State-dependent memory effects using caffeine and placebo do not extend to metamemory

The authors examined the impact of caffeine on human memory and predictions of memory (i.e., metamemory). On Day 1, 83 college students drank a sweetened beverage containing either caffeine (4 mg/kg body weight) or a placebo before they studied 40 pairs of words. While the participants studied, they predicted their future memory performance for each word pair. On Day 2, the participants again received caffeine or a placebo before the memory test. The participants who drank the same beverage on both days (either caffeine or a placebo) recalled more word pairs than did those who drank different beverages (caffeine on 1 day and a placebo on the other day). In contrast, memory predictions were more accurate when the beverages did not match on both days. These data provide evidence for state-dependent memory when caffeine is used, but not for state-dependent metamemory. People's memory and their predictions of memory can be influenced in different ways if they drink caffeine before they study or take a test.     

State-Dependent Memory Effects Using Caffeine and Placebo Do Not Extend to Metamemory

The authors examined the impact of caffeine on human memory and predictions of memory (i.e., metamemory). On Day 1, 83 college students drank a sweetened beverage containing either caffeine (4 mg/kg body weight) or a placebo before they studied 40 pairs of words. While the participants studied, they predicted their future memory performance for each word pair. On Day 2, the participants again received caffeine or a placebo before the memory test. The participants who drank the same beverage on both days (either caffeine or a placebo) recalled more word pairs than did those who drank different beverages (caffeine on 1 day and a placebo on the other day). In contrast, memory predictions were more accurate when the beverages did not match on both days. These data provide evidence for state-dependent memory when caffeine is used, but not for state-dependent metamemory. People's memory and their predictions of memory can be influenced in different ways if they drink caffeine before they study or take a test.     

Influence of cup stacking on hand-eye coordination and reaction time of second-grade students

Cup stacking has been adopted recently by many physical education programs to enhance rudimentary motor skills such as hand-eye coordination and ambidexterity as well as quickness and concentration; however, no empirical evidence has been published to support these claims. We examined the influence of cup stacking on hand-eye coordination and reaction time of 24 boys and 18 girls in second grade as measured by the Soda Pop and Yardstick tests, respectively. Two physical education classes were randomly assigned as treatment and control groups and were pre- and posttested for hand-eye coordination and reaction time. The treatment group participated in a 5-wk. cup-stacking program. Significant improvements were noted for both hand-eye coordination and reaction time between the pre- and posttest scores for this group but not for the control group. Therefore, cup stacking is indeed effective in enhancing hand-eye coordination and reaction time.     

Caffeine reduces the impact of drowsiness on driving errors

AimThe study examined the moderating effect of repeat-dose, chewing gum-administered caffeine on the well-established relationship between drowsiness and driving performance, under the conditions of accumulating sleep loss.Method50-h sleep deprivation protocol with a double-blind, placebo-controlled design. Eleven volunteers (6 male), aged 18–28 years were screened for pre-existing medical conditions (including sleep disturbances), tobacco and recreational drug use, recent time-zone travel and shift-work. They were randomly allocated to placebo or caffeine group and administered 4 oral doses of either caffeinated gum pellets (200 mg/dose) or non-caffeinated placebo gum every two hours (01:00, 03:00, 05:00, 07:00) on the first and second nights of the protocol. Participants were constantly monitored and remained awake for 50 h, while performing 15 identical, evenly-spaced 40-min monotonous driving tasks in a medium-fidelity moving-base driving simulator. Their drowsiness was monitored with a spectacle frame-mounted infra-red sensor registering ocular parameters and converting them into a Johns Drowsiness Scale (JDS) score every 60 s. Lane keeping and speed variability measures were used to assess driving performance.ResultsDriving performance declined and drowsiness increased from the first simulated drive to the last. When driving performance was examined in one-minute epochs synchronised with JDS scores, both lateral lane positioning and speed variability were found to be associated with drowsiness. The strength of this association was significantly weaker in the caffeine group, compared to placebo. Placebo group replicated the linear relationship between drowsiness and driving errors across the full range of JDS scores. This pattern was significantly weaker under the caffeine condition, and was even reversed at the upper range of JDS, with higher JDS scores not resulting in further degradation of driving performance. This dissociation between drowsiness and driving errors persisted across the 24-h cycle under the caffeine condition, despite caffeine being administered only during early morning hours.ConclusionStrategically timed, repeat 200 mg doses of caffeine administered via chewing gum can mitigate fatigue-induced impairments in driving performance by not only reducing drowsiness but also by significantly weakening its impact on driving errors. This dual effect of sustained drowsiness reduction and the dissociation between drowsiness levels and driving errors seems worth further investigation as it might offer an effective emergency countermeasure against driver drowsiness and its subsequent conversion into potentially fatal driving errors.     

