ABSTRACT
Two influential models that relate the development of visual behaviour in young infants to concurrent changes in the brain are Bronson’s “two visual systems” (1974, 1997) and Johnson’s model emphasizing the role of the primary visual cortex (1990, 1995; Johnson, Gilmore, & Csibra, 1998; Johnson, Posner, & Rothbart, 1991). Bronson was the first to take a specific hypothesis about neural systems developed in adult and animal studies and apply it to infant visual behaviour. His model was well received and many research studies interpreted their results in light of his model. Johnson took an established model of eye movement control (Schiller, 1985) and knowledge of the development of the primary visual area and presented a model that showed how infant visual behaviour was governed by changes in neural systems. Johnson’s model and similar models have generated a wide body of behavioural, psychophysiological, and neuropsychological research in infants and young children. Although both neurodevelopmental models were concerned with a variety of visual behaviour, I use these models in this chapter in their application to visual attention. Also, in this section I present a model I have been using to guide my research that relates developmental changes in a general attention/arousal system to visual attention development.
The most influential theory of developmental change in visual behaviour controlled by brain development is that of Gordon Bronson (1974, 1997; see also Karmel & Maisel, 1975; Maurer & Lewis, 1979; Salapatek, 1975). Bronson’s theory postulated two systems in the brain (e.g. Schneider, 1969) that control visual behaviour. The primary visual system has excellent visual acuity and is devoted to fine pattern visual analysis. The secondary visual system has poor visual acuity and responds to stimulus location and movement. It is dedicated to the detection and localization of targets in the periphery. The primary visual system is over-represented in the fovea and primary visual cortex and the secondary system is represented equally across the retina and in other areas of the brain involved in visual behaviour (e.g. the superior colliculus). According to Bronson, the secondary visual system is phylogenetically older and exists relatively mature at birth. Thus, newborn infant visual behaviour should respond primarily to movement, stimulus location, and peripheral visual information, but not to fine visual detail. The cortical components of the primary visual system show major developmental changes from 1 to 2 months of age until well into the second year. Thus, sensitivity to fine visual detail, attention to forms and objects, and memory for patterns should begin about 2 months of age and increase rapidly from 2 to 12 months. According to this model, the development of the brain areas involved in vision is directly responsible for changes in the infant’s visual behaviour and visual attention.
