Following classical fear conditioning, Ss were trained to jump a hurdle to escape the fear-eliciting stimuli. 2 groups were conditioned in the start box of the hurdle apparatus (Same CB) and 2 in a separate, but similar, conditioning box (Diff CB). Under each condition, 1 group had hurdle training after a 3-min., and the other, after a 24-hr., postconditioning delay. For the 2 Diff CB groups, hurdle training involved a generalized stimulus situation. All groups, except Group 3 min.-Diff CB, learned to jump the hurdle in 25 trials. The significant improvement in performance with an increase in postconditioning delay under the Diff CB, but not under the Same CB, condition was attributed to an increase in the strength of the fear response over time to generalized, but not to the original, stimuli.

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Shock intensity (.3 or 1.6 ma.) was combined faotorially with ITI (15, 30, or 45 sec.) in a shuttle-box avoidance task (n -20/group). Following 65 avoidance trials, rats were allowed, in the absence of both shock and the CS, to jump from one compartment of the shuttle box to an adjacent safe box. The 1.6-ma. groups made significantly fewer avoidance responses than the ,3-ma. groups but jumped into the safe box with significantly shorter latencies. The latter finding is contrary to ari interpretation of the inverse relationship between shuttle-box avoidance learning and shock intensity which is based on freezing responses but supports a reinforcement interpretation which emphasizes the role of fear of situational cues.That there is an inverse relationship between strength of shock and avoidance learning by rats in a shuttle box is well documented (e.g.,

The present study provided experimental support for Mowrer's conditioning theory of neurosis. Naive hooded rats were given fear-conditioning (CS-shock) trials in one side of a two-compartment apparatus. Then, in the absence of shock, they were allowed to escape fear by jumping a hurdle to a safe compartment. The hurdle-jumping response was considered to be analogous to anxiety-based symptomatic behavior indicative of psychopathology in that the performance of the response was unrelated to the receipt of further shock. All subjects learned the hurdle-jumping response, and then performance gradually declined until an extinction criterion was reached. Thus, a response instrumental in reducing fear was learned and was maintained over many trials. A subsequent single fear-conditioning trial led immediately to a high level of performance followed by gradual extinction. These findings imply that, when fear is extinguished, instrumental responding can cease even though some response strength remains; they suggest the importance for therapy of focusing on the extinction of both instrumental (symptomatic) behavior and fear. Evidence was also provided for the spontaneous recovery of fear. Some human behavior is paradoxical in the sense that it persists even though, from the viewpoint of an observer, the net effect of the behavior appears to be maladaptive because it does not protect the individual from any objective danger. However, the persistence of such behavior suggests that it has some functional significance for the individual, and its explanation is clearly demanded of any theory that purports to have general relevance. One of the historical attempts at such an explanation is based primarily upon research on learning conducted in the laboratory with infrahuman subjects. Eysenck (1979) calls it the "conditioning theory of neurosis," and its basic tenets can be traced from Mowrer (1939) and Miller (1948,1951, through Wynne (1954) andBrown (1961), to Stampfl and Levis (1967) and Levis and Boyd (1979).According to this theory, when a noxious or aversive event occurs, the neutral stimuli accompanying it acquire the capacity to elicit an emotional response, typically called fear or anxiety. These events constitute a classical conditioning procedure. The neutral stimuli, both discrete and situational stimuli, constitute the conditioned stimulus complex (CS); the noxious This research was supported in part by Grants MH-29232 and MH-36610 from the National Institute of Mental Health. Portions of these data were reported at the 1980 meeting of the Midwestern Psychological Association.The authors are indebted to Edward J. Callen for aid in the analysis of the data and for constructive comments on an earlier draft of this article.