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.     

Effects of time and event uncertainty upon sequential information processing

Two experiments were conducted to investigate the psychological refractory period (PRP), a delay induced into the second of two reaction times (RT) when the interstimulus interval (ISI) is short. In Experiment1, time and event uncertainty were factorially varied by providing or not providing S with foreknowledge of the ISI and the order in which the two events would occur, respectively. ISIs of0, 50, 100, 200, and400 msec were used. Time and event uncertainty produced independent degradation of both RTs. Also, the second RT (RT ₂ ) was delayed at50 msec ISI when both time and event certainty were present. Experiment 2 attempted to replicate this latter finding using ISIs of0, 25, 50, 75, and100 msec. Delays in RT ₂ were found for the middle three values of ISI. These results were interpreted as supporting a modified single channel theory of the PRP.     

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.     

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.     

Using Sex-Related Alcohol Expectancies to Predict Condom Use Among a General Sample of Men and Women in the United States

Sex-related alcohol expectancies (SRAE) are known to moderate the relationship between alcohol use and risky sexual behavior in high risk populations; however, SRAEs have not been thoroughly explored in populations traditionally viewed at lower risk for HIV and/or STI. Participants (n = 649) were recruited through internet-based direct marketing in the United States. Predictors of SRAE vary by gender. Controlling for alcohol use and other predictors, age predicted condom use among women, and SRAE was correlated with condom use for men. Sexual health programming geared towards non-traditionally identified high-risk populations is necessary and provides unique opportunities to increase condom usage.     

Does direction of walking impact binocular rivalry between competing patterns of optic flow?

When dissimilar monocular images are viewed simultaneously by the two eyes, stable binocular vision gives way to unstable vision characterized by alternations in dominance between the two images in a phenomenon called binocular rivalry. These alternations in perception reveal the existence of inhibitory interactions between neural representations associated with conflicting visual inputs. Binocular rivalry has been studied since the days of Wheatstone, but one recent strategy is to investigate its susceptibility to influences caused by one’s own motor activity. This paper focused on the activity of walking, which produces an expected, characteristic direction of optic flow dependent upon the direction of one’s walking. In a set of experiments, we employed virtual reality technology to present dichoptic stimuli to observers who walked forward, backward, or were sitting. Optic flow was presented to a given eye, and was sometimes congruent with the direction of walking, sometimes incongruent, and sometimes random, except when the participant was sitting. Our results indicate that, while walking had a reliable influence on rivalry dynamics, the predominance of congruent or incongruent motion did not.