[Martin Taylor 2016.09.07.15.47]
AGM: ... Regardless of the interest in steering maggots, the power law is unsolved PCT homework, which I still want to do.
Let's start by some stage-setting, then. We have two classes of perceptual situation. In one, exemplified by a car on a road or "drawing an ellipse", the actor can perceive some or all of a static curve that is to be followed -- a reference shape. In another, exemplified by the fly larva, there is an objective place to be reached while the path to be followed is unspecified. In neither case is time involved in the path itself, which eliminates any kind of 2-D target-following control system from consideration as the source of the power law.
At a low level, there may be a target-following system controlling a perception of location that follows a moving reference location produced somehow by control systems that include one of the ones suggested above, or there might be a 2D velocity control system and no target-following system of any kind. Also, somewhere at a higher level there must be a system that controls some perception that incorporates time, such the time to complete the task, whatever the task may be (find the source of the food odour, go around the ellipse as fast as you can, or whatever).
To model the task properly, we need to link these or related concepts, find out what variables are being controlled in different conditions, and determine parameter values for the components of the model. Surely the larva isn't controlling the same variable as the car driver -- or is it? Maybe direction toward a target is being controlled in both cases. In the case of the larva the target might be the source of the odour, and for the car driver it might be the direction to a point in the road X seconds ahead at the current velocity. Who knows? Yet?
Martin
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On 2016/09/5 4:00 PM, Alex Gomez-Marin wrote: