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At least 163 records · Page 9Linked to original sources
PubMed1988

Expectancy and visual-spatial attention: effects on perceptual quality.

When we expect important stimuli at a particular spatial location, how does our perceptual sensitivity change over space? Subjects were cued to expect a target stimulus at one location and then required to perform one of the following tasks at that and three other locations: luminance detection, brightness discrimination, orientation discrimination, or form discrimination. The analysis of subjects' performance according to signal detection theory revealed changes in both sensitivity and bias for each of these tasks. Sensitivity was maximally enhanced at the location where a target stimulus was expected and generally decreased with distance from that location. Factors that influenced the gradient of sensitivity were (a) the type of task performed and (b) the spatial distribution of the stimuli. Sensitivity fell off more steeply over distance for orientation and form discrimination than for luminance detection and brightness discrimination. In addition, it fell off more steeply when stimuli were near each other than when they were farther apart.

Attention↗
PubMed1990

Integrating information from separable psychological dimensions.

This article examines decision processes in the perception and categorization of stimuli composed of the separable psychological dimensions, orientation and size. The randomization technique (Ashby & Gott, 1988) of general recognition theory, which allows accurate estimation of a subject's decision boundary in a categorization task, is used in 4 experiments. Even though the stimulus components are clearly separable, it was found that Ss were not constrained to use separable response strategies, nor were they constrained to attend to distance to the prototypes. Instead, they used decision rules that were nearly optimal, even if this required information integration or for the Ss to attend to higher level category properties such as component correlation.

Adult↗
PubMed1995

Forms of inhibition in animal and human learning.

Forms of inhibition were identified in human predictive learning that are qualitatively similar to those identified by P.C. Holland (1984) in rats. When P (positive) signaled the outcome and PN (N = negative) signaled the absence of the outcome, participants learned the discrimination, but the negative cue did not suppress responding to a transfer cue. Post-learning reversal training, in which N was followed by the outcome, did not abolish the original discrimination. These 2 results imply a configural form of inhibition. Negative transfer, which indicated a 2nd, elemental form of inhibition, was observed when neither PN nor N were reinforced during the discrimination stage. Under these conditions, negative transfer and the original discrimination were both abolished by individually pairing N with the outcome. Empirical parallels and differences with the animal conditioning literature are discussed.

Adult↗
PubMed1990

The Kamin blocking effect, incidental learning and psychoticism.

The Kamin blocking effect consists in impaired learning of an association between a conditioned stimulus (CS2) and an unconditioned stimulus (UCS) if CS2 is presented simultaneously with a different CS (CS1) already associated with the UCS. It is well established with animal but not human subjects. In the two experiments presented here, the effect was clearly demonstrated with UCS = a computer-presented yellow square, CS1 = a blue square and CS2 = a noise (Expt 1) or two smaller white squares (Expt 2). The Kamin effect has, by some theorists, been attributed to switching of attention away from CS2, which conveys only redundant information. If so, the size of the effect should co-vary with indices of selective attention commonly used with human subjects. As predicted, the blocking effect was found to be smaller in subjects who displayed a high degree of incidental learning in either of two tasks in which intentional vs. incidental learning corresponded to (1) words vs. word position, or (2) a target initial word letter vs. non-target initial letters. We report elsewhere that the blocking effect is absent in acute schizophrenics. In the present experiments, however, there was no systematic relation between any of four measures of psychoticism, or intelligence, and either the blocking effect or incidental learning.

Adult↗
PubMed1990

Equivalence classes generated by sequence training.

