Don R. Cherek

Antisocial Personality Disorder and Alcohol‐Induced Aggression

This study compared the effects of alcohol on aggressive responding between subjects with antisocial personality disorder (ASPD) and subjects without ASPD. Eighteen alcohol drinking subjects (10 subjects without ASPD and 8 subjects with ASPD) underwent testing on a laboratory measure of aggression, the Point Subtraction Aggression Paradigm, after consumption of placebo and three doses of alcohol (0.25 g/kg, 0.5 g/kg, and 1.0 g/kg). There was a significant difference in the effect of alcohol on aggressive responding on the Point Subtraction Aggression Paradigm between subjects with ASPD and subjects without ASPD. Subjects with ASPD had a greater increase in aggressive responding after alcohol, compared with non-ASPD subjects. There was no difference between the two groups in the effect of alcohol on monetary-reinforced responding.

Effects of acute administration of diazepam and d-amphetamine on aggressive and escape responding of normal male subjects

Normal males participated in sessions providing two operant response options and were administered either diazepam (study I and II) ord-amphetamine (study II). The acute effects of diazepam on human aggressive responding, which ostensibly subtracted points from another person, were determined in study I. Study II was conducted to determine the extent to which social context and response consequence influenced diazepam (study I) andd-amphetamine (previous research) effects on aggressive responding. In study II, the other response option was escape responding which protected the subjects counter from point losses. Aggressive and escape responding were engendered by subtracting points from the subjects counter, and maintained by initiation of intervals free of point loss. Point subtractions were attributed to the other person (study I) or to a machine (study II). Responding to accumulate points exchangeable for money was available in both studies. Acute diazepam administration decreased aggressive responding in most subjects (study I), slightly increased escape responding (study II), and decreased responding to accumulate points. In study II,d-amphetamine increased both escape responding and responding to accumulate points. The effects ofd-amphetamine and diazepam were altered by the instructed source of point loss.

Differential effects of triazolam and ethanol on awareness, memory, and psychomotor performance

Eight normal, healthy, male volunteers each received four triazolam doses (0, 2, 4, and 8 micrograms/kg) and four ethanol doses (0, 0.25, 0.5 and 1.0 g/kg) in a double-blind, double-dummy experiment in which within-subject dose sequence was determined by a balanced Latin square design. Triazolam and ethanol produced dose-related and time-related effects on subject ratings of mood and perceived drug effects and objective measures of memory and psychomotor performance. Dose-response curves for the two drugs were not parallel, and therefore, comparisons of the two drugs were based upon comparisons of the high dose of each drug. Although the two high-dose conditions generally were not different from one another, there were differences in their relative effect sizes, which were important. The high dose of each drug produced comparable degrees of impairment on two different psychomotor tasks. Triazolam, but not ethanol, produced significant impairment on two different memory tasks. The relative effects of each drug on subject ratings of mood and perceived drug effects varied across different subject-rated measures. Only ethanol significantly increased subject ratings of alcohol strength and feeling drunk. In comparison to ethanol, triazolam tended to produce less-pronounced subject ratings of drug effect magnitude, drug liking, and estimated performance impairment. However, less-pronounced subjective effects of triazolam were not universally observed on all subject ratings. Triazolam produced greater effects on several sedative symptoms and produced comparable effects on several mood factor scales.

Laboratory and questionnaire measures of aggression among female parolees with violent or nonviolent histories

Female parolees were recruited into a laboratory study to determine the relationship between their previous aggression history, questionnaire measures of aggression, and behavioral measures of aggressive responding using a laboratory methodology: the Point Subtraction Aggression Paradigm (PSAP). Subjects were assigned to a violent or nonviolent group based on their criminal history. Subjects participated in sessions in which they were given three response options: (1) nonaggressive responding that earned money, (2) aggressive responding that ostensibly subtracted money from another fictitious person and was defined as aggressive since it resulted in the ostensible delivery of an aversive stimulus (subtraction of money) to another person, and (3) escape responding that protected the subjects earnings from periodic subtractions initiated by the fictitious other person. Results indicated that the violent female parolees emitted significantly more aggressive responses than subjects in the nonviolent group. This study provides additional external validity as well as evidence for convergent and discriminant validity for PSAP laboratory measurement of human aggressive responding and extends these findings to female parolees. Comparisons to previously published data with male parolees showed that gender differences were found among violent but not nonviolent parolees. Aggr. Behav. 26:291–307, 2000.

Possible amotivational effects following marijuana smoking under laboratory conditions

Human participants earned money by responding on a progressive-ratio (PR) schedule (initial value

Effects of triazolam on human aggressive, escape and point-maintained responding.

