Further explorations of event and emerging timing
Further explorations of event and emerging timing, by Howard N. Zelaznik, Purdue University
He's aiming this presentation at Grad Students and other people who aren't really familiar with his research. If true, pray Jesus.
Sort of an obvious statement: we know that timing is important; accuracy and precision are important throughout the use of motor skills. But does this mean that we can be certain that time is controlled throughout the system? Not necessarilly.
A motor skill that is frequently tested is tapping: a metronome starts a rhythm, and a subject taps out that rhythm even after the metronome ends. People use this approach because everyone intuitively believes that there is some general purpose clock somewhere in the system. So the question we're looking at today is whether or not this is a good technique to examine timing.
Tapping timing - 325,400,475,550 and 800 ms
Circle drawing timing - same periods
--pencil and paper, the goal is to draw a circle in rhythm with the metronome so they reach them twelve o'clock when the metronome fires.
They compare the two, testing timing precision for each after the metronome stops. So, "are individual differences in timing correlated across tasks?" NO! Similar timing missteps, but they do not correlate across subjects (if I understood right)
Timing to 12 o'clock vs. timing to 9 o'clock vs. tapping
--circle drawing and tapping seem to be using different timing systems; this is probably due to the involvement of multiple motor systems in circle drawing
--circle drawing: their velocity looks pretty much the same no matter what degree you look at
--tapping: maximum upward velocity of finger scales over time(?maybe?)
--tapping is more variable than circle drawing
Intermittent circles: draw a circle, than pause.
--continuous circles correlate (in terms of temporal discrimination) with neither tapping nor intermittent circles
--tapping, however, correlates with intermittent circles (both in terms of total time, time moving, and time paused)
--intermittent circles: only the time paused matters correlates to timing accuracy
Examining patients with unilateral cerebellar lesions perform circle drawing tasks and tapping task:
--tapping and intermittent circles: timing is much more variable in the impaired limb than the unimpaired limb. However, the continuous circle is the same in both. This seems to confirm the behavioral observation that a different system is responsible.
--examined slow vs. fast movements: seems to indicate (I'm not sure how) that smoothness of movement is responsible for accuracy in timing.
Simple framework: "a representation of time is used to time the onset of discrete events--tapping is a classic example--this is known as event timing."
--the other type of timing is "emergent timing," which is smooth rather than discrete and has no timing requirements. Yes, this sounds paradoxical: everyone in the room is having problems with this. His example is that if you're running around a track at a regular rate, you aren't producing time but rather effort: your total amount of muscular effort determines the timing. Trying to prove this, he went into some pilot data. I'm not going to relate anything about it other than that he seems to demonstrate that as little a change as smoothly tapping in the air rather than tapping in the table engages the emergent timing system. Just to make it clear: there is a continuum between the discrete and smooth actions.
And I wasn't able to park next to an outlet this morning, so the battery, it is dying. If I'm not able to post again this morning, that would probably be why.