Relation between Extinction Techniques and Extinction of Avoidance Response in Albino Rats

Abstract

The purpose of the present experiment was to examine the effects of extinction techniques-detention vs. fixed CS-on avoidance response. Also attempts are made to discuss the theory of extinction of avoidance response.
The experiment consisted of the following periods : 8 days of conditioning (I), 4 days of manipulation of extinction techniques, 10 days of extinction (I), 2 days of re-conditioning (II), and 10 days of re-extinction (II). Twenty trials were given per day. During conditioning Ss were trained, in a modified Mowrer-Miller's shuttle box, to avoid electric shock (US) by crossing from a compartment to the adjoining one when the buzzer (CS) was presented. After conditioning, they were divided into the following three groups : Detention Group was given twenty CS presentation of 5 seconds each per day without producing electric shock, with a barrier positioned to prevent rats from locomoting to the adjoining compartment ; For Fixed CS Group CS sounded for 5 seconds, even if rats had crossed within 5 seconds ; Ordinary Extinction Group was immediately exposed to the procedure of ordinary experimental extinction.
The results of the experiment were as follows (Fig. 1). Detention technique gave the irregular variation of the occurrence of CR in Extinction (I) and, for the most Ss in this group, brought about very strong resistance to extinction in Re-extinction (II). Fixed CS technique facilitated extinction of instrumental avoidance response for all Ss during Extinction (I), while re-conditioning led to large individual differences. From this group a peculiar subject appeared. Though this subject repressed the occurrence of CR for 1st and 2nd days during Re-extinction (II), it thereafter showed a rapid recovery of CR and reached the asymptote of responding 100% of the trial. Under the ordinary extinction, two Ss showed strong resistance to extinction during Extinction (I), and the Ss sowing strong resistance increased during Re-extinction (II). On trials without CR occurrence, other different responses were observed to CS presentations. It was also found that there appear consistently such responses as closely related to CR, or other behavior like grooming or face washing, and the stillness or freezing (Table 1-3, 5-9).
In the discussion it was proposed that the extinction of avoidance response would be performed on the basis of a relative relation of several kinds of power and that it consisted in keeping composure which would be able to accept a new learning. Consequently, it would be that, even if an extinction technique facilitates extinction of instrumental avoidance response, an elicited anxiety or state anxiety in a situation can never eliminate perfectly and it is held in the trait anxiety of animals. From these inferences, it was attempted to modify Solomon's theory and to interpret this in a wide sense. Therefore, extinction itself is considered to build up a relevant learning set, which reduces anxiety.
In this experiment fixed CS was a better extinction technique than detention.