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Biomedical subjects

G Wolford

Publications and source records attributed to G Wolford.

4 recordsLinked to original sources
PubMed1990

The conjunction fallacy?

Tversky and Kahneman (1983) showed that when subjects are asked to rate the likelihood of several alternatives, including single and joint events, they often make a "conjunction fallacy." That is, they rate the conjunction of two events as being more likely than one of the constituent events. This, they claim, is a fallacy, since the conjunction of two events can never be more probable than either of the component events. In addition, they found that prior training in probability theory does not decrease the likelihood of making this fallacy. We argue that in some contexts, an alternative that contains the conjunction of two events can be more probable than an alternative that contains only one of the conjunction's constituent events. We carried out four experiments in which we manipulated this context. The frequency of making a conjunction fallacy was affected by the manipulation of context. Furthermore, when the context was clearly specified, prior training in statistics influenced the ratings.

Decision Making↗
PubMed1988

Practice effects in backward masking.

In two experiments we demonstrate that much larger practice effects occur in a backward masking paradigm where patterned masks are used than in similar visual processing paradigms, such as lateral masking and whole report. In additional experiments we examine four possible explanations for the large practice effects: increased familiarity with the paradigm in general, learning about the targets, learning about the masks, and enhanced sensory processing. Because of failure to observe similar practice effects in related paradigms not involving backward masking and because of the sustained nature of the improvement, we reject the first explanation as a source of practice effect. Experiment 3 allowed us to reject target learning as a source of improvement as well; target sets were switched at the end of training, but no decrement in performance was observed. In Experiment 4, mask sets were switched at the end of training, revealing a significant decrement in performance. Learning about the specific masks, then, does contribute to the observed improvement. However, it is responsible for only about one third of the overall improvement in performance. The final experiment provides evidence that the residual improvement is due to enhanced sensory processing. In that experiment, training on backward masking led to a lowered threshold in a two-flash paradigm but not to a significant change in whole-report performance.

Attention↗
PubMed1982

Effect of distraction on reading versus listening.

Levy (1977) reported a series of experiments in which a distracting task (counting aloud) interfered more with reading than with listening. The results were interpreted as evidence of the importance of phonological recoding during reading. In a similar experiment we varied the nature of the distracting task, using one task related to speech (counting aloud) and one task not related to speech (manual response to a threshold shock). Both distracting tasks led to similar results, namely, more interference with reading than listening. On the basis of our results and a consideration of related literature, we ascribe the selective interference effect to the relative difficulty of reading over listening rather than to the importance of speech recoding in reading.

Attention↗