Ferrets, Behavior Patterns and Coordination of Relative Phase
					From my Ph.D. thesis. The original paper was published in: Biological Cybernetics , Jul 20, 1998, 78(6), 441-453
			The animation above describes several seconds out of the movement of a female ferret. She was exploring a large glass platform while I videotaped her from below (through the glass). Ten points on her body were measured frame-by-frame from the videotape and analyzed in the Mathematica programming environment, which also produced this animation. Naturally this was much less simple than it sounds, but I spare you the technical details (don’t you feel lucky?). This animation illustrates a most basic, yet mostly unexplored mystery in the field of Behavioral Neuroscience: how behavior patterns are born from the coordination of many simultaneous movements. Currently, no one actually knows how to define behavioral patterns in free movement. If the animal is walking on a straight line and in uniform speed, then simple patterns such as walking, running and galloping can be defined by the relative phase between the movements (more about that below), but once you give the animal free rein to move as it pleases, things really get complex. This is probably a main reason why the behavioral sciences are considered “soft” sciences, especially in comparison with neurophysiology or genetics: the basic building blocks – the behavioral patterns – aren’t algorithmically defined, and therefore cannot be objectively measured. Note that the stick figure in the animation above contains just nine sticks that connect 10 points from the animal’s body, and yet the movement feels “alive”. You can imagine what the animal is doing based only on these 10 points, and even perceive some nuances of the movement. This implies that the complexity of the movement is in there, captured in the numbers that specified the movement of these nine sticks. And yet, no one really knows how to recreate the magic of live movement. People who make computerized animation movies, for example, don’t know how to program their computers in order to get it. If they want movement that feels alive they have to do what I did – to measure and digitize the movement of real humans and animals. The simplest behavior patterns are strictly periodic movements, especially in locomotion: swimming (in fish, for example), crawling (in snakes), walking, running and gallop (in mammals). Such patterns can be defined by relative phase. Lets start from the simplest case possible: consider a single joint in periodic movement (say your hip joint while your walking):
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