One-trial simultaneous and backward fear conditioning as reflected in conditioned suppression of licking in rats

Abstract

In three experiments, groups of albino rats received one strictly simultaneous pairing ofa 4-sec auditory conditioned stimulus (CS) and a 4-sec I-rnA shock unconditioned stimulus (US). Other groups received a backward pairing, in which the US began before the CS, or a forward pairing, in which the CS began before the US. Control groups received only the US or received both the CS and the US but widely separated in time. Later, the CS was presented while the rats licked a drinking tube for water, and CS-elicited suppression of licking was taken as an index of the Pavlovian conditioned response (CR). It was found that groups receiving a single forward or a single simultaneous pairing suppressed more than groups that had received a backward pairing; and the backward groups, in turn, suppressed more than the control groups. It appears, then, that excitatory fear conditioning, as reflected in conditioned suppression of licking in rats, can be produced in a single trial by both backward and simultaneous conditioning procedures.

One-trial backward excitatory fear conditioning transfers across contexts

“…Perhaps if the differences between them were enhanced, backward excitatory fear conditioning would not survive. Second, although we have found statistically significant evidence for one-trial backward excitatory fear conditioning both here and in several other reports from this laboratory (Albert, 1990;Ayres et al, 1987;Mahoney & Ayres, 1976;Shurtleff & Ayres, 1981;van Willigen et al, 1987), none of those effects has been large. It is yet unclear whether these small effects simply reflect our ignorance about appropriate conditioning parameters or whether these effects are as large as they get.…”

“…According to these writers, there is little evidence in the experimental literature for one-trial Pavlovian fear conditioning. In contrast to Sturgis and Scott, we believe that there are numerous examples of one-trial fear conditioning in the animal experimental literature, including several reports from our own laboratory (Albert, 1990;Ayres, Haddad & Albert, 1987;Burkhardt & Ayres, 1978;Mahoney & Ayres, 1976;Shurtleff & Ayres, 1981;van Willigen, Emmett, Cote & Ayres, 1987). The present results will add to that body of data.…”

“…The lick tube was absent during conditioning. [For a discussion of the validity of the EU control procedures, see Mahoney and Ayres (1976). ]…”

“…Even so, evidence is mounting that backward fear conditioning procedures using a small number of trials can indeed establish measurable conditioned fear to the backward-paired CS (for a review, see Spetch, Wilkie & Pinel, 1981). Again, the demonstrations from our own laboratory seem especially relevant because they were based on only a single backward conditioning trial (Albert, 1990;Ayres et al, 1987;Mahoney & Ayres, 1976;Shurtleff & Ayres, 1981;van Willigen et al, 1987).Moreover, in contrast to an earlier claim for one-trial backward excitatory fear conditioning (Keith-Lucas & Guttman, 1975), these studies used white noise or tone as CSs, stimuli that are thought to have no particular biological relevance to the rat Ss.One undesirable aspect of the existing evidence for one-trial backward excitatory fear conditioning, however, is that every demonstration so far has involved testing for conditioning to the CS in the same context in which the conditioning took place. Clearly, human phobias transfer readily across contexts.…”

“…Even so, evidence is mounting that backward fear conditioning procedures using a small number of trials can indeed establish measurable conditioned fear to the backward-paired CS (for a review, see Spetch, Wilkie & Pinel, 1981). Again, the demonstrations from our own laboratory seem especially relevant because they were based on only a single backward conditioning trial (Albert, 1990;Ayres et al, 1987;Mahoney & Ayres, 1976;Shurtleff & Ayres, 1981;van Willigen et al, 1987).…”