Performance on creativity measures with examination‐taking instructions intended to induce high or low levels of test anxiety

The major purpose of this investigation was to ascertain whether differential levels of performance on three tests of creativity portraying divergent production of verbal (semantic), figural (visual), and mathematical (symbolic) responses would be associated with two sets of test‐taking instructions: (a) one intended to induce a relatively high level of anxiety or stress and (b) the other designed to minimize the degree of anxiety or stress in the testing experience. Participants were 132 private secondary school students (82 females and 50 males) in a college preparatory program who were divided into experimental and control groups. On the basis of three univariate four‐way factorial designs at each of two levels per variable (treatment x sex x test anxiety x mathematics anxiety) with the pretest serving as a covariate, it was observed that only in the instance of a mathematics fluency test did the experimental group exposed to anxiety‐inducing test‐taking instructions achieve a significantly lower mean score on the posttest than did the control group that had been administered instructions intended to minimize anxiety (p < .001). A marginally significant interaction occurred between gender and mathematics anxiety on the mathematics fluency test with highly‐anxious males showing a greater decrement in performance than highly‐anxious females when exposed to anxiety‐inducing instructions. The results were interpreted primarily within a conceptual framework developed by Tobias (1985), who proposed an integration of cognitive capacity and interference as explanatory constructs for decrements in the performance of tasks involving anxiety.     

Behavioral test systems in marmoset monkeys

A number of neurobehavioral methods have been developed to test behavior in marmoset monkeys. These test systems are (1) the bungalow test, which quantifies spontaneous explorative behavior, (2) the hand-eye coordination test, which tests a learned task of coordinated motor behavior, and (3) the fear-potentiated startle response, which tests and quantifies pathological anxiety manifested by a response of fright. The test systems are extensively discussed, and the value of these test systems is exemplified by applying them to neurological disorders to register disease activity and drug efficacy.     

Cardiovascular reactivity, mood, and task performance in deprived and nondeprived coffee drinkers

Forty habitual, heavy coffee drinkers (M = 5.7 cups/day) participated in two experimental sessions. Participants were deprived of their morning coffee for one of the laboratory sessions, not deprived the other. During each session, subjects consumed 12 oz of caffeinated coffee, decaffeinated coffee, or caffeine-free herbal tea. Measurements of heart rate, blood pressure, mood, and catecholamine response to deprivation and consumption of the beverage, alone and in combination with challenging tasks, were made. This study found that caffeine continues to cause blood pressure increases with chronic, heavy consumption and that these effects do not appear to habituate with regular use. Subjects reacted to behavioral challenge with fewer negative mood effects if they had consumed caffeine or coffee. Mild caffeine deprivation was associated with symptoms of stress.     

Training with anxiety has a positive effect on expert perceptual–motor performance under pressure

In two experiments, we examined whether training with anxiety can prevent choking in experts performing perceptual–motor tasks. In Experiment 1, 17 expert basketball players practised free throws over a 5-week period with or without induced anxiety. Only after training with anxiety did performance no longer deteriorate during the anxiety posttest. In Experiment 2, 17 expert dart players practised dart throwing from a position high or low on a climbing wall, thus with or without anxiety. Again, only after training with anxiety was performance maintained during the anxiety posttest, despite higher levels of anxiety, heart rate, and perceived effort. It is concluded that practising under anxiety can prevent choking in expert perceptual–motor performance, as one acclimatizes to the specific processes accompanying anxiety.     

