Renewal of Pavlovian conditioned inhibition

Prior research has demonstrated renewal, which is the ability of contextual cues to modulate excitatory responding to a Pavlovian conditioned stimulus (CS). In the present research, conditioned lick suppression in rats was used to examine similar contextual modulation of Pavlovian conditioned inhibition. After Pavlovian conditioned inhibition training with a CS in one context, subjects were exposed to pairings of the CS with an unconditioned stimulus (US) either in the same or in a second context. Results indicated that, when the CS was paired with the US in the second context, the CS retained its inhibitory control over behavior, provided that testing occurred in the context used for inhibition training. However, when the CS-US pairings occurred in the inhibition training context, the CS subsequently proved to be excitatory regardless of where testing occurred. These observations indicate that conditioned inhibition is subject to renewal.     

Bloom's Six Cognitive Levels Represent Two Levels of Performance

Abstract Two experiments were designed to further examine the levels of processing analysis of Bloom's taxonomy of the cognitive domain proposed by Kunen, Cohen & Solman (1981). In the first experiment six groups of secondary school students processed 20 principles at the levels of knowledge, comprehension, application, analysis, synthesis and evaluation respectively. The percentages of correctly recalled principle names, were adjusted for the fact that increasingly fewer students successfully completed the taxonomic orienting questions as their level increased from knowledge to evaluation. After adjustment these measures of incidental memory demonstrated a dichotomy of performance, with students who successfully synthesised or evaluated the material being superior. Also recorded in this experiment were measures of working memory and field dependence/independence. These scores proved to be better predictors of student performance on the taxonomic orienting tasks at the higher levels of the taxonomy, and they correctly ordered the levels of analysis, synthesis and evaluation. It was suggested that they provided some independent support for Bloom's contention that the complexity of the cognitive operations required to complete the taxonomic tasks increases with their level. The second experiment manipulated the six taxonomic orienting tasks in a repeated measures design, which required all students to process principles at each of the six levels in order from knowledge to evaluation. While there were minor differences in performance between the Year 7 and the Year 11 students who participated in this study, the adjusted incidental memory data again revealed a performance dichotomy with synthesis and evaluation forming the superior category. That the students demonstrated superior performance after synthesising and evaluating material, was interpreted as support for the continued practice of teaching them to operate at the higher taxonomic levels. This support was qualified, however, by noting that the benefits were confined to those who successfully completed the higher tasks.     

Interstimulus interval and viewing time effects in monkey list memory

Two rhesus monkeys were tested in 6- and 10-item list memory tasks for performance changes as a function of the exposure duration of the list stimuli and the interstimulus interval (ISI) between successive list stimuli. Accuracy increased with longer item exposure duration and tended to decrease with longer ISI duration. Humans, by contrast, typically show increases in accuracy with ISI, a result taken as evidence of rehearsal. The decrease in accuracy for monkeys suggests that they were not using rehearsal processes in these list memory experiments. Further tests in which choice accuracy with predictable ISIs was compared with choice accuracy with unpredictable ISIs also yielded no evidence of rehearsal by the monkeys. This apparent absence of rehearsal mechanisms in monkeys, in situations also shown to support human rehearsal, is discussed as a potential difference in the visual working memory processes of the two species.     

Discrimination reversal learning in newts

The results of field research suggest that, contrary to being behaviorally inflexible, some amphibians may have the ability to respond effectively to changing environments. The performance of seven newts (Triturus viridescens) was studied across 20 successive reversals of a spatial discrimination problem in a dry T-maze. Submersion in shaded water served as reinforcement for correct responses. The subjects showed a decrease in mean errors across reversals and across ordinal trials within sessions. These results are discussed in terms of the importance of using biologically relevant methodologies in the study of comparative animal learning.     

The acquisition of a running response as a function of odor buildup,squad rotation,and introduction of naive subjects

A three-phase experiment was conducted in which rats received a double-alternation schedule of reward and nonreward. During Phase 1, the baseline period, double-alternation behavior was displayed earlier and more strongly by subjects run last in the daily sequence. This finding suggests that both reward and nonreward odor cues are cumulative over subjects. During Phase 2, a subject-rotation procedure was initiated; that is, each day the last subject in the previous day’s running sequence was moved to the first position in the sequence, etc. Rotation to the first position in the group led to an immediate disruption of responding. During Phase 3, two naive rats were inserted at the beginning of the running sequence and two at the end. The results, which showed that the naive animals placed at the end of the sequence acquired the patterning response much faster than those placed in the beginning positions, are interpreted as reflecting preparedness to respond to such intensified odors.     

Classically conditioned heart rate and respiratory-motor activity in newborn and neonatal pygmy goats

Classical discrimination conditioning of heart rate (HR) and respiratory-motor (RM) activity was examined in 16 newborn (average age = 1 day) and 8 neonatal (average age = 2 weeks) pygmy goats over 4 days of conditioning involving an electric shock US and auditory CSs. On the 4th day, one-half of the animals in each group received a low to moderate dose of ethanol to test the resistance of the CRs to drug effects. Discriminated conditioning of RM activity but not HR occurred in the newborn group, indicating an absence of close coupling between skeletal-motor activity and HR at this early age. While the newborn group failed to show recognizable HR reactions to the CSs during the 4 days of testing, it did show a long-latency brady-cardia UR beginning at 2 days of age that may have been secondary to baroreceptor reflex actions. The neonatal group displayed conditioning of both HR and RM activity. The similar latencies of the two types of CRs during the CS suggested that they may have been related to each other. However, the fact that the RM CR developed a day before the HR CR, combined with the observation that ethanol modified the HR CR but not the RM CR, supports the view that there was considerable independence between the two types of CRs.