Developmental changes in inhibitory processing: evidence from psychophysiological measures
Introduction
Traditionally, developmental theories emphasize the role of changes in the capacity to store and process information in accounting for cognitive development. Several different concepts of capacity have appeared in the developmental literature (Halford, 1993). The first notion is capacity as a ‘resource’, a very global concept that can be applied to a broad range of phenomena. A resource is a type of mental energy that can be allocated to tasks but is limited in supply. Tasks vary in their demands on resources and if a task requires more resources than available, performance will suffer. Developmental psychologists have used this notion of capacity to account for children's errors on a wide variety of tasks. A more specific notion of capacity is associated with working memory. Case (1985), for example, proposed working memory to consist of three distinct components; a ‘total processing space’ is composed of an ‘operating space’ and a ‘storage space’. Total processing space is constant and does not increase during development. There is a trade-off between operating space and storage space so that more space is left for storage, as operating space becomes more efficient. Although total capacity does not vary with age, processing efficiency will increase so that less capacity is needed for operational function and more capacity can be used for storage of additional information or execution of other processes. According to this notion, the total amount of capacity is stable throughout development but, as processing becomes more efficient, more capacity can be made available to improve cognitive function. For somewhat different notions of capacity in the developmental literature the interested reader is referred to Pascual-Loene, 1970, Kail, 1988, Kail, 1991, Kail and Salthouse, 1994, Halford, 1993.
The idea that inhibitory processes may also contribute to the observed developmental changes emerged only gradually from recent investigations of children's cognitive development and other aspects of behavior (Howe and Pasnak, 1993). The view of inhibitory function as a major developmental dimension is suggested from findings indicating age differences in the ability to inhibit on a wide range of tasks. For example, as children grow older, they are better able to suppress reflexive or prepotent responses (Diamond, 1990, Diamond et al., 1994). Children become less sensitive to noise in selective attention tasks (Ridderinkhof and Van der Molen, 1995, Burack and Enns, 1997) and to distractors in memory tasks (Bjorklund and Harnishfeger, 1990). Children also become more likely to inhibit previously correct solutions that are currently incorrect (Welsh et al., 1991). These and other findings led developmental psychologists to consider inhibitory processes more seriously (Dempster, 1993, Bjorklund and Harnishfeger, 1995).
Section snippets
Development of inhibition
The recent interest in inhibitory ability materialized into two major models of cognitive development. Bjorklund and Harnishfeger (1990) derived from the cognitive aging literature (Hasher and Zacks, 1988) a model of inefficient inhibition that is basically an extension of the mental capacity notion. Dempster, 1992, Dempster, 1993 proposed another framework in which the susceptibility to interference holds a key position. He adopted a neuropsychological perspective assuming that developmental
Two-tiered inhibition model
Hierarchical control and competitive interaction are both important aspects of the influential ‘supervisory-system’ model proposed by Norman and Shallice (1986). This model assumes that a supervisory system is invoked whenever the need arises for top-down activation of relevant processing structures and inhibition of inappropriate actions or thoughts. Under most circumstances, however, actions and thoughts are selected automatically without coming to the attention of the supervisory system and
Psychophysiological analysis
The significance of a psychophysiological analysis of inhibition is at least three-fold. First, in many paradigms, inhibition must be inferred from the absence of overt behavior (e.g. the suppression of a prepared response on a ‘no-go’ trial). Psychophysiological measures can then be used to assess the temporal dynamics of inhibition. Secondly, psychophysiological measures are extremely useful when overt behavioral indices of inhibition are either difficult or impossible to obtain (e.g.
Conclusion
Two theories on the development of inhibitory processes emerged recently from the literature; ‘inefficient-inhibition’ theory proposed by Bjorklund and Harnishfeger, 1990, Bjorklund and Harnishfeger, 1995, Harnishfeger, 1995 and ‘susceptibility-to-interference’ theory submitted by Dempster, 1992, Dempster, 1993. Both theories assume that the development of inhibitory ability is closely associated to maturational changes of the frontal lobes. This inference is derived primarily from the striking
Acknowledgements
The writing of this article was facilitated by the support of the Netherlands Institute for Advanced Study in the Humanities and Social Sciences (NIAS) at Wassenaar, The Netherlands, and the hospitality provided by Dr Eric Soetens at the University of Brussels (VUB). The research reported in this article has been supported by NWO grants #575-63-082, #575-63-082B, and #575-63-082C, and NIH grant MH40418. The author wishes to thank Dick Jennings, Riek Somsen and Richard Ridderinkof for their
References (148)
Stimulus–response compatibility viewed from a cognitive psychophysiological perspective
- et al.
The development of selective attention as reflected by event-related brain potentials
J. Exp. Child Psychol.
(1995) - et al.
The resources construct in cognitive development: diverse sources of evidence and a theory of inefficient inhibition
Dev. Rev.
(1990) - et al.
The evolution of inhibition mechanisms and their role in human cognition and behavior
Neurophysiological correlates of cognitive development: changes in long-latency event-related potentials from childhood to adulthood
Electroencephalogr. Clin. Neurophysiol.
(1978)- et al.
N400-like potentials elicited by faces and knowledge inhibition
Cogn. Brain Res.
(1996) The rise and fall of the inhibitory mechanism: toward a unified theory of cognitive development and aging
Dev. Rev.
(1992)- et al.
Developmental changes in selective and integrative visual attention
J. Exp. Child Psychol.
(1985) - et al.
Selective attention in young children: the relations between visual search, filtering, and priming
J. Exp. Child Psychol.
(1987) The development of cognitive inhibition. Theories, definitions, and research evidence