Gordon Winocur

Retention of Connected Discourse

6 24-word English sentences were made up, 2 representing each of 3 levels of meaningfulness. Meaningfulness was defined in terms of the Thorndike-Lorge frequency of the words making up the sentences. The sentences were mounted on memory drums and learned by serial anticipation to a criterion of 100% correct responses or to a lower criterion, equivalent across level of meaningfulness. The retention intervals were 20 min. and 24 hr., the former providing a control for post-criterial drop. The measure of retention was the number of items lost during the interval. The main effects for both retention interval and meaningfulness were significant as was the interaction term between level of learning and retention interval. Because there were no significant interaction terms involving meaningfulness, it was concluded that the main effect for meaningfulness was an artifact resulting from differing degrees of associative strength at the end of learning. This conclusion was reinforced by scrutiny of 24-hr. loss scores, corrected for post-criterial drop.

Behavioral Changes in Rats following Bufotenine Injection

A time sampling procedure was used to observe the behavioral effects of IP bufotenine injection in the rat. The results indicated an attenuation of locomotor activity which varied directly as a function of drug dosage. In addition, all response components typically associated with a general activity pattern were selectively affected by bufotenine. Interpretation of the response decrement in terms of a generalized motor loss was not supported by other aspects of the data. Evidence suggesting that behavioral changes following bufotenine treatment are due to a disruption of sensory processes was discussed.

Effects of Bufotenine and p-Chlorophenylalanine on Stress Induced Behaviour*

Two experiments were conducted in which it was found that bufotenine attenuated, relative to controls: (1) the manifestation of frustrative behaviour as a function of non-reward in a double runway situation and (2) fear reactions typically observed in an open field test. In both experiments, p-chlorophenylalanine, a serotonin depletor, was used effectively to counteract the behavioural effects of bufotenine. The results were interpreted as being in agreement with the general hypothesis that bufotenine reduces an animals responsiveness to stimulus events. It was also suggested that the behavioural effects of bufotenine are related to its influence on normal serotonin metabolism.

Aversive consequences of electroconvulsive shock

Abstract The behavioral effects of repeated pairings of electroconvulsive shock with a neutral stimulus were examined in a conditioned suppression learning situation. The results confirmed the aversive effects of ECS and showed that fear produced in this way can be as effective as grid shock-induced fear in establishing a conditioned emotional response. There was no support for alternative hypotheses that ECS interferes with normal functioning by inducing conditioned inhibition or increased motor activity. Moreover, it was found that the traumatic effects of ECS are more closely related to the convulsive response itself than to any noxious after-effects occurring during recovery from the seizure.

Spontaneous activity in septal and hippocampal-lesioned rats.

30 rats were assigned in equal numbers to control, hippocampal, and septal groups. Ss were observed in a novel situation for three 15-min. sessions with 24 hr. between sessions and measures taken of their sniffing, walking, and grooming rates. The most important difference occurred in the third session when it was found that the type of lesion exerted control over the habituation of different responses. In walking, there was a tendency for Ss in the hippocampal and control groups to decrease their rate over time, while septal-lesioned Ss tended to increase their rate. Both septal and control groups decreased their sniffing rate, whereas the hippocampal group did not. In grooming, neither the hippocampal nor the septal group showed an increase in rate, whereas the control Ss did. The results of the septal-lesioned Ss were regarded as consistent with a conventional response-inhibition hypothesis while the data of the hippocampal group suggested a deficit in attentional mechanisms.

Electroconvulsive shock, stress, and avoidance conditioning

Sixty-three rats were divided in equal numbers, such that one group received a series of 10 ECS treatments paired with a light CS, a second group received 10 unpaired ECS treatments, and a third received no ECS. Seven Ss in each group were then assigned to one of three CS conditions (light CS, tone CS, no CS) for purposes of avoidance conditioning. The results showed that ECS groups failed to show normal weight gain, while exhibiting greater amounts of urination and defecation during treatment. ECS-treated Ss also required a greater number of trials to reach criterion on the avoidance problem, an effect which was not related to specific CS pairings. It was concluded that the stressful effects of ECS were persistent and disruptive enough to restrict new learning in an aversive situation.

Interaction of fear effects with habit strength.

Four groups of rats received 0, 3, 6 or 9 days of overtraining after having reached stable performance on a continuous reinforcement bar pressing schedule. Half the subjects in each group had previously been designated emotionally reactive or non-reactive in terms of defecation rates in an open-field test. Following training, there were four test days in which bar pressing in each group was examined in the presence or absence of white noise. The major findings were that, in both the reactive and non-reactive groups, white noise produced a fear reaction which significantly depressed bar pressing at low levels of habit strength while having an energizing effect at higher levels. The results were interpreted as supporting Bardachs (1960) hypothesis that anxiety introduced early in practice is more disruptive than when introduced late in practice.

INTER-ITEM ASSOCIATIVE STRENGTH AND PROACTIVE INHIBITION IN PAIRED-ASSOCIATE LEARNING

The experimental design was 2 × 2 factorial, with 2 levels of prior list (one or none), 2 of response term inter-item associative strength (high or low), and a 15-min. retention interval. The expectation was that high inter-item associative strength would reduce proactive inhibition. The hypothesis failed; the proportion of function words per list had no effect on recall.