Effect of eye movements on backward masking and perceived location

A typical trial of this masking experiment involves, in quick succession, presentation of five letters, evocation of an eye movement, and presentation of a spatially localized mask, either a visual-pattern mask or a metacontrast ring. The effect of the mask is to sappress the report of the letter that stimulates the same retinal location, even though the mask appears to cover or surround the letter whose position in real space it shares. Masking is. however, weaker when the eyes move than when they do not. An auxiliary experiment suggests that the spatial aspects of observable (reportable by S) stimulus persistence are unaffected by eye movements, and therefore that observable persistence differs from that susceptible to masking.     

Use of markov-encoded sequential information in numerical signal detection

Twelve Ss made binary decisions with feedback on numbers from one of two normal distributions with equal variances and unequal means. Sequences of distribution choices corresponded to first-order two-state Markov processes with probabilities of change of state of p₁ = p₂ = .50, p₁ = p₂ = .75, and p₁ = p₂ = .25. Performance was best (in d’ terms) when p₁ = p₂ ≠ .50. First-order sequential response dependencies tended to mirror the first-order stimulus dependencies. Violations of a fixed cutoff point decision rule were concentrated in the region of the average critical point, with a bandwidth of about 1/2σ, in which violations were strikingly more frequent than would be expected if they had occurred randomly. These results imply that in this task Ss are using a criterion-band decision rule instead of a fixed cutoff point rule, and that they are basing decisions in the region of the criterion band on information extracted from the sequence of decisions presented to them. The average bandwidth is generally different from the optimum bandwidth used by an ideal O in combining the two sources of information.     

Temporal summation at the warmth threshold

Threshold levels for warmth aroused by infrared irradiation were measured in sLx Ss at durations between 0.05 and 10 sec. Beyond a critical duration of about a second, the threshold does not depend on duration. Below critical duration time t trades for irradiance ? by the formula ? = kt^?0.82. That these properties do not depend much on areal extent of stimulation was demonstrated by a study that compared temporal summation for two different areas of the same S’s skin. Individual differences in apparent absolute sensitivity were explored under the rubric of the theory of signal detection.     

Teaching experimental psychology with on-line computers

The purpose of this paper is to describe the use of on-line computers in the teaching of experimental methodology. Computer models are featured.     

Conditions affecting attempts to convert fate control to behavior control

This study examined the extent to which male and female subjects rewarded another like-sexed person as a function of his (her) performance, their fate control over his (her) rewards, and the extent to which he (she) had counterpower. Results supported hypotheses derived from social exchange theory and past studies of equity in that male (but not female) subjects tended to reward differentially the other most when their own payment was determined by his performance and they had high fate control. This effect, however, was not substantial, and, therefore, results suggest that persons are somewhat reluctant to convert their fate control to behavior control even under conditions in which such behavior is reasonable.     

Self-regulation in the modification of disruptive classroom behavior

This study compared self-regulation and external regulation procedures in the treatment of children's disruptive classroom behavior. After baseline data were collected, three of the four most disruptive children in each of 10 first- and second-grade classrooms received reinforcement for achieving low rates of disruptive behavior. The fourth child served as a control subject throughout the experiment. Two of the three experimental subjects were then taught to self-observe their own disruptive behavior. In the final reinforcement period, these subjects were given control over dispensing reinforcers to themselves, based on their self-collected behavioral data while subjects in the other experimental group continued with the externally managed reinforcement. In extinction, reinforcement was discontinued for all subjects, but one of the self-regulation subjects in each classroom continued overtly to self-observe. Results indicated that both reinforcement programs reduced disruptive behavior. The self-regulation procedures were slightly more effective in reducing disruptiveness than was the external regulation procedure, and this advantage persisted into extinction. These results suggest that self-regulation procedures provide a practical, inexpensive, and powerful alternative in dealing with disruptive behavior in children.     

Response system processes in absolute judgment

Consistent relationships are found between Ss′ absolute judgments of the value of a stimulus and the previous sequence of both stimuli and responses. The form and magnitude of these sequential effects are shown to depend on the presence or absence of feedback and on task difficulty. The pattern of the sequential effects found allows the conclusion that they are due to purely response-system processes. A two-stage model of the judgment process is proposed, and it is argued that observed assimilative effects account for the central tendency effects observed in category judgments.     

Two studies of visual search for word targets with controlled rates of presentation*

The two studies reported involve the visual search of word lists for a target item when the rate of presentation is controlled and the words are presented tachistoscopically. In the first study, the target is differentiated physically from the filler items by being capitalized. When the target is the last item in a list, it is readily identified at all presentation rates, but when it is the first word or is embedded in a list, recognition accuracy is inversely related to presentation rate. In the second study, the differentiation between target and filler items is in terms of the presence or absence of category membership. All Ss at all presentation rates do significantly better on lists with an animal word as a target and a set of unrelated words as filler items than on the converse arrangement.