Behm. Res. Thu. Vol. 27, No. I. pp. 9-18, 1989 COOS7967/89 53.00 + 0.00 Printed in Great Britain. All nghtsreserved Copyright & 1989 Pergamon Press plc THE INCUBATION THEORY OF FEAR/ANXIETY: EXPERIMENTAL INVESTIGATION IN A HUMAN LABORATORY MODEL OF PAVLOVIAN CONDITIONINGt BONIFACIO SANDIN* and PALOMA CHOROT Departamento de Psicologia de la Personalidad, Facultad de Psicologia, Universidad National de Education a Distancia (UNED); Ciudad Universitaria, Madrid, Spain zyxwvutsrqponmlkjihgfedcba (Received IS March 1988) Summary-The aim of this work was to test Eysenck’s incubation theory of fear/anxiety in human Pavlovian B conditioning of heart rate (HR) responses. The conditioned stimuli (CSs) were phobia- relevant slides (snakes and spiders) and the unconditioned stimuli (UC%) were aversive noises. The subjects were presented with two levels of noise intensity during acquisition and three levels of nonreinforced CS presentation (CS-only) in a delay differential (CS+/CS-) conditioning paradigm (2 x 3 x 2). Consistent with the incubation theory, conditioned HR acceleratoryresponses weresustained (resistance to extinction) for high-noise intensity and short-presentations of CS-only subjects. During the extinction phase, HR acceleratoryresponses quickly extinguished in low-noise intensity groups after the first presentations of CS-only. These findings were interpreted as support for the incubation theory of phobic fear. Eysenck has recently postulated a modern conditioning theoryof neurosis (Eysenck, 1979, 1985) knownas the “incubation” theory of fear/anxiety which is a refinement of the two classical models offeredby Watson (Watson and Rayner, 1920) and Mowrer (1940)respectively. In the new conditioning model of neurosis the traditional view of Pavlovianextinction is amended and is added the law of incubation or enhancement (“paradoxical enhancement”). According to the law of incubation, the exposure of the conditioned stimulusonly (CS-only) may, under certain conditions, have the effect of increasing the strength of the conditioned response (CR), rather than reducing it. The major conditionsfavouringincubation are: (1) Pavlovian B conditioning; (2) strong unconditioned stimuli; and (3) short exposures of the CS-only. In addition, the model incorporates the Seligman’s hypothesis of “preparedness”; certain CSs (e.g. snakes, spiders, etc.) are biologically prepared to be more readily connected with fear/anxiety responses than others. Prepared stimuli are more readily acquired and more resistant to extinction than unprepared ones(tjhman, 1979; Seligman, 1971). Eysenck (1985) states that neurotic behavior is acquired and maintained through Pavlovian B conditioning rather than with Pavlovian A conditioning. Pavlovian A conditioning is exemplified by the typical example of Pavlovian conditioning, i.e. the dog’s salivary response conditioned to the sound of a bell by pairing the bell and feeding the animal. In Pavlovian A conditioning the motivation has to be manipulated externally to the conditioning paradigm and is not produced by the conditioning paradigm itself. Moreover, in PavlovianA type CRs and UCRs are rather different and dissimilar, e.g. the UCR involves eating and the CR involves salivation. In Pavlovian B conditioning (i.e. aversive conditioning) stimulation by the UCS is not contingent on the subject’s instrumental acts,and hence has less dependence upon the motivational state of the organism; furthermore, CRs and UCRs are similarsincethe CR appears to act as partial *Correspondence: Departamento de Psicologia de la Personalidad, Universidad National de Education a Distancia (UNED), Apartado 60148, 28040 Madrid, Spain. tPart of this paper was first presented at the 17th Annual Meeting of European Association for Behaviour Therapy in Amsterdam, August 1987. 9