The aim of the present study was to clarify the factor that might underlie the reflection-impulsivity, as assessed by performance on the Matching Familiar Figures (MFF) test. On the psychodynamic processes which determined the cognitive style dimension of the reflection-impulsivity, Kagan has hypothesized that the fear of making an error was an important determinant of the reflective tendency. However, few studies supporting Kagan's hypothesis were found. In this study it was hypothesized that there were cognitive style differences of inner standard on response accuracy brought to the task together with the motivation to do well. To examine the difference of this standard, a risk-taking task and a perceptual recognition task were administered to 44 reflective and 42 impulsive second-and fifth-graders (second-graders: 24 reflectives, 20 impulsives; fifth-graders: 22 reflectives, 22 impulsives). In addition, the causal attribution task for their failures on the unresolvable maze task was administered to assess the impulsive and reflective children's directions to the causal attribution, and then to infer the cognitive style differences of having high hope of success. On the risk-taking task, the impulsive boys took more risks than the impulsive girls and the reflective children. Secondly, to compare with the impulsive children, the reflective ones showed more delayed responses on a perceptual recognition task. These results suggested that there might be cognitive style differences in the standard of the response accuracy which would be used as cues for selecting the solution strategies. It was considered, therefore, that the impulsive children might underestimate task difficulty due to low criterion for accuracy. The second conclusion which might be drawn from the results of the causal attribution was that the reflective children wanted themselves to be perceived as effortful in the intellectual task situation because they emphasized the intrinsic value of effort. Through the results obtained by the present experiments, the mental model about the higher decision processes, in which solution strategies might be determined under a response uncertainty situation, was presented.