Synchrony Effects in Inhibitory Control Over Thought and Action
Total Page:16
File Type:pdf, Size:1020Kb
Journal of Experlnlelllal Psychology: Copyright 1998 by the American Psychological Association. Inc. Human Perception and Performance 0096-1523/98/$3.00 1998, Vol. 24, No. 2. 363-379 Synchrony Effects in Inhibitory Control Over Thought and Action Cynthia E May Lynn Hasher University of Arizona Duke University Two experiments explore whether synchrony between peak circadian arousal periods and time of testing influences inhibitory efficiency for younger and older adults. Experiment 1 assesses inhibitory control over no-longer-relevant thoughts, and Experiment 2 assesses control over unwanted but strong responses, as well as performance on neuropsychological tasks that index frontal function. Inhibitory control is greatest at optimal times for both age groups and is generally greater for younger than for older adults. Performance on 2 neuropsyehological measures (Stroop and Trails) also changes over the day, at least for older adults, and is correlated with inhibitory indexes, suggesting that for older adults changes in inhibition may be mediated by circadian variations in frontal functioning. By contrast, access to well-learned responses is not vulnerable to synchrony or age effects. Inhibition is gaining increasing importance in current ling responses that are highly practiced and thus are likely to theories of cognitive psychology as a mechanism critical for be emitted quickly and prior to careful evaluation. Thus, control over thought and action (see, e.g., Dagenbach & efficient inhibition functions both to prevent social faux pas Carr, 1994; Dempster & Brainerd, 1995; Hasher, Zacks, & and to maintain goal-oriented actions. May, in press). With respect to control over thought, By virtue of its functions in controlling thought and inhibitory mechanisms are believed to prevent irrelevant or action, inhibition is an essential component of numerous marginally relevant information from entering working cognitive processes--including selective attention and per- memory and to dampen activation of information that was ceptual recognition, speech production and language compre- once relevant but later becomes inappropriate for current hension, memory encoding and retrieval, and response goals (Hasher & Zacks, 1988; Navon, 1989a, 1989b). For control (e.g., Anderson, Bjork, & Bjork, 1994; Arbuckle & example, inhibition is thought to assist retrieval of weakly Gold, 1993; Dagenbach & Carr, 1994; Gernsbacher & Faust, activated information in the midst of strong competitors 1991; Hasher & Zacks, 1988; Logan, 1994; Shapiro & (Dagenbach & Carr, 1994), to suppress inappropriate inter- Raymond, 1994; Zacks & Hasher, 1994). By contrast, pretations of ambiguous words (Gemsbacher & Faust, 1991; inefficient inhibition may be a significant contributor to the Simpson & Kang, 1994; Stoltzfus, 1992), and to dampen problems of diminished attention, memory, and control over no-longer-relevant information (Hartman & Hasher, 1991; action that are exhibited by many special populations-- Zacks & Hasher, 1994). Thus, inhibition functions to keep including patients with obsessive--compulsive disorder (OCD; thoughts on goal-centered paths. e.g., Enright & Beech, 1993; Ferraro, Johnson, & Won- Inhibition also functions to keep actions goal centered by derlich, 1995), children with attention deficit hyperactivity preventing the production of inappropriate responses (Lo- disorder (ADHD; Lorsbach, Wilson, & Reimer, 1995; gan, 1983, 1985). Inhibition holds candidate responses in Schachar, Tannock, & Logan, 1993), and patients with abeyance until they can be evaluated for their appropriate- schizophrenia (e.g., Beech & Claridge, 1987; Beech, Baylis, ness and suppresses those responses that are disconfirmed as Smithson, & Claridge, 1989). Given the broad impact of undesirable. Inhibition is particularly important for control- inhibitory processing on cognitive functioning, isolating the conditions or variables that affect inhibitory efficiency can This work was funded by grants from the National Institute on have significant implications for a variety of behaviors and Aging (AGO 4306 and AG1 2753) and by fellowships from the populations. National Science Foundation and the James McKeen Cattell Foundation. A number of variables are now believed to influence the We greatly appreciate the valuable assistance of Daniel Kimball, efficiency of inhibitory mechanisms. Inhibitory efficiency Rachel Salit, and Darin Weichmann in the data collection for this may be reduced by injury to the frontal lobes (e.g., project. We also extend thanks to Angela Howell for assistance at Shimamura, 1995), by depression and stress (LinviUe, in various stages of the project and to Michael Kane for helpful press), and by the presence of a number of behavioral comments on an earlier draft. As well, Lynn Hasher is grateful to disorders, including, for example, ADHD (Lorsbach, Wil- the University of Toronto and the Rotman Research Centre of son, & Reimer, 1995) and OCD (e.g., Enright & Beech, Bayerest Hospital for sabbatical support. 