A device for presenting attack opportunity as a reinforcer for operant behavior

A device is described which automatically measures barpresses reinforced by short opportunities to attack male mice. Data on barpress rates indicate rapid and reliable acquisition of preferences for reinforcer bars and rapid abolition of this preference when the reinforcement contingency is subsequently eliminated. The data are less reliable for reversal learning.     

Determinants of reinforcer accumulation during an operant task.

Responses by rats on an earn lever made available food pellets that were delivered to a food cup by responses on a second, collect, lever. The rats could either collect and immediately consume or accumulate (defined as the percentage of multiple earn responses and as the number of pellets earned before a collect response) earned pellets. In Experiment 1, accumulation varied as a function of variations in the earn or collect response requirements and whether the earn and collect levers were proximal (31 cm) or distal (248 cm) to one another. Some accumulation occurred under all but one of the conditions, but generally was higher when the earn and collect levers were distal to one another, particularly when the earn response requirement was fixed-ratio (FR) 1. In Experiment 2, the contributions of responses and time to accumulation were assessed by comparing an FR 20 earn response requirement to a condition in which only a single earn response was required at the end of a time interval nominally yoked to the FR interval. When 248 cm separated the earn and collect levers, accumulation was always greater in the FR condition, and it was not systematically related to reinforcement rate. In Experiment 3, increasing the earn response requirement with a progressive-ratio schedule that reset only with a collect response increased the likelihood of accumulation when the collect and earn levers were 248 cm apart, even though such accumulation increased the next earn response requirement. Reinforcer accumulation is an understudied dimension of operant behavior that relates to the analysis of such phenomena as hoarding and self-control, in that they too involve accumulating versus immediately collecting or consuming reinforcers.     

Feedback to attendants as a reinforcer for applying operant techniques

After varying lengths of baseline, initiation of a feedback system increased the daily use of operant training methods by non-professional hall personnel in a state institution for retarded children.     

Aggression as a reinforcer: operant behavior in the mouse-killing rat

Two experiments examined mouse killing as a reinforcer of key pressing by rats that killed mice. In Experiment I, mouse-killing rats performed the key-pressing response when each press was reinforced with presentation of a mouse. Offered a choice between a key that yielded presentation of mice and one that did not, the rats preferred the key that yielded mice. When the contingency was reversed, the rats preferred the other key and continued to kill mice. In Experiment II, mouse-killing rats that did not kill rat pups performed a key-pressing response reinforced with presentation of mice on a variable-interval schedule. In tests for responding reinforced on that schedule with presentation of normal mice, anesthetized mice, dead mice, or rat pups, these rats that killed mice but not rat pups exhibited a decline in response rate when rat pups were the reinforcer. Altering the condition of the mice did not significantly affect performance.     

Brain stimulation as a reinforcer: intermittent schedules

Rats with chronically implanted, bipolar electrodes in the septal and medial forebrain bundle areas, in addition to the region of the mammillary bodies of the posterior hypothalamus, were trained to press a permanently mounted lever in order to produce a second, retractable lever. Rewarding brain stimulation was programmed on the retractable lever; following completion of the programmed number of CRF response-stimulations, that lever was retracted from the box. Responding on the permanent lever could reintroduce the retractable lever. Fixed interval, fixed ratio, DRL, and variable interval schedules were programmed on the permanent lever in the range of schedule parameters often used with conventional reinforcers. Typical effects are described, and it is concluded that there are no striking differences between brain-stimulation reinforcement and the conventional reinforcers.     

Handwriting as an operant

An apparatus was designed to monitor handwriting behavior. Two subjects were studied under various schedules of monetary reinforcement for handwriting. The different schedules engendered and maintained distinctive response patterns but the rates of sustained responding did not vary across schedules. The development of fixed-interval performance following continuous reinforcement resembled the same transition in lower animals. In one subject, availability of reading material interacted with the schedule to determine response pattern. It was suggested that handwriting may be a more appropriate response for the experimental analysis of human behavior than the more frequently used button-pushing or lever-pulling responses.     

Wind as an aversive stimulus

Two monkeys were trained on an escape-avoidance procedure in which a lever press delayed exposure to wind by 20 sec. For 5 hr, subjects alternately worked 15 min and rested 15 min, and performed this schedule when the wind was 5, 10, and 20 mph and the temperatures were 50, 60, and 70° F. Analysis of variance showed that the percent of wind avoided was related to both the velocity of the wind and the temperature during the exposure. When the wind was 10 and 20 mph it was avoided almost continuously regardless of the temperature.     

The reliability of an extrapolated measure of an aversive threshold of pain from radiant stimulation

The relationship between the logarithm of pain threshold latency (sec) and the logarithm of the stimulus intensity (mcal/cm²/sec) has been shown to be linear, and the extrapolated x-intercept value of the linear equation could be a useful measure in pain research. In order to assess the reliability of the x-intercept, pain latency thresholds, were obtained from 23 Ss by utilizing the D’Amour-Smith modification of the dolorimetric technique and by testing under a variety of conditions at each of four stimulus intensities. The empirically determined log t (sec) values were shown to be slightly, but significantly, higher when stimulation was applied to either the dominant limb or to the legs rather than to the nondominant limb or to the arms. The computed slope and x-intercept values did not differ between limbs or between dominant and nondominant sides. None of the three measures changed significantly between the two sessions. The x-intercept value was interpreted as an index of a threshold of aversion and its meaning and applicability were discussed.     

Acute alcohol intoxication paired with aversive reinforcement: ethanol odor as a conditioned reinforcer in rat pups

Previous research has suggested that infant rats process ethanol sensory properties during acute alcohol intoxication. The present study was designed in order to examine if alcohol odor could act as an aversive conditioned stimulus after the organism experiences the state of intoxication paired with nociceptive stimulation (footshock). In a first experiment 11-day-old pups received intragastric alcohol administration (1.5 g/kg). At different postabsorptive intervals footshock was presented (0-30, 30-60, 60-90, or 90-120 min). An explicitly unpaired control group which experienced footshock prior to the state of intoxication was also employed. All animals were subsequently tested in terms of alcohol intake and ethanol locational odor preferences. Both assessments indicated that pups which were exposed to the unconditioned peripheral stimulus 30-60 min after receiving ethanol expressed strong alcohol aversions. In a second experiment pups were exposed to footshock during this postabsorptive interval. Twenty four hours later, pups experienced ambient ethanol odor paired with soft or rough texture surfaces. Differential texture aversions were registered in experimental animals when compared with controls which suffered the state of intoxication explicitly unpaired with footshock, or unpaired presentations of ethanol odor and the tactile stimuli under consideration. These results appear to support the hypothesis concerning orosensory processing during an acute state of intoxication. Additionally it seems that the hedonic value of sensory attributes of this drug varies as a function of associative processes occurring during such a state.