EFFECTS OF CAFFEINE ON CLASSROOM BEHAVIOR,SUSTAINED ATTENTION,AND A MEMORY TASK IN PRESCHOOL CHILDREN

The effects of caffeine on the behavior of young children is an important issue, as children in our society consume considerable amounts of caffeine, primarily in soft drinks. This study investigated the effects of normative amounts of caffeine on the behavior of 6 normal children in a kindergarten setting. Using a reversal design, counterbalanced for order of conditions, children's behavior was examined during a baseline condition, a caffeinated beverage condition, and a noncaffeinated beverage condition. Measures included direct observation of off-task and gross motor activity, actometer readings of movement, a Continuous Performance Test, a Paired Associates Learning Test, and teacher ratings of classroom behavior. Results suggest that caffeine exerts only small and inconsistent effects on the classroom behavior of kindergarten children. These results cast doubt on the importance of caffeine as a variable controlling the classroom behavior of normal kindergartners.     

A consciousness-sampling analysis of test anxiety and performance

In order to evaluate cognitive-interference, reassertion, and reaction-to-performance models of test anxiety, 82 students completed the Test Anxiety Scale, provided state measures of anxiety just before and after a course examination, described their preparation for the test, and reported thought content and state anxiety up to six times during the test. Test Anxiety Scale scores were predictive of pre- and posttest state anxiety but not performance or problem-solving thought frequency during the test. Thought content was significantly but weakly correlated with performance, which was well correlated with posttest state anxiety but not with pretest anxiety. Pretest state anxiety was virtually uncorrelated with posttest state anxiety, with the correlations gradually declining during the test. Question-answering thought content correlated inversely with anxiety during the test. There was no group for whom anxiety appeared to facilitate performance. Preparation correlated only with performance. The pattern of results appears inconsistent with a cognitive-interference interpretation of test anxiety and suggests that in the naturalistic setting used, anxiety is more clearly an effect than a cause of poor performance.     

Caffeine deprivation state modulates expression of acquired liking for caffeine-paired flavours

Previous studies found that caffeine consumers acquired a liking for the flavour of novel caffeinated drinks when these drinks were consumed repeatedly in a caffeine-deprived, but not nondeprived, state. Expression of this acquired liking appeared acutely sensitive to current caffeine deprivation state, but the use of between-subjects designs confounded interpretation of those studies. The present study evaluated these findings further using a within-subject design, with one flavour paired with caffeine (CS + ) and the second with the absence of caffeine (CS–). During four CS + and four CS– training days, 32 moderate caffeine consumers alternatively consumed a novel flavoured drink a CS + paired with caffeine and a CS– flavour paired with placebo. Participants evaluated both drinks before and after training in two motivational states: caffeine deprived and nondeprived. As predicted, pleasantness ratings for the caffeine-paired flavour increased overall. However, this acquired liking was only significant when tested in a caffeine-deprived state. These data are consistent with a conditioned-flavour preference model and imply that expression of acquired liking for a novel caffeinated flavour depends on the need for the effects of caffeine at the time when the drink is evaluated.     

Caffeine deprivation state modulates expression of acquired liking for caffeine-paired flavours

Previous studies found that caffeine consumers acquired a liking for the flavour of novel caffeinated drinks when these drinks were consumed repeatedly in a caffeine-deprived, but not nondeprived, state. Expression of this acquired liking appeared acutely sensitive to current caffeine deprivation state, but the use of between-subjects designs confounded interpretation of those studies. The present study evaluated these findings further using a within-subject design, with one flavour paired with caffeine (CS + ) and the second with the absence of caffeine (CS-). During four CS + and four CS- training days, 32 moderate caffeine consumers alternatively consumed a novel flavoured drink a CS + paired with caffeine and a CS- flavour paired with placebo. Participants evaluated both drinks before and after training in two motivational states: caffeine deprived and nondeprived. As predicted, pleasantness ratings for the caffeine-paired flavour increased overall. However, this acquired liking was only significant when tested in a caffeine-deprived state. These data are consistent with a conditioned-flavour preference model and imply that expression of acquired liking for a novel caffeinated flavour depends on the need for the effects of caffeine at the time when the drink is evaluated.     

