In order to design the intended personality impressions of a robot in human–robot body contact situations, we should identify the impression formation mechanism, both systematically and quantitatively. In this study, we examine how the humanlike appearance of a robot influences the causal relationships between touch sensations and personality impressions, by using a child-type android robot called Affetto. Each of the 40 Japanese participants joined in one of the two conditions in which the humanlike appearance is different. As a result of the factor and path analyses on the evaluation scores of the touch sensations and personality impressions provided by the participants,the causal structures were found to be different for the two conditions: the number of causal relationships was larger for the condition in which the robot appearance was more humanlike. This suggests a personality forming mechanism by which the interpersonal cognitive function is activated more strongly to associate the touch sensations with personality, by perceiving the humanlike features of a robot.