Genetic influences on the development of spatial skills during early adolescence

The course of development of skill at face encoding is disrupted in early adolescence. Evidence is provided that the timing of this disruption is under genetic control. Regardless of their age, girls in the midst of pubertal change encode faces less efficiently than prepubescent or postpubescent controls. This maturational influence on face encoding is contrasted with a different effect of pubertal development on another visuo-spatial ability, performance on the Embedded Figures Test (EFT). Regardless of their pubertal status at time of testing, girls who mature earlier are disadvantaged on EFT compared to those who mature later. The results for EFT replicate earlier findings on the relation between individual differences in the age at which adolescence begins and certain spatial skills. Several possible explanations for each of these effects—that of maturational status on face encoding and that of maturation rate on EFT—are discussed. Consideration of the relation between physical and mental growth is advocated as a source of constraints on explanations of cognitive development.     

The development of contrast constancy

The mature visual system possesses mechanisms that enable invariant perception of the contrast of an object and its features as the object undergoes changes in distance. This phenomenon, which has been called contrast constancy, obtains at suprathreshold contrasts only. Some models of contrast constancy assume the presence of narrowband spatial-frequency channels. An implication of M.S. Banks, B.R. Stephens, and E.E. Hartmann (1985, Journal of Experimental Child Psychology, 40, 501-527) is that contrast constancy should not be observed at 6 weeks but may be observed at 12 weeks. We examined this implication by investigating the development of contrast constancy in 6- and 12-week-old infants. Two sine wave gratings, differing in spatial frequency by a factor of 3, were presented side-by-side. The contrast of one grating was varied in order to estimate the contrast at which preference for the two gratings was equal. The equal preference points for 6-week-olds were predictable from their contrast thresholds. The 12-week-olds' equal preference points for low-contrast stimuli were predictable from their contrast thresholds, but those for intermediate and high-contrast stimuli were not. Thus, if one accepts the assumption that equal preference in infants is analogous to apparent contrast matches in adults, these data imply that contrast constancy is observed at 12 weeks but not 6 weeks. The perceptual consequences of this developmental transition are discussed.     

Integrative bargaining in a competitive market

The behavioral decision theory literature was used to identify the determinants of negotiation success in an integrative bargaining, free-market exercise. This study provides a novel methodology for studying negotiation. Specifically, buyers and sellers were allowed to engage in negotiations with as many competitors as possible in a fixed time period. The results suggest that integrative bargaining behavior increases and the market converges toward a Nash equilibrium as negotiators gain experience. In addition, the results suggest that (1) positively framed negotiators (“What will be my net profit from the transaction?”) complete more transactions than negatively framed negotiators (“What will be my expenses on this transaction?”), (2) negotiators who are given moderately difficult profit constraints in order to be allowed to complete a transaction achieve more profitable transactions than negotiators without such constraints, and (3) both framing and the existence of constraints affect the total profitability of the negotiator.     

Grammatical class effects in relation to normal and aphasic sentence processing

Agrammatic, Broca's aphasic patients, Wernicke's aphasic patients, and neurologically intact control subjects were asked to detect target letters in prose passages and in a scrambled word passage. The targets were embedded, in some instances, in content words (open-class vocabulary items), and in other instances, in function words (closed-class vocabulary items). With respect to the prose passages, both the control subjects and Wernicke's aphasic patients were more apt to notice target letters when they appeared in the open-class items than when in closed-class items; by contrast, the agrammatic Broca's patients showed no vocabulary class detection difference. The Wernicke's patients were not entirely normal, however: Whereas the normal subjects showed a much smaller vocabulary class effect for letter detection in the scrambled condition, the Wernicke's maintained the pattern they had shown in the prose condition. These and other findings obtained on the letter cancellation task are discussed in relation to lexical access mechanisms geared to sentence parsing.     

MA and Togetherness (Ittaikan) in the Narratives of Dancers and Spectators: Sharing an Uncertain Space

The Japanese concept/character MA (間), commonly translated as “gap, interval, or the in between,” partakes in many forms of Japanese arts and daily-life practices. In this article, we report the results of a qualitative research on the meaning or experience of MA and its relation with the feeling of togetherness in the context of contemporary dance improvisation. We interviewed performers and spectators (all professional dancers) while they watched the videotaped and reduced stick-figure versions of short dance improvisations created in a laboratory installed with motion-capture sensors. Based on the individual narratives, and inspired by Japanese and occidental aesthetic writings, we elaborate a specific understanding of MA as attending to the event's preacceleration, and how this experience causally relates to the feeling of togetherness (一体感, ittaikan). We propose that MA, understood not extensionally (as an empty space or a silent gap), but intentionally/internally as a certain quality of attention or perceptual mode, is fertile ground for serendipity. MA as an interpersonal ethical construct suggests a transsubjective difference as a foundation for a collective coming together.     

Pauses and syntax in American sign language

Research on spoken languages has shown that the durations of silent pauses in a sentence are strongly related to the syntactic structure of the sentence. A similar analysis of the pauses (holds) in a passage in American Sign Language reveals that sequences of signs are also interspersed with holds of different lengths: long holds appear to indicate the ends of sentences; shorter holds, the break between two conjoined sentences; and the shortest holds, breaks between internal constituents. Thus, pausal analysis is a guide to parsing sentences in ASL.     

Interpersonal evaluations,attitudes and attraction

The effect of interpersonal evaluations (e.g., judging a person's intelligence) on attraction toward an anonymous person (person-one) was investigated. The study was conducted to assess attraction in five interpersonal relationships in which evaluations commonly occur. Attraction of subjects toward person-one was greater for positive than for negative evaluations when person-one evaluated either the subjects or himself, when a second anonymous person evaluated person-one and the attitudes of person-one were similar to those of the subjects, and when the second person evaluated both person-one and the subjects. When person-one evaluated the subjects, attraction toward person-one was found predictable using the Byrne-Rhamey rule.     

Visual tracking and existence constancy in 5-month-old infants

Visual fixation and cardiac deceleration for 36 infants 20–24 weeks old were recorded during three kinds of events in which objects moving on a linear trajectory were temporarily occluded by a screen: (1) a familiar object appeared on both sides of the screen; (2) a novel object appeared on both sides of the screen; and (3) a novel object appeared to change to a familiar one behind the screen. Infant attention was related to novelty and familiarity of objects and there was no evidence of behavior reflecting the expectancy that a stable object continued to exist behind the screen. These findings are in conflict with those of previous tracking studies and the discussion focuses upon explanations for this discrepancy.