Does covert attention speed up information processing?

21. April 2010

Attended stimuli are perceived earlier than unattended ones. This phenomenon of “prior entry” is well established since the 19th century. Early in the 20th century, the psychologist Edward Titchener appointed it as his fourth law of attention: “The stimulus, for which we are predisposed, requires less time than a like stimulus, to produce its full conscious effect. Or, in popular terms, the object of attention comes to consciousness more quickly than the objects that we are not attending to”. According to recent research, prior entry seems to be involved in a multitude of misperceptions such as the flash-lag effect, the shooting-line illusion, and order errors in the attentional blink.

Interestingly, however, it is not yet known whether attention does indeed speed up (conscious) perception. The finding itself can equally well be explained by a slowing down of the unattended comparison stimulus. I will propose a method based on Bundesen’s Theory of Visual Attention which allows to independently estimate possible acceleration and deceleration effects.