Perception of Kinematic Characteristics in the Motion of Lifted Weight

It has been widely shown that human observers are able to perceive lifted weight from the observation of a point-light display of the lifter's action. In the experiments reported here, the kinematic information used by observers to perceive a lifted weight was determined. In Experiment 1, observers (N equals: 30) were able to identify weights (5, 10, 15, 20, and 25 kg) successfully by observing only the lift phase of the action. Other procedures, such as walking while holding the weight and placing the weight on a table, did not result in significantly improved estimations. In Experiment 2, the kinematic patterns used by 4 lifters with weights varying from 5 to 25 kg were examined. Changes in weight lifted resulted in changes in lift velocity, hip angle, and dwell time. In Experiment 3, in which 15 observers participated, these 3 kinematic variables were experimentally manipulated. The results indicated that observation was most significantly influenced by variations in lift velocity. The results are discussed in relation to kinematic specification of dynamics and heuristic approaches.     

The measurement of perceived opportunity for occupational attainment

Many writers implicate perceptions of the opportunity structure in the labor market as essential components of the formation, stability, and enactment of socioeconomic achievement attitudes. These perceptions of opportunity are thought to be observed structural constraints and reflective of more than just pure motivation. Previous attempts at measuring “perceived opportunity” have no consistent approach or conceptualization. This study evaluates a 10-item scale of perceived occupational opportunity in an attempt to overcome many of these problems. Using panel data covering the period of career decision making and labor force entry (adolescence to young adulthood), the internal reliability and construct validity of the linear composite are assessed. The scale's external validity is then further explored within the context of a structural equation model linking perceived opportunity to social origins, adolescent career plans, and early socioeconomic attainments.     

Evaluation of prenatal androgen and ovarian secretions on receptivity in female and male rats

Offspring of rats infected daily from Day 16 through Day 20 of gestation with either 2 mg of testosterone propionate (TP) in .1 ml of sesame oil or oil alone were tested for sexual receptivity following injections of 3.3 microgram of estradiol benzoate (EB) and .5 mg of progesterone (P) beginning at 40, 80, or 120 days of age. At each age, neonatally gonadectomized males and females from TP-injected litters exhibited less receptivity than corresponding oil-injected controls. Prenatally androgenized females were similar to neonatally castrated oil-injected males at all ages. Ovarian implants from birth to 35 days of age significantly increased receptivity in neonatally castrated males and androgenized females. Increasing the age at which testing was initiated systematically reduced receptivity in all groups.     

A Scale to Aid in the Retention or Dismissal Decision

Freshman students on probation as a result of unsatisfactory first semesters in college are generally dismissed after the second semester if their work does not show improvement. A special MMPI scale was developed to assist in determining retention and dismissal. The procedure employed involved the matching of individuals from retained and dismissed groups of students on certain intellective and non-intellective factors. MMPI items that discriminated between these criterion groups were identified, and an RD scale (retained-dismissed) was composed of these items. The scale was successfully cross-validated on a large sample of freshman probation students. An expectancy table for the prediction of retention or dismissal was constructed from the data.