Orienting attention within visual fields: how efficient is interhemispheric transfer?

Institute of Cognitive Studies, Universityof California, BerkeleyFive experiments are reported examining the effect of attentional orienting on lexicaldecisions within visual half-fields. In Experiment 1, following baseline performance,subjects were instructed to improve performance to the right or left of the fixationpoint. In Experiment 2, trials were run in blocks with all items to one side of thefixation point. In Experiment 3, completely valid position indicators as to the locationof the next item to be shown were presented prior to the stimulus item. In Experiment4, to examine practice effects, no instructions or cuing were given to subjects. InExperiment 5, subjects were urged to improve performance, but with no instructionsas to location. As a summary of our results, it can be stated that (a) consistent visualfield differences in lexical decision performance are present, even when subjectswere informed, prior to viewing, of the spatial location of the next stimulus item,(b) Lexical decision information initially input to one cerebral hemisphere is pri-marily processed in that hemisphere. Interhemispheric transfer of this type of lan-guage information seems to be done primarily as the end product of a cognitiveprocess.Under normal circumstances, when viewingobjects or events in the world, we bring fovealvision to bear on whatever has attracted ourattention, thus ensuring the presentation ofidentical information to both hemispheres ofthe brain. Usually, under these conditions fo-veal vision and the orienting of attention arecoordinate.When information is presented to only onevisual half-field, as in a cerebral lateralizationexperiment, there is an abnormal situation inwhich visual fixation is on a defined point andattention must (usually) be directed to eachside of that fixation point. A cooperative sub-ject in such a setting has divided his or herattention to each side of a fixation point,knowing that information will randomly ap-pear to either side. The assumption is madethat the subject's attention is divided equally

[1]  R. Remington.  Attention and saccadic eye movements. , 1980, Journal of experimental psychology. Human perception and performance.

[2]  J B Hellige,et al.  Effects of concurrent verbal memory on recognition of stimuli from the left and right visual fields. , 1976, Journal of experimental psychology. Human perception and performance.

[3]  R. C. Oldfield.  The assessment and analysis of handedness: the Edinburgh inventory. , 1971, Neuropsychologia.

[4]  Lillian Leiber.  Lexical decisions in the right and left cerebral hemispheres , 1976, Brain and Language.

[5]  W. F. Battig,et al.  Handbook of semantic word norms , 1978 .

[6]  M. Posner,et al.  Attention and the detection of signals. , 1980, Journal of experimental psychology.

[7]  Marilyn L. Shaw,et al.  A capacity allocation model for reaction time. , 1978 .

[8]  A. Friedman,et al.  Hemispheres as independent resource systems: limited-capacity processing and cerebral specialization. , 1981 .

[9]  J. Bradshaw,et al.  Visual field differences in verbal tasks: Effects of task familiarity and sex of subject , 1978, Brain and Language.

[10]  J. Hellige.  Cerebral hemisphere asymmetry: Method, theory, and application , 1983 .

[11]  G. Underwood.  Strategies of information processing , 1980 .

[12]  G. Shulman,et al.  Moving attention through visual space. , 1979, Journal of experimental psychology. Human perception and performance.

[13]  M. Posner,et al.  Orienting of Attention* , 1980, The Quarterly journal of experimental psychology.

[14]  C. Chiarello,et al.  Choosing sides: On the variability of language lateralization in normal subjects , 1984, Neuropsychologia.

[15]  S. Hillyard,et al.  Visual evoked potentials and selective attention to points in space , 1977 .

[16]  J B Hellige,et al.  Information processing in the cerebral hemispheres: selective hemispheric activation and capacity limitations. , 1979, Journal of experimental psychology. General.

[17]  C. Barry.  Hemispheric asymmetry in lexical access and phonological encoding , 1981, Neuropsychologia.

[18]  J. Beaumont.  Divided visual field studies of cerebral organisation , 1982 .

[19]  Charles Curtis Eriksen,et al.  The extent of processing of noise elements during selective encoding from visual displays , 1973 .

[20]  M. Coltheart.  Lexical access in simple reading tasks , 1978 .

[21]  S. Dornič,et al.  Attention and performance V , 1976 .

[22]  Alinda Friedman,et al.  Dividing attention within and between hemispheres: testing a multiple resources approach to limited-capacity information processing. , 1982 .

[23]  J. Bradshaw,et al.  The nature of hemispheric specialization in man , 1981, Behavioral and Brain Sciences.

[24]  Nico Brand,et al.  Word matching and Lexical Decisions: A Visual Half-Field study , 1983, Brain and Language.