Different slopes for different folks: Process analysis of spatial aptitude

Adults differing in spatial ability were tested on problems involving the mental rotation of familiar alphanumeric stimuli and unfamiliar stimuli drawn from the Primary Mental Abilities Space Test. Individual differences in spatial ability were associated with speed rather than accuracy of mental rotation processes. Ability differences were correlated with the time to rotate familiar alphanumerics and the additional time to encode, compare, and rotate unfamiliar stimuli. The results are discussed in terms of differences in elementary information processes associated with the representation and transformation of visual information.     

Weeping: Evidence for a cognitive theory

According to a two-factor cognitive theory of weeping, schema-incongruent information and efforts to assimilate it create arousal; resolution, giving up of the schema, and cessation of the assimilation efforts result in arousal reduction and may be associated with emotional tears. To assess these predictions, female subjects were shown an emotional film under one of two conditions. In one condition only schema-induction and incongruity phases were viewed, while the other condition viewed the complete film (i.e., schema-induction, incongruity, and resolution). Consistent with expectations, incongruity was associated with increased stress and depressed mood. Only subjects who viewed the complete film reported significant decreases in these states. The final scene, assumed to trigger schema change, produced the greatest amount of weeping.This paper is adapted from a portion of a doctoral dissertation conducted by the first author. We gratefully acknowledge the assistance of Walter Katkovsky and Raymond Ditrichs. A version of this paper was presented at a meeting of the Western Psychological Association, May 1986.     

Baroreflex responses to the stress of severe hemorrhage in the rat

In two groups of anesthetized (sodium pentobarbital), mature Sprague-Dawley rats, 1) aged 2 years and weighing 300–400 grams, 2) aged 6 months weighing 200–300 grams, baroreflex-induced circulatory responses to pressor (graded doses phenylephrine) and depressor (graded doses nitroglycerine) agents were compared to those occurring during progressive hemorrhage in the same animals. Graded withdrawals of blood from the femoral artery elicited progressive hypotension accompanied by bradycardia rather than expected tachycardia. Graded doses of phenylephrine (2.5 ug to 40 ug bolus, via femoral vein) regularly induced elevations in arterial blood pressurewith associated reflex bradycardia. Similarly graded doses of nitroglycerine induced a marked decline in arterial blood pressure,without expected tachycardia. As hypotension became more severe (during hemorrhage), atrioventricular conduction slowed and A-V block developed, resulting in statistically greater slowing in ventricular than in atrial excitation and contractile cycles. Heart failure during hemorrhage in the rat is characterized sequentially by severe bradycardia, depressed atrial contractile force, impaired conduction and A-V block, terminating in ventricular, atrial, and finally, in pacemaker failure. Baroreceptor reflexes were blunted or even absent in both young and old animals during induced hypotension.     

Suppression of optokinesis by a stabilized target: Effects of instruction and stimulus frequency

Subjects viewed a foveally stabilized target presented against a background field of dots moving sinusoidally. Several different modes of viewing the target were used (subjects were instructed to gaze, look, or hold), and the frequency of sinusoidal field motion was varied from 1/32 to 2 Hz. In line with previous findings, the presence of a stabilized target resulted in substantial suppression of optokinesis. The characteristics of this suppression (gain and phase of slow residual eye movements) were dependent on both the mode of viewing the target and the frequency of field motion. When subjects used an imaginary target, little suppression occurred. These findings provide an overall profile of dynamic characteristics of mechanisms involved in the suppression of optokinesis. They support the view that this suppression is significantly determined by the presence of a target against a moving background (even without retinal slip), and by the mode of attending to the target.     

Autonomic nervous control of heart rate orienting and alpha responses in dog

The object of this experiment is to study the autonomic nervous control of alpha responses elicited in classical conditioning. Twenty-two mongrel dogs were trained in classical discriminative conditioning. Typical two-phase tachycardic responses were observed in positive (CS+) trials while only the earliest, phase 1, response was observed in negative (CS-) trials. The phase 1 response, which was identical in CS+ and CS-trials, was compared in dogs before and after selective SA-nodal parasympathectomy (N=7) and beta-adrenergic blockade (N=11). The phase 1 tachycardic response was eliminated by selective SA-nodal parasympathectomy but not by beta-adrenergic blockade. We conclude that the phase 1 response observed in both CS+ and CS-trials with similar time sequence and magnitude is an alpha response. The heart rate orienting response results from a withdrawal of parasympathetic activity with little or no change in sympathetic tone.     

Age differences in encoding and retrieving details of a pediatric examination

Baker-Ward, Gordon, Ornstein, Larus, and Clubb (1993) showed that recall improves over ages 3–7 for events experienced during a physical examination. We used a joint multinomial model to ask whether the improvement was due to encoding, to retrieval, or to likelihood to report. The model fit the Baker-Ward et al. data well and showed that (1) retrieval and reporting cannot be distinguished and (2) the observed effects were due primarily to age-related improvement in retrieval reporting rather than in encoding.     

On people’s understanding of the diagnostic implications of probabilistic data

Two lines of prior research into the conditions under which people seek information are examined in light of two statistical definitions of diagnosticity. Five experiments are reported. In two, subjects selected information in order to test a hypothesis. In the remaining three, they selected information in order to convince someone else of the truth of a known hypothesis. A total of 567 university students served as subjects. The two primary conclusions were as follows: (1) When the task is highly structured by the environment, subjects select information diagnostically, and (2) when the task is less structured, so that subjects must seek relevant information not manifest, they select information pseudodiagnostically. Possible relations to other laboratory inference tasks and to clinical judgment are discussed.     

A note on the nonmetric analysis of psychological intervals for an unknown ordering of stimuli

A modified version of a coordinate adjustment technique which permits the analysis of comparisons of psychological intervals for an unknown ordering of stimuli is described and compared to the original version and to TORSCA. For configurations with a large number of points, knowledge of the rank order of the stimuli does not improve the solution. For configurations with a small number of points, the performance of the new algorithm with an unknown ordering is equivalent to TORSCA.This research was supported by a grant from the Natural Sciences and Engineering Research Council of Canada.