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At least 883 records · Page 49Linked to original sources
PubMed1992

How pigeons estimate rates of prey encounter.

Pigeons were trained on operant schedules simulating successive encounters with prey items. When items were encountered on variable-interval schedules, birds were more likely to accept a poor item (long delay to food) the longer they had just searched, as if they were averaging prey density over a short memory window (Experiment 1). Responding as if the immediate future would be like the immediate past was reversed when a short search predicted a long search next time (Experiment 2). Experience with different degrees of environmental predictability appeared to change the length of the memory window (Experiment 3). The results may reflect linear waiting (Higa, Wynne, & Staddon, 1991), but they differ in some respects. The findings have implications for possible mechanisms of adjusting behavior to current reinforcement conditions.

Analysis of Variance↗
PubMed2006

Adjusting behavioral methods when applying nonlinear dynamical measures to stimulus rate.

A nonlinear dynamical perspective addresses an area of behavior that tends to be ignored: trial-to-trial variability under seemingly identical conditions. Data exhibiting sequence effects are excellent candidates for a nonlinear dynamical analysis, because of their dependence on previous trial events. When applying nonlinear dynamical tools to behavioral data, the assumptions underlying the tools may require changes in experimental methodology. In this paper, the assumptions of trial timing and their potential impact on nonlinear dynamical analysis are explored. This is done with the intent of initiating a discussion on the appropriate control of trial timing. To examine these issues, each participant's response times on simple two-choice tasks were treated as a time series and submitted along with two comparisons to two nonlinear dynamical measures. Two experimental variables, stimulus rate and stimulus-response mapping, were manipulated in order to examine the issue of controlling trial timing via stimulus rate. Significant differences between the observed and comparison time series were found for estimated dimensionalities(m). Differences in dimensionality(m) estimates were also found between the experimental variables. Of the two methods for controlling stimulus rate, response-stimulus-interval and inter-stimulus-interval, the latter is recommended when applying nonlinear dynamical measures.

Analysis of Variance↗
PubMed1990

Dentistry's future at the University of Southern California.

Participation in the National Dental Education Program has been a most important activity. It has had great impact on the future well-being of the USC School of Dentistry. Success in Phases 1 and 2 was, of course, important. However, the involvement in training sessions, where ideas were exchanged and new skills learned, was probably of more importance. Communication with university officials suddenly became easier--we now spoke a common language and could respond more effectively than before. While the outcomes will be important in changing the school's course, the process leading to the outcomes will also produce significant change. Planning took on new meaning at USC. We are now able to respond to opportunities that come knocking at our door. We are able to see relationships previously invisible. We are beginning to recognize that what each does, in whatever activity, matters a great deal. We--faculty, students, staff, and alumni--are interdependent to a larger degree than previously thought. Challenging years are in store for the USC School of Dentistry. Much needs to be done to ensure dentistry's future at USC into the 21st century. The school is located at the right place at the right time. The external environment beckons for increased involvement by the School of Dentistry. If the school can address the challenges posed by the changed internal environment, it is well positioned to become the most important resource in dental education, in dental care, and in dental information in the Southwest.

California↗
PubMed1990

Strategy knowledge and strategy change in skilled performance: a study of the game Othello.

Skill and skill development in playing the game Othello were investigated. In particular, we studied the role of strategies and strategy change, rather than focusing on knowledge of particular board patterns. The history of the development of the game suggests a shift from positional to mobility strategies, a change which also is reproduced in the development of individual players. The first two studies used historical analysis of tournament transcripts to study strategy change. The third study investigated one possible basis for the greater accessibility or ease of positional versus mobility strategy, namely differential encoding and memorability of typical board patterns. Study 3 demonstrated that completely naive as well as positional players remember positional games and moves more easily than mobility games and moves. The easier mastery of positional strategy may be caused in part by the greater ease of encoding typical positional patterns. We suggest that strategic change and conceptual reorganization may be particularly important for domains where the naive encoding of events is not the most apt. We also suggest that similarities exist between strategy change in Othello and other domains.

Attention↗
PubMed1989

A test of the response deprivation hypothesis in a multiple-response context.

Reinforcement contingencies defined by the response deprivation hypothesis were evaluated in two multiple-response contexts. In one context a high probability response was freely available, and in the other context a low probability response was freely available. In the presence of the low probability, freely available response, a consistent reinforcement effect was evident for all 3 moderately mentally retarded participants; however, in the presence of the high probability response, the reinforcement effect was attenuated. Results were qualitatively consistent with several recent mathematical descriptions of behavior emphasizing the importance of the context in which reinforcement contingencies are introduced.

Adolescent↗
PubMed1989

Effects of a freely available response on the schedule performance of mentally retarded persons.

The effects of a freely available response on the schedule performance of 84 mentally retarded persons were examined in a laboratory setting. Instrumental performance exceeded performance of the free response in contingent schedules; the opposite occurred in noncontingent schedules. Also, instrumental performance decreased whereas responding on the free response increased across increasing probability levels of the freely available response. We concluded that increases of instrumental performance in the response deprivation schedules employed were due to the contingency and not noncontingent deprivation and that the effectiveness of therapeutic reinforcement programs is influenced by the presence of alternative responses.

Adolescent↗
PubMed1985

Motor skill acquisition by individuals with Down syndrome.

Motor skill acquisition of subjects with Down syndrome on a pursuit tracking task was assessed in comparison to groups of mentally retarded subjects without Down syndrome and nonretarded subjects matched for functional age and chronological age (CA). Thirty-seven male subjects performed eight trials on a subject-paced pursuit tracking task. The main finding was that subjects with Down syndrome did not respond to directional probability in the same manner shown by the retarded or the nonretarded subjects matched for CA or functional age. This difference in strategy was also reflected in their greater emphasis on accuracy rather than speed. Finally, these effects were consistent across the subjects with Down syndrome despite the large intersubject variability seen in their performance.

Adolescent↗
PubMedDate not supplied

[Comparison of the effect of sidnocarb and other psychostimulants on discrimination and prediction processes in performing conditioned food-procuring reflexes].

In an Y-shaped maze a differentiation of the positive and negative reflex signals given at random in a ratio of 50 to 50 per cent and an active selection of one of two feeding troughs, reinforced at varying frequency (0.1--0.9), were determined. Sydnocarb (10--20 mg/kg) had no influence on the realization of the food-procurement response, but improved the discrimination of the signals. Only small doses of amphetamine (0.5 mg/kg), caffein (20 mg/kg) and acephen (10 mg/kg) also improved the response to conditioned signals. Sydnocarb reduced the number of runs to a rarely reinforced feeding trough and, at the same time, stimulated an active choice of the latter. Amphetamine largely facilitated an active choice of the runs direction. Caffein displayed a tendency to reduce the number of wrong approaches. Acephen hampered an active choice of compartments in the Y-maze without impairing the ability to distinguish the frequency of the feeding troughs reinforcement.

Acoustic Stimulation↗