Two Visual Systems and Two Theories of Perception

Norman, J. (2002). Two Visual Systems and Two Theories of Perception: An Attempt to Reconcile the Constructivist and Ecological Approaches. Behavioral and Brain Sciences, 25 (1), 73–144.

I am reviewing this paper because it gives some directions for implementing Ernest's visual system. In this paper, Norman analyzes the so-called dual-process approach to vision. He describes these two processes as follows:

Purpose:
- Process 1: picks up visual information to generate adapted behavior.
- Process 2: recognizes and identifies objects and events in the environment.

Human neuro-anatomy:
- Process 1: dorsal (occipito-dorsal and parietal, toward bimodal areas vision/motor).
- Process 2: ventral (occipito-ventral, toward bimodal areas vision/audition).

Information theory:
- Process 1: related to Gibson's (1979) ecological cognition theory. Invariants are picked-up in the visual scene to constitute affordances.
- Process 2: related to Helmholtz's constructivist theory of vision. Pictoral clues are perceived to construct/recollect a representation of objects.

Consciousness:
- Process 1: triggers behavior while the subject has no explicit consciousness of why this behavior is triggered.
- Process 2: the subject is conscious of seeing the objects that this process identifies.

How to use it for Ernest?

So far, only process 1 has been implemented in Ernest. Norman's paper suggests that process 2 should be implemented in parallel. Process 2 requires an iconic memory associated with skills for learning new icons and recognizing icons. Process 1 and process 2 should be interconnected. The process of recognizing icons (process 1) may require to trigger information-pick-up behavior (process 2). Moreover, recognized icons should participate to the selection of forthcoming behavior.

References

Gibson, J. J. (1979). The ecological approach to visual perception. Boston: Houghton Mifflin.