Olivier Georgeon's research blog—also known as the story of little Ernest, the developmental agent.

Keywords: situated cognition, constructivist learning, intrinsic motivation, bottom-up self-programming, individuation, theory of enaction, developmental learning, artificial sense-making, biologically inspired cognitive architectures, agnostic agents (without ontological assumptions about the environment).

Friday, October 16, 2009

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:

- 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.

- 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.


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

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