tuller, turvey, fitch (1982) coordinative structures - synergies

Tuller, Turvey, Fitch (1982)

Coordinative structures - synergies

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Focus Questions

1. The examples of coordinative structures as equations of constraint over the degrees of freedom of the body become more complex as the paper progresses. How do the simpler examples (the pistol marksperson, the breathing example, maybe also the handstand) compare to the first of the more complex – the airplane? What are the similarities and what is the main difference between the two sets?

2. What do you think are the key similarities (or similarity) between the airplane example and the quadrupedal (horse) gait example? Also, what limb relationships characterized the different phase relationships of the horse’s gait?

3. What promising features of the mass spring system make it a potential candidate as a coordinative structure (or something that links elements of the motor apparatus via equations of constraint)?

4. What evidence is offered in support of such mass spring systems in humans?5. How do mass spring systems compare to limit cycle oscillators, roughly?

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An old version of a synergy

• Industrial revolution – steam power available to all industry driven by flywheel

• Used in cotton industry, trains, cars, etc. How to regulate the fuel to

the flywheel to keep motion stable?

Could pay someone to regulate it?

Wages – expensive.

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An old version of a synergy

• James Watt invented a self-regulating system to solve the problem of stable engine speed. Became known as the

Watt governor Components:

• Pulley» Driven by the

engine speed.

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An old version of a synergy

• James Watt invented a self-regulating system to solve the problem of stable engine speed. Became known as the

Watt governor Components:

• Weights

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An old version of a synergy

• James Watt invented a self-regulating system to solve the problem of stable engine speed. Became known as the

Watt governor Components:

• Idle speed plate

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An old version of a synergy

• James Watt invented a self-regulating system to solve the problem of stable engine speed. Became known as the

Watt governor Components:

• Main shaft» Allows rotation

from pulley• Two scissor arms

» Allows arms to flex

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An old version of a synergy

• James Watt invented a self-regulating system to solve the problem of stable engine speed. Became known as the

Watt governor Components:

• Bearings» Allows

compression and stretch of unit

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An old version of a synergy

• James Watt invented a self-regulating system to solve the problem of stable engine speed. Became known as the

Watt governor Components:

• Sliding collar

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An old version of a synergy

• As pulley speeds up… Shaft increases rotation speed Balls fly out due to centripetal

force Scissor arms contract Sliding collar comes down Sliding collar is attached to valve

controlling fuel line Fuel line closes Engine decreases speed Pulley slows down to idling

speed

• All completely self-regulating (self-organizing)

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An old version of a synergy

• In action… https://www.youtube.com/watch?v=Nr9UtEhyvfk

• Key points Relationship between arm angle and engine speed is complex

Arm angle modulates engine speed, but at the same time engine speed modulates arm angle…it’s a heterarchy. What’s controlling what?

Co-determined and co-determining To have a person do it would have introduced slow modulation

and error The governor is instantaneous

It seems to be similar to the non-representational models of dynamic control espoused by Turvey

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An old version of a synergy

• The governor and representation… The governor is non-representational

No symbol manipulation, no abstract modeling No discrete sequence of events, so no algorithm Therefore governor not computational

• “The continuous and simultaneous relations of causal inference that obtain among the various factors involved, it is this distinctive kind of causal profile that both invites treatment in terms of an alternative dynamic analysis, and that causes problems for the traditional, computational, and representational approach.”

• Tim Van Gelder (1995):

A newer version of a synergy

• Tensegrity – Turvey again… Haptic perception and action https://www.youtube.com/watch?v=BLR7ZTSel9M (time out – 15 min video)

Note reference to fractal dimensionality at the end

A newer (still) version of a synergy

A newer (still) version of a synergy

• Riley, Shockley, van Orden (2012) Speed of perception Speed of action

Turvey presentation last spring• “How do you get from PE teacher to this?”• Answer – witnessing speed of execution. How can it be done?

Spotting a forged statue immediately Blink (Gladwell, 2005)

Ultra-fast cognition Is information processing even possible? Seems impossible to compute that quickly Proposal: cognition is a vast self-organizing complex system

A newer (still) version of a synergy

• Riley, Shockley, van Orden (2012) Not open-loop, not closed loop, but “strange loop”

Self-organization allows for mutual entrainment rather than sequences of hierarchical control

Zero-lag mechanical feedback – preflexes (Nishikawa, 2007)

A newer (still) version of a synergy

• Riley, Shockley, van Orden (2012) Ultrafast action

Synergies in speech• Say /b/ as in Bob – lips must be in contact

» Synergy is between elements of the lips, not stored in some executive

» Means higher level intervention is unnecessary• Tug jaw down – correction in 5-10ms. • Dynamic feedback links components directly to each other

» Anticipation stronger» Inappropriate actions ruled out

A newer (still) version of a synergy

• Riley, Shockley, van Orden (2012) Exquisite context sensitivity

Synergies are context-sensitive• CPGs

» Inhibitors can switch to excitatory» Neurons can be recruited that had no previous role» Separate networks can come together

• Changes in synergy components coincide with behavior change Synergies from cognition all the way down

• Context and cognition• Intentions limit d of f• Behaviors limited to those consistent with intentions• Shifts away from this breaks the symmetry of the synergy and results in

ultrafast switching to some other synergy.