Correlations between rats' spatial location and intracranial stimulation administration affects rate of acquisition and asymptotic level of time allocation preference in the open field

The present experiment explores the effects of the response (1-sec occupancy of a target area in an open field)-reinforcer (intracranial stimulation) contingency on time allocation in the open field in rats. The probability of reinforcement given response (X) and the probability of reinforcement given nonresponse (Y) were varied randomly across sessions within a subject. The 21 contingency treatments explored included all possible combinations of values (0, .1, .2, .3, .4, .5) of X and Y such that X ≥ Y. The results indicate that rate of acquisition and asymptotic level of time allocation preference to the target area are negatively related to the value of Y (for any given value of X). Variations in X (for any given value of Y) were less effective. Evaluation of proposed contingency metrics revealed that the Weber fraction (X − Y)/X most closely approximates performance, and that the value of the difference detection threshold derived from the Weber fraction is a constant.     

Retardation of autoshaping following pretraining with unpredictable food: Effects of changing the context between pretraining and testing

In Experiment 1, pigeons exposed to US ONLY pretraining were observed to be retarded in the acquisition of autoshaping relative to naive controls; however, gross changes in contextual stimuli between pretraining and testing alleviated the retardation effect. In Experiment 2, groups of pigeons exposed to CS ONLY, US ONLY, or random CS-US presentations (TRC) were tested for the acquisition of autoshaping. The US ONLY and TRC groups were retarded relative to naive controls. The context change manipulation eliminated the US ONLY retardation effect and attenuated, but did not eliminate, the TRC retardation effect. Context blocking accounts for the US ONLY effect and contributes to the TRC effect; however, context-independent retardation following TRC pretraining suggests the operation of the learned irrelevance cognition.     

Stimulus generalization of auto-shaped key-pecking following interdimensional and extradimensional training

In three experiments, groups of pigeons were tested for wavelength generalization of auto-shaped key-pecking following different types of training. In Experiment I, one group received auto-shape trials with a 555-nm CS. Another group received auto-shape trials with a 555-nm CS and a white CS. A third group received auto-shape trials with a 555-nm CS and a white CS, except the white CS was nonreinforced. The third group yielded the sharpest gradient, whereas the second group yielded the flattest gradient. In Experiment II, one group received auto-shape trials with a 555-nm CS. A second group received auto-shape trials with a 555-nm CS and a compound CS consisting of a vertical white line on a 555-nm background. A third group received auto-shape trials with a 555-nm CS and a compound CS, except that the compound was nonreinforced. The third group yielded the sharpest wavelength gradient, whereas the second group yielded the flattest. In Experiment III, exposure differences to 555 nm in Experiment II resulting from differential speeds of auto-shape acquisition were controlled by the use of an ITI manipulation. Amount of exposure to 555 nm was shown not to be responsible for the results of Experiment II.     

Attending to multiple sources of information: I. The integration of information in decision making

Information relevant to a decision is often available from several sources, such as different sensory modalities or different spatial locations. Processing or utilization of such information is often selective in that some sources seem to have more influence on a decision or response than others. Many different theoretical mechanisms have been proposed to account for such selective (i.e., attentional) aspects of human information processing. This paper considers theoretical mechanisms which operate to integrate separate sources of information in order to make a binary decision. In particular, these mechanisms are studied in simple visual and auditory detection tasks as well as a Bayesian decision problem. Data from these experiments reject the idea that one integrates the relevant information from several sources prior to making a decision. Rather, one seems to form separate decisions about the information from each source and then integrate these decisions in order to select a response.     

Intergroup contact: The typical member and the exception to the rule

Three studies examined the role of the perceived typicalness of an out-group member on her effectiveness in improving evaluations of her group. Subjects were students at two adjacent colleges. In the first study they interacted with a member of the out-group college. The interaction was either pleasant or unpleasant, and the contact person either confirmed or disconfirmed several stereotypes of the out-group (typicalness manipulation). Subjects evaluated the out-group most favorably when they interacted with the typical-pleasant member of the out-group. The second study demonstrated that contact with a highly typical member is not beneficial if her typicalness is based on stereotypes that reflect negatively on the subject's in-group. Several explanations of the typicalness findings were considered in a third study. Support was found for the hypothesis that the more typical member is perceived to be more predictive of the personality and actions of other out-group members.     

