Effects of a classical conditioned ‘fear signal’ and ‘safety signal’ on nondiscriminated avoidance behavior

Abstract

Rats were trained to avoid shock on a Sidman schedule in a shuttle apparatus; then they were tested with a probe stimulus that in a Pavlovian session for different groups signalled shock. or absence of shock. The danger signal increased the rate of avoidance responding and the safety signal decreased it. Two control procedures are compared.Several investigators have reported that fear conditioned by Pavlovian procedures can affect instrumental behavior (Hammond, 1966(Hammond, , 1967Rescorla & LoLordo, 1965). The procedure involved in these studies is to establish a conditioned fear signal (CS+) by explicitly pairing a signal with electric shock and then looking for facilitation by CS+ of a previously learned avoidance response. Alternatively, fear conditioning can be shown by the suppression of appetitive behavior by CS+ in a CER situation.A related procedure involves the presentation of a signal (CSl which explicitly predicts the nonoccurrence of shock and then looking for a suppression of avoidance responding in the aversive case, or an enhancement of response 'rate in the appetitive CER case whenever the CS-is presented. On the assumption that both CS+ and CS-effects are genuine, Rescorla (1967) has recommended a control procedure with a random CS-US pairing which, presumably, allows the CS to gain no associative control over the behavior since it consistently predicts neither the occurrence nor nonoccurrence of shock.There is some reason, however, to doubt the validity of Rescorla's assumpti~ns. The present experiment is concerned with whether Pavlovian training is given in a situation other than the test situation. Are the same effects obtained when S is a rat rather than a dog? Do the effects occur when a control other than Rescorla's random control procedure is used? Do the danger signal and safety signal effects appear when appropriate allowance is made for possible sensitization effects?Subjects. The Ss were 24 female Long-Evans rats approximately 110 days old at the beginning of the experiment.Apparatus. The shuttle apparatus was 36 in. x 5 in. high with metal walls. The floor was 3/8 in. stainless steel bars spaced on I·in. centers. A 2·in.barrier. located in the center of the box. had two parallel 1/8.in. stainless steel bars wired to a 120 V source through 250 K resistance across its top. Responses were detected by a photocell located 1·3/4 in. above the barrier.The Pavlovian conditiOning apparatus was a IO-in. square box with a grid floor similar to the shuttle box floor and metal wa1Is which were included as an element in the grid floor.Shock was provided to the apparatus by a Grason-Stadler shocker-scrambIer. model EI064GS. All programming and recording was done by appropriate electronic equipment isolated from the apparatus.Procedure. AD Ss were given frye training sessions with a Sidman procedure in the shuttle apparatus with an R-S interval of 30 sec and an s.s interval of 5 sec. Shock intensity was 1.25 rnA and shock duration was .25 sec. Each session lasted until S had made 300 responses.Fol...

Unsignalled Avoidance in a Shuttlebox: A Rapid Acquisition, High‐efficiency Paradigm

“…The advantages of the unsignalled shuttlebox arrangement include the following: (1) There are no "failures to learn" so frequently encountered in both shuttlebox signalled escape-avoidance (Brush, 1966) and unsignalled bar-press avoidance (Weissman, 1962); (2) No response shaping is required, as is frequently the case in unsignalled bar-press avoidance (Riess, 1970a); (3) Acquisition proceeds much more rapidly than is the case in either of the two traditional arrangements, and this is true of both response rates and shocks avoided; (4) There is no initial period of higher shock rates, as is often the case in both signalled shuttlebox avoidance and unsignalled bar-press avoidance; (5) After acquisition, there is a minimum of "bursting" (Sidman, 1958) and other gross local response rate fluctuations found in lever-press avoidance which detract from within-session stability and add variability to the results; (6) There are no gross topographical problems analogous to the lever holding often found in barpress avoidance; (7) Terminal performance is characterized by a higher percentage of shocks avoided than is customarily found in either traditional type of avoidance; and, lastly, (8) There are no "avoidance decrements" frequently reported for signalled escape-avoidance (Anderson and Nakamura 1964). In addition, unsignalled shuttlebox avoidance provides a highly sensitive baseline for studies where behavior other than avoidance itself is of primary importance and these include shock intensity effects (Johnson and Church, 1965;Martin and Riess, 1969;Riess and Martin, 1969;Scobie, 1969); self-punitive behavior (Riess, 1970b); aversive properties of stimuli other than shock (Riess, 1970 c, d); Pavlovian conditioning (Grossen and Bolles, 1968;Herendeen and Anderson, 1968;Riess, 1969;Riess and Martin, 1969;Riess and Farrar, in press;Scobie, 1969); response topography requirements (Riess, 1971); and observational learning (Riess, in press). It is suggested that most of the problems typically encountered by investigators confining their efforts to the study of signalled shuttlebox escape-avoidance or unsignalled lever-press avoidance can be eliminated by a combination of the free-operant paradigm and the shuttlebox apparatus.…”

“…Scobie (1970) has since combined the shuttlebox apparatus and the free-operant paradigm in successful avoidance conditioning with goldfish. The freeoperant shuttlebox combination has also been employed with rats with increasing frequency in recent years (Grossen and Bolles, 1968; …”

“…Scobie (1970) has since combined the shuttlebox apparatus and the free-operant paradigm in successful avoidance conditioning with goldfish. The freeoperant shuttlebox combination has also been employed with rats with increasing frequency in recent years (Grossen and Bolles, 1968;Herendeen and Anderson, 1968;Johnson and Church, 1965;Martin and Riess, 1969;Riess, 1969Riess, 1972;Riess and Bath, 1970;Riess and Farrar, in press;Riess and Martin, 1969;Scobie, 1969) The subjects received 18 daily 21-min unsignalled avoidance sessions. Each hurdle cross (i.e., when both forepaws were seen by the experimenter to have touched the floor of the new compartment) postponed the next shock 20 sec (R-S interval) and shocks were presented every 5 sec in the absence of a response (S-S interval).…”

Acquisition and extinction of facilitation in the C57BL/6J mouse

“…First, in Experiment 1, nonreinforced presentations of the facilitator were embedded in a discrimination procedure that has been shown to sometimes endow the nonreinforced stimulus with inhibitory properties (Grossen & Bolles, 1968;Hammond, 1967Hammond, , 1968. This raises the possibility that the facilitator may have acquired sufficient inhibition to offset its response-enhancing function in Group D. Second, there were 16 sessions of extinction in Experiment 1, but only 6 sessions in the study by Rescorla (1986a) and 8 sessions in the study by Holland (1989b).…”

Effects of stimulus associated with amobarbital administration on avoidance behavior

“…For example, the presentation of a stimulus which has previously been paired with shock (pavlovian fear conditioning) during ongoing avoidance behavior enhances the response rate (e.g., Grossen & Bolles, 1968;Kamano, 1970;Rescorla & LoLordo, 1965). On the other hand, presenting a stimulus which has previously been paired with food suppresses avoidance responding (Bull & Overmier, 1969;Grossen, Kostansek, & Bolles, 1969).…”