The sensory basis of avoidance responding in the rat : Relative dominance of auditory or visual warning signals and safety signals

Three experiments determined the relative degree of stimulus control exerted by the elements of a compound auditory-visual stimulus when this stimulus was presented in various temporal relationships to a barpress avoidance response. When the compound discriminative stimulus for barpress avoidance responding consisted of onset of white noise and onset of either light or darkness, the white noise always exerted dominant control. When the compound discriminative stimulus consisted of offset of white noise and onset of light, neither element controlled avoidance responding. On the other hand, when a barpress avoidance response produced a compound feedback stimulus consisting of onset of white noise and onset of either light or darkness, the visual element always exerted dominant control. When the compound feedback stimulus consisted of offset of white noise and onset of light, both elements exerted stimulus control.     

Effects of extradimensional discrimination training upon previously acquired stimulus control

In Experiment 1, three groups of pigeons were taught to discriminate vertical lines (positive) from horizontal (negative). One group was then given true-discrimination training between two colors, a second group was equally reinforced for responding to the colors (pseudodiscrimination), while the third group was not run. The pseudodiscrimination group then provided a flatter gradient on the dimension of line orientation than either of the others, which did not differ. A second experiment demonstrated that this flattening effect could be completely counteracted when pseudodiscrimination was followed by true discrimination before the generalization test. The results are discussed within the framework of current research on attentional factors governing generalization gradients; pseudodiscrimination affects tests of stimulus control rather than its acquisition. When it intervenes between acquisition and testing, it appears to produce a “lapse” rather than a “loss” of the memory of the first-trained stimuli.     

Constraints on Pavlovian conditioning of the pigeon: Relative conditioned reinforcing effects of red-light and tone CSs paired with food

Recent Pavlovian conditioning experiments presented all possible CS-US combinations of red-light and tone CSs and food and shock USs to separate groups of pigeons. Pigeons receiving shock USs demonstrated conditioned head raising followed by prancing to both CSs, but CRs were acquired more rapidly to tone than to red light. Although pigeons receiving food USs rapidly acquired a conditioned response of pecking to the red-light CS, there was no evidence of conditioned responding in groups receiving tone-food pairings. This outcome left open the possibility that Pavlovian pairings of tone and food may have resulted in association formation that was not revealed in performance. The present series of experiments attempted to reveal that association, using an indirect method of assessment, conditioned reinforcement. Experiment 1 demonstrated that both red light and tone paired with food became positive conditioned reinforcers, suggesting that an association between tone and food was formed in the same number of Pavlovian conditioning trials that previously failed to yield any direct evidence of conditioning. Experiment 2, which presented fewer conditioning trials, revealed that the tone-food association was formed less rapidly than the red light-food association. Experiment 3 demonstrated that the observed outcomes were not attributable to unconditioned, rather than conditioned, reinforcing effects of the Css.     

The effects upon food-reinforced pecking and treadle-pressing of auditory and visual signals for response-independent food

Seven pigeons whose key-pecking was maintained by food reinforcement on a differential-reinforcement-of-low-rates 12-sec limited-hold 4-sec schedule and 12 other pigeons whose treadle-pressing was maintained by the same schedule received appetitive Pavlovian conditioning trials superimposed upon the instrumental baseline. Half the birds in each group received a tone as the CS, and the other half received a stimulus change on the key. Each CS was 20 sec long, and was immediately followed by 10-sec access to grain. The visual CS markedly facilitated the rate of pecking on the key for the birds whose baseline response was pecking. The visual CS produced auto-shaping of the key-peck and tended to produce suppression of treadle-pressing for the birds whose baseline response was treadle-pressing. The auditory CS produced inconsistent effects across birds regardless of the baseline response. In all cases the conditioned effects extinguished when response-independent food was omitted.     

