Decision making is justified using a variety of external information. In this study, we set up an experimental situation that justifies the first decision based on a bar graph as external information. We examined how top-down factors such as impressions and attitudes affect the judgment and graph comprehension. Our hypothesis includes the following two points;(1) The first decision making may be made based on the top-down factors. (2) In the graph comprehension phase, in order to justify the first decision, the bias to selectively consider information consistent with the decision is strengthened, and the influence of top-down factors may disappear relatively. As results of two experiments, there was no significant effect of the impression on the decision, but the effect from the attitude was observed. In addition, there was no significant effect of impression and attitude on understanding of the graph after the decision. These results were discussed, compared to previous research findings by Fukuoka et al. (2019), dealing with situations where the decision was made after the graph comprehension.
