Visual timing in hitting an accelerating ball

To investigate the timing of actions relative to events in the environment, we observed subjects leaping to punch a falling ball. We analysed their knee and elbow angles as functions of time for three ball-drop heights, finding that the differences in the functions for the different heights could be explained on the basis that the subjects were gearing their actions to a particular optic variable. This variable specifies the time remaining before contact with an object if the closing velocity is constant; for the falling ball it gives an increasingly accurate estimate of the time-to-contact. Our visuo-moto control model incorporates a delay parameter, the value of which was estimated from the data. In addition, correlations indicated that the knee and elbow were generally quite tightly coupled. The relationship of this task to laboratory tracking tasks and to the timing of actions in everyday life is described.     

Pigeons are attracted to a perceived gain without an actual gain

Reference dependence refers to the reduced value of a reward that is less than expected, or the added value of a reward that is greater than expected. There is evidence that when pigeons are offered an alternative that has 1 pellet versus an alternative that has 2 pellets, but one of the two pellets offered will be removed, the pigeons prefer the originally presented 1 pellet (loss aversion). In the present research, we tested for the opposite effect (gain attraction). In Experiments 1 and 2, pigeons could choose between 2 pellets, each one on a distinctive background. If they chose the optimal alternative, they received a second pellet. In Experiment 2, the second pellet obtained was the one not initially chosen (a task sometimes referred to as the ephemeral reward task). Pigeons learned to choose optimally in both experiments. In Experiment 3, we tested the pigeons for reference dependence. Pigeons were given an alternative that offered them one pellet or two pellets, if they chose the one-pellet alternative, they received an additional pellet, and if they chose the two-pellet alternative, they received the two pellets. In keeping with the reference dependence hypothesis, the pigeons preferred the 1-pellet alternative that gave them an extra pellet. These effects are related to similar findings with humans, including the endowment effect.

     

The Application of Family Systems Theory to Organizational Consultation: A Content Analysis

A content analysis was performed on 43 articles published between 1970 and 1998 discerned as relating family systems theory (FST) frameworks and constructs to organizational consultation. Frameworks and constructs were coded and then investigated in relation to four independent variables: type of organization, decade of article publication, gender, and educational training of author. Results indicate that the use of FST frameworks and constructs vary depending upon the characteristics of the organization, time period, and consultant. Results highlight specific FST frameworks and constructs most common in organizational consultation.     

INCREASING SEAT BELT USE ON A COLLEGE CAMPUS: AN EVALUATION OF TWO PROMPTING PROCEDURES

Seat belt use is an important factor in the prevention of automobile accidents involving injuries and fatalities. The current study used a multielement design to compare the “Click It or Ticket” and “Please Buckle Up—I Care” procedures. Results indicate that the Click It or Ticket prompt resulted in a 20‐percentage‐point increase in seat belt use, and Please Buckle Up—I Care resulted in a 14‐percentage‐point increase.     

Presentation modality,rehearsal-prevention conditions,and auditory confusions in tests of short-term memory

Ss were presented four-letter sequences either auditorily or visually and asked for ordered recall after 0, 2.1, 4.2, 8.4, or 12.6 sec of digit categorization. Three different rehearsal-prevention conditions were required during presentation of the memory set: categorizing, suppressing (saying "dah"), or pronouncing each letter. Recall was worst after categorizing, best after pronouncing. Auditory presentation led to better recall after no delay but more rapid forgetting than visual presentation, regardless of the rehearsal-prevention condition. These results, and analyses of auditory confusions, are inconsistent with a view of memory which asserts that sensory information is encoded auditorily regardless of presentation modality or vocalization behavior during presentation.