Brief Report Impulsiveness and resource allocation: Testing Humphreys and Revelle’s (1984) explanation of impulsive personality Luke D. Smillie a, * , Gillian B. Yeo b , Katie L. Lang a,c a Department of Psychology, Goldsmiths, University of London, United Kingdom b School of Psychology, University of Western Australia, Australia c National and Specialist OCD Service for Young People, South London and Maudsley NHS Trust, United Kingdom article info Article history: Available online 12 July 2009 Keywords: Impulsiveness Effort Resource allocation Relative-judgement abstract Humphreys and Revelle [Humphreys, M. S., Revelle, W. (1984). Personality, motivation and performance: A theory of the relationship between individual differences and information processing. Psychological Review, 91, 153–184] suggest that impulsive individuals have relatively greater capacity to improve per- formance through task-directed resource allocation. This implies that there will be a differential effect of increases in effort intensity on performance for high and low impulsive individuals. Two quasi-experi- ments tested this prediction using a relative-judgement task (total N = 108, 68 females), however neither revealed the predicted interaction. In light of these findings, we re-consider the Humphreys–Revelle model in relation to independent but potentially related theory and research. Crown Copyright Ó 2009 Published by Elsevier Inc. All rights reserved. 1. Introduction Impulsiveness is a trait comprising deficits in planning and behavioural restraint (Arce & Santesteban, 2006). 1 Various expla- nations of impulsive personality have been proposed with varying degrees of empirical support. In this paper we examine an explana- tion of Impulsiveness suggested by Humphreys and Revelle (1984) as part of an integrative model of personality, motivation and cog- nition. Despite the influence of their paper (>200 citations), and empirical support for their model (e.g., Matthews, Davies, & Lees, 1990), the prediction made with respect to Impulsiveness does not appear to have been tested. The Humphreys–Revelle model is based upon two informa- tion-processing functions (Resource Allocation and Short Term Memory), and offers an explanation for personality-performance effects on some cognitive tasks (e.g., Revelle, Humphreys, Simon, & Gilliland, 1980). Although a full description of their model is beyond the scope of this paper, the key points of their argument with respect to impulsive personality can be described thusly: first, low-impulsives are thought to be over-aroused whilst high-impulsives are thought to be under-aroused, perhaps chron- ically or at least in the morning (see Dickman, 2000, for compar- ison of perspectives). Second, lower arousal increases one’s capacity to improve performance via increased resource alloca- tion (i.e., by intensifying cognitive effort, Kanfer & Ackerman, 1989). This is because the benefit of increased resource allocation for cognitive performance is counteracted by a Short Term Mem- ory cost of high arousal. From this, Humphreys and Revelle (1984, p. 171) hypothesised that high-impulsive individuals, relative to their low-impulsive counterparts, should be better able to im- prove their performance by intensifying cognitive effort (espe- cially in the morning). As such, one would expect to find a significant interaction between within-person changes in effort intensity and between-person differences in Impulsiveness, when predicting performance on relevant cognitive tasks. 2. Study 1 In study 1 we examined the cross-level interaction between effort intensity (within-subjects) and Impulsiveness (between- subjects) when predicting performance (a speed-accuracy criterion) on a relative-judgement task. 3. Methods 3.1. Participants Sixty-nine students (41 females, age: M = 19.43, SD = 2.63) from the University of Queensland participated for course credit, and were described elsewhere (Smillie, Yeo, Furnham, & Jackson, 2006). Participants were tested between 8 am and 6 pm. 0092-6566/$ - see front matter Crown Copyright Ó 2009 Published by Elsevier Inc. All rights reserved. doi:10.1016/j.jrp.2009.07.005 * Corresponding author. Address: Department of Psychology, Goldsmiths, Uni- versity of London, London SE14 6NW, United Kingdom. E-mail address: l.smillie@gold.ac.uk (L.D. Smillie). 1 This definition for impulsivity is in reasonable agreement with the majority of conceptualisations in the field, but diverges strongly from some alternative concep- tualisations (such as ‘Functional Impulsivity’; the tendency to behave in a rapid, error- prone manner when such behaviour is optimal; Dickman, 2000). Journal of Research in Personality 43 (2009) 1083–1086 Contents lists available at ScienceDirect Journal of Research in Personality journal homepage: www.elsevier.com/locate/jrp