Rats chronically treated with yeast ribonucleic acid showed enhanced acquisition of an escape response, thus replicating a previously reported effect. The nature of the enhancement, however, as well as the results from a food-rewarded discrimination task, does not suggest that yeast ribonucleic acid improves the learning or memory processes in the rat.
Rats with bilateral hippocampal lesions drank 16–21% more water postoperatively than Ss receiving posterior neocortical lesions or unoperated controls. Data were based on ad lib intake measures over 2 months following surgery. Both lesioned groups consumed slightly more food than unoperated Ss. No differences in body weights developed.
In three lists containing the same subset of 15 standard words of medium rated meaningfulness (m′) and 15 context words of varying m′ recall of the context words increased directly with their m′. Recall of the standard words did not vary reliably, but tended to be most affected by contextual meaningfulness under number-assignment instructions under which recall increased with the...
Upon being given a stimulus word, Ss were given three guesses to discover the strongest or the second strongest associate of the word. As expected from response-hierarchy approach to problem solving, improvement over successive guesses was greater for the weaker associate.
Two groups of rats were first trained to traverse a runway, one with large and the other with small food rewards. Both groups were then given additional training with small rewards until their performance equalized. In final training, both groups were shifted to the larger rewards. The group with a prior history of large rewards, evidenced savings in the final stage of training...
A continuous technique for studying short-term memory of paired-associates was used. For 4, 6, or 8 stimuli, recall was found to be a decreasing function of the number of pairs of items interpolated between study and test on a given item. Reliable differences between the functions for 4, 6, and 8 stimuli were found.
Extensive central gray lesions did not interfere with septal self-stimulation behavior or escape responding to aversive dorsomedial tegmental stimulation.
Sucrose reinforcement thresholds were determined for bar pressing. Hungry Ss showed lower thresholds than non-deprived Ss and thirsty Ss did not prefer sucrose at all.
Irrelevant stimuli each associated with a 50% reinforcement schedule were either present on all or on half of initial discrimination training trials. For different groups in test problem training a previously irrelevant stimulus was either the positive or the negative discriminandum, with a novel stimulus as the other discriminandum, or both discriminanda were novel stimuli. No...
To test the hypothesis that “positive” (+ only) and “positive and negative” (+ & −) reinforcement schedules will affect conditioning of a random noun schedule, 30 Ss were randomly selected and placed into 3 groups (control, + only, and + & −). The nouns to be conditioned were of the animate form where conditioning was done by generalized conditioned reinforcers “mmm—hmm” for the...
Postural sway was elicited in human Ss using various combinations of low frequency-low amplitude sinusoidal electrical stimulation at the mastoid processes. Amount of sway was a V-shaped function of the stimulus frequency at low amplitude and an inverted V function at the higher amplitude. Amplitude-frequency combinations optimal for eliciting overall sway were different from...
Male rats made hyperactive and sexually inept by rearing in isolation showed higher rates of response in a single response task and lower proficiency in a competing response situation than did normal, socially-reared litter-mates. These results and a marked reduction in errors on the competing response task by Ss of both rearing conditions which were more experienced in the...
When the sides of a contour triangle are sequentially presented, Ss report a sequential “flow” of brightness within the sides or a sequential “growth” of the sides. Modal report of this movement occurs in all three sides when the interside intervals are equal and 100 msec. Increasing the probability of contour scanning eye movements leads to an increase in this type of apparent...
Temperature measurements of the eyes of adult albino rabbits showed consistent gradients from the anterior surface of the retina to the outer surface of the cornea. Average difference between temperature at the retina and at the outer surface of the cornea was 5.01°C. Between rectal temperature and temperature at the outer surface of the cornea, average difference was 5.84°C...
Activation of the frontal association response field of the cerebral cortex of cat by a brief train of electric shocks is shown to induce a subsequent marked depression of nonspecific evoked cortical association responses and an enhancement of the later components of evoked primary sensory responses. Both effects have been reported to accompany behavioral attending. The two...
This study demonstrated that reflexive fighting could be classically conditioned to a 80-db buzzer, usingboth simultaneous and delayed conditioning paradigms.
Rats learned to avoid a place where they received grid shock to their feet when the grid shock was followed 10 sec. later by electroconvulsive shock. The avoidance learning was significantly greater than for rats that received only grid shock or only electroconvulsive shock.
A group of 7 to 9 yr. old children were tested in a two-choice situation under 100%, 67% alternating, 50% alternating or 50% random schedules of reward regardless of the choice they made. Continuous reward resulted in significantly more alternating responses than any of the partial reward conditions. The ratio of reward to nonreward or the regularity of the schedule had no effect...
An experiment was conducted to determine the effects of an asymmetrical, distractor stimulus placed at varied distances from the objective median plane on the amount of shift of the apparent median plane. A non-monotonic relationship was found between degree of asymmetry and amount of shift. Although all degrees of asymmetry effected a shift in apparent median plane, the largest...
A simulated decision making, environment was used to examine the relationship between experimentally induced failure and Ss perceptions of success and failure. The obtained relationship between induced and perceived failure was generally linear, with a significant higher order trend. The implications of these findings for homeostatic and adaptation level theories of perception...
The technique and advantages of a new implantation method is described.
Murray & Kohfeld (1965) interpret stimulus intensity dynamism in terms of the relation between pre-test AL and test signal intensities. An alternative assumption is made about the AL for one of their groups, and a reinterpretation of their findings is offered which incorporates a tension level intermediary between the aforementioned relationship and performance.
Attraction toward a stranger is a positive linear function of the proportion of his responses to an attitude scale which are similar to those of the S. Though various experimenters have utilized different stimulus modes for presenting the stranger, the effects of such stimulus differences have not been systematically compared nor has the linear function been demonstrated to be...
There are similarities between pigeons’ behavior under interval reinforcement schedules and the behavior of rats in runways. A free-operant experiment analogous in certain respects to the double-runway procedure produced large “frustration effects” in pigeons, lending support to this comparison.