A "Threshold Effect" of Selective Attention on the Dichotic REA With Children

Abstract

This study examined the threshold effect hypothesis of selective attention on the magnitude of the dichotic right-ear advantage (REA) with young children. We hypothesized that children, in contrast to adults, might find it more difficult to selectively attend to stimuli that were presented to the left side of space (ear) even with an increase in the time available to orient attention. Attention was manipulated by presenting a lateralized tone cue to the targeted ear at shorter (150, 450, and 750 msec) and longer (500, 1,250, and 2,000 msec) stimulus-onset asynchronies (SOAs). Previous work with adults demonstrated that the magnitude of the REA was attenuated when sufficient opportunity to orient attention to the left ear (LE) was available. In contrast, results of this study indicated that for children (M age = 8 years 7 months) the magnitude of the REA was not attenuated even when SOA to the LE was lengthened. Specifically, REAs obtained beyond 750-msec SOA (i.e., 1,250 and 2,000-msec SOA) were not substantially attenuated from that obtained at 450 to 500-msec SOA. By assessing shorter and longer SOAs, we demonstrated that young children were unable to maintain attention to the left side of space (i.e., LE) for more than a brief period of time. In essence, children lack flexibility in overcoming the attentional bias toward the right ear even when more time is available for processing of stimuli. This may be the result of incomplete development of one or more cortical regions in the brain associated with interhemispheric attentional processing capacity.Dichotic listening paradigms were quite successful in yielding perceptual asymmetries for language-based discriminations with normal as well as with clinical populations (see Bryden, 1988;Obrzut, 1988 for reviews). The dichotic listening task in-

Hemispheric asymmetry of the right ear advantage in dichotic listening

“…The fact that reaction time also favored the right ear input was explained by the additional processing time required by a ''stimulus-directed compatibility effect'' (Swanson et al, 1978, p. 274). Additional support for the attentional model is provided by a body of research showing that degree, and even direction, of interaural asymmetry can be substantially altered by a variety of stratagems involving the manipulation of attention (Dean and Hua, 1982;Murray, 1983;Obrzut et al, 1986;Woldorff et al, 1991;Mondor and Bryden, 1991;Obrzut et al, 1993;OÕLeary et al, 1996;Gadea et al, 1997;Obrzut et al, 1999;Yund et al, 1999;Voyer and Flight, 2001;Voyer et al, 2002; but see Asbjornsen et al, 1990) for a counter view. In summary, most of the theoretical posits of the structural model concerning the REA appear have been supported.…”

The Role of Dichotic Listening Performance and Tasks of Executive Functions in Reading Impairment: A Discriminant Function Analysis

“…The directed attention (Bryden, Munhall, & Allard, 1983;Obrzut, Hynd, Obrzut, & Pirozzolo, 1981) or forced attention procedure (Hugdahl & Andersson, 1986) have, in addition to controlling for random biasing of attention, also shown to be useful for assessing auditory attention skills in several clinical samples, including learning disabled and reading impaired samples (Asbjørnsen & Bryden, 1998;Obrzut, Boliek, & Bryden, 1997), and psychiatric samples (Bruder, 1988;Bruder, Schnur, Fergeson, Mukherjee, et al, 1994;Hugdahl & Wester, 1992;Hugdahl, Wester, & Asbjørnsen, 1990;Loberg, Hugdahl, & Green, 1999;Nachshon, 1988;Thakur & Mukundan, 1988). Performance on directed attention dichotic tasks discriminates between groups of learning disabled children and both age and reading matched controls (Asbjørnsen & Bryden, 1998;Bakker & Kappers, 1988;Boliek, Obrzut, & Shaw, 1988;Helland & Asbjørnsen, 2000, 2001Hiscock & Kinsbourne, 1982;Hugdahl, Ellertsen, Waaler, & Kløve, 1989;Hynd, Obrzut, Weed, & Hynd, 1979;Kershner & Graham, 1995;Kershner & Micallef, 1991;Kershner & Micallef, 1992;Kershner & Morton, 1990;Obrzut, 1988;Obrzut, Boliek, & Bryden, 1997;Obrzut, Conrad, Bryden, & Boliek, 1988;Obrzut, Horgesheimer, & Boliek, 1999;Obrzut, Hynd, & Obrzut, 1983;Obrzut, Hynd, Obrzut, & Leitgeb, 1980). Few studies have addressed how DL performance could be related to the reading impairment per se and/or addi...…”

Comment on Delayed Left-Ear Accuracy in Dichotic Listening

“…Thus, the work of numerous authors (1,11,13) offers insight as to why Moulden and Persinger's developmental findings (10) paralleled those from studies using left-ear-focus conditions (1) despite methodological differences in the stimuli and how the tests were administered. The literature mentioned in this comment supports the notion that the developmental effects observed by Moulden and Persinger (10) may be more closely related to the emergence of an interhemispheric resource allocator than the development of a baseline perceptual asymmetry per se.…”

“…tion (8) in children. Work by Obrzut, et al (11) suggests such phenomena may be related to the development of the flexible attentional systems necessary for overcoming baseline perceptual asymmetries. An additional comparison that can be made across the results from the different test paradigms is the sensitivity of the left-ear dichotic-listening responses to developmental sex differences.…”

“…Despite the methodological differences outlined above, Moulden and Persinger's results (10) paralleled previous findmgs of improved forced-leftear recall accuracy across age groups (1) and in relation to readmg acquisi-tion (8) in children. Work by Obrzut, et al (11) suggests such phenomena may be related to the development of the flexible attentional systems necessary for overcoming baseline perceptual asymmetries. An additional comparison that can be made across the results from the different test paradigms is the sensitivity of the left-ear dichotic-listening responses to developmental sex differences.…”