Elsevier

Acta Psychologica

Volume 42, Issue 4, July 1978, Pages 313-329
Acta Psychologica

Early selective-attention effect on evoked potential reinterpreted

https://doi.org/10.1016/0001-6918(78)90006-9Get rights and content

Abstract

In a dichotic listening situation stimuli were presented one at a time and at random to either ear of the subject at constant inter-stimulus intervals of 800 msec. The subject's task was to detect and count occasional slightly different stimuli in one ear. In Experiment 1, these ‘signal’ stimuli were slightly louder, and in Experiment 2 they had a slightly higher pitch, than the much more frequent, ‘standard’, stimuli. In both experiments signals occured randomly at either ear. Separate evoked potentials from three different locations were recorded for each of the four kinds of stimuli (attended signals, unattended signals, attended standards, unattended standards). Contrary to Hillyard et al. (1973), no early (N1 component) evoked-potential enhancement was observed to stimuli to the attended ear as compared with those to the unattended ear, but there was a later negative shift superimposed on potentials elicited by the former stimuli. This negative shift was considered identical to the N1 enhancement of Hillyard and his colleagues which in the present study was forced, by the longer inter-stimulus interval used, to demonstrate temporal dissociation with the N1 component. The ‘Hillyard effect’ was, consequently, explained as being caused by a superimposition of a CNV kind of negative shift on the evoked potential to the attended stimuli rather than by a growth of the ‘real’ N1 component of the evoked potential.

References (21)

There are more references available in the full text version of this article.

Cited by (0)

The experiments were carried out in the Institute for Perception TNO, Soesterberg, in the summer of 1975 when S. Mäntysalo worked there as a visiting scholar, supported by Suomen Tiedeakatemia (The Finnish Academy of Science and Letters). Please send requests for reprints to A.W.K. Gaillard, Institute for Perception TNO, Kampweg 5, Soesterberg, The Netherlands.

∗∗

Present address: Department of Psychology, University of Helsinki, Ritarikatu 5, 00170 Helsinki 17, Finland.

View full text