PSYC Call for Commentators: INDIVIDUAL DIFFERENCES IN COLOR STROOP

Koch/Gobell/Roid: INDIVIDUAL DIFFERENCES IN COLOR STROOP The target article below has just appeared in PSYCOLOQUY, a refereed journal of Open Peer Commentary sponsored by the American Psychological Association. Qualified professional biobehavioral, neural or cognitive scientists are hereby invited to submit Open Peer Commentary on it. Please email or see websites for Instructions if you are not familiar with format or acceptance criteria for PSYCOLOQUY commentaries (all submissions are refereed). To submit articles and commentaries or to seek information: EMAIL: psyc(a)pucc.princeton.edu URL: http://www.princeton.edu/~harnad/psyc.html http://www.cogsci.soton.ac.uk/psyc AUTHORS' RATIONALE FOR SOLICITING COMMENTARY: We have found a pattern of individual differences on the Stroop color-word test that do not seem to be among those reported previously (MacLeod, 1991). Two separate attempts to identify the source of these individual differences have failed, although we kept finding the same patterns of responding. We hope the article will draw attention to the need to examine individual differences in Stroop processing and and that the Psycoloquy it elicits will help identify their basis. ----------------------------------------------------------------------- psycoloquy.99.10.025.stroop-differences.1.koch Thu Sep 16 1999 ISSN 1055-0143 (27 paragraphs, 29 references, 599 lines) PSYCOLOQUY is sponsored by the American Psychological Association (APA) Copyright 1999 Christopher Koch, Joetta Gobell, & Gale H. Roid EXPLORING INDIVIDUAL DIFFERENCES IN STROOP PROCESSING WITH CLUSTER ANALYSIS Target Article on Stroop-Differences Christopher Koch, Joetta Gobell, & Gale H. Roid Department of Psychology George Fox University 414 N. Meridian St. Newberg OR 97132 USA ckoch(a)georgefox.edu http://www.georgefox.edu/people/faculty/ckoch/ ABSTRACT: A relatively small number of studies of the Stroop task has examined individual differences in age, sex, hemispheric processing, and language. The amount of interference is the primary dependent measure in most studies, not the factors that contribute to the interference. In the present target article, cluster analysis is used to identify groups of participants who respond similarly on the Stroop task. Integrated color-word Stroop stimuli were presented for varying durations in the first study. Significant individual differences were found. A cluster analysis identified two groups of subjects. One group responded consistently across durations and conditions while the other responded more erratically. Potential sources of individual differences were examined in a second study. 120 subjects were given the Color and Word Test along with selected subtests of the Stanford Binet Intelligence Test, age appropriate Wechsler tests, and the Detroit Tests of Learning Aptitude. Again, cluster analysis found two groups of subjects. The group with higher scores on visual reasoning and short-term memory produced more interference. KEYWORDS: cluster analysis, individual differences, short-term memory, Stroop interference, visual reasoning