Identification,discrimination, and match-to-sample as instances of comparative judgment

Identification, discrimination, and match-to-sample paradigms are discussed in the context of a comparative judgment between an external stimulus and a memorial representation. An experiment comparing the paradigms at different levels of stimulus dimensionality is described. The absence of clear-cut interactions of the paradigms with dimensionality differences is offered as support for the contention that the three seemingly diverse procedures may be considered as part of a comparative judgment continuum,with performance differences reflecting increased memorial demands.     

A comparison of game theory and learning theory

It is shown that Estes' formula for the asymptotic behavior of a subject under conditions of partial reinforcement can be derived from the assumption that the subject is behaving rationally in a certain game-theoretic sense and attempting to minimax his regret. This result illustrates the need for specifying the frame of reference or set of the subject when using the assumption of rationality to predict his behavior.     

Background and career orientations of women with mathematical aptitude

A “person-thing” career motivation continuum was tested as a model for structuring this investigation of the personal characteristics and career influences of women in mathematics who entered teaching or nonteaching careers. Women mathematicians who chose to teach were hypothesized to be more person-oriented in career development (i.e., they would be more influenced in the development of career interest by people). In contrast, women who chose careers in mathematically oriented fields, until recently considered nontraditional for their sex (engineering, physical science, accounting, economics, computer science), were expected to be more attracted to the “ideas” or “things” of mathematics.This hypothesis was tested in its null form by comparing personality traits and career influences for two groups of university senior women. Each group was composed of 30 subjects who had elected at least 24 semester credit hours in mathematics. Subjects were randomly selected after individuals were first stratified into two groups, according to whether they chose teaching or nonteaching careers in math-related areas.Second order personality traits derived from subjects' responses to Cattell's 16 PF Questionnaire were employed to assess personality differences. A biographical questionnaire was utilized for collecting data relative to career-influence factors. Multivariate analysis of variance and chi square statistical models were employed for data analysis.The two groups differed significantly in overall personality profiles. This difference was related to the nonteaching group's having scored significantly higher (than did the teaching group) on both the creativity and independence personality factors. Related to career influence, the nonteaching women appeared to develop their interests in mathematics somewhat earlier than did their counterparts who chose to teach. Women teachers were more attracted to their careers because of the influence of people engaged in mathematically oriented work. More of the nonteaching women cited influences associated with mathematics, itself, such as books, demonstrations and independent studies, as paramount in their career decision-making. Also, men were seen as more influential in fostering their career development by the non-teaching group, while in contrast, the teachers chose women as more influential in the development of their interests in mathematics.These findings appear to support the “person-thing” hypothesis associated with the development of career interests for women in mathematics.     

Position reversal training in the virginia opossum: Evidence for the acquisition of a learning set

To obtain an estimate of the learning ability of opossums, five tame ones were trained on a series of position reversals to a criterion. With 4 trials per day there was no consistent improvement over a series of 15 reversals. When each daily session was increased to as many trials as needed to reach criterion, errors dropped sharply, indicating the formation of a position learning set. Upon return to 4 trials per day, 3 of 4 animals continued to perform with few errors, showing transfer of learning set. Opossums do more poorly than rats on this task, which is in agreement with the relative phyletic level of the two species.     

Cathodal tDCS of the Left Posterior Parietal Cortex Increases Proprioceptive Drift

In aiming movements the limb position drifts away from the defined target after some trials without visual feedback, a phenomenon defined as proprioceptive drift (PD). There are no studies investigating the association between the posterior parietal cortex (PPC) and PD in aiming movements. Therefore, cathodal and sham transcranial direct current stimulation (tDCS) were applied to the left PPC concomitantly with the performance of movements with or without vision. Cathodal tDCS applied without vision produced a higher level of PD and higher rates of drift accumulation while it decreased peak velocity and maintained the number of error corrections, not affecting movement amplitude. The proprioceptive information seems to produce an effective reference to movement, but with PPC stimulation it causes a negative impact on position.     

Infant visual fixation: The effect of concentricity,curvilinearity, and number of directions

The goal of the study was to define certain of the effective dimensions of visual stimulation in the infant's visual environment by analyzing the well-documented preference for the bullseye over a pattern of horizontal stripes. The stimuli were ten black and white patterns, including the bullseye and the stripes, designed to vary along three dimensions: concentricity, curvilinearity and number of directions within the stimulus. The dependent measure was total fixation time corrected for position bias. The subects, 18 three-month-old infants, were tested three times each in order to present them with the ten stimuli in all possible combinations with positions reversed.All three dimensions were found to be effective in varying degrees. The results were discussed in terms of underlying mechanisms and the infant's ability to process information from a multidimensional stimulus.