The influence of the victim on shock induced aggression in rats.

In two studies, free-roaming male rats (aggressors) were shocked in the presence of male target rats restrained in either an upright or a supine posure. In addition, in Experiment II, two levels of aggressor shock intensity (0.8 mA or 2.0 mA) were used while targets received one of three levels of shock (0.5 mA, 1.5 mA, or 2.5 mA). In both studies, upright targets were attacked less than supine targets. Frequency of aggression was directly related to level of aggressor shock intensity in Experiment II. Also, attack by 0.8-mA aggressors against supine targets was inversely related to level of target shock intensity. The low level of attack against upright targets was interpreted in terms of a threat diaplay. Similarily, it was concluded that the target shock-intensity effect in Experiment II was due to specific threat behaviors displayed by those supine rats that received the highest-intensity shocks.     

Choice and the dependability of stimuli that predict shock and safety

This study assessed whether choosing a signalled shock condition over an unsignalled one is controlled by a stimulus that predicts the presence of shock (Experiment I), or by a stimulus that predicts the absence of shock (Experiment II). The dependability of these stimuli as predictors of either the presence or the absence of shock was parametrically varied over a wide range, and subjects (rats) were given an option to change from an unsignalled to a signalled condition. In the first experiment, all shocks were preceded by signals; however, the probability of a signal being followed by shock varied from 1.0 to 0.02. The data obtained indicate that the dependability of the signal as a predictor of shock is unimportant. Rats changed to the signalled condition when the signal was completely dependable (all signals followed by shock) and when the dependability of the signal was systematically degraded. In the second experiment, all signals were followed by shock; however, some shocks were not preceded by a signal. The data show that the dependability of a stimulus predicting the absence of shock is important in that, as dependability decreases, changing to the signalled condition also decreases.     

Gasoline conservation: a procedure for measuring and reducing the driving of college students

The study sought to motivate college students to reduce the number of miles they drove each day and thus save gasoline. Students in two psychology classes were divided by class into two groups. The experimental group was offered various combinations of prizes such as cash, a tour of a mental-health facility, car servicing, and a university parking sticker for reducing driving. The value of the prize received was scaled in terms of per cent reduction in driving. The contrast group received no inducements. The condition in which the experimental group's mileage reduction was reinforced was counterbalanced by two baseline conditions. Several special recording procedures were used to reduce and detect the possibility of subjects altering their odometers, the source of the driving data. Experimental subjects reduced their average daily mileage by 20% relative to the initial baseline; the contrast group did not change. During the one-month reinforcement condition, the 12 experimental subjects saved some 170 gallons (worth $102) of gasoline.     

DEVELOPMENT AND EVALUATION OF TREATMENT PARADIGMS FOR THE SUPPRESSION OF SMOKING BEHAVIOR1

A multiple-baseline component-analysis design was employed to assess the effectiveness of three treatment programs for suppressing the cigarette smoking behavior of 24 subjects. Satiation, cognitive control, and contingent shock procedures were evaluated. The results demonstrated a consistent relationship between contingent shock and suppression of smoking. It was further indicated that subjects should be exposed to the number of sessions necessary to achieve total suppression in order to gain maximally from treatment and to avoid relapse. Neither the satiation component nor the cognitive control component was correlated with clear, permanent decrements in smoking frequencies. To date, no other treatment program has demonstrated the dramatic effects of the contingent shock procedures used in the present study.     

Food and intracranial stimulation responding suppressed with regular-interval shock.

Attenuation of conditioned suppression during intracranial stimulation was compared with that during food reinforcement. Response rates controlled by food and by brain stimulation were equalized on a multiple schedule by adjusting the stimulating current. When foot shock was delivered during timeout periods separating response components, responding for food was significantly more suppressed than responding for brain stimulation. When components were shortened from 10 to 2 minutes, responding maintained by either food or brain stimulation showed a similar temporal pattern of suppression preceding each shock, but responding in the component involving food remained significantly more suppressed. Explanations for the attenuated suppression during brain stimulation based on neural disruption, stimulus blocking, and analgesic properties were questioned. The increased responding during brain stimulation seemed to reflect greater response strength relative to food reinforced responding.     

Responding in the squirrel monkey under fixed-ratio schedules of stimulus termination

Key pressing was maintained under a fixed-ratio schedule in which electric shock was scheduled for delivery at a fixed time (t seconds) after each stimulus onset, and every n^th response terminated the stimulus and initiated a timeout from shock. Under this procedure, the higher the rate of responding, the briefer the duration of the stimulus presentation and the lower the frequency of shock delivery. The effects of several schedule parameters were studied to determine whether the maintenance of responding was dependent on an inverse relation between response rate and shock frequency. Shock rate and shock frequency were made independent of response rate by decreasing the value of t to 0.5 second and delivering shock only during the first presentation of the stimulus after a fixed time, including stimulus and timeout durations, had elapsed since the previous shock. The experiments showed that shock frequency and response rate are inversely related when t is of relatively long duration compared to the value of the fixed-ratio parameter, but that a decrease in shock rate or frequency due to a high rate of responding is not necessary for the maintenance of responding under a fixed-ratio schedule of stimulus termination.     

Schedule-induced biting under fixed-interval schedules of food or electric-shock presentation

Squirrel monkeys pressed a lever under fixed-interval schedules of food or of electric-shock presentation. Both schedules induced repeated biting on a latex hose. Whether lever pressing was controlled by food or by electric shock, a pattern of decreasing hose biting and increasing lever pressing occurred within fixed-interval cycles. As the fixed-interval duration was increased from 6 to 600 sec, average rates of lever pressing decreased under both schedules. Average rates of hose biting first increased with increasing parameter value, reaching a maximum at values that varied from 60 to 337 sec in different monkeys, and then declined at higher values. d-Amphetamine at appropriate doses increased overall rates of lever pressing maintained by food or by shock, but either did not affect or decreased overall rates of hose biting. When no timeout period occurred between fixed-interval cycles, the monkeys bit most frequently immediately after food or electric shock was presented. When there was a timeout period, hose biting began shortly after the start of the fixed-interval cycles, with little or no hose biting immediately after food or electric shock was presented. Most hose biting appeared to be schedule-induced rather than food- or shock-induced.     

Brief exposure to contingent reinforcement produces a sustained increment in the strength of an elicited response.

Squirrel monkeys' lever pressing produced by response-independent shock was measured before, and for an extended period following, exposure to a shock-avoidance procedure. Following avoidance training, the frequency of responding increased by multiples of 10 to 50 across subjects and evidence little or no decrement for up to 6 months of postreinforcement testing. Manual responding produced by intense environmental stimulation may be substantially strengthened by a brief history of reinforcement, such that it is sustained over long periods without reinforcement.     

Choice for signaled over unsignaled shock as a function of signal length.

Subjects chose between signaled and unsignaled shock conditions while signal length was varied between .5 and 2.0 seconds in steps of .5 seconds in both ascending and descending series. Preference for the signaled condition failed to develop initially for five of six subjects when signals were .5 or 1.0 seconds but became strong for all subjects when signals were 2.0 seconds (ascending series). Preference declined when signals were shortened, but for most subjects this decline was small (descending series). Since discriminable shock-free periods were present in the signaled condition at all signal lengths, these results suggest that safety may not be a sufficient condition for preference to develop for signaled shock.