The effects of assertive training on performance in highly anxious adolescents

The effects of assertive training on measures of assertiveness, state anxiety, and mathematics performance in highly anxious adolescents were investigated. A group of 96 highly anxious 9th graders was assigned to one of four treatment groups. Pretest and posttest assessment included the Adolescent Self-Expression Scale (a measure of assertiveness), the State-Trait Anxiety Inventory, and the Mathematics Problems and Concepts subtests of the California Achievement Test. Experimental treatment consisted of four assertive training sessions, while placebo treatment for the control groups consisted of four career development training sessions. Posttest was administered to all four groups. A MANOVA was used to analyze all of the data on the students who took the pre- and posttest and attended two or more training sessions. Assertive training resulted in increased assertiveness and decreased state anxiety, with no significant effect on mathematics performance, and no significant effect due to sex. It was concluded that assertive training is a counseling technique which can be used effectively with 9th graders.     

Efficacy of self-instructional training for reducing children''s anxiety in an evaluative situation

Fifty-six fourth-grade children were categorized as either high or low in trait anxiety and then assigned to a self-instruction treatment, minimal-treatment, or no-treatment control condition. At both pretest and posttest, the subjects recited a memorized poem while being videotaped with the expectation that they would be judged on their performance. State anxiety measures, a behavior rating of anxiety, a measure of performance accuracy and the time involved in reciting a poem were obtained at both pretest and posttest. Contrary to expectation, the self-instructional training resulted in subjects' exhibiting greater signs of behavioral anxiety, subjects' hurrying through the task (taking less time to recite the poem) and high trait-anxiety subjects' reporting more state anxiety while anticipating reciting the poem. Correlational analyses indicated that trait anxiety was significantly related to the measures of state anxiety and the behavior rating of anxiety but not to performance accuracy.     

Trait-anger enhances effects of caffeine on psychomotor vigilance performance

This study examined the combined effects of caffeine and the personality attribute of trait-anger on the speed of psychomotor vigilance performance during sleep deprivation. 23 young adult soldiers (19 male) were administered the State-Trait Anger Expression Inventory-2 when well-rested. Participants were then sleep deprived for three consecutive nights (77 hours total) during which they completed repeated psychomotor vigilance testing. Half of the participants received four doses of oral caffeine (200 mg every 2 hr.; 800 mg total) each night, while the other half were administered a placebo. For the first night, higher scores on trait-anger, outward anger expression, and intensity of anger expression predicted better sustained overnight vigilance performance, but only for those volunteers receiving caffeine. These correlations were not significant for the subsequent nights. Findings suggest a possible synergistic effect between personality traits associated with arousal of the central nervous system and vigilance-promoting effects of caffeine.     

Arousal and recognition memory: The effects of impulsivity,caffeine and time on task

Systematic changes in performance on memory tasks have been observed as a function of the number of prior items or lists learned. In an attempt to determine whether this was an ‘attentional’ phenomenon the effect of arousal (as indexed by Impulsivity and manipulated by caffeine) on memory performance was examined. One hundred college students were given either 4 mg of caffeine/kg body weight or a placebo and then shown four lists (two 24-item and two 80-item) of four letter words. A forced-choice recognition test for the last 20 items was given immediately after each list. The performance of the high impulsives who were given a placebo (least aroused subjects) declined as a function of the number of prior lists learned. Low impulsives (more aroused) showed significantly less decline. Caffeine significantly improved recognition memory especially on the final lists. Decrements in memory performance, as a function of number of prior litsts, are thus reduced by the same variables which reduce vigilance decrements. It is suggested that common explanations will be required.     

Reinforcing effects of caffeine in coffee and capsules.

