F. T. Crawford

Escape and avoidance responding in the toad

Southern toads, Bufo terrestris terrestris, were given 20 daily trials in a one-way avoidance box for five days. The frequency of no responses decreased, avoidance responses increased, and escape responses remained essentially the same. There was an increase in the number of avoidance responses in each daily session of trials, followed by a lower initial level of avoidance responding on the following day. An improvement in performance as measured by response latency was also observed. The pattern of response latencies was consistent with that of the avoidance responses in that there was a decline in response latency over daily trials with higher initial levels on the early trials of the following day.

Escape conditioning in snakes employing vibratory stimulation

Eight rat snakes were given 50 paired presentations of light and vibratory stimulation. Ss were tested in a two compartment chamber with a 12 hr. interval between each trial. Moving from one compartment to the other terminated and permitted escape from the vibratory stimulus. Data from two Ss was discarded because of inadequate responsiveness. Except for the terminal block of trials Ss demonstrated a progressive decline in escape time. Individual Ss, however, were highly variable in their performance.

Runway behavior of the gray rat snake with food and water reinforcement

Two groups of gray rat snakes were given training in an enclosed alleyway. Both groups were maintained on a seven day food and water deprivation schedule. Ss of the experimental group were run to food and water reinforcement. Control Ss were run in the same manner except that there was no reinforcement in the goal box. All Ss received one trial every seven days unless they were moulting. Measures of latency and running time produced diverging curves for the experimental and control groups, due principally to the increase in both measures for the latter group.

Amino acid analysis of planarians following conditioning

Four groups from a study of partial reinforcement effects upon classically conditioned planarians were subjected to amino acid analysis. Results of the amino acid analysis were found to have significant correlations with behavioral measures.

Distribution of practice in the classical conditioning of planarians

Eighty Ss were divided into four groups receiving training conditions of either light, shock, light paired with shock, or neither light nor shock. Half of each group were given trials 30 sec. apart and the remainder were given trials 60 sec. apart. Conditioning occurred only among Ss given paired light and shock with spaced training producing significantly greater conditioning. Half of all Ss were then given either massed or spaced extinction trials. Massing and spacing of acquisition trials were found to be of more significant influence upon rate of extinction than were the massing and Spacing of extinction trials.

The effects of magnesium pemoline upon repeated acquisition and extinction of a bar press response

Six groups of six rats were run for 15-min daily sessions in an operant situation under either magnesium pemoline (MP) or saline Conditions. The design consisted of four days of acquisition followed by two days of extinction repeated four times. The results indicated that there was a slight tendency for MP to maintain more resistance to extinction as measured by response rate. The differential resistance is decreased by further acquisition-extinction sessions beyond the second set. The possible facilitating effects of MP are apparently reduced by the repeated exposure to the acquisition-extinction conditions.

Operant rate in the turtle as a function of temperature

Fresh water turtles were trained to press a lever for food reinforcement. Sessions were conducted in a test chamber containing water which varied from 58° to 85°F. Individual response rates were not identical, but the functions tended to be parallel.

Response rate of turtles to fixed ratio reinforcement

Two groups of turtles were given training on fixed ratio schedules of reinforcement. The first group was trained daily in 10 min. sessions but increases in ratio schedule were not made in unitary increments. The second group was trained with a two day interval between 30 min. training sessions with unitary increments in the ratio schedules. The performance of the groups was similar in that subjects in neither group showed a significant increase in response rate. The performance of the first, however, was sustained over higher ratio schedules before showing decreased response rates.

Spontaneous recovery of a classically conditioned response by planarians

Thirty flatworms, Cura foremanii, were classically conditioned with light and shock. Ss were given acquisition training of 20 trials a day for five days and then were divided into two matched groups. One group was given 40 extinction trials on day six. The other group was given 20 extinction trials on day six and 20 extinction trials on day seven. Spontaneous recovery of the response was demonstrated by significant differences between the groups as a result of the 24-hr. delay in extinction trials.

A further study of amino acid analysis and conditioning of planarians

Two groups of planaria regenerated from heads or tails were subdivided into groups in which CS and UCS were either paired or non-paired. After 120 presentations of CS and UCS the animals were subjected to amino acid analysis. Significant behavioral differences were found, but biochemical-behavioral correlations were not significant.