Relative novelty of conditioning context influences directionality of glycemic conditioning

Previous experiments in which insulin was administered in a Pavlovian conditioning procedure obtained both hyperglycemic and hypoglycemic conditioned responses (CRs). In the present experiment the relationship of the conditioning context and the housing environment was varied. Two environments, wastebasket (WB) and metal cage (MC), were varied factorially as housing and conditioning contexts. Subgroups were injected with either insulin or saline for 6 days and then, on a test day for conditioning, all animals were administered saline. The results suggested that a hyperglycemic CR could be expected when the conditioning context is different from the housing context, but a hypoglycemic CR could be expected when the conditioning context and housing context are similar. The magnitude and reliability of conditioning were greater when it was conducted in the WB context than when conditioning was conducted in the MC context. These results are discussed in terms of stress arising from relative novelty of the conditioning environment and in terms of the salience of the conditioned stimulus (CS) used in glycemic conditioning studies.     

Contextual conditioning

Eastern and Western interpretations of contextual control of phasic conditional responses (transswitching) are contrasted. The Eastern (Asratyan, 1965) approach emphasizes the role of the tonic conditional stimulus and the (hypothetical) tonic response it evokes. The Western (Lachnit, 1986) approach emphasizes the role of compound conditional stimuli. Although Lachnit showed that transswitching-like results can be obtained without a tonic stimulus, attempts to simulate transswitching experiments using a computer model of the Rescorla-Wagner theory (Kimmel and Lachnit, 1988) have shown that predictions from the theory approximate empirical results in human classical conditioning only when the tonic stimulus is given far greater weight than the phasic stimulus. In other words, only when the Rescorla-Wagner theory is made more like Asratyan’s theory, can the compound conditional stimulus approach account for real empirical transswitching data.     

Reevaluating evaluative conditioning: a nonassociative explanation of conditioning effects in the visual evaluative conditioning paradigm.

In 2 studies, the authors investigated whether evaluative conditioning (EC) is an associative phenomenon. Experiment 1 compared a standard EC paradigm with nonpaired and no-treatment control conditions. EC effects were obtained only when the conditioned stimulus (CS) and unconditioned stimulus (UCS) were rated as perceptually similar. However, similar EC effects were obtained in both control groups. An earlier failure to obtain EC effects was reanalyzed in Experiment 2. Conditioning-like effects were found when comparing a CS with the most perceptually similar UCSs used in the procedure but not when analyzing a CS rating with respect to the UCS with which it was paired during conditioning. The implications are that EC effects found in many studies are not due to associative learning and that the special characteristics of EC (conditioning without awareness and resistance to extinction) are probably nonassociative artifacts of the EC paradigm.     

Operant conditioning of goats

A procedure is described for establishing an operant response in goats. The operanda are two lucite panels which can be transilluminated. The goats press the panels with their muzzles and are reinforced with whole oats. All six subjects showed reliable and accurate performance in brightness discrimination, including cessation of responding during time-out periods.     

Mathematical biophysics of conditioning

It is shown that from a somewhat more precise form of the fundamental postulates, used in a previous paper as a starting point for a system of mathematical biophysics of psychological phenomena, a mechanism can be derived, which represents the important features of conditioning.     

Human classical conditioning

Recent reports of failure to obtain blocking in human galvanic skin response (GSR) conditioning, together with our own equivocal results with eyelid conditioning, have motivated us to re-examine the status of the conditioned stimulus (CS) in human conditioning studies. The issues raised by compound stimuli, by contextual cues and occasion setting stimuli, and by cross-modal transfer are considered in the light of data from our laboratories. These data include observations on the interchangeability of stimulus modalities during acquisition, the use of varying information loads embedded in occasion setting displays, the comparison of alternative blocking designs and the analysis of response topography in relation to stimulus variability. They suggested that an adequate account of the CS in human conditioning studies must recognize that it is dynamically processed and reprocessed both during and after acquisition.     

Effects of contextual conditioning and unconditional stimulus presentation on performance in appetitive conditioning

Four experiments with rat subjects examined the effects of contextual conditioning on conditioned appetitive performance. Experiment 1 compared the effects of contextual conditioning on performance to conditioned stimuli (CSs) with different conditioning histories. Contextual conditioning enhanced performance to the CS if the CS had first been conditioned and then extinguished, but had no effect on performance when the CS had been merely paired or unpaired with food. Experiments 2 and 3 then asked whether the effect on the extinguished CS was due to contextual conditioning acting as a cue for conditioning. In Experiment 2, extinction procedures in which extra unconditioned stimuli (USs) were presented during the intertrial intervals were found to reduce the CS's sensitivity to enhancement by contextual conditioning, but had no effect on spontaneous recovery. In Experiment 3, USs added to conditioning or extinction acquired the ability to cue the corresponding performance. Under some conditions, USs added to conditioning could suppress performance (Experiment 4). The results suggest that contextual conditioning has complex effects that can be better understood by recognizing that contextual conditioning, as well as the USs that create it,Mayacquire discriminative control over conditioned responding.