Set and temporal integration

An experiment was conducted to explore the temporal structure of set formation in a complex reaction time (RT) task. On each trial an instruction [I-event] was given telling Ss whether identity of color or form on a separately presented alternative display (A-event) was the dimension relevant on that trial. The A-event consisted of a pattern of four colored forms. The two forms on one side were matched for color and on the other side for form. S’s task was to depress one of two keys. The correct key was homolateral to the matched relevant dimension. The basic independent variable was the time interval separating the I- and A-events (ISI). At short ISIs, RT wasa linear function oflSI with slope equal to -0.5. RT was independent of the order in which the events occurred at short ISIs, although at longer ISIs (3 sec) RT was longer when the A-event followed the I-event. Also, RT was shorter at short ISIs when color was the relevant dimension rather than form. although this difference disappearedat longer ISIs. The results were discussed in relation to information processing models and previous research dealing with partialadvance information.     

Tables for the determination of the significance of skewness and of the significance of the difference in the skewness of two independent distributions

Several of the more popular statistics texts used in psychology are reviewed with respect to their treatment of the measurement and interpretation of skewness. Some areas in psychology where measures of skewness of distributions may yield significant information are indicated. Tables of 1%, 2% and 5% points of moment measures of skewness and tables of the 1% and 5% points of the difference in skewness of two uncorrelated distributions are presented. These tables are approximations based on the approximate normality of skewness in large samples from normal populations. The limited confidence with which these tables can be used in the absence of exact knowledge of the distribution function of the underlying statistics is indicated.The opinions expressed in this article are those of the author and are not to be interpreted as official War Department policy.     

Risky visuomotor choices during rapid reaching in childhood

Many everyday actions are implicit gambles because imprecisions in our visuomotor systems place probabilities on our success or failure. Choosing optimal action strategies involves weighting the costs and gains of potential outcomes by their corresponding probabilities, and requires stable representations of one's own imprecisions. How this ability is acquired during development in childhood when visuomotor skills change drastically is unknown. In a rewarded rapid reaching task, 6‐ to 11‐year‐old children followed ‘risk‐seeking’ strategies leading to overly high point‐loss. Adults' performance, in contrast, was close to optimal. Children's errors were not explained by distorted estimates of value or probability, but may reflect different action selection criteria or immature integration of value and probability information while planning movements. These findings provide a starting point for understanding children's risk‐taking in everyday visuomotor situations when suboptimal choices can be dangerous. Moreover, children's risky visuomotor decisions mirror those reported for non‐motor gambles, raising the possibility that common processes underlie development across decision‐making domains.     

Additional cross‐cultural evidence on the selective usage of nonmaterial beliefs in explaining life events

Two studies, one conducted in the Netherlands (N=87) and one in Italy with two samples—Catholic Youth (N=41) and Young Communists (N=41)—assessed the cross‐cultural generality of the previously confirmed hypothesis (Pepitone & Saffiotti, 1997) that six universal nonmaterial beliefs—fate, God, luck, chance, just punishment, and just reward—are used selectively to interpret life events. A ‘selective correspondence’ between the six beliefs and the standard life event cases specifically constructed to engage the belief‐specializations was predicted. All three samples showed the predicted correspondence in terms of significant ordinal correlations in a 6 nonmaterial belief ×9 life events classification. In addition, the findings are consistent with the assumption that the degree of selective correspondence depends upon the importance of beliefs in the sample under study. Copyright © 1999 John Wiley & Sons, Ltd.