Arousal and the Bakan vigilance task: The effects of noise intensity and the presence of others

The joint effects of social setting and loud noise on task performance are examined. In a modified version of the Bakan vigilance task subjects were required to detect a sequence of two identical even digits and to report the two digits preceding the signal. Two types of acoustic environment were compared: loud noise at 90 dBC and quiet noise at 60 dBC. Two types of social setting were employed: “pair” where two subjects worked in the same room on similar tasks, and “single” where a subject performed the task alone. The effects of noise and the presence of another did not interact. Loud noise increased the speed of responses to signals early in the task. This effect is attributed to noise-induced arousal. There was a higher incidence of recall errors in pre-signal digits when subjects were in pairs. This effect is attributed to distraction. This research was part of a series of studies sponsored by the Social Science Research Council (Grant HR 5563 awarded to Dr. A.J. Chapman and Dr. D.M. Jones).     

Double standards: Memory loading in temporal reference memory

Three experiments compared human performance on temporal generalization tasks with either one or two different, and distinct, standard durations encoded. In the first two experiments participants received presentations of two different standards at the beginning of each trial block and were instructed to encode either one or both of them. When instructed to encode one standard they then had to judge whether each of a number of comparison stimuli was or was not that standard. When instructed to encode both they were then tested using just one of the standards but the participants were unaware, at the time of encoding, which standard would later be used as a reference. No marked effect of the number of temporal standards encoded was found. In Experiment 3 participants received either one or two temporal standards and had to use both when two were presented. This manipulation produced flatter generalization gradients when two standards were encoded than when just one was, and modelling attributed this difference mainly to an increase in reference memory variability in the double-standard case. This suggests that the variability of representation of durations in temporal reference memory can be systematically increased by increasing temporal reference memory load.     

More is not necessarily better: Examining the nature of the temporal reference memory component in timing

Three experiments compared the timing performance of humans on a modified temporal generalization task with 1, 3, or 5 presentations of the standard duration. In all three experiments subjects received presentations of a standard duration at the beginning of a trial block and then had to judge whether each of a number of comparison stimuli was or was not the standard. The duration of the standard changed between blocks. The three experiments varied the experimental design (between or within subjects), task difficulty (how closely the comparison stimuli were spaced around the standards), and presence or absence of feedback on performance accuracy. Number of presentations of the standard never affected the proportion of identifications of the standard when it was presented, nor other features of the temporal generalization gradients observed. The implications for the operation of reference memories within the scalar timing system were explored via models that made different assumptions about how the individual presentations of the standard were stored and used.     

The persistent impact of incidental experience

As we perform daily activities—driving to work, unlocking the office door, or grabbing a coffee cup—our actions seem automatic and preprogrammed. Nonetheless, routine, well-practiced behavior is continually modulated by incidental experience: In repetitive experimental tasks, recent (~4) trials reliably influence performance and action choice. Psychological theories downplay the significance of sequential effects, explaining them as rapidly decaying perturbations of behavior, with no long-term consequences. We challenged this traditional perspective in two experiments designed to probe the impact of more distant experience, finding evidence for effects spanning up to a thousand intermediate trials. We present a normative theory in which these persistent effects reflect optimal adaptation to a dynamic environment exhibiting varying rates of change. The theory predicts a heavy-tailed decaying influence of past experience, consistent with our data, and suggests that individual incidental experiences are catalogued in a temporally extended memory utilized in order to optimize subsequent behavior.     

Examiner Errors on the WAIS-R: A Source of Concern

Munchausen syndrome (MS) is characterized by patients' chronic and relentless pursuit of medical treatment for combinations of symptoms of consciously self-inflicted injury and falsely reported symptomatology. MS patients are adults, as are perpetrators of Munchausen syndrome by proxy (MSBP). MSBP is an unusual form of child abuse in which a parent, usually the mother, brings a child for medical attention with symptoms falsified or directly induced by the mother. Most reports of MSBP have been of a few cases appearing in medical and pediatric literature. Motivation in both disorders is unclear, and diagnosis and treatment present difficult problems that require more research.     

The Interrelationships Between Anxiety,Motor Performance and Electromyography

Notterman (1975) argued, contrary to my 1974 article, that the data obtained by Notterman and Page (1962) confirm the important role of proprioception in skilled performance. I argue that these data are in fact ambiguous when it comes to distinguishing the effects of proprioception from those of outflow control.