The effects of distributed training on retention of operant conditioning in human infants

Long-term retention of operant footkicking acquired in the mobile conjugate reinforcement paradigm was assessed as a function of the distribution of training time. In the first study, 3-month-old infants were trained for either one 18-min session or for two 9-min or three 6-min sessions separated by 24-hr intervals. All infants exhibited retention during a test administered immediately after training, but only those trained in a single session continued to perform the conditioned response during cued-recall tests 7 or 14 days later. Infants trained in three sessions showed no evidence of remembering the contingency even after a week. A warm-up decrement, seen in the day-to-day performance of infants in the distributed conditions, was eliminated in the second study by the interpolation of a nonreinforcement period at the outset of daily sessions. This procedure also enhanced long-term retention such that infants trained in three 6-min session now remembered the contingency for 14 days and did not differ from infants who had received a single 18-min session. Whether distributed training facilitates or impairs long-term retention appears to depend on the opportunity for infants to acquire a sufficient number (or kind) of effective retrieval cues during original learning.     

The effect of associations and expectations on lexical decision making in normals, alcoholics, and alcoholic Korsakoff patients

This study examined whether patients with Korsakoff's disease suffer from increased PI during encoding. The ability of the name of one category, e.g., BIRD, to prime the processing of members of another category, e.g., BODY PARTS, in a lexical decision task was used to assess the amount of PI during encoding. This task required a subject to inhibit the normal associations to BIRD. Young normals (25 years), older normals (48 years), alcoholics (45 years), and alcoholic Korsakoff patients (59 years) performed two lexical decision tasks. In the first experiment, the appearance of the neutral prime XXX 750 msec before the probe signaled that if the probe was a word, there was a 75% chance that it was from a particular category (e.g., BODY PARTS). The prime facilitated reaction time for words from the expected category for all four groups. The prime slowed reaction time for words that were not from the expected category for the young normals but did not influence reaction time for unexpected words for the three older groups. The second experiment was identical to the first except that a category word was used as the prime. The category word used as the prime was unrelated to the category of the words that were likely to follow it. For example, BIRD might be used to signal the likelihood that the word would be from the category, BODY PARTS. Again, young normals were slower to respond to unexpected probe words, but the three older groups were not. Again, the prime facilitated reaction time for expected words for the young normals, older normals, and alcoholics. However, the word prime did not facilitate reaction time for expected words for the alcoholic Korsakoff patients. That the word prime did not facilitate reaction time for the Korsakoff patients was viewed as evidence that they were unable to inhibit its normal associations and were more sensitive to PI from these associations than the other subjects.     

Interactive effects of deprivation in the albino rat

The interactive effects of feeding and drinking schedules were investigated in three experiments. Twenty-four hour water-deprived rats consumed their entire obligatory water intake prior to feeding, whereas 24-hr food-deprived rats consumed only small quantities of food prior to drinking. This drinking was apparently due to a shift of water stores rather than an actual negative water balance. Experiment 3 investigated the effects of 24, 48, or 72 hr of water, food, or total deprivation. Water-deprived rats did not adequately suppress food intake and became thirstier than totally deprived rats. The effects of total deprivation were essentially identical to those of food deprivation. These experiments indicate the degree to which deprivation schedules impose restrictions on the reinforcement parameters of behavioral experiments.     

The efficacy of auditory and visual conjugate reinforcers in infant conditioning

The effectiveness of the separate auditory and visual components of a combined auditory-visual conjugate reinforcer was assessed in 273-month-old infants. All conditions of contingent reinforcement were equally effective in promoting acquisition, but only the removal of the singly presented auditory component resulted in significant response diminution. Although noncontingent stimulation in all conditions was ineffective in altering operant footkicks, it did sustain visual attention at a high level equivalent to that produced by contingent stimulation over the major portion of acquisition. The results were discussed in terms of the reinforcing properties of varied stimulation.     

Effects of sucrose concentration and goal units on runway behavior in the rat

Experiment 1 investigated the between-S and within-S effects of sucrose concentration (32 and 6%) and number of goal units (equal volumes of sucrose presented in single or multiple goal cups). The goal-unit variable had no effect on behavior under any of several test conditions employed. Within-S effects of sucrose concentration were approximately equal to between-S effects; no contrast effects were found. When 64 and 6% sucrose solutions were used as reinforcers in Experiment 2, a simultaneous, but not a successive, negative contrast effect was found. Results were discussed in terms of possible functional differences between the successive and simultaneous contrast paradigms and between sucrose solutions and solid food as reinforcers.     

