Effects of food priming on instrumental acquisition and performance

Four experiments investigated the effects of a priming food reinforcement, given 0 or 75 sec pretrial, on runway performance of rats. The studies differed in the use of between-versus-within-subject designs, and by using food or water as the goal reinforcer. In Experiment 1, using food as the goal reward, subjects primed with food 0 sec pretrial conditioned slower than subjects primed 75 sec pretrial. In Experiment 2, using water as the goal reward, subjects primed with food 0 sec pretrial conditioned faster. These differences were evident on both prefed trials and on nonprefed test trials. Experiments 3 and 4 showed an opposite pattern of results when within-subject comparisons of 0- and 75-sec pretrial intervals were used: Food priming immediately pretrial facilitated food-rewarded running but inhibited water-rewarded running. The results suggest prefeeding has differential effects on acquisition and performance of instrumental behavior, and also depending upon the similarity of the priming and goal reinforcers.     

Effect of preacquisition UCS exposure on classical conditioning of the rabbit's nictitating membrane response

Conditioning of the rabbit nictitating membrane response was found to be inversely related to the number (0, 50, 200, 350) and intensity, (0, 1, 3, 5 mA) of preacquisition UCS exposures and directly related to the interval between preexposure and acquisition (0 or 24 hr). The results were discussed in terms of sensory adaptation, habituation, blocking, and emotional reactivity.     

Effects of naloxone on acquisition and extinction of jump-up avoidance behavior in rats

Two experiments were carried out to assess the effects of the opioid antagonist, naloxone, on the acquisition and extinction of shock avoidance by rats in the jump-up apparatus. In Experiment 1 naloxone pretreatment facilitated acquisition but had no effect on extinction of avoidance behavior. In the second experiment the effect of naloxone on acquisition was replicated and in addition, it was shown that naloxone enhanced freezing when a response prevention or flooding procedure was introduced. Again naloxone failed to alter the course of extinction, nor did it interact with the effects of flooding which, by itself, facilitated extinction. The results suggest that naloxone's effects are limited to increasing the functional intensity of the US, and provide further support for the dissociation between extinction of avoidance behavior and other indices of fear.     

A comparison of attentional and control shift models of the performance of concurrent tasks

A concurrent verbal task was superimposed upon the performance of a practiced bimanual motor skill by right-handed Ss. Addition of the verbal task did not increase the total number of errors; however, a significant interaction between hands and conditions was observed. The right hand made significantly more errors under the verbal condition, while the left hand made non-significantly fewer errors under that condition. These findings were interpreted as supporting an attentional model rather than a model which proposes that addition of the verbal task causes control of the right hand to shift to the non-verbal right hemisphere.     

The effectiveness of visual and gustatory conditioned stimuli in human classical aversive conditioning with electric shock

Thirty-six undergraduate volunteers, divided into three equal groups, were given electric shock while sipping a colored, unflavored solution (Group I): a flavored, colorless solution (Group 2); or a colored, flavored solution (Group 3), in order to determine whether human Ss respond differentially to visual and gustatory cues when the UCS is aversive electric shock. Using a standard classical discrimination procedure, the CS + was blue water for Group 1, citric acid solution for Group 2, and blue citric acid solution for Group 3. For all groups the CS- was plain water, which was never paired with electric shock. The dependent variables were derived from Staats' A-R-D theory: attitudinal change (A) and a performance measure of sip-size taken during conditioning trials (D) both confirmed the hypothesis that taste can be an effective CS when the UCS is shock, in contrast to results typically obtained with rats where visual but not taste cues are effective with a shock UCS.     

Male alcoholics,secondary psychopathy and Eysenck's theory of personality

The scores of several samples of male alcoholics and others on the MAC Scale (an MMPI-derived scale for the differentiation of male alcohol abusers from non-substance-abusing male psychiatric outpatients) are summarized, and the responses of the false negatives and false positives from the scale's standardization samples are analyzed. The following 7conclusions were reached: (1) There are two broad classes of male alcoholics—those who fall into the E + N + quadrant of secondary psychopathy and those who fall into the E - N + quadrant of neurotic introversion; (2) Unselected runs of male alcoholics populate these two quadrants in a quite stable ratio of 17 to 3, respectively; (3) Pari passu, Eysenck's placement of alcoholics in the E + N + quadrant will be upheld in approximately 85% of the cases while those who hold that alcoholics are ‘dysthymics who also drink too much’ will find themselves in error in approximately similar degree.     

Partial reward training level and reward magnitude: Effects on acquisition and extinction

Two groups of 10 rats each received either a large magnitude (0.90 g) or a small magnitude (0.18 g) of partial reward (PR) and seven successive acquisition-extinction sessions in the runway. The large magnitude PR group ran much faster than the small magnitude PR group in the early acquisition sessions with differences between the groups declining over sessions. In the early extinction sessions, the large magnitude PR group showed greater resistance to extinction than the small magnitude PR group, but in the late extinction sessions this relation reversed itself. Finally, resistance to extinction decreased over sessions, this decrease being greater under a large than under a small magnitude of PR.     