1993). In addition, inhibitory efficiency follows a develop- Correspondence concerning this article should be addressed to Cynthia P. May, Department of Psychology, Room 312, University mental course, increasing in childhood and then diminishing of Arizona, Tucson, Arizona 85721, or to Lynn Hasher, Department in old age (Bjorklund & Hamishfeger, 1990; Dempster, of Psychology, Box 90085, Duke University, Durham, North 1992; Hasher & Zacks, 1988; McDowd, Oseas-Kreger, & Carolina 27708. Electronic mall may be sent via Intemet to Filion, 1995; Zacks & Hasher, 1994) and diminishing even cmay @aruba.ccit.arizona.edu or lhasher @acpob.duke.edu. further in Alzheimer's disease (Sullivan, Faust, & Balota, 363 364 MAY AND HASHER 1995). In the present investigation, we examined the possi- inappropriate motor responses. Both groups demonstrated bility that inhibitory efficiency is also affected by variations greater inhibitory efficiency at peak relative to off-peak in circadian arousal. times, and inhibitory efficiency was generally greater for The question of whether inhibitory functioning varies younger than for older adults (see Hartman & Hasher, 1991; with circadian arousal comes from the finding that, like a McDowd et al., 1995; Zacks & Hasher, 1994). The magni- number of biological processes (e.g., blood pressure, hor- tude of age differences in inhibitory functioning varied over mone secretion, and body temperature; Home & Ostberg, the day, depending on when testing occurred: When younger 1976; Hrushesky, 1994), aspects of cognitive functioning are adults were at their peak but older adults were not, age governed by individual differences in circadian rhythms differences were quite robust; however, when older but not (e.g., Bodenhausen, 1990; May, Hasher, & Stoltzfus, 1993), younger adults were at their peak, age differences were with dramatic changes in cognitive functioning over the day. reduced and in some cases eliminated. This pattern of For example, decisions are more analytic (Bodenhausen, synchrony effects was also observed in performance on two 1990), detection of targets is better (Home, Brass, & Pettitt, standard neuropsychological tasks, and these scores corre- 1980), and recall and recognition of prose are more accurate lated with stopping performance in some instances. These (May et al., 1993; Petros, Beckwith, & Anderson, 1990) data join with others reported earlier (May et al., 1993) to when testing times are in synchrony with individuals' peak suggest that age differences on at least some tasks will be in circadian arousal than when they are not. We refer to the exaggerated without careful attention to synchrony effects. finding that performance is optimal when testing times Finally, synchrony did not affect performance on all cogni- match peak arousal periods as the synchrony effect. tive tasks; specifically, it had virtually no effect on those The aim of the present investigation was to explore tasks in which a correct response required the production, directly the possibility that inhibitory functioning, as re- rather than the inhibition, of strong, well-learned responses. flected by control over thought and action, is affected by individual differences in circadian arousal. In the two studies Experiment 1 reported here, we investigated the impact of synchrony on inhibitory control over thought and action by examining the In Experiment 1, we examined people's ability to sup- inhibition of no-longer-relevant information and the inhibi- press no-longer-relevant information by using a garden-path tion of inappropriate motor responses, respectively, at peak procedure (Hartman & Hasher, 1991). For this task, partici- and off-peak times of day. pants generated endings to normatively high-cloze sentences We examined synchrony effects in two groups of people: (e.g., "Before you go to bed turn off the . Expected college students aged 18-23 years and older adults aged ending: "lights"). For critical sentenc~ generated 60-75 years. An age comparison was included here because, ending (e.g., "lights") was disconfirmed and was replaced relative to younger adults, older adults have been shown to by an experimenter-provided target ending (e.g., "stove"), suffer impairments in inhibitory functioning (Harem & which participants were to remember. The question of Hasher, 1992; Hartman & Hasher, 1991; McDowd et al., interest was whether participants would suppress the discon- 1995; Stoltzfus, Hasher, Zacks, Ulivi, & Goldstein, 1993), firmed endings of critical sentences