Transfer of a response controlling stimulus duration across discrimination problems

In the acquisition phase, pigeons learned to peck at a changeover key to shorten the duration of S? but not of S+ presented on the food key in a discrimination problem. In the transfer phase, the significance of S+ and S? was changed through extinction of both, equal reinforcement, or discrimination reversal, while the changeover key was not available. Transfer tests then showed appropriate modification of the changeover response. Similar transfer was demonstrated across orthogonal stimulus dimensions. Further analytic studies showed that this transfer of the changeover response did not depend upon mediation due to differential response rates to the food key. This research strategy enriches the study of the “second learning process” by providing an indicator of stimulus control in all phases of the procedure. Direct transfer between different problems also indicates that discriminative stimuli, although physically dissimilar, have the same “psychological value” for the subject.     

Blocking and unblocking of conditioned analgesia

Two experiments with rat subjects assessed the blocking phenomenon using inhibition of responding to painful thermal stimulation as an index of conditioned analgesia established through conditioned stimulus (CS)-shock pairings. In Experiment 1, a group of rats receiving the standard blocking procedure ($\text{A+}\text{AB+}$) showed shorter response latencies during a hot plate test of pain sensitivity in the presence of the added CS than groups of rats receiving various blocking control procedures. Experiment 2 replicated the blocking outcome of Experiment 1 and also demonstrated that the addition of a second shock unconditioned stimulus (US) during the compound conditioning phase attenuated the blocking effect; i.e., unblocking was observed. However, the deletion of a second shock US during compound conditioning in a group that had received two shocks on each trial in the first phase of the experiment failed to result in unblocking. These data extend the associative account of conditioned analgesia to situations involving stimulus selection and the implications for the analysis of aversive learning are discussed.     

Distinguishing between social reinforcement and social elicitation

The theoretical, procedural, analytic, and interpretive components of Poulson's (1983, Journal of Experimental Child Psychology, 36, 471–489) study were considered in an effort to clarify the distinction between social reinforcement and social elicitation. Contrary to Poulson's contention, DRO was not, and cannot by definition be, a control for reinforcement. More importantly, the speciestypical, social nature of the infant probably reflects the collaborative influence of elicitation and reinforcement. By carefully unravelling these two interacting processes, future conditioning studies might specially enhance our knowledge of early social development.     

The effect of S− on observing behavior

Eight pigeons were run on a one-key, discrete-trials observing procedure. Pecks during a trial produced S⁺ and S^?, colored key lights which signalled whether the trial would end with response-independent grain reinforcement or nonreinforcement. S⁺ and S^? were produced on a VI schedule which began operating at the onset of the trial. In the main experimental condition, only a response preceded by at least 6 sec of nonresponding could produce S^? on nonreinforced trials; any response which satisfied the VI requirement produced S⁺ on reinforced trials. This procedure allowed the birds to produce S⁺ on reinforced trials with or without producing S^? on nonreinforced trials. The subjects learned to produce fewer S^?s over sessions, indicating that S^? had a punishing effect on observing. The results were taken as evidence for the conditioned reinforcement hypothesis of observing and against the uncertainty reduction hypothesis.     

Verbal reports of stimulus effects on learning: Introspection revisited

The accuracy of subjects' verbal reports on the respective causal roles of relevant and irrelevant stimulus factors on learning was investigated. In two experiments, university undergraduates learned strings of letters that were either grammatically structured or unstructured (a causal variable) and either color coded or black (a salient but irrelevant variable). Results indicated that subjects reported more causal impact of color than structure on the learnability of lists, despite the fact that the latter variable and not color had an actual effect on learning. It was proposed that verbal reports of stimulus effects on one's own behavior can be regarded as a task in estimates of covariation rather than direct retrieval of memory traces.     

Visual dominance in inhibitory conditioning in the pigeon

In a conditioned inhibition paradigm (A+, B+, AX?_, pigeons received either of two keylight stimuli reliably followed by food (A+, B+). However, when one of these keylights was accompanied by another stimulus, food did not follow (AX?). For some groups, the putative inhibitor was a tone, whereas for others it was illumination of a red houselight. The birds pecked the A and B stimuli at a high rate. When X was red houselight, the birds pecked A at a much lower rate in the presence of X. When X was a tone, discrimination between A and AX was much poorer. Moreover, in a transfer test, red houselight inhibited responding to the other keylight, B, but tone did not. These results indicate that red houselight becomes a conditioned inhibitor more quickly than tone in appetitive situations, just as red houselight becomes a conditioned excitor more quickly in those situations. These results contradict the assertion that the latter outcome occurs because red houselight is a stronger appetitive excitor than tone at the start of the experiment (the “head start” hypothesis).     

