A PARADIGM FOR OPERANT CONDITIONING IN BLOW FLIES (PHORMIA TERRAE NOVAE ROBINEAU‐DESVOIDY, 1830)

An operant conditioning situation for the blow fly (Protophormia terrae novae) is described. Individual flies are trained to enter and reenter a hole as the operant response. Only a few sessions of contingent reinforcement are required to increase response rates. When the response is no longer followed by food, the rate of entering the hole decreases. Control procedures revealed that rate of responding is not a simple overall result of feeding or of aging. The flies entered into the hole only if the response was required to obtain the food.     

Chemical diffusion by vacancy pairs in intermetallic compounds with the B2 structure

This paper is concerned with the implications of vacancy-pair mechanisms on chemical diffusion in intermetallic compounds with the B2 structure. The discussion specifically includes the so-called triple-defect mechanism. It is shown that the vacancy-pair mechanism cannot contribute to chemical diffusion in the intermetallic compound at the stoichiometric composition AB. Focusing on the triple-defect mechanism we extend it to non-stoichiometric compositions by including isolated antistructural atoms. By means of Monte Carlo simulation we show that the efficiency of the triple-defect mechanism in providing for chemical diffusion increases linearly with increasing antistructural atom composition but the efficiency remains relatively low unless the composition is highly non-stoichiometric.     

Perceptual-Motor Contributions to Static and Dynamic Balance Control in Children

The authors addressed balance control in children from the perspective of skill development and examined the relationship between specific perceptual and motor skills and static and dynamic balance performance. Fifty 11- to 13-year-old children performed a series of 1-legged balance tasks while standing on a force platform. Postural control was reflected in the maximum displacement of the center of mass in anterior-posterior and mediolateral directions. Simple visual, discrimination, and choice reaction times; sustained attention; visuomotor coordination; kinesthesis; and depth perception were also assessed in a series of perceptual and motor tests. The correlation analysis revealed that balancing under static conditions was strongly associated with the ability to perceive and process visual information, which is important for feedback-based control of balance. On the other hand, when greater task demands were imposed on the system under dynamic balancing conditions, the ability to respond to the destabilizing hip abductions-adductions in order to maintain equilibrium was associated with motor response speed, suggesting the use of a descending, feedforward control strategy. Therefore, like adults, 11- to 13-year-old children have the ability to select varying balance strategies (feedback, feedforward, or both), depending on the constraints of a particular task.     

Transfer Variables in Tracking Skills

In the present work the effect of two task variables on transfer were studied: shape of the track-circular or triangular; and target speed-constant or variable. One or both of these variables was changed on transfer. Experimental conditions were (a) 10 preshift and 10 post-shift trials, and (b) 20 single-trial alternations of two tasks. 22 groups of 12 Ss each were tested. Condition (a) showed positive transfer with single variable change and zero or negative transfer with simultaneous change in two variables, and condition (b) annulled all transfer effects. Results are discussed in terms of commonality between tasks and receptor and perceptual anticipation.     

Hostility on the TAT as a Function of Defensive Inhibition and Stimulus Situation

It was hypothesized that there would be significant differences in the aggressive imagery of inhibited and uninhibited subjects when TAT cards or instructions strongly suggested an aggressive response but not when the experimental conditions did not suggest hostile themes. This prediction was verified on a sample of women but no support was found in a sample of men. The findings were related to other studies in the literature and directions for further research suggested.     

Motivation for Parenthood

Summary: The relationships between the tendency of subjects to perceive temporal zones as interrelated or discrete and other temporal behaviors and personality factors were explored in two studies, one using 115 college students and the other 60 college students, employing the Personal Orientation Inventory the Temporal Orientation Inventory, and the Circles Test. Subjects who obtained higher time-relatedness scores were found to demonstrate greater self-actualization, evaluate the present time mode more positively, overestimate time intervals in an estimation task, and to perform less accurately in time estimation than low time relaters.     

March of the Living, a Holocaust Educational Tour: Effect on Adolescent Jewish Identity

March of the Living (MOTL) is a worldwide two-week trip for high school seniors to learn about the Holocaust by traveling to sites of concentration/death camps and Jewish historical sites in Poland and Israel. The mission statement of MOTL International states that participants will be able to “bolster their Jewish identity by acquainting them with the rich Jewish heritage in pre-war Eastern Europe.” However, this claim has never been studied quantitatively. Therefore, 152 adolescents who participated in MOTL voluntarily completed an initial background questionnaire, a Jewish Identity Survey and a Global Domains Survey pre-MOTL, end-Poland and end-Israel. Results suggest that Jewish identity did not substantially increase overall or from one time period to the next.