Stimulus-independent thought depends on central executive resources

Stimulus-independent thoughts (SITs) are streams of thoughts and images unrelated to immediate sensory input. Four experiments examined the contribution of aspects of working memory to production of SITs. In Experiments 1 and 2, interventions that were targeted on, respectively, phonological and visuospatial components of working memory both interfered with production of SITs, but there was evidence that these tasks also made demands on central executive resources. Experiments 3 and 4 specifically examined the hypothesis that production of SITs and control of nonproceduralized tasks both depend on central executive resources, and so should show mutual interference. In Experiment 3, prior practice on pursuit rotor and memory tasks reduced the interference with SITs from concurrent task performance. In Experiment 4, randomness within a task involving random-number generation was less when SITs were being produced concurrently than it was when they were not. The results suggest that production of SITs depends on central executive resources.     

A classroom demonstration of self-monitoring, reactivity, and interobserver agreement

A brief classroom demonstration designed to introduce students to the concepts of self-monitoring, reactivity, and interobserver agreement is presented. The demonstration provides students with opportunities to monitor their own behavior, record the behavior of others, and calculate interobserver agreement percentages. Results of using the demonstration with students from two classes are presented.     

Meaning dominance norms for 120 homographs

Over the past two decades, homographs have been used in psychological experiments aimed at testing a variety of theoretical issues concerning memory and language. Often, such research requires prior knowledge of the dominance relations among various meanings of the homographs. Previously available homograph meaning norms are limited because they are now more than 10 years old, and they have typically reported only the two most dominant meanings even though many homographs have three or more common meanings. This paper presents normative data on 120 homographs from a relatively large, heterogeneous sample of subjects (N = 100). Meaning dominance was assessed by having subjects write the first definition that came to mind for each homograph. Definition responses were grouped by similarity, and the resulting meaning categories were verified against dictionary meaning classifications. The number of distinct meanings varied from two to six for the homographs investigated, and frequency of response is reported for all definition categories.     

Perceptual and conceptual priming in a semantic reprocessing task

Two experiments are reported that addressed the relative involvement and nature of perceptual and conceptual priming in a semantically complex task. Both experiments investigated facilitation from repeated semantic comparison trials in which subjects decided whether two words had the same meaning (e.g.,moist damp). The first experiment compared the magnitude and persistence of perceptual and conceptual priming components. Perceptual priming effects were modest, and contrary to some previous evidence, they did not appear to be more persistent than nonperceptual priming effects. The second experiment investigated the memory processes involved when perceptual priming was eliminated through a modality change between prime and target trials. Evidence suggested that conceptual priming primarily involved memory for the meaning comparison processes rather than better access to existing memory for the stimulus words.     

Book reviews

Darwin's Dangerous Idea, Daniel C. Dennett, 1995. London, Penguin. 587 pp., hbk £25, ISBN: 0–713–99090–2

Verificationism: Its History and Prospects, C. J. Misak, 1995. London and New York, Routledge. xviii + 254 pp. ISBN: 0–415–12597–9(hbk); 0–415–12598–7(pbk)

Abductive Inference: Computation, Philosophy, Technology, John R. Josephson & Susan G. Josephson (Eds), 1994. Cambridge, Cambridge University Press 306 pp.

Physics and Metaphysics. Theories of Space and Time, Jennifer Trusted, 1994. London, Routledge 210 pp.     

Assessing decision strategies using HyperCard

The use of “process-tracing” techniques for examining individuals’ decision strategies has been criticized widely for yielding results that are uninformative and often confounded. The present paper describes a new technique based on a “structural” approach that allows efficient assessment of finely discriminated decision strategies via a HyperCard program called DECOUT. The program presents individuals with an information matrix (e.g., describing five alternative pesticides on three attributes). Individuals are asked to choose the best or the worst alternative in the matrix for 12 problems. Information in the matrix is constructed so that choice of an alternative by an individual is uniquely associated with use of one particular decision strategy. The strategies include information integration, maximin, maximax, pessimism-optimism, and minimax-regret processes. An experiment using the program is described, and possible directions for future research and development are discussed.