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, May 20, 2011

Ernest 10.3

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In his management of space, Ernest 10.3 distinguishes between two concentric zones: the peripersonal space and the extrapersonal space.

The peripersonal space is the realm of proximal perception: touch, kinematic perception (bumping), and taste (eating). The peripersonal space covers the 3x3 matrix of grid cells surrounding Ernest.

In contrast, the extrapersonal space is the realm of distal perception: sight (that also works as a kind of olfaction for Ernest). The extrapersonal space covers the rest of the surrounding world beyond the peripersonal space.

Researchers in neuropsychology have argued that these two spaces were handled by partially distinct parts of the brain in the vertebrate. Moreover, behaviors would be driven by different motivational systems. Behaviors in the peripersonal space would be related to consumatory motivation associated with the noradrenergic system. Behaviors in the extrapersonal space would be related to incentive associated with the dopaminergic system (Previc, 1998, p124).

Following these views, we have endowed Ernest with a (partially) distinct motivational system associated with each space. This video shows that this new dual-space motivational system makes Ernest much better at avoiding bumping and at catching fish in shoal. See steps 93-98 when Ernest hesitates between moving toward another shoal or keeping eating the same shoal.

Similar to Ernest 10.1, Ernest 10.3 constructs a local map of his peripersonal space (displayed in the upper-right corner). This local map is a place of multimodal integration that facilitates behavioral consistency across the two spaces, peripersonal and extrapersonal.

After the initial learning phase (roughly up to step 80 in this video), Ernest 10.3 exhibits a more coherent spatial behavior than poor Ernest 9.3, in particular, Ernest now avoids bumping as well as useless turning toward walls.

Also worthy of noting is that Ernest adopts a head bobbing behavior (like birds) consisting of turning left then right after eating (from step 128 on). We explain this strategy by that Ernest's sensory system is mostly sensitive to movement (see the discussion on Ernest 8.1 strategy learning).


Previc F.H, 1998, The neuropsychology of 3-D space. Psychological Bulletin, 124 (2). pp 124-164.

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