On the detection of stepwise changes in a constant signal level

A stepwise change in the frequency of a continuous pure tone is taken as an element signal. The detectability of a single step is compared with the detectability of a pattern composed of two such steps in order to determine the ways in which the steps interact and how these interactions depend upon the time interval between the steps. It is shown that two positive steps separated by D msec interact by summation (d’ for two steps being greater than d’ for a single step) and that this summation is 100% even when D=100 msec. The extent of summation decreases as D is increased beyond 100 msec, leveling off at about 40% when D is near 1,000 msec. A positive step followed by a negative step (an increment) presents a more complex picture. When D=0 msec, the pattern is the null signal, and, of course, the two steps subtract completely. As D is increased, the extent of subtraction decreases, becoming zero when D is about 400 msec. Increasing D beyond 400 msec results in summation, reaching about 40% when D=2,000 msec. For D less than about 1,000 msec, the sign of the second step in a two-step signal is important: two steps of like sign summate, and two steps of unlike sign subtract. However, when the two steps are separated by about 2,000 msec, the sign of the second step is irrelevant: summation occurs, and the extent, about 40%, is the same for two steps of like sign and two steps of unlike sign. A brief theoretical discussion stresses the extant need for an information-processing theory of signal detection.     

Stereoscopic acuity for photometrically matched background wavelengths at scotopic and photopic levels

Two Ss made equidistance settings in a two-rod apparatus using white and four chromatic (red, yellow, Feen, and blue) backgrounds, photometrically matched at each of eight or nine teat levels within a total retinal-illuminance range of 4 log units. The binocular depth setting were analyzed in terms of the angular magnitude of both the Yariable error, η_AD, and the constant error, η_ΔR When η_AD is plotted as a function of retinal illuminance, the curves for each of the four chromatic IIIId white backlfound coditions show that at low retinal illuminances, η_AD, is initially large, and with increasing background illumination, η_AD progressively decreases to approach a final low asymptotic value. As predicted by the duplicity theory of vision, each experimental curve shows a dircontinulty at about ?1.0 lot td (corresponding to a background luminance value of about 0.0069 fL with the 2.5-mm artificial pupil used) reflecting the transition from rod to cone functioning. The curves representing the different wavelengths essentially overlap throughout the total illumination range, indicating that, for both rod and cone vision, wavelength has no differential effect on the variability of depth settings. The data for η_ΔR are less regular than those for η_AD and the rod-cone discontinuities appear less pronounced. The data are analyzed in terms of the relative contribution of the rod and cone mechanisms to performance level.     

Low-variance stimulus-response latencies: Deterministic internal delays?

When special procedures are used to minimize S-R latency variance, all responses fall within a distribution which has a standard deviation near 10 msec. This minimum SD is the same whether the mean latency is at the simple RT limit or as much as 400 msec longer than that limit. Over this range, the latency distribution is everywhere the same, symmetrical and highly-peaked and not typical of RT. Above a mean latency of 550 msec, variance increases as the mean increases in the way that would be expected if SD/M were constant for the delay in excess of 550. By way of interpretation, it is proposed that there are internal time delays which can be inserted into the S-R chain. These delays can be adjusted to any value between 0 and about 400 msec, but once set, they can be deterministic. Other considerations are discussed which suggest that the deterministic time delays are in the afferent part of the S-R chain.     

Memory scanning by children: Meaningfulness and mediation

Two experiments were performed for the purpose of isolating factors that influence speed of memory scanning by children. The first experiment revealed an interaction involving age and type of stimulus. Young children required relatively greater time to process ambiguous stimuli. The second experiment, involving a pretraining phase designed to induce mediation, showed that preschool children scan representations more rapidly when given instructions to apply a mediator.     

Androgyny as type and androgyny as behavior: Implications for gender schema in males and females

Blending represents the integration of masculine and feminine behaviors within a discrete social situation. This process represents an alternative view of androgyny, commonly conceived in terms of extensive masculine and feminine repertories allowing flexibility in sex role display from situation to situation. The present study was concerned with the simple relations between each of these two androgyny constructs and gender schema (the perception, processing, and recall of information in terms of conventional sex role stereotypes) as well as higher order relations that consider their interactions. No gender-schema effects of any kind were evident for males. Men were equally sensitive to sex role stereotypes whether they were or were not androgynous types, whether they reported more or less androgynous behavior, or whether they combined the two forms of androgyny or not. Androgynous types of women were the least concerned about traditional sex role distinctions between men and women, just as feminine women displayed the strongest gender-schema effects. However, the lack of concern for sex role stereotypes was restricted to androgynous types of women who did not blend their feminine and masculine attributes into androgynous behavior.     

Information seeking of high- and low-anxiety subjects after receiving positive and negative self-relevant feedback

The present paper reports an experiment in which subjects received fictitious intelligence test feedback that was either negatively or positively discrepant with their self-evaluation. They were then given an opportunity to choose among several articles containing information that either derogated intelligence tests (test-disparaging information) or argued for their validity (test-supporting information). The main finding of this study consists of an interaction between the personality factor anxiety and the feedback variable: High-anxiety subjects prefer test-disparaging information significantly more in the negative feedback condition than in the positive feedback condition, whereas low-anxiety subjects show no difference in preference for test-related information as a function of the feedback condition. These results are in line with past theoretical reasoning and experimental findings showing that high-anxiety subjects feel more threatened by negative self-relevant feedback than do low-anxiety subjects.     

Dimensions of problem behavior in deaf children

The Behavior Problem Checklist was completed by the teachers of 192 deaf students who attended a special day school for the deaf. Three separate factor analyses were performed. Four factors that correspond to the dimensions found in earlier research and previously labeled conduct disorder, personality problems, immaturity inadequacy, and socialized delinquency were found. An additional factor labeled passive inferiority was also extracted.We wish to acknowledge the cooperation of Mr. Richard Dirst and his excellent faculty at the Atlanta Area School for the Deaf.     

Ultrastable stimulus-response latencies: Acquisition and stimulus control

Modifications were made to Kristofferson’s (1976) response-stimulus synchronization procedure which resulted in a further reduction in the estimate of minimum S-R latency variance. Minimum variances near 50 msec² were obtained whether mean latency was 310 or 550 msec. Within this range, latency distributions were the same, symmetrical and sharp-peaked, and unlike typical RT. All responses fell within a 50-msec time window. This independence of mean latency and latency variance was present throughout acquisition. A special technique allowed isolation of the controlling stimulus for synchronization timing, and showed that subjects were able to transfer control to another modality with no loss of performance. Results are discussed in terms of support for the notion of nonvariable, internally timed delays which can be inserted in the S-R chain. These delays are easily adjustable, but, once set, are deterministic. The role of feedback in acquisition and maintenance of synchronization performance is also examined.