Personal adaptation levels were cen

Personal adaptation levels were central to Kahneman and Miller’s (1986) “norm theory.” which proposed that reality is experienced against a background of what is usual (and also what might have been, J2B, described earlier). A stimulus that differs from its current norm is perceived as novel or even surprising, and affective response to abnormal events were thought to be greater than for the same events when they are normal to a person. This expected emotional amplification relative to a judgmental standard implies that novel events will elicit stronger feelings than familiar ones. More generally, a new different stimulus takes on special importance, contrasting with an established standard of comparison. However, the special pleasure or pain from a novel input was predicted by norm theory to decline (within the limits created by the nature of the stimulus) as the judgment norm adjusts to stimuli that become routine over time, in a process of “hedonic adaptation.”
Landy (1978) and Bowling, Beehr, Wagner, and Libkuman (2005) have examined response changes of this kind in terms of “opponent process” theory (Solomon & Corbit, 1974). This envisages that the primary response to a stimulus is accompanied by an opposite process, which encourages a return to a person’s equilibrium state. The opponent process is assumed to operate more slowly than the primary process, and it can “overshoot” beyond an original level. Mental processes of that kind are difficult to examine empirically, especially when experimental manipulation of single variables is not possible, as in organizations. Although several findings about adaptation are consistent with opponent process theory, direct support or refutation is not yet available with respect to its specific mechanisms.