Independence of stimulus discriminability from absolute rate of reinforcement in a signal-detection procedure.

Three experiments are reported in which two pigeons were trained to detect differences in stimulus duration under varying levels of absolute rate of reinforcement. Two red stimuli, differing in duration, were arranged probabilistically on the center key of a three-key chamber. On completion of the center-key duration, the center keylight was extinguished and the two side keys were illuminated white. Correct responses were left-key pecks following the shorter duration and right-key pecks following the longer duration. In Experiment 1, relative rate of reinforcement for correct responses was held constant and absolute rate of reinforcement was varied in seven conditions from continuous reinforcement to a variable-interval 90-second schedule. In Experiment 2, relative rate of reinforcement was manipulated across three different absolute rates of reinforcement (continuous reinforcement, variable-interval 15-second, and variable-interval 45-second). Stimulus discriminability was unaffected by changes in absolute or relative rates of reinforcement. Experiment 3 showed that discriminability was also unaffected by arranging the same consequences (three-second blackout) for unreinforced correct responses and errors.     

Autoshaped key pecking maintained by access to a social space.

When four experimentally naive pigeons were exposed to occasional forward pairings of a keylight followed by a doorlight (that signaled access to a large social space), all subjects began to peck the lit key. In a second experiment, where the keylight either preceded the presentation of the doorlight or was presented independently of it, key pecking was maintained only in the former circumstance. The unconditioned stimulus in these experiments--arrival in the social space--did not elicit pecking. Hence, the conditioned response of key pecking and the unconditioned response of entering the social space differed. This demonstration of autoshaping with a social-space unconditioned stimulus argues against a stimulus-substitution account of the findings.     

Matching, maximizing, and the behavioral unit: concurrent reinforcement of response sequences.

Pigeons pecked two keys in a probability matching situation in which four two-peck sequences were intermittently reinforced: left-left, left-right, right-left and right-right. In Phase 1, relative reinforcement rate was varied with respect to the first response of a sequence: reinforcers were differentially assigned for left-left and left-right sequences as opposed to right-left and right-right sequences. The second response of reinforced sequences occurred equally on the left and right keys across conditions. In Phase II, relative reinforcement rate was varied for sequences that involve an alternation as opposed to those that did not. The relative outputs of the different sequences matched the relative reinforcement rates for the different sequences in both phases. Relative response rates for key pecks did not always match relative reinforcement rates. The intertrial interval separating responses was varied in both phases; increases in the intertrial interval affected the relative frequency of different sequences. The results demonstrate that response sequences acted as functional units influencing choice and thus support a structural account of choice. At the same time, the matching of relative sequence proportion and relative reinforcement rate supports a matching account.     

Phencyclidine discrimination in the pigeon using color tracking under second-order schedules

Pigeons were trained to track different key colors, depending on whether they had been injected with phencyclidine or saline prior to the session. A second-order schedule was used to generate large numbers of responses prior to the initial food delivery. The procedure offers several advantages over traditional procedures for studying drug discrimination.     

Personality correlates of the attitude toward women scale

The full and short versions of the Attitudes Towards Women Scale, the Eysenck Personality Questionnaire, the Trait Anxiety Scale and the Group Embedded Figures Test were administered to 95 freshmen (male and female). Results indicated a relationship between liberal attitudes toward women and emotional stability. Scores on the Attitudes Toward Women Scale also tended to be independent of Lie scores.     

Verbal ability and mental processing speed

The notion that verbal ability is related to mental processing speed was examined using tasks that systematically varied in semantic content. Subjects’ reaction times were measured in five tasks involving arrow matching, physical identity word matching, or taxonomic identity word matching. The findings indicated that matching tasks using different decision rules and different stimuli were all related to verbal ability. In fact, reaction time for subjects required to judge whether two arrows pointed in the same direction was the best predictor of verbal ability. One explanation of the results is that speed of information processing (a general factor) may be the important component of verbal ability which is measured by seemingly different matching tasks.     

Units of episodic memory in perceptual recognition

Two studies examined the cognitive units of sentence memory using a perceptual recognition task. Four candidate cognitive units were considered: concepts, propositions, integrated propositions, and nonintegrated propositions. Subjects first received a list of acquisition sentences and then were asked to reproduce sentences presented under a white-noise mask. These masked sentences were replicas of the acquisition sentences, were formed of recombined clauses from the acquisition sentences, or were formed of recombined words from the acquisition sentences. Reproduction accuracy was employed as the dependent measure. Results supported propositions (operationalized by clauses) as cognitive units of episodic memory. No conclusive evidence was obtained for concepts, integrated propositions, or nonintegrated propositions as cognitive units. The utility of perceptual recognition tasks for studying the cognitive units of episodic memory is discussed.     

TREATMENT OF SELF-INJURIOUS BEHAVIOR USING A WATER MIST: INITIAL RESPONSE SUPPRESSION AND GENERALIZATION

This study evaluated the effects of a fine mist of water applied to the face contingent upon self-injurious behavior (SIB) exhibited by profoundly retarded persons. In Experiment 1, results of individual reversal designs showed substantial reductions in a variety of SIB's (mouthing, hand biting, skin tearing, and head banging) for seven participants. In Experiment 2, two participants who frequently bit their hands were each observed in two different settings. Following initial baselines in each setting, a series of manipulations was undertaken to compare the effects of mild verbal punishment (“No”) with those of a combined treatment (“No” plus mist procedure). Results in one setting indicated that “No” suppressed SIB only after it was first paired with the water mist. Data also suggested that, once acquired, the punishing properties of “No” could be extended to a second setting in which the mist was never applied, and that these effects could be generalized across therapists. Results of these experiments indicate that the water mist procedure may be an effective alternative to traditional punishment techniques. Although conclusions regarding generalization are limited due to the brevity of the maintenance conditions, the data suggest that treatment gains may be transferred to more acceptable forms of social punishment and reinforcement.     

Is the holocaust relevant to sociobiology?

Sociobiologists have emphasized that altruism and benevolent behavior are part of the genetic repertoire of most animals and certainly of man. They have constructed a theory of ethics as a biological phenomenon without reference to the concept of evil. It is concluded here however, that holocaust behavior is not equivalent to the natural manifestation of an incompletely tamed animal flashing its teeth. Biologists have been too rigid in trying to equate ethical behavior with social behavior. The added dimension of ethical behavior is a special kind of sensitivity to the needs of others, just as evil is the total lack of it. The evolution of this moral sense may itself have important selective value for the human species, whose survival depends on creating maximal diversity in its gene pool.