The mutilated dentition: an alternative approach.

To provide esthetic yet inexpensive restoration of severely carious anterior teeth, stainless steel posts with composite resin cores for crowns were used as interim substitutes for more costly crowns.

Effects of signals preceding and following shock on baseline responding during a conditioned-suppression procedure.

Long-Evans rats were exposed to a succession of conditioned-suppression procedures involving pairings of (1) signal-shock, (2) shock-signal, and (3) a signal-shock-signal sequence in which first and second signals were at first physically identical. Traditional suppression of food-reinforced responding was obtained under the signal-shock arrangement, and exposure to the shock-signal sequence resulted in conditioned enhancement of responding during the signal. The signal-shock-signal condition reliably suppressed responding during the first signal, but produced no differential effect on response rate during the second signal.

Conditioned suppression of an avoidance response.

A signal followed by shock was presented at irregular intervals during a free-operant avoidance schedule. The effects of this procedure were studied in terms of the rate of unavoided shock in the presence and absence of the signal and the rate of response before and during the signal. Three shock intensities were employed.

Effects of cycle length on performance on a temporally defined avoidance schedule.

Three rats were trained on a temporally defined avoidance schedule logically similar to a fixed-interval, limited-hold positive reinforcement schedule. This avoidance schedule was composed of time periods during which responses had no scheduled consequences alternating with time periods during which a response precluded shock. As with fixed-interval length and response rate on positive reinforcement schedules, an inverse relationship was obtained between the length of the no-consequence interval and response rate during the no-consequence interval.

The effect of a pre-shock signal on a free-operant avoidance response.

After 25 free-operant avoidance training sessions, a 1-min signal followed by a brief shock was presented on the average of once every 4 min. During the signal, the avoidance schedule was suspended (20 sessions). Response rates during the signal were markedly reduced.

Lever holding under free-operant avoidance.

Rate of response under a free-operant avoidance procedure decreases as the response-shock interval increases. The present experiment demonstrated an inverse relation between rate of response and lever-holding time. An invariance was found in the total time per session that a subject was in contact with the lever.

METHOD FOR DISCRIMINATIVE AVOIDANCE TRAINING.

Experiments were performed in which the typical procedure for obtaining discriminated avoidance behavior with rats in a lever-pressing apparatus was compared with a new procedure which allowed only avoidance but not escape from the shock. When either escape or avoidance is possible, the rats make a majority of escape responses, but where escape is impossible avoidance behavior is rapidly established.