The surface of behaviour created by competing tropisms. Moths circling candles, and so on. Often creates fractal / biological forms.

For more information on conflict patterns, see: http://online.sfsu.edu/~psych200/unit10/101.htm. It is quite common for automated and human systems to follow an ApproachAvoidanceGradient. An example is given on the PartingPhilosophersProblem.

''I'm not sure a moth circling a candle is a good example. Moths circle candles, lights, etc., due to a fooled navigational mechanism rather than an equilibrium in approach vs avoidance drives. Whether the moth circles or strikes the flame apparently depends entirely on the angle of incidence when it encounters the light. See http://park.org/Canada/Museum/insects/evolution/navigation.html''

Living in a bug-rich rainforest, I can assure you that very few moths actually self-immolate. Otherwise, open fires would be a simple way for hunter-gatherers to get a free feed. 

''Curious. My lamp fixtures are full of small, crispy, dead moths.''
* I think you need to invite some hunter-gatherers around pronto!

And it matters little whether or not the evolutionary advantage of the mechanisms underlying the ApproachAvoidanceGradient is to do with navigation or anything else. But other good examples are SlimeMould signalling (http://en.wikipedia.org/wiki/Slime_mould), bird flocking (http://en.wikipedia.org/wiki/Boids), and BraitenbergVehicles. A particularly odd one is the PeterHallEffect.

''Bird flocking - or at least the AI simulation thereof - is a clear and excellent example. However, moths circling lights are generally understood to be a failure of a simple navigation mechanism and not a form of approach-avoidance.''

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MayZeroSix