The effects of shock intensity and intertrial interval duration on the operant level of a shuttle-avoidance response

Role of unconditioned stimulus escape and avoidance in discriminative avoidance learning in the gerbil (Meriones unguiculatus).

“…One final point of discussion concerns the enhancement of shuttle response probability by CS presentations in all CC groups except CC-3.0. A similar CS-produced increase in response probability in the shuttle box in the absence of an avoidance contingency has been reported by Cicala, Masterson, and Kubitsky (1971) and Cicala, Ulm, and Drews (1971). Since adventitious reinforcement of shuttling did not occur in the present experiment in either the .1-or 1.0-sec.…”

The effects of CS and US intensity on shuttlebox avoidance

“…Thus, while intense CSS increase discriminability of the avoidance contingency, they may also increase anticipatory responding. This interpretation is supported by the recent report of Cicala & Ulm (1971) indicating that shuttlebox crossings are greater during presentation of a 10-sec 80-dB white noise that has never been paired with shock than during nonstimulus periods. A count of the avoidances on the first trial as a function of CS intensity in the present experiment showed that 0, 7, and 8 Ss of the 70-, 80-, and 90-dB CS groups, respectively, avoided on the first trial.…”

The effects of prefear conditioning shock intensity on initial shuttle response rate

“…The present results are strikingly similar to the findings of eieala, Ulm, & Drews (1971), who measured crossing rate in an avoidanee eonditioning situation with intermittent shock presentations and no behaviorally eontingent reinforcement. They found that erossing rate deereased as shoek intensity increased, that the deerease in rate during eS-on periods paralleled the decrease during eS-off periods, and that the eS-on rate was eonsistently higher than the eS-off rate.…”

“…Shuttle avoidance leaming has been shown to be inversely related to shock intensity (Moyer & Korn, 1964;Cicala & Kremer, 1969) and directly related to intertrial interval (ITI) duration (Murphy & Miller, 1956;Brush, 1962). Arecent experiment (Cicala, Ulm, & Drews, 1971) demonstrated that these effects emerge in shuttle-avoidance responding in the absence of escape or avoidance contingencies. This finding suggests that shock intensity and ITI duration affect shuttle-avoidance learning by modifying the operant level of the shuttle response, providing differential probabilities of response reinforcement.…”