In a residential research ward the reinforcing and subjective effects of caffeine were studied under double-blind conditions in volunteer subjects with histories of heavy coffee drinking. In Experiment 1, 6 subjects had 13 opportunities each day to self-administer either a caffeine (100 mg) or a placebo capsule for periods of 14 to 61 days. All subjects developed a clear preference for caffeine, with intake of caffeine becoming relatively stable after preference had been attained. Preference for caffeine was demonstrated whether or not preference testing was preceded by a period of 10 to 37 days of caffeine abstinence, suggesting that a recent history of heavy caffeine intake (tolerance/dependence) was not a necessary condition for caffeine to function as a reinforcer. In Experiment 2, 6 subjects had 10 opportunities each day to self-administer a cup of coffee or (on different days) a capsule, dependent upon completing a work requirement that progressively increased and then decreased over days. Each day, one of four conditions was studied: caffeinated coffee (100 mg/cup), decaffeinated coffee, caffeine capsules (100 mg/capsule), or placebo capsules. Caffeinated coffee maintained the most self-administration, significantly higher than decaffeinated coffee and placebo capsules but not different from caffeine capsules. Both decaffeinated coffee and caffeine capsules were significantly higher than placebo capsules but not different from each other. In both experiments, subject ratings of "linking" of coffee or capsules covaried with the self-administration measures. These experiments provide the clearest demonstrations to date of the reinforcing effects of caffeine in capsules and in coffee.     

Effects of test-wiseness training on test anxiety,locus of control and reading achievement in elementary school children

Abstract

Fifth and sixth grade children were randomly assigned to either a control or an experimental condition in a pretest, posttest, delayed posttest design. The experimental group received instruction and practice in test-taking, and the control group received a placebo treatment. Dependent variables were four components of test anxiety, locus of control and achievement. Factor analysis of pretest data supported I. Sarason's four-factor conceptualization of test anxiety (worry, test-irrelevant thinking, tension, and bodily reactions to test taking). Posttest data generally supported the hypothesized treatment effects. As predicted, children in the experimental condition had higher reading scores, greater internality, and less test-irrelevant thinking. The delayed posttest scores indicated a diminished effect on the achievement and internality measures; however, the amount of test-irrelevant thinking remained lower in the experimental condition.     

Smell and taste function in the visually impaired

Surprisingly few quantitative studies have addressed the question of whether visually impaired individuals evidence, perhaps in compensation for their loss of vision, increased acuteness in their other senses. In this experiment we sought to determine whether blind subjects outperform sighted subjects on a number of basic tests of chemosensory function. Over 50 blind and 75 sighted subjects were administered the following olfactory and gustatory tests: the University of Pennsylvania Smell Identification Test (UPSIT); a 16-item odor discrimination test; and a suprathreshold taste test in which measures of taste-quality identification and ratings of the perceived intensity and pleasantness of sucrose, citric acid, sodium chloride, and caffeine were obtained. In addition, 39 blind subjects and 77 sighted subjects were administered a single staircase phenyl ethyl alcohol (PEA) odor detection threshold test. Twenty-three of the sighted subjects were employed by the Philadelphia Water Department and trained to serve on its water quality evaluation panel. The primary findings of the study were that (a) the blind subjects did not outperform sighted subjects on any test of chemosensory function and (b) the trained subjects significantly outperformed the other two groups on the odor detection, odor discrimination, and taste identification tests, and nearly outperformed the blind subjects on the UPSIT. The citric acid concentrations received larger pleasantness ratings from the trained panel members than from the blind subjects, whose ratings did not differ significantly from those of the untrained sighted subjects. Overall, the data imply that blindness, per se, has little influence on chemosensory function and add further support to the notion that specialized training enhances performance on a number of chemosensory tasks.     

Effects of Alprazolam on Complex Human Functioning1

Benzodiazepines can reduce anxiety, can have favorable effects upon sleep, and may diminish problems that interfere with patients' quality of life. On the other hand, these drugs can generate transient anterograde amnesia and may diminish aspects of task performance. Research on the impact of alprazolam and other “tranquilizing” drugs has generally focused on tasks that remain below the complex efforts of managerial or professional personnel. Alprazolam-induced reduction of anxiety under challenging conditions might aid complex task performance, yet anterograde amnesia might interfere. In the present research, managers participated in validated complex simulation tasks. In a double-blind, dual crossover design, placebo, 0.5 mg, or 1.0 mg alprazolam was administered on 2 occasions during the task day. Drug treatment diminished performance on measures that require sequential actions but improved performance on measures less subject to short term memory but more determined by long-term style of functioning. Thus, depending on task requirements, positive or negative alteration of performance might occur.