E-ISSN : 2733-4538
It has been known that aversive environmental factors influence anxiety reaction, including the development of neurosis and schizoprenia. The tendency for an unpredictable stressor to produce more severe anxiety than a predictable one would seem to have considerable generality. This hypothesis, presented by Imada and Nageishi(1982), states that the animal is less stressed when shock is not only time-predictable but also locus-predictable. Answering this hypothetical question is obviously important for understanding how aversive anticipation produces anxiety. The present experiment utilized the time, locus, predictability and unpredictability design to study effects of aversive anticipation. : stress responses of animals that could predict when and where electric shocks would occur (because each shock was presented fixedly) were compared with stress responses of animals that could not prediet when and where the same shock would occur (because each shock was presented randomly). This study measured changes in body weight, stomach ulceration and heart rate in rats of two by two design groups(time, locus, predictability, unpredictability groups) and one control group (non-shock group). All these measures-weight loss, stomach ulceration and heart rate showed the same effects. Rats that received electric shock unpredictably showed greater somatic reactions than animals which received the same shock predictably. The time-unpredictable group had higher levels than time-predictable group (P<.05), but the locus-unpredictable group had not higher levels than the locus-predictable group and the difference between the locus-predictable and the locus-unpredictable was hardly significant. Experimental effect in the present study was not as great as that of Weiss(1970). As would be expected, the shock conditions raised heart rate levels. Greater rises of heart rates were seen in the unpredictable groups than in the predictable groups. After of 5 mins, 30 mins and 2 hrs, the differences were significant (P<.05), but the groups did not show significant at the end of 19 hrs. The hypothesis, presented by Imada and Nageishi(1982), about the time-predictability preference was verified(P<.05), whereas that of locus-predictability preference was not. The suggestion of these results, which await more detailed analysis, is that time condition is a more important factor in producing anxiety than the locus condition.