On choosing an inexpensive microcomputer for the experimental psychology laboratory

This report compares currently available. Inexpensive (minimum stand-alone disk-based con-figuration under $2,000), mass-produced microcomputers from the viewpoint of their applicability as experiment control, stimulus generation, and data collection devices for the experimental psychology laboratory.     

Summation of response rates to discriminative stimuli associated with qualitatively different reinforcers

In Experiment I, a four-ply multiple schedule was used to study the effects on rate of responding in rats of food, water, and food and/or water reinforcement under different deprivation conditions. Food and water were associated separately with different stimuli, the combination of which was associated with food and water together, or with food or water randomly. Rates in the presence of the combined stimuli were consistently intermediate to the rates generated by the separate stimuli, a result seemingly incompatible with a "summation" hypothesis. Experiment II was a simplified systematic replication of Experiment I, verifying the major findings.     

Feature saliency and recognition memory for schematic faces

Memory for schematic faces was studied using a recognition memory paradigm. Ss indicated whether two faces, separated by delays of 6, 12, or 18 sec, were the same or different. Theoretical interest centered on the effects of component feature saliency on response bias and detectability. The main results were that there were fewer misses and more false alarms on the more salient features. Analysis showed that the main effect of feature saliency was on response bias, not detectability.     

Laterality and directional preferences in a simple perceptual-motor task

The superiority of tensor or outward movements of hand and arm over flexor or inward movements has been described, but no evidence has been found relating to directional preferences in simple perceptual-motor tasks.

One hundred children, aged 9 to 13, 50 being right-handed writers and 50 left-handed writers, were tested on a stroke-making task, using both preferred and non-preferred hands. 75 per cent, of them exhibited a preference for outward movements of both hands, a finding which applied equally to both handedness groups. Thus an explanation based on writing habits is discounted.     

On memory for metaphor

Three experiments investigated how metaphors are represented in memory and the effects on memory of variables known to affect metaphor comprehension. Ten theoretically relevant dimensions were examined. In Experiments 1 and 2, free recall across a variety of orienting tasks was consistently and positively predicted by the rated imageability of metaphoric topics (sentence subjects) and the rated number of interpretations for each metaphor. The number of interpretations effect was reversed in the cued recall task of Experiment 3, as metaphors with fewer interpretations were remembered better. These and other results supported previous suggestions that memory for metaphor involves wholistic representations akin to metaphoric grounds. They also revealed consistent differences in the roles of several variables in comprehension and memory for metaphor.     

Effect of a signalled delay between an action and outcome on human judgement of causality

Three experiments examined the influence of a stimulus inserted between an action (pressing the space bar of a computer) and an associated delayed outcome (a triangle lighting up on the screen) on ratings of the causal effectiveness of that action. In Experiment 1, subjects rated an action that produced an outcome immediately as more causally effective than an action that produced a delayed outcome. The rating of the causal effectiveness of an action that produced a delayed outcome in which the delay was filled by a stimulus was higher than the rating of actions that produced the outcome after an unsignalled delay. In Experiment 2, the effect of a stimulus presented uncorrelated with the action or the outcome was examined and found not to enhance the rating of causal effectiveness of an action that produced a delayed outcome. In Experiment 3, the degree of correlation between the stimulus and the consequence was examined. Ratings of the causal effectiveness of the action were greater the higher percentage of delay intervals that were signalled.