Nick Perham

Frequency versus probability formats in statistical word problems

Three experiments examined peoples ability to incorporate base rate information when judging posterior probabilities. Specifically, we tested the (Cosmides, L., & Tooby, J. (1996). Are humans good intuitive statisticians after all? Rethinking some conclusions from the literature on judgement under uncertainty. Cognition, 58, 1-73) conclusion that peoples reasoning appears to follow Bayesian principles when they are presented with information in a frequency format, but not when information is presented as one case probabilities. First, we found that frequency formats were not generally associated with better performance than probability formats unless they were presented in a manner which facilitated construction of a set inclusion mental model. Second, we demonstrated that the use of frequency information may promote biases in the weighting of information. When participants are asked to express their judgements in frequency rather than probability format, they were more likely to produce the base rate as their answer, ignoring diagnostic evidence.

Background beliefs in Bayesian inference

We report five experiments in which the role of background beliefs in social judgments of posterior probability was investigated. From a Bayesian perspective, people should combine prior probabilities (or base rates) and diagnostic evidence with equal weighting, although previous research shows that base rates are often underweighted. These experiments were designed so that either piece of information was supplied either by personal beliefs or by presented statistics, and regression analyses were performed on individual participants to assess the relative influence of information. We found that both prior probabilities and diagnostic information significantly influenced judgments, whether supplied by beliefs or by statistical information, but that belief-based information tended to dominate the judgments made.

Deontic Reasoning With Emotional Content: Evolutionary Psychology or Decision Theory?

Three experiments investigated the contrasting predictions of the evolutionary and decision-theoretic approaches to deontic reasoning. Two experiments embedded a hazard management (HM) rule in a social contract scenario that should lead to competition between innate modules. A 3rd experiment used a pure HM task. Threatening material was also introduced into the antecedent, p, of a deontic rule, if p then must q. According to the evolutionary approach, more HM responses (Cosmides & Tooby, 2000) are predicted when p is threatening, whereas decision theory predicts fewer. All 3 experiments were consistent with decision theory. Other theories are discussed, and it is concluded that they cannot account for the behavior observed in these experiments.

Reduction in auditory distraction by retrieval strategy.

Most research on auditory distraction on task performance focuses on those features of the sound that determine a drop in efficiency, with scant regard for examining the processing properties inherent in the focal task. We report how one such property, retrieval strategy, can also influence the degree of disruption by background sound. Using a task that called for the retrieval of realistic train journey information, we showed that retrieval by categories of verbal sequences was not susceptible to disruption by office sound—65–75 dB(A). However, versions of the task requiring either free or serial recall showed evidence of disruption, a pattern of results consistent with the changing-state account of the irrelevant sound effect, which highlights the key role of serial rehearsal in determining disruption.

Syntax and serial recall: How language supports short-term memory for order

The extent to which familiar syntax supports short-term serial recall of visually presented six-item sequences was shown by the superior recall of lists in which item pairs appeared in the order of “adjective–noun” (items 1–2, 3–4, 5–6)—congruent with English syntax—compared to when the order of items within pairs was reversed. The findings complement other evidence suggesting that short-term memory is an assemblage of language processing and production processes more than it is a bespoke short-term memory storage system.

To what extent does nonanalytic reasoning contribute to visual learning in cytopathology

Acquisition of visual interpretation skills in cytopathology may involve 2 strategies. Analytic strategies require trainees to base their interpretive decisions on carefully considered and often exhaustive cytomorphologic feature lists, a process that can be time‐consuming and inefficient. In contrast, nonanalytic pattern recognition strategies are rarely encouraged during training, even though this approach is characteristic of expert diagnostic behavior. This study evaluated the potential role of nonanalytic learning in cytopathology as an efficient alternative to analytic training.

Boundaries of Semantic Distraction: Dominance and Lexicality Act at Retrieval

Three experiments investigated memory for semantic information with the goal of determining boundary conditions for the manifestation of semantic auditory distraction. Irrelevant speech disrupted the free recall of semantic category- exemplars to an equal degree regardless of whether the speech coincided with presentation or test phases of the task (Experiment 1), and this occurred regardless of whether it comprised random words or coherent sentences (Experiment 2). The effects of background speech were greater when the irrelevant speech was semantically related to the to-be-remembered material, but only when the irrelevant words were high in output dominance (Experiment 3). The implications of these findings in relation to the processing of task material and the processing of background speech are discussed.

Untutored discrimination training on paired cell images influences visual learning in cytopathology

Cytologists must learn how to discriminate cells that might be visually very similar but have different neoplastic potential. The mechanism by which trainees learn this task is poorly researched and is the focus of the current investigation. Cognitive science offers a theoretical platform from which to design meaningful experiments that could lead to novel training strategies.

Mental arithmetic and non-speech office noise: An exploration of interference-by-content

An interference-by-content account of auditory distraction - in which the impairment to task performance derives from the similarity of what is being recalled and what is being ignored - was explored concerning mental arithmetic performance. Participants completed both a serial recall and a mental arithmetic task in the presence of quiet, office noise with speech (OS) and office noise without speech (ONS). Both tasks revealed that the two office noise conditions significantly impaired performance. That the ONS produced this deficit suggests that an interference-by-content account cannot explain impairment to mental arithmetic performance by background sound.

The Susceptibility of a Call Center-Like Task to Disruption by Extraneous Sound: The Role of Semantic Relatedness

Irrelevant noise in the work environment has long been viewed as a source of annoyance and disturbance with speech being rated as the worst (e.g. Nemecek and Grandjean, 1973; Kjellberg and Landstrom, 1994). This may be particularly detrimental in environments where background speech is prevalent, such as call centers. Furthermore, additional disruption may occur when the background speech is similar to items in the primary task. We report an experiment that examined the effects of speech and the role of semantic similarity using a call center-like task. Analyses showed that although both similar and dissimilar speech noise conditions were worse than a quiet noise condition, there was no difference between the two speech conditions. Results are discussed in light of the changing-state account of the irrelevant sound effect.