Development of infant prehension handedness: A longitudinal analysis during the 6- to 14-month age period

Handedness is a developmental phenomenon that becomes distinctively identifiable during infancy. Although infant hand-use preferences sometimes have been reported as unstable, other evidence demonstrates that infant hand-use preference for apprehending objects can be reliably assessed during the second half of the infant's first year of life. The current study provides further insight into the stability of prehension preferences. We modeled individual and group level patterns of prehension handedness during the period from 6 to 14 months of age. We examined the developmental trajectories for prehension handedness in relation to the sampling rate at which preferences are assessed. The results revealed interesting developmental changes in prehension handedness that can only be identified when using monthly sampling intervals. We conclude that using non-linear multilevel models of infant handedness with monthly sampling intervals permit us to accurately capture the developmental changes in manual skills that occur during this period of infancy.     

Interactions between endogenous and exogenous attention during vigilance

The ability to remain vigilant over long periods of time is critical for many everyday tasks, but controlled studies of visual sustained attention show that performance declines over time when observers are required to respond to rare stimulus events (targets) occurring in a sequence of standard stimulus events (nontargets). When target discrimination is perceptually difficult, this vigilance decrement manifests as a decline in perceptual sensitivity. We examined whether sudden-onset stimuli could act as exogenous attentional cues to improve sensitivity during a traditional sustained attention task. Sudden-onset cues presented immediately before each stimulus attenuated the sensitivity decrement, but only when stimulus timing (the interstimulus interval [ISI]) was constant. When stimulus timing was variable, exogenous cues increased overall sensitivity but did not prevent performance decline. Finally, independent of the effects of sudden onsets, a constant ISI improved vigilance performance. Our results demonstrate that exogenous attention enhances perceptual sensitivity during vigilance performance, but that this effect is dependent on observers’ being able to predict the timing of stimulus events. Such a result indicates a strong interaction between endogenous and exogenous attention during vigilance. We relate our findings to a resource model of vigilance, as well as to theories of endogenous and exogenous attention over short time periods.     

Spatial cuing in a stereoscopic display: Evidence for a “depth-aware” attentional focus

Two experiments were conducted to explore whether attentional selection occurs in depth, or whether attentional focus is “depth blind,” as suggested by Ghiradelli and Folk (1996). In Experiment 1, observers viewed stereoscopic displays in which one of four spatial locations was cued. Two of the locations were at a near-depth location and two were at a far-depth location, and a single target was presented along with three distractors. The results indicated a larger cost in reaction time for switching attention inx,y and depth than inx,y alone, supporting a “depth-aware” attentional spotlight. In Experiment 2, no distractors were present, similar to the displays used by Ghiradelli and Folk. In this experiment, no effect for switching attention in depth was found, indicating that the selectivity of attention in depth depends on the perceptual load imposed on observers by the tasks and displays.     

Information and choice of subjects in the senior school

Selection of subjects for the final two years of secondary schooling is a task of vital importance for the adolescent. Data from 1,048 16-year-olds in Australia are reported. The findings suggest that many adolescents do not seek or do not access the information which is necessary for rational decision-making. Adolescents are, however, able to differentiate between information sources on the basis of their usefulness. Implications for career advisers are discussed.     

Reviews

Karantin by V. Maksimov, Possev, Frankfurt, 1973, 364 pp. French translation: En Quarantine by Vladimir Maximov, Grasset, Paris, 1974, 304 pp. 34 F.

Red Star Over Tibet, by Dawa Norbu, Collins, London, 1974, 254 pp. £3.50.

La Repressione Culturale In Lituania, Edizioni Jaca Book, Milano, 1972. A cura di Felix Milani, Centro Studi Russia Cristiana, Via Martinengo, Milano. 190 pp.     

The limits of visual resolution in natural scene viewing

We examined the limits of visual resolution in natural scene viewing, using a gaze-contingent multiresolutional display having a gaze-centred area-of-interest and decreasing resolution with eccentricity. Twelve participants viewed high-resolution scenes in which gaze-contingent multiresolutional versions occasionally appeared for single fixations. Both detection of image degradation (five filtering levels plus a no-area-of-interest control) in the gaze-contingent multiresolutional display, and eye fixation durations, were well predicted by a model of eccentricity-dependent contrast sensitivity. The results also illuminate the time course of detecting image filtering. Detection did not occur for fixations below 100 ms, and reached asymptote for fixations above 200 ms. Detectable filtering lengthened fixation durations by 160 ms, and interference from an imminent manual response occurred by 400-450 ms, often lengthening the next fixation. We provide an estimate of the limits of visual resolution in natural scene viewing useful for theories of scene perception, and help bridge the literature on spatial vision and eye movement control.     

Use of landmarks and allocentric reference frames for the control of locomotion

In the present study we assessed the use of landmarks and scene layout information for the control of locomotion. Observers were presented displays simulating forward locomotion through a random dot field with the horizontal position perturbed by a sum-of-sines function and were asked to steer and null out the horizontal disturbance of the path of locomotion. The results indicate greater control gain and accuracy when presented with a repeating layout of landmarks as compared to a changing layout of landmarks. Debriefing responses suggest that observers may have implicitly learned the layout of the repeating pattern. These results suggest that observers use an allocentric representation of the scene for steering control. A model for the control of locomotion is discussed that utilizes both scene-based information and optic flow.     

Individual problem‐solving styles and attitudes toward divergent thinking before and after training

ABSTRACT:

Afield experiment was conducted to examine the mediating effect of individual creative problem‐solving style on the impact of training in creative thinking. This intensive hands‐on training emphasized a specific three‐phase process which synchronizes divergence and convergence in problem‐finding, problem‐solving, and implementation. Two attitudes associated with divergent thinking were measured before and after training. The sample was comprised of a mixture of organizational members representing both managers (n = 90) and non‐managers (n = 66) and a variety of functional specialties, hierarchical levels, and types of business organizations. The most significant finding was that the optimizer style of creative problem‐solving improved more than the other three styles (generator, conceptualizer, and implementor) on measures of both creative thinking attitudes.     

A test of the social development model during the transition to junior high with Mexican American adolescents

Mexican American adolescents have higher rates of externalizing problems than their peers from other ethnic and racial groups. To begin the process of understanding factors related to externalizing problems in this population, this study used the social development model (SDM) and prospective data across the transition to junior high school from 750 diverse Mexican American families. In addition, the authors examined whether familism values provided a protective effect for relations within the model. Results showed that the SDM worked well for this sample. As expected, association with deviant peers was the primary predictor of externalizing behaviors. There was support for a protective effect in that adolescents with higher familism values had slower rates of increase in association with deviant peers from 5th to 7th grades than those with lower familism values. Future research needs to determine whether additional culturally appropriate modifications of the SDM would increase its usefulness for Mexican American adolescents.