Interpretation and matching bias in a reasoning task

Subjects were required to construct verifying and falsifying cases of conditional rules in which the presence and absence of negative components was varied. Their responses gave some indication of consistent interpretation of the rules, generally conforming to Wason's (1966) idea of a “defective” truth table. Much of their behaviour, however, seemed to be determined by a task variable in the form of a tendency to construct instances which matched, rather than altered, the values named in the rules.     

Assessing treatability in mentally disordered offenders: A conceptual and methodological note

The assessment of treatability in mentally disordered offenders has rarely been addressed through empirical research, despite its frequent use in clinical and legal decision-making. We describe four necessary steps for establishing the requisite research base for treatability evaluations: (a) criterion specification, (b) the development of reliable measures, (c) the validation of these measures with treatment outcome data, and (d) the incorporation of environmental and base rate information.     

Competing with reasoning: A test of the working memory hypothesis

An experiment is reported in which subjects attempted conditional reasoning problems while concurrently articulating a series of digits, with or without memory load. Logical performance was not impaired by the competing tasks and the latency of responding was actually faster under concurrent articulation, without memory load, than in a control group. The results are discussed with reference to the Baddeley and Hitch (1974) model of working memory.     

APL functions for interactive data analysis: Principal components analysis

APL functions to support principal components analysis are presented: a general-purpose function to obtain eigen values and eigen vectors, a more specialized function to convert these into the results commonly given by principal components analysis, and a user interface function that accesses filed data, offers flexibility in data selection, and produces labeled output. A brief introduction to the logic and uses of principal components analysis is included. General-purpose support functions to simplify file use and to increase the range of options available to the user are also provided.     

APL functions for interactive data analysis: Preparation of data files

APL functions to support preparation of data files are presented: a function to manage the entry of raw data, functions to display the entered data in formats convenient for checking, a function to support correction of errors, a function to organize the data into tables and file them, and a user interface function that provides menu selection of the data preparation functions. General-purpose support functions to assist in file use and in menu selection are also provided.     

APL functions for interactive data analysis: Graphics and labels

APL functions designed to provide labeled plots and histograms are described. Support functions that augment a data file with necessary information to label output and to maintain a common plotting scale are also described. APL code and illustrative output are presented.