This study examined how the level of desire to acquire an ability and the perceived probability that it may be acquired affect self-assessment of the ability. From three categories, (1) desire to acquire is strong and desired level of acquisition is high, (2) desire is strong and desired level of acquisition is average, and (3) desire is weak, ten abilities each were chosen by each of 77 undergraduates. They also indicated the perceived probability that each ability might be acquired. Then, self-assessment behavior for each ability was measured with the choice and preference among four tasks that differed in terms of ability diagnosticity. The main results were as follows: (a) High-diagnostic tasks were chosen more often than the others, regardless of the desire to acquire and the probability. (b) Preference for high-diagnostic tasks was stronger when the desired acquisition level was high or average and the perceived probability was high. (c) Subjects' reason for self-assessment was their need to acquire accurate selfknowledge. The results suggest that expectation of future self-enhancement affects the likelihood of self-assessment behavior.
