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At least 703 records · Page 39Linked to original sources
PubMed2002

Probability matching: encouraging optimal responding in humans.

Two hundred undergraduate students participated in a repeated-trials binary choice procedure in which choice of one outcome was correct on 75% of trials. Subjects received 192 trials and were divided into five conditions: (1) control; (2) subjects were given the actual probabilities; (3) subjects were told if they did well they could leave early; (4) competition condition; (5) midway through the task subjects were asked to recommend a strategy for another subject. Half of the subjects in each group were told that the best they could do was to be correct on 75% of the trials. This manipulation permitted assessment of the hypothesis that subjects in probability-matching tasks are seeking a strategy that will be correct on 100% of the trials. The results partially confirmed this hypothesis. In addition, two of the variables improved performance significantly (giving probabilities and asking subjects to recommend a strategy). However, while subjects in all groups improved significantly over trials, optimal choice did not occur in this task.

Adult↗
PubMed2005

Reasoning about conjunctive probabilistic concepts in childhood.

While adults are known to exhibit biases when making conjunctive probability judgments, little is known about childhood competencies in this area. Participants (aged between four and five years, eight and ten years, and a group of young adults) attempted to select the more likely of two events, a single event, and a conjunctive event containing, as one of its components, the single event. The problems were such that the objective probabilities of the component events were potentially available. Children in both age groups were generally successful when the single event was likely. However, when it was unlikely, a majority of children rejected it, choosing the conjunctive event instead, thereby committing the conjunction fallacy. A substantial minority of adults also committed the fallacy under equivalent conditions. It is concluded that under certain conditions children are capable of normative conjunctive judgments but that the mechanisms underpinning this capacity remain to be fully understood.

Adult↗
PubMed1982

Behavioral treatment for the anticipatory nausea and vomiting induced by cancer chemotherapy.

The nausea and vomiting experienced by one in four cancer patients in anticipation of chemotherapy is probably a learned response to treatment. To determine whether behavioral approaches for altering learned responses might be useful treatments for these symptoms, we compared the effects of "systematic desensitization" (a behavioral treatment in which relaxation is learned as a response to situations in which patients have had anticipatory nausea and vomiting) with those of counseling and of no treatment. Sixty ambulatory cancer patients with anticipatory nausea and vomiting before their third and fourth chemotherapy treatments were randomized equally to the three groups. Significantly more patients receiving desensitization reported no anticipatory nausea before their fifth and sixth chemotherapy treatments than patients given counseling (P less than 0.05) or no treatment (P less than 0.01). Desensitized patients also reported significantly less severe anticipatory nausea (P less than 0.01) and vomiting (P less than 0.05) and a shorter duration of anticipatory nausea (P less than 0.01). We conclude that systematic desensitization appears to have an antiemetic effect in cancer patients who receive chemotherapy, and may be useful in the management of these problems.

Adult↗
PubMed1990

How the visual system detects changes in the direction of moving targets.

To determine how the visual system represents information about change in target direction, we studied the detection of such change under conditions of varying stimulus certainty. Target direction was either held constant over trials or was allowed to vary randomly. When target direction was constant the observer could be certain about that stimulus characteristic; randomizing the target direction rendered the observer uncertain. We measured response times (RTs) to changes in target direction following initial trajectories of varying time and distance. In different conditions, the observer was uncertain about either the direction of the initial trajectory, or the direction of change or both. With brief initial trajectories in random directions, uncertainty about initial direction elevated RTs by 50 ms or more. When the initial trajectories were at least 500 ms, this directional uncertainty ceased to affect RTs; then, only uncertainty about the direction of change affected RTs. We discuss the implications of these results for (i) schemes by which the visual system might code directional change; (ii) the visual integration time for directional information; and (iii) adaptational processes in motion perception.

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