Low-cost microcomputer networking: How to get high throughput on a low budget

A very low-cost, high-throughput laboratory data acquisition and experiment control system may be configured by using a star network architecture with a low-cost microcomputer as network controller and one or more microprocessor-based single-board controllers as satellites. A network of this type, using Apple II microcomputer ($1,500 with 48K RAM and one minidiskette drive) as main node and up to seven KIM-1 microcontrollers ($159 each) as satellites is described, and its development is discussed in detail.     

Switching time between overt and covert speech: Generative attention

Four experiments investigated a new phenomenon: the existence of a very large switching time effect that occurs from rapidly alternating between overt and covert (mouthed) speech. This is referred to as an intensity switching effect, and the time taken for each switch is, in itself, long enough for a spoken or mouthed character (letter or digit) to be produced. In Experiments 1 and 2, the intensity switching effect was shown to be different from the switching that occurs between categories of materials (letters and digits) because it is both much larger and much more resistant to practice effects. The intensity switching effect was also shown to be distinct from a memory load effect, since it holds even for perceptually available lists. In Experiments 3 and 4, the issue of a peripheral vs. a central origin of intensity switching was addressed. Evidence was found for a central origin. In addition, two models -of response intensity representation were contrasted: a symbolic or digital model, with intensity altered by parameter substitution, and an analog model, with intensity represented by a moving pointer on an intensity continuum. The results supported the symbolic model. It is concluded that the intensity switching effect is a measure of control processes at work in altering the intensity parameters of the vocal response system.     

A watched pot sometimes boils: a study of duration experience

The ‘watched pot’ phenomenon — the lengthening of duration experience when one is attentively and perhaps impatiently waiting for some event to occur — was studied in three experiments. In them, each observer attended for a duration of 270 sec to a liquid-containing beaker on an electrical burner. Observers who were told that the experiment concerned time perception (prospective paradigm) reproduced the duration as longer than those told that it concerned visual perception (retrospective paradigm). In the prospective paradigm, reproductions were longer if the liquid did not boil than if it did, and an interruption (task-unrelated questioning) shortened reproductions if the liquid did not boil but had no effect if it did. In the retrospective paradigm, if there was boiling or questioning or both, reproductions were longer than if there was neither. Results have implications for hypotheses about duration experience.     

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.     

Effects of nitrous oxide on reactions to “stress”

It has been demonstrated that exposure to the stress of a situation involving conflict or frustration may interfere significantly with subsequent learning. Behaviour under stress is characterized by experiences of “anxiety” and by widespread physiological changes. Inhalation of nitrous oxide has the general effect of reducing the extent of these symptoms.

The present investigation using insoluble and soluble problems has demonstrated that both nitrous oxide and exposure to stress impair learning; but that, when subjects are exposed to stress while under the influence of the drug, the effects of the stress on subsequent learning are abolished. It is suggested that these empirical results may be accounted for either in terms of “anxiety-reduction” or in terms of transfer effects.     

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.