ABSTRACT
Students who are new to cognitive neuroscience might believe that the eyes do the seeing and the brain merely interprets the image on the retina. This is far from the truth. Although the eyes play an undeniably crucial role in vision, the brain is involved in actively constructing a visual representation of the world that is not a literal reproduction of the pattern of light falling on the eyes. For example, the brain divides a continuous pattern of light into discrete objects and surfaces, and translates the two-dimensional retinal image into a three-dimensional interactive model of the environment. In fact, the brain is biased to perceive objects when there is not necessarily an object there. Consider the Kanizsa illusion (p. 108) —it is quite hard to perceive the stimulus as three corners as opposed to one triangle. The brain makes inferences during visual perception that go beyond the raw information given. Psychologists make a distinction between sensation and perception. Sensation refers to the effects of a stimulus on the sensory organs, whereas perception involves the elaboration and interpretation of that sensory stimulus based on, for example, knowledge of how objects are structured. This chapter will consider many examples of the constructive nature of the seeing brain,
From eye to brain 108
Cortical blindness and “blindsight” 114
Functional specialization of the visual cortex beyond V1 115
Recognizing objects 120
Recognizing faces 126
Vision imagined 132
Summary and key points of the chapter 133
Example essay questions 134
Recommended further reading 134
recognition of objects and faces.
