Age effects in dichotic listening to consonant-vowel syllables: interactions with attention.
A relatively large sample of individuals (N = 240) ranging from 7 to 70 years were studied with the dichotic listening (DL) technique as a measure of language lateralization. Two questions were asked: (a) Is there a developmental effect for the right-ear advantage (REA) with age? (b) Is there a developmental effect for attentional modulation of the REA? The participants were all right-handed, healthy individuals tested in Sweden and Norway. The stimuli were dichotic presentations of consonant-vowel (CV) syllable pairs. There were 3 different attentional conditions: nonforced (NF) attention, with no specific instructions about focusing of attention; forced-right (FR) attention, with instructions to focus attention on the right-ear stimulus; and forced-left (FL) attention, with instructions to focus attention on the left-ear stimulus. The results showed a REA in all age groups, except for the 9-year-olds, in the NF condition. In the FR condition, all age groups showed a REA. The youngest age groups did not, however, increase the REA to the same degree as the older age groups, as indicated by the significant age x ear interaction. In the FL condition, all age groups, with the exception of the youngest groups, showed a left-ear advantage (LEA). It is concluded that the REA effect in DL is subject to developmental effects and that attentional effects on laterality also develop with increasing age.
Hugdahl
K
K
Department of Biological and Medical Psychology, University of Bergen, Norway. hugdahl@psych.uib.no
Carlsson
G
G
Eichele
T
T
D000293:Adolescent; D000328:Adult; D000367:Age Factors; D000368:Aged; D001288:Attention; D002648:Child; D004007:Dichotic Listening Tests; D005260:Female; D006801:Humans; D008297:Male; D008875:Middle Aged; D010700:Phonetics; D000091402:Prohibitins; D013063:Speech Discrimination Tests; D013067:Speech Perception / Q000502:physiology*; D011795:Surveys and Questionnaires