the rate of visual search reflected the speed of preattentive localization processes, and in the other task it additionally reflected letter identification process speeds. The data revealed that localization processes become faster from ages 8 to 12 and remain stable thereafter, and that identification processes increase in speed primarily from ages 8 to 10. Performance on a subsequent recognition task indicated that subjects of all ages were employing a similar encoding strategy during visual search. Furthermore, subjects retained general information about the features of irrelevant background letters even though recognition accuracy for more specific information about letter names was not high. The finding that localization and identification processes have different rates of development confirms the hypothesized distinction between the two and implies that developmental studies of visual scanning speed must focus upon changes in the relationships among various processes or component skills throughout development.     

The effect of mere presence on social facilitation: An unobtrusive test

An unobstrusive experimental manipulation was used to test the hypothesis that the mere presence of others can influence an individual's performance. A task was employed for which there were no clear performance criteria, and which was very unlikely to engender evaluation aprehension. Performance times on this task (dressing and undressing in familiar and unfamiliar clothing) were compared for subjects working alone, in the presence of a passive inattentive person, and in the presence of an attentive spectator. In contrast with the Alone condition, both social conditions (Audience and Incidental Audience) enhanced performance on the well-learned aspects of the task (dressing and undressing with one's own clothing) and hindered performance on the more complex aspects (working with unfamiliar clothing). It is concluded that the mere presence of others is a sufficient condition for social facilitation and social interference effects.     

Personality characteristics,parent behaviors,and sex of subject in relation to cheating

College students were given the opportunity to falsify self-reported scores on a task to gain course credit. Personality and perceived parent behavior data were obtained in a counterbalanced design. Male cheaters were significantly higher in Aggression, Exhibition, Social Recognition, and Harmavoidance but lower in Autonomy (PRF scales) and ACT scores. Female transgressors were reliably lower in harmavoidance and higher in Impulsivity than noncheaters. Among males, no parent scales differentiated transgressors and resisters. Among females, parent scales reflecting reports of lower father warmth and fewer maternal equalitarian interactions but higher Hostile Control significantly differentiated cheaters from noncheaters. These findings were discussed, particularly in terms of the sex differences which suggest that males and females may cheat for different reasons.