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).

Thursday, October 8, 2009

Perception/action coordination

video
In this experiment, Ernest can touch to his right and to his left in addition to to his front. As before, squares flash yellow when Ernest touches them, and red when Ernest bumps into them (see this post for a detailed legend of the video).

Furthermore, the turn schemas now have feedback status. These status are:
- S, if Ernest turns toward an empty square.
- F, if Ernest turns toward a wall. The wall flashes pink to indicate that Ernest has rubbed it while turning.
In both cases, the turn action is performed.

As before, when Ernest starts, he does not know the linkages between the different schemas.

This experiment shows that Ernest is able to learn to consider certain schemas as perceptions and other as actions, and to learn the linkage between these perceptions and these actions.

At the beginning of the video, Ernest moves frantically. He keeps bumping and scratching walls. He is unable to predict the consequences of his acts and he keeps expressing his "surprise" by saying "Ho!".

After a while, he learns to touch forward before moving forward, to touch to the right before turning to the right, and to touch to the left before turning to the left.

Then, he learns a habit consisting of touching to the left when he is facing a wall. If the square to the left is empty then he turns left. If the square to the left is a wall then he touches to the right. If the square to the right is empty then he turns right. With this strategy, he manages to go all the way around his environment.

The settings for generating this behavior were not easy to find. They are as follows:

- [touch empty (forward, left, or right), 0] Ernest is indifferent of touching empty squares.
- [sense wall (forward, left, or right), -1] Ernest slightly dislikes sensing walls.
- [move forwar, 10] Ernest enjoys very much moving forward.
- [bump wall, -10] Ernest dislikes very much bumping into walls.
- [turn toward empty square (left or right), 0 ] Ernest is indifferent of turning toward an empty square.
- [turn toward wall (left or right), -5] Ernest dislikes turning toward walls.


Two insights from this experiment:

- The learning is faster if schemas that are associated with high emotions are never forgotten, either positive or negative emotions.

- Without the feedback from the turn schemas, Ernest would have a lot of trouble establishing the linkage between sensing to the sides and turning. He would usually end up finding less elegant regularities.

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