In Experiment 1, 3, adult females were taught with verbal instructions and contingencies to select, in sequence, three arbitrary visual stimuli from an array of five stimuli. After four different sequences were taught, match-to-sample tests assessed emergent conditional relations among all stimuli that had been selected in the same order in the sequences. Subjects' performances indicated development of four stimulus classes, three based on ordinal position and one based on nonselection. Next, match-to-sample training established conditional relations between each of four novel figures and one member of each of the ordinal stimulus classes. Tests confirmed that the classes were equivalence classes, each expanded by one new member. In subsequent sequence tests, the new stimuli were selected in a sequence that was consistent with ordinal class membership. Experiment 2 replicated Experiment 1 with 2 different adult females, but the verbal instructions were omitted. Results were similar to Experiment 1, except that extensive review and retesting were required before expansion of the ordinal classes with the novel figures was observed.

Adult↗
PubMed1990

Cue interaction in human contingency judgment.

Most studies of human contingency judgment have been based on the assumption that frequency information about one predictor is assessed in isolation of information about other predictors. Recent evidence, however, suggests that the judged predictive strength of one cue is influenced by the predictive strengths of other copresent cues. Two experiments demonstrate that stimuli with the same outcome contingencies may nonetheless have different predictive strengths as the result of cue interaction. The first experiment, in which a within-subject design was used, provides a demonstration of blocking. A stimulus presented in compound with a strong predictor was rated as less predictive than another stimulus that was presented in compound with a nonpredictive cue. In the second experiment, cue interactions in conditioned inhibition were examined. A stimulus gained negative predictive strength as the result of compound presentations with a positive predictor when the outcome was not presented. This negative predictor was compared with an otherwise analogous stimulus that was not presented in compound with a positive predictor. These results support the use of animal-conditioning models as accounts of human contingency learning.

Adult↗
PubMed1989

Patient teaching for elders.

There are many myths regarding elders' abilities to learn, which may affect the nurse's approach to the older person during patient teaching. Physiological changes of aging have an effect on learning and must be considered by the nurse when a teaching plan is developed. The older person has the capability to learn and probably will do so when the time is right, when the plan is right, and when motivated to learn. Learning is facilitated by a one-to-one encounter, but also may occur in a group or community setting.

Aged↗
PubMed1983

Alcohol and proactive interference: a test of response eccentricity theory of alcohol's psychological effects.

A theory is offered which proposes that alcohol induces eccentricity in the neurophysiological mechanism by which responses are selected for emission by the nervous system. Hence, in a specific stimulus situation, normally high probability responses decrease in frequency, while lower probability responses increase in frequency. From this postulate, the prediction is derived that in a verbal paired-associate learning task administered over two days, alcohol will decrease proactive interference from first-day learning (high probability associate) and result in enhanced acquisition of second day items. This paper reports two experimental tests of the prediction, each of which employs four subject groups tested over two days. Experiment 1 (n = 24) provides tentative support while ruling out some potential confounds. With these confounds eliminated, Experiment 2 (n = 40) confirms the prediction in a more direct test. A variety of possible alternative explanations for the counter-intuitive finding of improved cognitive performance under alcohol are evaluated against the theory proposed, as are other recent theories which address the variable behavioral effects of alcohol. Finally, the new data gathered on the effects of imagery instructions on proactive interference are considered.

Adult↗
PubMed1990

The diagnostic value of cerebellar-vestibular tests in detecting learning disabilities, dyslexia, and attention deficit disorder.

Neurological and optokinetic measures of cerebellar-vestibular (CV) dysfunctioning were shown to be of significant diagnostic value in differentiating between learning disabled subjects and controls matched for chronological age, sex, handedness, IQ, and background (ns = 35). Although traditionally used electronystagmographic positional and caloric parameters were not similarly discriminating, quantitative measures of vertical nystagmus in various eyes-closed positions appeared to have diagnostic potential and were related significantly to such CV-determined neurological signs as positive monopedal Romberg. As a substantial majority of learning disabled (82.9%) evidenced ADD-like symptoms and since learning disabled subsamples with and without Attention Deficit Disorder (ADD) shared similar coexisting symptoms and CV signs, it appeared probable that learning disabilities and ADD were reflections of the same underlying CV determinants.

Adolescent↗