CHAPTER 5, SLIDE SET 5 Supplement: Hysteresis,
perception-action coupling, more walk-run data, energetics
Slide 3
Hysteresis 12 3 54 Listen to this first! Then proceed with the
others, going from 1 to 5
http://perso.wanadoo.fr/l.d.v.dujardin/ct/cusp.html#applet2
Slide 4
Hysteresis Walk Run Speed (control parameter) Order parameters
The difference in the speed (at which the person is
running/walking) when the transition is made from walking to
running, compared to when the switch is made from running to
walking, signifies the presence of hysteresis further definition in
audio 1. 2.
Slide 5
Perception-action coupling The swinging room (Lee &
Aronson, 74) The swinging room was (is?) a box hanging from the
ceiling of a large hall Participant stands in center of fake room,
looking at front wall (field of view filled with fake room)
Experimenter (Lee) stands behind fake room, holding a rod
connecting the back walls, so that he can swing the room back and
forth an inch or 2
Slide 6
Perception-action coupling The swinging room (Lee &
Aronson, 74) Direction of motion of swinging room
Slide 7
Perception-action coupling So which way would you sway
(relative to the room)? Direction of motion of swinging room ?
Slide 8
Perception-action coupling Other applications of (tau - time to
contact - used to guide movement) Echolocation in bats Diving
gannets Driving, feeding (hand to mouth), kicking, running,
steering, catching, etc., etc., etc.
Slide 9
Shapiro et al.s data (1981) Note the change in proportion of
time spent in phases of step cycle as speed increases... A change
in a control parameter drives a change in an order parameter
Slide 10
Energetics in Walk-Run transitions There have been many
research investigations into the kinds of things I discuss here.
Heres another few excerpts... First bit discusses hysteresis
Slide 11
Energetics in Walk-Run transitions Heres a summary of data...
They did roughly the same thing as Shapiro, but also reduced speed
Note that hysteresis appears as predicted. But why? What are the
causes of the transition?
Slide 12
Energetics in Walk-Run transitions A quick review of why we
might expect such transitions... Open systems use energy as the
basis for behavioral self- organization
Slide 13
Energetics in Walk-Run transitions When you look at the energy
expended by different ways of moving, it seems to explain
things...
Slide 14
Energetics in Walk-Run transitions Some more data from same
experiment as before... Totally fits the theoretical picture that
has energy cost at the top of the tree, leading the system to
complex adaptations in gait.