The E.E.G.,Visual Imagery and Attention

The claim that persons may be broadly classified into imaginal types on the basis of their E.E.G. records is examined. It is found that a given individual may show a different “type” of E.E.G. from one occasion to the next. A group of persons, known to indulge spontaneously in certain recognizable varieties of vivid visual imagery, contained the same proportion of the different E.E.G. “types” as a large control sample. It was found that subjects could experience changing or static visual images without any blocking of the alpha rhythm providing that difficulty was not experienced in perceiving the images. Flat E.E.G. records were not found to be associated with regular respiration.

It is proposed that the previously reported association between alpha blocking and the appearance of visual imagery could have arisen from the fact that difficulty in thinking (a) activates mechanisms which desynchronize E.E.G. potentials, (b) provokes the emergence of visual images.