Effects of alcohol on prolonged cognitive performance measured with Stroop's Color Word Test

24 men and 24 women were randomly assigned in equal numbers to an Alcohol group, a Placebo group, or a Control group. The alcohol dose was 1.0 ml of 100% alcohol/kg of body weight. Subjects were tested three consecutive times using Stroop's Color Word Test. The dependent measures were total time needed to complete the test, number of errors made and number of hesitations. Data were grouped into three blocks of 100 words. Results indicated that number of hesitations was too insensitive a measure to yield any significant effects. On the two first measures alcohol had a detrimental effect in that the Alcohol group needed more time to complete the test and made more errors than the Placebo group. There was also a significant interaction of alcohol dose by sex by blocks on both these measures, indicating that the detrimental effect of alcohol over time was restricted to women. Different implications of the results were discussed.     

Anxiety and performance in runners: Effects of stress and anxiety on physical performance

Abstract

The aim of this study was to investigate the effects of state and trait anxiety on physical performance under both neutral and stressful conditions. In Study I, 43 male and female track athletes answered the State-Trait Anxiety Inventory and twice underwent ergometric testing in the physiology laboratory after receiving a neutral or a stress-inducing instruction. In Study II, these 43 runners completed the state scale shortly before a test run in a practice session and once again just before the start in an official competition. Results showed a significant increase in self-reported state anxiety under the stress condition in both the laboratory and the field setting. At the same time, the mean physical performance, measured as physiological performance parameters (maximum oxygen intake, physical work capacity) or as running performance, significantly deteriorated under stress. The induced stress affected the heart rate in addition to the mere physical work load, with no sign of compensation occurring during the entire period of ergometric testing. Effects of anxiety on performance were tested by separate 2(trait) × 3(state) ANOVAs for each situation. For both laboratory situations, and for the practice situation as well, no significant relationships, neither linear nor nonlinear, were detected. In the competition situation, however, an inverted-U relationship was found in the low trait-anxious subgroup.     

Effects of warned and unwarned demand transitions on vigilance performance and stress

The present study was designed to explore the effects of warned and unwarned demand transitions in vigilance on performance and self-reported stress. Twenty observers (10 women and 10 men) were assigned at random to each of six conditions resulting from the factorial combination of signal salience (high and low salience signals) and switching (no switch, switch with warning, and switch without warning). Performance metrics and self-reported stress state (Task Engagement, Distress, and Worry) were collected. While demand transitions did destabilize subsequent performance, increasing intra-individual variability, overall performance efficiency was uninfluenced by either switching or warning. Demand transitions, whether warned or not, increased self-reported distress. A dynamic model of performance stress may be necessary and research employing vigilance tasks in the future may be useful for developing this performance-stress model.     

Effects of prolonged deprivation on learned helplessness

The influence of prolonged deprivation on response to uncontrollable outcome was investigated among 104 young Indian students. They received an unsolvable block design task followed by an anagram solution test and an attribution questionnaire. As predicted, the high-deprived and the female students displayed greater helplessness than their low-deprived and male counterparts, and they attributed uncontrollable outcome more to internal, stable, and global causes.     

Energetic effects of stimulus intensity on prolonged simple reaction-time performance

The efficiency of cognition is modulated by energetic factors like effort, fatigue or circadian variation, which affect even the most basic cognitive operations. For instance, speeded detection in simple reaction-time (SRT) tasks usually slows down over time. The literature suggests that either mindlessness due to routinization or mental fatigue due to attentional resource depletion might underlie this decrement. We tested these assumptions in three 25-min visual SRT tasks using easy-to-detect high-intensity and hard-to-detect low-intensity stimuli presented in both blocked and mixed fashion. Mindlessness theory predicts that less monotonous stimulation (i.e. the mixed presentation) would mitigate the time-related decrement for high- and low-intensity stimuli alike, whereas resource-depletion theory predicts opposite effects of mixed presentation on high- versus low-intensity stimuli. Indeed, stimulus intensity and presentation mode cross-interacted significantly, indicating that the performance decline was steeper for high-intensity stimuli but less steep for low-intensity stimuli during mixed compared to blocked presentation, respectively. These results strongly suggest that the time-related efficiency decrement during prolonged SRT performance is related to accumulating mental fatigue. A conjecture is put forward that explains both resource depletion and mindlessness from the perspective of self-regulation. Our study underscores the need to incorporate energetic factors into models of cognition to facilitate their translation into real-world applications.     

Fatigue during prolonged performance on a simple compensatory tracking task

Two basic activities are involved in radar operating, watchkeeping and target tracking. Deterioration of watchkeeping performance has been explained by a hypothesis which relates absence of sensory variation and failure to attend to one part of the display continuously (Broadbent, 1951). This paper describes a preliminary experiment to examine deterioration on a simple compensatory tracking task.

Twenty-one subjects were each tested for an uninterrupted period of two hours. They were required to keep a target correctly aligned by cranking a handwheel at a constant speed, and it was expected that failures to attend to the display would result in target deviations. Analysis of the results showed that both number of errors and mean duration of errors increased significantly in consecutive half-hour periods, and that there were large individual differences in performance.     

The impact of cognitive interference on performance during prolonged sleep loss

Summary A study was conducted on the effects of off-task cognitions on performance during sleep deprivation. Subjects answered the Thought Occurrence Questionnaire, assessing their proneness to engage in off-task cognitions, and were deprived of sleep for 72 hours, during which they performed a variety of tasks including visual discrimination and three versions of a logical reasoning task in which cognitive load was varied systematically. In addition, every day subjects answered the Cognitive Interference Questionnaire, which taps off-task cognitions during the experiment. Results indicated that subjects who habitually engage in off-task cognitions performed worse during 72 hours of sleep loss than subjects who do not engage in such distracting activities. In addition, it was found that the engagement in off-task cognitions increased during the 72 hours of sleep loss and such an engagement was related to deficits in performance accuracy. The mechanisms of off-task cognitions and sleep loss underlying these effects are discussed.     

Effects of gravitational and optical stimulation on the perception of target elevation

To examine the combined effects of gravitational and optical stimulation on perceived target elevation, we independently altered gravitational-inertial force and both the orientation and the structure of a background visual array. While being exposed to 1.0, 1.5, or 2.0 Gz in the human centrifuge at NASA Ames Research Center, observers attempted to set a target to the apparent horizon. The target was viewed against the far wall of a box that was pitched at various angles. The box was brightly illuminated, had only its interior edges dimly illuminated, or was kept dark. Observers lowered their target settings as Gz was increased; this effect was weakened when the box was illuminated. Also, when the box was visible, settings were displaced in the same direction as that in which the box was pitched. We attribute our results to the combined influence of otolith-oculomotor mechanisms that underlie the elevator illusion and visual-oculomotor mechanisms (optostatic responses) that underlie the perceptual effects of viewing pitched visual arrays.     

Effects of stress on recall

Subjects in experimental conditions were exposed to a traumatic autopsy colour slide (labelled either as of New York Police Department (NYPD) or MGM studio origin) embedded in a neutral series of travel scenes, while control subjects saw a neutral target. Subjects in the high-stress condition showed a significant decrease in memory for neutral slides which followed the NYPD-labelled traumatic stimulus (p < 0.001). Results support evidence in the eyewitness memory field which indicate reduced recall under elevated levels of stress.