Thesis (Ph.D.)--Boston University. / The general problem investigated in this research was the relationship of set and the defense of repression to perceptual recognition. A. comparison was made of the perceptual recognition threshold scores and the slope scores af a High Repressor and a Low Repressor group on three series of pictures -- an Aggressive series, a Neutral with a Theme series, and a Neutral without a Theme series. Three hundred and eighty-six students were administered a sentence-completion test which was used as the defense measure. This test was devised specifically to assess the repression of aggression. On the basis of extreme scores on this test, twenty-four subjects were selected as a High Repressor group and twenty-four subjects as a Low Repressor group. A Medium Repressor group was selected from the scores tbat fell between the High Repressor and the Low Repressor groups. Each member of these groups was individually administered a perceptual recognition task [TRUNCATED]