Perception of groups,size of opposition,and social influence

Two experiments investigated the relationship between social influence and the number of persons attempting influence. The organization of these persons was varied so that subjects either perceived them as a single group, as several distinct groups, or as an aggregate of unrelated individuals. Conformity was found to increase as the number of separate individuals and groups (distinct social entities) in opposition increased. But varying the size of a single group had little effect on subjects' level of conformity. Furthermore, even when subjects had a partner (social supporter), they conformed more when the opposition was categorized as several entities than as a single group. Overall, findings from the studies suggest that the manner in which persons are initially organized into groups and aggregates of individuals affects their persuasive impact on observers. Implications of these findings for research on social influence were considered.     

Contextual determinants of retrieval in three-month-old infants

Three-month old infants learned to kick to produce movement in an overhead crib mobile on a conjugate reinforcement (FRI) schedule. All infants were trained in the presence of one of two distinctive crib bumpers. In Experiment 1, infants receiving cued-recall tests in the presence of the original training bumper remembered the conditioned association 1 week later, but those tested in the presence of a different bumper did not. Two weeks later, neither training group evidenced retention of the contingency. In Experiment 2, infants who received a 3-min exposure (“a reactivation treatment”) to the original training bumper 24 h prior to the 2-week retention test exhibited excellent long-term retention, whereas those exposed to a different bumper as a reminder did not, irrepective of whether it was identical to the test bumper or not. These findings demonstrate that the context alone, even though it was never exclusively paired with reinforcement, can act as a retrieval cue.     

Effects of personal competence on the significance of interpersonal agreement and disagreement: Physiological activation and social evaluations

Two psychological theories, affect-reinforcement theory and consistency theory, were compared for their usefulness in predicting arousal during a social episode. One-hundred twelve males met in pairs to discuss their attitudes on one topic. Half of the subjects rated themselves as competent to defend the correctness of their attitude; the other half rated themselves as not competent to defend the correctness of their position on the specific topic under discussion. The topic was selected by the experimenter such that half of the pairs were in agreement in their attitude, while the other half of pairs had opposing attitudes for the topic. The three factors (competence of Person A, competence of Person B, and similarity of attitude) were crossed to produce eight conditions. Skin conductance was continuously recorded throughout the social interaction. Following the discussion period, subjects rated each other on the Evaluative-Behavioral Attraction Measure. Skin conductance data supported the affect-reinforcement hypothesis with a significant interaction between self-rated competence and similarity of attitude factors (p < .05). Hearing disagreement from the other person was highly arousing when a subject said he was competent to present his position on the topic. Other significant effects for physiological activation during the social episode, which were not predicted, are consistent with the affect-reinforcement theory. There was no significant effect for the attraction measure.     

Retention of conditioned inhibition in a bar-press suppression paradigm

In three experiments, the retention of conditioned inhibition in rats was examined over long intervals. Retention deficits of conditioned inhibition were found at 21 days, although conditioned excitation was relatively stable over time. This loss of conditioned inhibition was demonstrated using both the summation and the retardation of learning techniques in a bar-press suppression paradigm. Furthermore, retention differences were found between within-groups and between-groups generalization tests of conditioned inhibition, using the summation procedure. These differences were interpreted within a retrieval-oriented model of memory.     

Observational goals and schema activation: A theoretical framework for behavior perception

A framework for behavioral observation is described in which the processing of a stream of behavior is influenced by an individual's prior knowledge about behavior, organized into cognitive “schemas.” It is proposed that observational goals determine the selection of goal-relevant schemas which, in turn, influence the observer's processing of an actor's behavior. Subjects watched a series of videotaped sequences featuring a female actor with instructions either to form an impression of her or to remember the details of the tasks she engaged in. They were then asked to answer questions that were either consistent or inconsistent with these instructions. Subjects were also instructed to unitize the actions or events that occurred in the sequence (D. A. Newtson, Journal of Personality and Social Psychology, 1973, 28 28–38). According to the unitizing measure, subjects observing with different goals attended to different behavioral features. Further, impression-forming subjects were apparently more influenced by their implicit theories of personality than were task-learning subjects when asked to give ratings of the actor's personality, and task-learning subjects were relatively more accurate in recalling task-related details. Implications of this framework and these results for research in behavioral unitization and implicit personality theory are discussed.