Francis Cecil Sumner: his views and influence on African American higher education.

During the mid-1920s, Francis Cecil Sumner, the first African American to earn a PhD in psychology, published 2 articles concerning strategies for the higher education of African American youths. These articles called for a system of segregated education emphasizing an "industrial" style advocated by Booker T. Washington, as well as suggesting a measure of character development. The justification cited by Sumner for such unequal education for African Americans was the cultural inferiority of that population. The present article argues that Sumner's views were couched in terms that fit the prevailing paradigm of the White establishment, with the purpose of generating political and economic support for any type of higher education for African Americans. Evidence drawn from Sumner's early education and his graduate school days at Clark University, as well as testimonials from colleagues and students, are provided in support of this hypothesis.

Allocation of attention and practice in the production of time intervals.

During a baseline trial, participants attempted to produce a 60-sec. interval while working at either a simple tracing task or others that involved mirror-tracing. Subsequent practice with the assigned task, expected to reduce the need for allocation of attention to mirror-tracing for those groups, produced predictable effects on a second trial of duration producing. Those performing mirror-tracing reduced production times on the post-practice trial, while those performing simple tracing showed no change after practice. These results are interpreted within the attentional allocation model of estimation of prospective duration.

Contrasting task demands alter the perceived duration of brief time intervals.

Four experiments were performed to assess the effects of task differences on duration judgments. Experiments 1 and 2 used the method of reproduction in prospective, within-subjects designs; their results supported previous research on the effects of task difficulty. Both experiments, using tasks that varied along somewhat different dimensions, found that subjects provided reproduction values that varied inversely with task difficulty. That is, while subjects tended to underreproduce across all tasks, the more difficult the task performed during the target interval, the greater the extent of the underreproduction. Experiments 3 and 4 used a modification of the reproduction method by placing demands upon the subjects during both the target interval and the reproduction phase of each trial; they demonstrated that the greater the degree of contrast between demands made by the task performed during the target interval and those made during reproduction, the less accurate the duration reproduction. The results are discussed in terms of the contextual and resource allocation models of duration estimation.

Anchoring effects on judgement, estimation, and discrimination of numerosity.

Three experiments (N = 234) examined anchoring effects on judgement, estimation, and discrimination of numerosity. Subjects were anchored by preexposing them to random dot patterns with a mean quantity of 25, 50, or 75 dots. Subsequent testing with patterns having greater or less numerosity than the anchoring point resulted in predictable effects, including positive or negative contrast effects for numerosity judgements (Exp. 1), positive or negative contrast for the numerical estimation of quantity (Exp. 2), and a larger number of errors when subjects attempted simultaneous discrimination between two dot patterns (Exp. 3). The results extend previous findings for anchoring effects to the stimulus dimension of numerosity.

Chemosensory and hormonal mediation of social memory in male rats.

The persistence with which adult male rats investigated a juvenile conspecific was significantly reduced following preexposure to either the juvenile or chemosensory stimuli (soiled bedding or urine) from that juvenile. The reduced persistence did not occur when the chemosensory stimulus came from a juvenile different from the one with which the subject was subsequently tested, which suggests the presence of a chemosensorily mediated social memory. It is suggested that any such memory may have adaptive value in that it permits a male rat to more readily identify a novel conspecific. Also, the lack of reduced persistence of social investigatory behavior in castrated subjects demonstrates the importance of male gonadal hormones in the formation, storage, and/or retrieval of the proposed chemosensorily mediated social memory.

Selection for agonistic behavior in wild female mice.

This article reports the results of 11 generations of selective breeding for isolation-induced, interfemale aggression in Mus musculus. Within-family selection was used to form two high, two low, and two unselected control lines, beginning with a population of wild-trapped mice. Selection was successful in establishing the divergent lines, so that in recent generations about 50% of high-line animals attack, as do 25% of controls and 5% of lows. Realized heritabilities for eight generations of selection were 0.12 for H1, 0.14 for H2, 0.34 for L1, and 0.46 for L2. Male aggression has apparently not shown a correlated response to selection for female aggression. Group housing reduces the aggression of female mice, but the order of the lines is maintained under either isolation or group housing. Practical problems encountered in this selection program are discussed.

Correlated characters in selection for aggressiveness in female mice. II. Maternal aggressiveness.

The present study investigated whether maternal aggression has shown a correlated response in a program of artificial selection for isolation-induced interfemale aggression in housemice. Females from the first replicate of lines (H1, C1, L1) and the second replicate of lines (H2, C2, L2) from generation S5 were given daily aggression tests for 20 consecutive days following the birth of their first litter. Evidence of a correlated response was found for replicate 2, but results for replicate 1 provided no evidence of a correlated response. In generation S10, when better separation of the lines on isolation-induced aggression had occurred, the study was repeated. In S10 there was clear evidence of a correlated response in both of the replicates.