50) or received money without responding on a fixed-time (FT) schedule. During the session, participants could terminate the PR schedule and initiate an FT 200-s schedule. In Experiment 1, increases in monetary value produced increased number of responses, time spent, and money earned in the PR component. In Experiment 2, marijuana smoking produced potency-related reductions in the number of responses, time spent, and money earned in the PR component, effects that can be interpreted as amotivational. Increasing the monetary value of the reinforcer diminished the acute marijuana effects on PR responding, suggesting that marijuana exerted an effect primarily on reinforcers of a smaller magnitude.

The effects of codeine on human aggressive responding

Placebo and triazolam (0.125, 0.25 and 0.5 mg/70 kg of body weight) were administered to male subjects under double-blind conditions prior to experimental sessions which provided three operant response options. These options were: 1) responding maintained by the presentation of points exchangeable for money, 2) responding which ostensibly resulted in the subtraction of points from a fictitious person was termed aggressive since this responding resulted in the delivery of an aversive stimulus to another person, and 3) responding which ostensibly protected the subjects point counter from subtractions initiated by the other person and was termed escape. Aggressive and escape responding were initiated by subtracting points from the subject. Point subtractions were attributed to the other person. Aggressive and escape responding were maintained by initiation of provocation-free intervals (PFI), during which no further point subtractions were presented. Triazolam produced dose-dependent decreases in point-maintained and escape responding. The effects of triazolam on aggressive responding varied across subjects.

Human Aggressive and Escape Responding: Effects of Provocation Frequency

Ten healthy male research subjects received placebo, 25, 50 and 75 mg/70 kg of codeine in a controlled laboratory setting. During each session subjects had two response options. The non-aggressive response option was maintained by points exchangeable for ten cents. The aggressive response option ostensibly subtracted a point from the subjects fictitious partner. Aggressive responding was engendered by point subtractions attributed to a fictitious partner. Codeine did not significantly alter the frequency of monetarily reinforced, nonaggressive, responding. Aggressive responding was significantly increased at the 50 mg/70 kg dose of codeine. The frequency of aggressive responses during the placebo sessions preceding administration of the first codeine dose were significantly and positively correlated with scores on the Buss-Durkee Hostility Scale. Aggressive responding increased for four of five subjects scoring below the median on the Buss-Durkee Hostility Scale at the 50 mg/70 kg dose; while administration of 50 mg/70 kg increased aggressive responding of one subject who scored above the median. Aggressive responding for both groups of subjects was unaffected by the 75 mg/70 kg dose.

Effects of inequity on human free-operant cooperative responding : a validation study

The effect of point loss frequency on aggressive and escape responding was investigated in two experiments. Subjects could respond on levers marked “A,” “B,” or “C” available as nonreversible options. Subjects were instructed that “A” responses earned points exchangeable for money, “B” responses subtracted points from a second subject, and “Cm responses protected their counter from point loss for a period of time. These options were defined as nonaggressive (A), aggressive (B), and escape (C) responses, respectively. A variable time schedule of point loss engendered aggressive and escape responding. The preexperimental instructions attributed point losses to the subject’s fictitious partner. Levers B and C responding escaped point loss by initiating an interval free of provocation (PFI). In Experiment 1 systematically decreasing PFI increased the frequency of point loss and increased aggressive responding for three of the four subjects. In Experiment 2 Pfi durations were systematically alternated between 500 seconds and 125 seconds in an Abab or Baba design. Escape responding increased as a function of increased provocation frequency for all subjects. Order of exposure affected frequency of aggressive and escape responses.

Effects of secobarbital on human aggressive and non-Aggressive responding

The effect of disparities in reinforcement frequency on human free-operant cooperative responding was examined. Points exchangeable for money maintained responding. Two schedule components alternated during a session. A random interval (Rl) 60-s schedule of point additions was in effect during the first component and a concurrent RI 60-s RI 60-s schedule was in effect during the second component. Subjects were instructed that the second component was initiated by another subject and that they had the option of earning points by working with, or independently of, the other subject. Independent responses earned points added to a counter marked “YOUR EARNINGS.” Cooperative responses earned points added simultaneously to a counter marked “YOUR EARNINGS” and “OTHERS EARNINGS.” Disparities of reinforcement were produced during the first component by increasing the frequency of point additions to either the subject’s or the fictitious other person’s counter. Disparities benefiting the fictitious other subject reduced cooperative responding, decreased independent responding, and had no effect on nonsocial responding during the first component. Disparities benefiting the subject increased cooperative responding in one subject.