Concurrent-schedule performance in dairy cows: persistent undermatching.

Performance of dairy cows responding under concurrent variable-interval variable-interval schedules of food delivery was examined, with results analyzed in terms of the generalized matching equation. In Experiment 1, bias measures indicated that crushed barley was preferred over meatmeal when these foods were available under the alternative schedules. For whole-session data, substantial undermatching of response and time-allocation ratios to obtained reinforcement ratios was evident. Postreinforcement pause time ratios approximately matched obtained reinforcement rates. Subtracting these times from total time-allocation values yielded net time-allocation ratios that undermatched obtained reinforcement ratios to a greater degree than did whole-session time-allocation ratios. In Experiment 2, substantial undermatching was evident when the same foods (hay for 2 cows, crushed barley for 2 others) were available under the alternative schedules. Food-related activities and other defined behavior not related to food were quantified by direct observation, and were found to occupy a substantial proportion (roughly 40% to 80%) of experimental sessions. Subtracting the time spent in these activities from the time allocated to each component schedule did not reduce the degree of undermatching obtained. Across all conditions in both experiments, slopes of regression lines relating behavioral outputs to environmental inputs characteristically were below 0.6, which agrees with prior findings and suggests that, contrary to suggestions in the literature, undermatching in dairy cows is not the result of using different foods under alternative schedules or differential pausing under those schedules.     

Selecting University Lecturers: What is and Should be Done

This paper presents a survey designed to identify the procedures used by British university departments when selecting academic staff and compare them with typical practice in other UK organizations. The results indicate that, compared with other large organizations, university departments make much less use of psychometric tests or assessment centres, relying heavily on the application form, a single interview and a presentation. There were no differences between academic departments of English, Biology or Psychology and the level of academic appointment only affected the composition of the interview panel. Possible reasons for the failure to use modern objective methods of selection are considered. It is argued that universities should apply more objective selection methods based on a full analysis of the competencies required of the higher education lecturer.     

Cognitive influences on perceived change in social support,motivation, and symptoms of depression

In settings ranging from informal conversation to medical interviews and surveys, people are often asked to judge changes in subjective states that are important to them, such as perceived social support, motivation to cope with a negative life event, and symptoms of depression. How accurate are such reports, and are there theories of cognitive processes that can predict the most likely types of misperception? To address these questions, self-report survey data were collected from 224 recently unemployed adults. The measures assessed current subjective states of self and social environment at two times, separated by 4 months. Among the results, persons with high self-esteem were particularly likely to underestimate changes for the worse between the two survey waves–evidence of an optimistic response bias. When the dimension being judged was unstable and ambiguous, people were more likely to overestimate improvement–evidence of an optimistic response style. The findings were evaluated in terms of alternate theories of cognitive bias and in terms of implications for subsequent studies and application.     

ACPE: A computerized system for running small-group decision-making experiments

Small groups are called upon to make important policy decisions under a wide variety of procedural constraints. ACPE is a flexible, computerized system for conducting small-group voting experiments. It permits researchers to examine the impact of electronic communication on group deliberation and choice. The system runs under a variety of different personal computer networks and is designed to permit the specification of voting rules, communication, and group sizes. The system also facilitates the study of group process by tracking all messages sent and votes taken. An experiment in which the system was used is briefly described.     

Response Form, Force, And Number: Effects On Concurrent-schedule Performance

Six hens responded on concurrent variable-interval (key-peck) variable-interval (door-push) schedules of reinforcement in which the second-order (fixed-ratio) requirements on the alternatives (Experiment 1) or the required door forces (Experiment 2) were varied. The key-peck and door-push response (measured as fixed-ratio completion) and time data were well described by the generalized matching law. However, the manipulations of fixed-ratio requirement and required response force differed in their effects. The manipulations of fixed-ratio size affected the response and time measures differently, producing fairly constant, multiplicative biases only in terms of response allocation. It was argued that variations in fixed-ratio size necessarily change the time allocated to that response unit, and thus changes in time bias were not necessarily a fundamental effect of changing the ratio. In contrast, the changes in response bias were a fundamental result of changes in ratio size. The response-force manipulations produced similar bias shifts in terms of response and time allocation, but they appeared to combine with relative reinforcement rate to affect choice interactively. Specifically, behavior appeared to be biased towards the least effortful (i.e., key-peck) response, but the increases in door force had a larger effect on bias when the hens were making this response infrequently (on a lean schedule). The different effects of the fixed-ratio and response-force manipulations on concurrent performance were partially accounted for by the differing times required to complete each response unit under those manipulations, but this would not account for the interaction. The interaction would be consonant with increased response effort decreasing the effective value of the associated reinforcement schedule.     

The relationship between age and depressive symptoms in two national surveys.

There is inconsistency in the literature on the relationship between age and depressive symptoms. Although a careful review shows that some of this inconsistency can be reconciled by recognizing the nonlinear relationship (Newmann, 1989), 2 additional issues remain unclear. One is that most previous studies used depression screening scales that contain somatic items that could introduce an age bias. The other is that most previous studies combined samples of men and women even though there is evidence that the sex difference in depressive symptoms varies with age. These 2 issues are addressed in this article, using analyzed data from 2 large national surveys. There is a consistent, but quite modest, nonlinear association between age, somatic, and nonsomatic depressive symptoms in both surveys. There is no significant sex difference in the age curves.