Validating a selection test,a predictive probability approach

The problem of inferring the validity of a selection test (x) as a predictor of some criterion (y) when completexy data are not available is investigated. The basic approach is to construct the predictive probability distribution of the unobservedy scores and then derive interval estimates of the least squares regression weights, the difference in averagey scores for selected and unselected cases, and the residual variance in predictingy fromx. Further, an approximation to the predictive distribution of the squared correlation betweenx andy in a future group is derived.     

An optimal property of least squares weights in prediction models

In predicting scores fromp > 1 observed scores in a sample of sizeñ, the optimal strategy (minimum expected loss), under certain assumptions, is shown to be based upon the least squares regression weights computed from a previous sample. Letting represent the correlation between and the predicted values , and letting represent the correlation between and a different set of predicted values , where w is any weighting system which is not a function of , it is shown that the probability of being less than cannot exceed .50. The relationship of this result to previous research and practical implications are discussed.     

An investigation of bilateral asymmetries in electrodermal activity

Research in cerebral laterality supports the idea that functional differences between the left and right hemispheres exist with respect to cognitive style and perceptual ability. Related research, which has examined autonomic nervous system (ANS) correlates of cerebral laterality, suggests that a component of the ANS, electrodermal activity (EDA), is also lateralized. Some findings in the literature report the occurrence of bilateral asymmetries in phasic and tonic EDA as a function of a left or right hemisphere preference for information processing. This experiment used normal male subjects who were either left or right movers in a test of Conjugate Lateral Eye Movement (CLEM). This selection procedure served to maximize a subject’s preference for either a right or left hemisphere mode of information processing. Bilateral EDA was recorded continuously while subjects performed a visual recognition task using word (left hemisphere) and shape (right hemisphere) stimuli. The data do not support the contention that performance on a procedure chosen to selectively activate a given hemisphere elicits asymmetric tonic and/or phasic EDA. The results show no significant difference in the frequency of elicited skin conductance responses under either of the experimental conditions. Bilateral tonic EDA rose continuously over time and did not vary in either hand as a function of task. The present results fail to offer support for either of the hypotheses which argue for I) increased contralateralexcitation with selective hemispheric activation, or 2) increased contralateralinhibition of the EDR with hemispheric arousal.     

Estimating correlations with missing data,a bayesian approach

The posterior distribution of the bivariate correlation is analytically derived given a data set wherex is completely observed buty is missing at random for a portion of the sample. Interval estimates of the correlation are then constructed from the posterior distribution in terms of highest density regions (HDRs). Various choices for the form of the prior distribution are explored. For each of these priors, the resulting Bayesian HDRs are compared with each other and with intervals derived from maximum likelihood theory.     

The P300 component of the event-related brain potential in a short-term memory paradigm]

In numerous investigations the P300-component of the event-related-brain-potential (ERP) has proved a valid indicator of memory activities. The present study explores the amplitude of the P300 in an isolated short term memory task with variant difficulties. In two experiments the reproduction of senseless memory material was examined using the categories "syllables" and "consonants". One syllable was thereby synonymous with the so-called "chunk" which represents a subjective unit arising from grouping of memory material. The results show a significant increase in P300-amplitude in a line with memory load in both categories. On the contrary there is no significant difference in the amplitude of P300 between the two categories. These results suggest that the costs for storing one syllable are comparable with those for one consonant.     

The position of school psychologists in negotiations: One viewpoint

Teachers' associations are becoming increasingly militant. They tend not to represent psychologists in negotiations. School psychologists need both representation and to take a position in relation to work stoppages. He has the following options: (a) identify completely with the teachers' association and its methods and goals and refuse to report during work stoppages; (b) identify with management and perform management duties during the stoppage; or (c) negotiate separately with boards of education, but neither take part in the work stoppage nor assume duties beyond his normal role and function. The last appears to be the better alternative provided the psychologist makes his position clear to both labor and management organizations prior to a work stoppage.     

The effects of alcohol consumption and expectancies in an experimental date rape analogue

This study examined the impact of perceived token resistance and the psychological and pharmacological effects of alcohol consumption on men's discrimination of when a female wants her partner to stop his sexual advances. In a 2 (alcohol vs. no alcohol) × 2 (expectancy vs. no expectancy) × 2 (perceived token resistance vs. no resistance) randomized factorial design, male college students were exposed to an audiotape of a date rape. Before listening, participants were told that on the previous date the woman did not resist sexual contact or that she initially objected to the contact but the man was able to obtain the level of intimacy he desired. Relative to participants assigned to the no-alcohol expectancy or no-alcohol consumption group, participants in the alcohol expectancy and alcohol consumption groups took significantly longer to determine that the man should refrain from attempting further sexual contact. The implications of the findings are discussed.This investigation was carried out by the first author under the supervision of the second author in partial fulfillment of the requirements for the degree of Doctor of Philosophy.