Evaluation of infant vocal conditioning.

The use of the operant conditioning paradigm, as it has been applied to infant social, vocal behavior, reflects a failure to take into account the social nature of human infants over and above the rigid theoretical rationale of the paradigm. It is argued that: (1) the baseline procedure used in operant conditioning studies is methodologically and conceptually invalid; (2) the reinforcing stimulus used in social conditioning studies elicits the very response that it is assigned to reinforce; and (3) the effect of the response-reinforcer relationship is not the reinforcement (strengthening) of vocal response rate.     

Constraints on Pavlovian aversive conditioning: Implications for avoidance learning in the rat

Four experiments investigated the relative degree of control exerted by several conditional stimuli when each stimulus: (a) preceded shock, (b) followed shock, and preceded a shock-free interval, (c) was independent of shock, or (d) was novel. When the onset of an auditory stimulus had preceded shock (Experiments 1, 2A, and 3), it always exerted conditioned excitatory control. When the same stimulus preceded a shock-free interval, it never exerted conditioned inhibitory control. When the onset of light (Experiments 2B, 4), silence (2C), or darkness (1, 2D) preceded a shock-free interval, it always exerted conditioned inhibitory control. However, when one of the latter stimuli preceded shock, it failed to exert excitatory control. Several models of this phenomenon were tested. The implications of these results for the species-specific defence reaction and two-factor theory accounts of avoidance learning were outlined.     

Developmental changes in selective and integrative visual attention

School-aged children and adults performed two speeded classification tasks designed to examine the relation between selective and integrative aspects of visual attention. Stimuli consisted of two parentheses (Experiment 1) or two arrows (Experiment 2) separated by 0.5 to 16 degrees visual angle. In a selective attention task, observers classified stimuli on the basis of one of the two elements. Younger children experienced more interference when the elements were closely spaced than older children and adults. In an integrative attention task, stimuli were classified on the basis of both of the elements. Here age differences were most pronounced when elements were separated by large visual angles. These findings suggest that the ability to contract and expand the size of the attentional "spotlight" improves with age in the school years.     

Blocking of a taste aversion by prior pairings of exteroceptive stimuli with illness

Although rats preferentially associate gustatory stimuli with illness, this does not imply that other types of stimuli cannot be associated with illness. In Experiment 1, rats consuming tap water in a distinctive environment prior to illness subsequently suppressed ingestion in that environment, whereas rats poisoned or injected with saline 10 hr later did not. It was also found that rats poisoned after drinking saccharin in the environment paired with illness developed weaker saccharin aversions than identically trained rats which drank saccharin in a different location. In Experiment 2, degrading the correlation between injection-related cues and illness by interpolating saline injections between LiCl preexposures attenuated the decremental effects of illness preexposure. The strength of the exteroceptive cue-illness associations observed in these studies suggests that theories based on evolutionary arguments are not the most appropriate frame of reference for analyzing stimulus selection in poison-induced avoidance.     

Persistence of response prevention effects following retraining of escape behavior

This study evaluated the effects of response prevention procedures on the extinction of escape behavior following the reinstatement of shock-escape training prior to the start of extinction. Female hooded rats were assigned to four groups (N = 10) in a factorial design which orthogonally combined response prevention or pseudo-prevention procedures with escape retraining or no retraining procedures. Results showed that prevention reliably impaired shock-escape behavior on early retraining trials; but this effect dissipated completely by the end of retraining. In extinction, prevention reliably facilitated the extinction of escape behavior relative to that of pseudo-prevention controls; but the degree of facilitation was reliably attenuated by retraining procedures. These findings were related to the competing response interpretation of prevention effects.     