Blocking in successive differential conditioning: Prior acquisition of control by internal cues blocks the acquisition of control by brightness

In each of four experiments the acquisition of discriminative stimulus control by brightness cues (black vs white runway) in a successive go/no-go instrumental discrimination was blocked in groups given prior discrimination training with internal (reward-produced and intertrial interval-related) cues as relevant discriminanda and brightness cues irrelevant. The blocking effects obtained here in instrumental conditioning were substantial and in most cases complete. Blocking occurred whether brightness in Phase I varied across trials but was uncorrelated with reinforcement (varied-irrelevant, V-I, condition) or whether all Phase 1 trials occurred to a single value on the brightness dimension (constant-irrelevant, C-I, condition) which then served as a redundant S+ cue in Phase 2 while the previously unexperienced brightness cue was added to the S- stimulus compound, or vice versa. Blocking in the V-I condition was shown not to be due simply to nondifferential reinforcement of brightness in Phase 1, but to depend on the prior acquisition of discriminative stimulus control by internal cues. As in Pavlovian conditioning, blocking here was an increasing function of amount of prior conditioning to the blocking stimulus. The results encourage the prospect that the procedures used here can be developed into a viable instrumental conditioning companion to the Pavlovian procedures now used almost exclusively to study blocking.     

Stimulus intensity effects on auditory and visual reaction processes.

Literature on the effect of stimulus intensity on reaction processes was reviewed. It was shown that there is no agreement as to whether intensity effects are limited to encoding or whether they are extended to later processing stages. The situation can be characterized as an asymmetry between modalities: vision is consistent with the first alternative and audition with the second.Chronometric analysis was used to bear on the question. It was shown that the effects of visual intensity and foreperiod (FP) are additive in a simple RT situation both for constant and mixed blocks FP. Auditory intensity and FP interact in both simple and two-choice situations. In a control experiment visual intensity and S-R compatibility were found to be additive. The asymmetry was accounted for by auditory alerting, previously discussed by several authors.The framework of stimulus intensity research utilizing RT measures was briefly evaluated.     

Information extraction during visual search: A developmental progression

Five developmental experiments examine the role of context in visual search. Experiments I and II presented either lists or paragraphs that were either in meaningful context or scrambled. Results showed a significant interaction of these variables. Experiment II examined within-item context or predictability and replicated and extended the work of Brand (1971) and Ingling (1972). Experiments IV and V examined search through lists of various widths; results showed a significant interaction of Grade × Position × Width reflecting the different perceptual spans of children and adults. Although these were search tasks, appropriate comparisons between list and paragraph performance were made allowing interpretations of the results to be supportive of a model of reading in which meaningfulness, predictability, and peripheral vision play critical roles.     

The effect of cuing after backward conditioning trials

Rats were given backward pairings of a tone (CS) and shock (US) and were then tested for response to the CS in a lick suppression test. Animals given a cuing or reminder treatment prior to the test exhibited enhanced suppression in the presence of the tone relative to a variety of control conditions. The cue-induced suppression enhancement did not appear to result from sensitization or short-term motivational changes nor did it seem to depend on second-order conditioning of the test context. The effect appeared more robust as the number of backward conditioning trials preceding the cue increased. The results were discussed in terms of current explanations of backward conditioning effects.     

Reliability of electrodermal habituation measures under two conditions of stimulus intensity

The present study investigated test-retest reliability of habituation of the evoked skin conductance response. Subjects received 20 presentations of a 1000-Hz, 3-sec tone at the same time of day on two separate occasions, separated by an interval of 97–160 days. Thirteen subjects received stimuli of 90 dB, while for 24 subjects, stimulus intensity was 70 dB. Interstimulus interval was 21 sec for both groups. Both absolute rate of habituation and trials to criterion displayed moderate reliability, and the relationships between habituation measures and other aspects of electrodermal activity were in agreement with previous findings.     

The choice reaction times of single and dual jointed actions

The choice reaction times of dual (elbow and wrist) and single (elbow) jointed movements were measured using ‘mixed’ (dual and single) and ‘matched’ (both dual or both single) response pairings. Although subjects found it more difficult to execute dual jointed actions (as shown by error rate), there was no concomitant prolongation of latencies for acceptable responses. In the light of these findings, the utility of CRT as an index of motor programming complexity, and the claim that pre-programming of responses is precluded with CRT testing, were discussed.     

The role of a guessing strategy in the Bransford-Franks paradigm

Within the framework of the Bransford-Franks paradigm, variations of two memory models and a guessing strategy hypothesis were evaluated using concepts that differed in the number of atomic units each contained (‘concept size’). Results showed that, though the precise patterns of recognition for concept size were not completely consistent with any of the explanations, the changes in the patterns across concept size agreed with the guessing strategy hypothesis. It was argued that the subject's interpretation of the guessing strategy is likely to be a similar but simpler version of the experimenter-theorist's formal model, with the consequence that, while less sensitive to the finer details of the formal model, it will still reflect coarser differences.     

Stimulus control of responding in the early trials of differential conditioning

In Experiment 1 two groups of rats were given 12 differential conditioning trials, seven to the rewarded alley (S+) and five to the nonrewarded alley (S?), prior to being extinguished in both alleys. Group S?S+ received S+ trials, following S? trials in acquisition, while Group S+S? did not receive S+ trials following S? trials in acquisition. In extinction S+ and S? trials were presented according to a quasi-random sequence for both groups. Running on the last 3 trials of acquisition was found to be faster following S+ than following S? trials. Group S?S+ showed greater resistance to extinction and less discriminative responding in extinction than Group S+S?. These results suggest that responding in differential conditioning is controlled not merely by S+ and S? but by the memories of reward (S^R) and of nonreward (S^N) as well. When the joint effects of both classes of cues were considered, e.g., S^R+S+, responding in the early trials of differential conditioning was shown to be highly orderly. Experiment 2 was highly similar to Experiment 1 except that Groups S?S+ and S+S? were equated along dimensions not equated in Experiment 1. The results obtained in Experiment 2 were highly similar to those obtained in Experiment 1.