Effect of distance instructions on size judgments

The proposition that in a reduced-cue setting subjects could use cognitive information about an object's distance to make accurate judgments of its size was tested. An improved paradigm was used to determine the effects of distance instructions per se. This paradigm also allowed independent tests of the effectiveness of cue reduction. The data indicated that cue reduction was successful and that the specific distance tendency governed size judgments when there were no distance instructions. When distance instructions were given, they produced size judgments in precisely the ratio predicted by the size-distance invariance hypothesis. However, there was a large constant error, which reflects a tendency of college students to overestimate the amount of distance signified by a verbal instruction. Hence, cognitive information in the form of verbal distance instructions has precise effects on size judgments, but the latter are not veridical, even in the absence of anchor effects from the specific distance tendency and residual perceptual cues.     

The Impact of Case Characteristics and Prior Jury Experience on Jury Verdicts1

An archival analysis of records from 206 criminal cases was used to evaluate the impact of personal and situational factors on jury verdicts. In particular, we evaluated whether repeated jury service produced bias in jurors that was sufficient to affect jury decisions. A variety of case characteristics and indices of prior jury experience was examined for their relative impact on trial outcomes. Several of the case characteristics were related to verdicts, but the personal characteristics were not. Although more than half of the juries contained experienced jurors, juror experience had little influence on verdicts in either major or subsidiary analyses. However, there was a slight tendency for small juries with large proportions of experienced jurors to convict. This result is consistent with data from Kentucky; a meta-analysis across the two data sets indicates that it is a reliable finding. The results have implications for the determination of jury size. We suggest that future research examine the possibility that increasing jury size may reduce the influence of an individual's bias by providing a balance of other jurors with no or offsetting biases.     

Eliminating selective stimulus control: a comparison of two procedures for teaching mentally retarded children to respond to compound stimuli

Selective stimulus control occurs when behavior fails to come under control of all characteristics of a compound stimulus after discrimination training. Two different assessment procedures, one used in prior research and the other incorporating incorrect stimuli (S - 's) which differed minimally from the correct stimulus (S+), were used to detect stimulus control deficits characteristic of selective stimulus control. The efficacy of two training procedures in eliminating selective stimulus control observed with three trainable mentally retarded children was evaluated in Experiment 1. A training procedure using S - 's that were minimally different from the S+ was designed to reduce the probability that stimulus discriminations could be based on stimulus characteristics other than experimenter-specified characteristics defining the S+. This procedure proved more effective in preventing and eliminating selective stimulus control as measured by both assessment procedures than an alternate discrimination training procedure that failed to impact the more stringent measures of selective stimulus control. Experiment 2 indicated that these improvements in stimulus control were not a function of varying degrees of difficulty between stimulus sets or of a prior history of discrimination training with the less effective training procedure. The need for better assessment procedures to detect selective stimulus control and suggestions for further improvements in discrimination training procedures are discussed.     

Gait characteristics of children during free ascent climbing performances

The purpose of this study was to examine the characteristics of children's climbing performances with an emphasis placed on determining the appropriate dimensions of climbing apparatus as shown by the gait patterns adopted by the users. Seventy-two male and female children were selected and assigned to one of eight groups according to their age. The population comprised children whose ages ranged between 1.5 and 5.5 years with groups designated every 6 months (total eight groups). Each subject performed three trials consisting of an ascent of a 1.83 X 1.83 m climbing structure. The wooden climbing frame incorporated a regular matrix of handholds/footholds with a between rung difference of 0.15 meters. On command, the subjects climbed from a target area centered at the bottom of the frame to the top where the parent or guardian was located to offer encouragement. all trials were filmed using one 16 mm motion-picture camera. A large mirror placed in the field of vision permitted the recording of both the rear and lateral views. The temporal and displacement characteristics of a representative gait cycle for each subject were analyzed. The results provided little evidence to indicate either an age related or overall preferred consistent climbing gait. However, the most common method of ascent (38.92%) involved an order of peripheral segment movement of the right leg followed by right arm then left leg followed by left arm. A statistical analysis utilizing analysis of variance procedures with Newman Keuls post-hoc evaluation (p<0.05) conducted on the temporal characteristics of a gait cycle during a trial by each subject revealed: (1) that both the absolute contact and airborne times for the upper and lower limb segments were greater for the subjects between 1.5 and 2.5 years than for the subjects between 4.5 and 5.5 years, (2) that there existed an age dependent systematic decrease in the relative contact times for the lower limb segments, (3) that the age dependent decreases in the absolute lower limb airborne times were relatively greater than the corresponding decreases in the contact times with a significant linear trend being recorded. While the preferred horizontal spacing was found to be approximately 0.15 meters for all subjects, the preferred inclined spacing between consecutive handholds/footholds was found to be age dependent.     

Cortical localization of finger spelling and oral language: A case study

Finger spelling of letters and words was mapped by means of the cortical stimulation procedure in a hearing patient undergoing a left dominant anterior temporal lobe resection for relief of a seizure disorder. Finger spelling was disrupted at five sites: three overlapping with one or more oral language functions at sites in the classical posterior language area, two relating only to finger spelling in the anterior temporal region. Following the resection which included these latter sites, both short- and long-term postoperative deficits in finger spelling are described. Implications for the organization of manually based communication behavior in the left hemisphere are discussed.     

On the exponent in the "generalized" matching equation

A power function equation between ratios of behavior and ratios of reinforcement rates has been called a generalized form of Herrnstein's (1961) matching law, even without a formal relationship having been shown between the two equations. The present work uses a functional relationship to prove that when ratios of reinforcement are not equivalent to ratios of behavior, and the transform leading to this inequality is consistent for every pair of reinforcement rates, the result is a power function relationship between response and reinforcement ratios. The label “generalized matching equation” for the power function equation is thus validated formally.     

Nonverbal communication of couples in conflict

This article examined the rates, contextual meanings, and attributional meanings of nonverbal behavior occurring during role-played conflict between dating couples. Eighty couples reported perceptions of their own behaviors and their partners' behaviors and were observed in a laboratory setting by trained raters. The nonverbal channel was used significantly more by females than by males and to express approval rather than disapproval. However, the nonverbal-disapproval summary category demonstrated weak validity. Eye contact had the most complex, unexpected contextual meanings. Reduced eye contact appeared to variously convey disapproval, cues of lower interpersonal power, and a reduction of intimacy to compensate for accompanying increases in other approval behaviors. Despite significant correlations between nonverbal and verbal behaviors, dating partners rarely based their perceptions of their behavior or their partners' behavior upon their rates of nonverbal behaviors.     

Comments on Thomas and Jamison's “a test of the X-linked genetic hypothesis for sex differences on Piaget's water-level task”

In this paper H. Thomas and W. Jamison's (Developmental Review, 1981, 1, 274–283) formulation and evaluation of an X-linked genetic model for explaining male superiority on Piaget's water horizontality task is examined. Criticisms are leveled against (1) the suitability of the model invoked for explaining the sex difference found, (2) the power of the statistical test used to evaluate the model, and (3) the appropriateness of their correction factors. A research strategy for advancing our understanding of the sex difference in performance at this task is suggested.