Perceptual vigilance and defense revisited: evidence against Blum's psychoanalytic theory of subliminal perception.

Blum's (1954) interpretation of psychoanalytic theory leads him to predict that Ss will defend against a threatening stimulus which is just below a recognition threshold and be vigilant toward the same stimulus when it is farther below the same threshold. 7 males and 9 females were presented the same four Blacky pictures, at the same speed and illumination, and using the same procedure as Blum. The results offered no support for the theory of perceptual vigilance or defense. The many weaknesses inherent in Blum's theory and supporting methodology were discussed.