Roger Dunn

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Pigeons' choice between reliable (100%) and unreliable (50%) reinforcement was studied using a concurrent-chains procedure. Initial links were fixed-ratio 1 schedules, and terminal links were equal fixed-time schedules. The duration of the terminal links was varied across conditions. The terminal link on the reliable side always ended in food; the terminal(More)
The present study examined the effects of matching and mismatching American middle-school students with a preference for learning alone or learning with peers with selected instructional treatments in order to determine the impact upon their attitudes and achievement in social studies. Analysis revealed that the learning-alone preference performed(More)
The authors examined the associations that underlie the orientations of bilingual Latino college students toward family and school. Participants completed, in English or Spanish, 3 implicit association tests assessing their attitude toward family vs. school, identifications with these concepts, and self-esteem. Results revealed a more positive attitude(More)
Pigeons were presented with a concurrent-chains schedule in which both choice alternatives led to the same terminal-link stimulus, which was followed by food. Superimposed on the food-reinforced presentations of the terminal-link stimulus was a second schedule of presentations of the same stimulus that were followed by no food. The absolute number of these(More)
Pigeons' choices between alternatives that provided different percentages of reinforcement in mixed schedules were studied using the concurrent-chains procedure. In Experiment 1, the alternatives were terminal-link schedules that were equal in delay and magnitude of reinforcement, but that provided different percentages of reinforcement, with one schedule(More)
Delay-reduction theory states that the effectiveness of a stimulus as a conditioned reinforcer may be predicted most accurately by the reduction in time to primary reinforcement correlated with its onset. We review support for the theory and then discuss two new types of experiments that assess it. One compares models of choice in situations wherein the(More)
Pigeons responded on concurrent chains with equal initial- and terminal-link durations. In all conditions, the terminal links of one chain ended reliably in reinforcement; the terminal links on the alternative chain ended in either food or blackout. In Experiment 1, the terminal-link stimuli were correlated with (signaled) the outcome, and the durations of(More)
Pigeons were presented a concurrent-chains schedule of reinforcement that had terminal links of equal duration. The initial links of the schedule were periodically interrupted by 15-s periods during which an extinction schedule was in effect. The extinction periods were presented on either a response-contingent or a noncontingent basis. Relative response(More)
Pigeons responded on identical concurrent variable-interval schedules (choice phase), producing outcomes of either periodic reinforcement schedules always terminating in reinforcement (reliable schedule) or otherwise identical schedules providing reinforcement on only a percentage of instances (percentage reinforcement schedule). Comparisons of this type(More)
Relative reinforcer duration was varied in concurrent schedules with a fixed-ratio four changeover requirement. The schedule in effect after each reinforcer was randomly chosen. For all three pigeons, relative response rates overmatched relative reinforcer durations. Time allocation was less extreme and, on the average, matched relative reinforcer duration.(More)