The effects of overtraining and successive extinctions upon nictitating membrane conditioning in the rabbit

In Expt. I Group SAE (N = 16) received four successive acquisitions and extinctions of a classically conditioned nictitating membrane response while Group OTC (N = 8) received an equivalent amount of acquisition training followed by a single extinction session. Successive extinctions resulted in a decrease in resistance to extinction (Rn), but extended acquisition training had no significant effect. In Expt. II a total of 96 subjects participated in a factorial study of the effects of various amounts of overtraining at two different UCS intensities. When CR amplitude was asymptotic extended training had no significant effect upon Rn; when amplitude was below asymptote Rn was correspondingly reduced.     

II. The comparability of the WISC-R and WAIS among 16-year-old EMR children

Thirty 16-year-old EMR children were administered the WAIS and WISC-R in counterbalance order to determine the comparability of the two assessment instruments. The WAIS was found to yield significantly higher Verbal, Performance, and Full Scale IQ scores. The comparisons of corresponding subtests indicate that all WAIS subtests were significantly higher than the WISC-R except Picture Completion. Correlations between corresponding WAIS and WISC-R IQ scales and subtests, however, were significant. The results suggest differences between the two instruments among children of subnormal intelligence, thus presenting the possibility that a child may be differentially classified based on the selection of the intelligence test.     

Development of strategies for recalling letter sequences

Kindergarten, second-grade, and fourth-grade children (6, 8, and 10 years of age, respectively) were asked to recall letter sequences on a task that required the use of: (a) a verbal strategy; (b) a positional strategy; or (c) either strategy. Additional trials, allowing either strategy, were interspersed among those requiring a verbal or positional strategy; strategy use was determined from performance on these interspersed trials. The results show that children at all grade levels attempted to use a task-appropriate strategy. Performance on the verbal task showed a more marked developmental increase than did performance on the positional task. A second experiment replicated the first with the interspersed trials removed. A third experiment was designed to determine whether letter names interfered with older children's efficient use of a positional strategy. Even with this source of interference removed, the developmental pattern of Experiments 1 and 2 was replicated. There was a Sex by Condition interaction in Experiments 2 and 3 which showed that males do better in the condition requiring a positional strategy, and females do better in the condition requiring a verbal strategy.     

Observer recorder error as affected by different tasks and different expectancy inducements

Four experiments were designed to investigate the effects of systematic observer/recorder error on experimental results where experimenters had been induced to expect certain results. In the first experiment, experimenters were induced to expect certain outcomes for three different tasks. No observer error nor experimenter-effects were observed. Postexperimental interviews indicated some suspiciousness as well as failure to understand the hypotheses on the part of experimenters. In the second experiment expectancies were induced in observers who did not act as experimenters. No observer effects were noted, and again postexperimental interviews indicated manipulation failure. In the third experiment experimenters were asked to attempt to influence subjects' responses. Three tasks were used, but in two of these tasks observer error was controlled rather than measured. No differences in subjects' responses were noted for any of the measures. However, significant observer/recorder error was noted for both male and female experimenters in the task where such error was measurable. In the fourth experiment experimenters were again asked to influence subjects' responses. For the two tasks used observer error was measured. A predicted Task × Observer Error Interaction was obtained. Again, no differences in subjects' responses were noted.     

The effects of humor-induced arousal upon aggressive behavior

The present experiment attempted to reconcile previous results in the area of humor and aggression. It was hypothesized that humor serves two functions, arousal and attentional shift, with regard to its influence on the relation of prior anger arousal and aggression. As a test of this assumption, subjects in the present experiment were subjected to three forms of humor (high arousing, low arousing, nonhumor) after being angered or treated in a neutral manner by a confederate. In an analysis on subsequent aggression toward the confederate, it was found that female subjects reduced their aggression after exposure to low arousing humor while maintaining aggression at a high level for high arousing stimuli. Male subjects were not influenced by humor exposure. Possible reasons for this sex difference are examined in light of the arousal and attentional shift properties of humorous stimuli.