Causal Analyses in Interpersonal Relations: On Importance of the Control Condition

Most studies of interpersonal relations employ the high and low levels of an independent variable and attribute the high–low difference to the high level only. However, such a difference can be due to the positivity effect of the high level, the negativity effect of the low level, or both. To specify the loci of the high–low difference, a control condition is necessary. In my research into interpersonal attraction and impression formation, I ascertained the magnitude of the positivity and negativity effects relative to the response to a control condition of no-individuating information. The negativity effects of dissimilar attitudes and negative traits were greater than the positivity effects of similar attitudes and positive traits. One source of this positive–negative asymmetry was the person positivity bias in the participants. A greater weighting of negative than positive level could be another factor. Research is needed to separate the contributions of these two variables to the positive–negative asymmetry demonstrated.