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A computerized task was used in two studies to examine the influence of stimulants, sedatives, and fatigue on single-target and divided-attention responses in different parts of the visual field. The drug effects were evaluated over time with repeated behavioral and subjective measures against ascending and descending drug levels. In the first study, 18 fully rested participants received placebo, alprazolam (0.5 mg), and dextroamphetamine (10 mg). Alprazolam impairs performance, whereas dextroamphetamine induces enhancement and tunnel vision. Study 2 exposed 32 participants to fatigue and no fatigue with a repeated-measures crossover design. Four independent groups subsequently received placebo, dextroamphetamine (10 mg), caffeine (250 mg), or alcohol (.07%). Under fatigue, stimulants have no performance-enhancing effects, whereas impairment from alcohol is severe. Under no fatigue, alcohol has a modest effect, caffeine has no effect, and dextroamphetamine significantly enhances divided-attention performance coincident with tunnel vision. Participants rate all drug effects more stimulating and less sedating while fatigued. Implications for transportation safety are discussed. Actual or potential applications of this research include driver and pilot training.

The relationships between attitudes toward alcohol and actual drinking behavior were examined. Attitudes toward specific drinking behaviors correlated better with those behaviors than did more global attitudes. Heavy drinkers believed that drinking heavily resulted in positive experiences.

Rats housed continuously in a test environment for 25 days were offered water, 5% v/v ethanol, 10% v/v ethanol, and propylene glycol at 7.5% w/v. The propylene glycol concentration represented a caloric midpoint between the 5 and 10% ethanol. After 10 baseline sessions, during which preference for the four solutions was shown to be statistically equal, shock schedules were introduced. The consumption of ethanol at both concentrations showed significant peaks for the interval immediately following 12 min of shock each hour. Intake peaks were not observed for the water or propylene glycol. Baseline blood alcohol levels were negligible, but blood levels under shock averaged 143 mg/dl and ranged from 45.0 mg/dl to 295.0 mg/dl. After the shock sessions were terminated, baseline drinking indicated no significant change in preference relative to pre-shock baselines. but there was an elevation in preference for 5% ethanol relative to the other fluids. The preference for propylene glycol or water did not change.

Two experiments are presented which describe the temporal and volumetric changes in ethanol consumption by rats exposed to recurring schedules of inescapable random shock. The animals in Experiment 1, which had a choice between ethanol and water, increased their voluntary ethanol consumption immediately after the shock schedule. The postshock changes occurred with both 5% and 10% V/V ethanol, were specific to the presence of shock and were not reflected by measures of total daily ethanol intake. Experiment 2 exposed rats to extended 22 hr stress sessions, during which each animal had four simultaneous fluid choices available: water, saccharin 0.1% W/V, ethanol 5% V/V, and ethanol 10% V/V. Temporal intake patterns for both 5% and 10% ethanol showed pronounced peaks for the interval immediately following the shock schedule. A shift of intake from 5% to 10% ethanol was also demonstrated with increasing time under shock, while saccharin and water intake decreased. The results are interpreted as a relationship between voluntary ethanol intake and escape from the consequences of stress.

Two experiments are presented which describe the temporal and volumetric changes in ethanol consumption with rats exposed to recurring schedules of inescapable random shock stress. The animals in Experiment I had an ethanol and water choice and the data demonstrated cumulative increases in voluntary ethanol consumption which occurred immediately after the shock schedule. The post shock changes occurred with both 5% and 10% V/V ethanol, were specific to the appearance of shock and were not reflected by measures of total daily ethanol intake. Experiment II exposed rats to extended 22 hr. stress sessions and each animal had four simultaneous fluid choices available: water, saccharin. 1% W/V, ethanol 5% V/V, and ethanol 10% V/V. Temporal intake patterns for both 5% and 10% ethanol showed pronounced peaks for the interval immediately following the shock schedule. A progressive shift of intake from 5% to 10% ethanol was also evidenced with increasing time under shock, while saccharin and water intake decreased. Blood ethanol levels during shock increased significantly from baseline for all animals and ranged from 30 to 162 mg/100 ml. The results are interpreted as a relationship between voluntary ethanol intake and escape from the consequences of stress.

Forty subjects who were pretested on their beliefs and attitudes toward drinking and driving were later tested in a laboratory on the extent of their subjective and objective cognitive impairment from placebo, low and high alcohol doses. A second study conducted at college drinking parties validated some of the laboratory findings.

This study assessed women and men on a divided attention task, body sway, and subjective (self-report) estimates of impairment across different doses of alcohol. Twelve females and 12 males (mean age of 20.4 years) were given placebo, low, and high doses of alcohol in random order across sessions. Each subject was tested 3 times during each session. The study controlled for recent drinking history by restricting participation to light drinkers who were matched on age and education. Alcohol doses were adjusted for body fat and equivalent blood alcohol concentrations (BACs) were attained in the two gender groups. The results indicated that women and men did not differ in their extent of cognitive impairment at placebo and low alcohol doses. However, women showed significantly more cognitive impairment than their male counterparts at the high alcohol doses, even with equivalent BACs. The sway measure was influenced only by BAC and not by the gender of the subject. Sway observations were less sensitive and more variable than estimates of cognitive impairment. The subjective impairment data indicated that female subjects were less sensitive than males to the effects of alcohol at both the low and high doses. Implications for future research on cognitive impairment are discussed.