Memory storage and retrieval within and across modalities in children

Twenty-four kindergarten and fourth grade children were asked to locate a display card which had been visually or verbally presented. A probe, which identified the card to be located, was presented verbally and visually equally often. The children's ability to recall the location of an item did not differ as a function of the modality to which the material was presented. Nor was recall significantly affected when the presentation modality differed from the probe modality, suggesting that children as young as 5 can cross these sensory modalities to retrieve material with no loss in accuracy. Serial position curves suggest that the verbal and visual material is not stored in a common intersensory store. The primacy effect is found to be stronger with visually presented material and the recency effect strongest with auditorily presented material. Probe modality did not influence the serial position curves.     

The role of quantification operators in the development of conservation of quantity

An analysis of the quantitative processes underlying conservation of quantity is presented. Models of quantitative operators (subitizing, counting, estimation) are derived from adult performance in quantification tasks, and some features of the operators are described. The emergence of conservation is described in terms of the development of the operators and a set of rules which evoke them and coordinate their results. Empirical data related to the developmental argument is discussed.     

Preexposure pointing frequency effects on adaptation to prismatic viewing

The effect of frequency of preexposure pointing was studied to delermine its effect on subsequent adaptation to a prismatic exposure. Results showed that when Ss pointed equally to each target in a preexposure pointing task, adaptation was found to be greatest for the target on S’s prismatically shifted visual field periphery. However, when Ss pointed more frequently in the preexposure condition to a more central targe:, adaptation was geatest for this target.     

The critical distance of interaction in the Zöllner illusion

Two experiments attempted to de termine the distance (as visual angle) over which the Zöllner distortion of a straight line could be produced by a background field. Experiment 1 showed that the background lines did not need to intersect the test line in order to distort it but could exert this effect up to a distance of 1 deg visual angle from it. Experiment 2 indicated that when the background lines do intersect the test line portions of these formed beyond an angle of 1 deg do not contribute to the distortion. These values may indicate the size of the cortical receptive fields interacting to produce the illusion.     

Effects of initial limb position on the accuracy, reaction time and electromyographic patterns of rapid movements

An experiment was performed to determine the effects of initial limb condition on final accuracy of rapid, elbow flexion movements in the horizontal plane. Electromyographic (EMG) recordings were also taken from an agonist (biceps) and antagonist (triceps) muscle by means of bipolar surface electrodes. In the experiment the subject's forearm was passively oscillated by means of an electric motor, and when an auditory buzzer sounded, the subject was required to react as quickly as possible and rapidly move to the previously learned target angle. Thus, movements could be initiated from either static or moving starting positions. The results indicated that general accuracy was not greatly affected by these manipulations, however, constant error and pre-motor reaction time suggested that subjects may have been utilizing initial limb condition information contrary to a mass-spring view. EMG data showed that the timing characteristics of the agonist and antagonist muscles were modulated, depending on the type of movement produced, supporting an impulse-timing model (Wallace 1981).     

Differential cerebral involvement in the cognitive functioning of bilinguals

The cognitive processing strategies of two groups of French-English bilinguals were studied by means of an auditory Stroop test designed to evaluate cerebral hemispheric involvement. An “early bilingual” group were bilingual before the age of 5, and a “late bilingual” group were bilingual after the age of 10. Stimuli were words uttered in pitches that were related to word meanings either congruently (as in the word “high” uttered in a high pitch) or incongruently (the word “haute” uttered in a low pitch). In one condition, subjects were to differentiate low from high pitches, disregarding meaning, while in a second condition, they were to disregard pitch and respond to word meanings. Measures of field independence were also taken. Results of data analyses suggest that male early bilinguals—the most field independent subgroup—process meaning efficiently in both cerebral hemispheres, but process pitch better in the right hemisphere. However, male late bilinguals and female bilinguals, both early and late, process meaning more rapidly in the right cerebral hemisphere and pitch equally rapidly in both hemispheres. The findings are interpreted as reflecting hemisphere-based strategy and sex differences in information-processing by the two bilingual groups.