# VS: Control of Behavior

[Eetu Pikkarainen 2017-04-11]

[Martin Taylor 2017.04.09.17.29]

Then I suggested that the PCT analysis of the article <http://www.nature.com/articles/srep45722

might be a good exercise some of
the readers less familiar with PCT modelling, and in a second message (the one to which you were responding), I said that this was why I posted the link in the first place.

Martin,

As a newcomer I would like to take the challenge. It is though quite demanding challenge for me because in addition
that kind of research is not familiar to me. Anyway I try to give some preliminary comments about it. Hopefully someone continues and corrects mine.

Of course the first thing that took my attention was the assumption that we plan our movements beforehand. The control
of the movement then means control against that prevailing plan. As if when reaching to a point we would draw straight line in our mind and the tried to control that our hand remains on that line. From PCT point of view we have a perception of our hand position
and the target position and their distance. Also we have a reference value for that perception according to which the distance should be zero. This error between perception and reference causes lower ECUs do what they use to do in this kind of situations.
So there is in a way a plan, a practiced plan but it is not âdrawnâ? in the moment of task instruction.

Actually if the âcontrolled variableâ? is the distance between the hand and the target then there does not seem to
be much difference between the cases of point or bar as a target? There is anyway one point in the bar where the distance is shortest and that point is the ânaturalâ? target for the movement. So Why the differences in the results of the research?

What I did not understand is the figure 4.C. Why the hand force curve does not follow the perturbation (disturbance?)
curve?

Eetu

[Eetu Pikkarainen 2017-04-11]

[Martin Taylor 2017.04.09.17.29]

Then I suggested that the PCT analysis of the article <http://www.nature.com/articles/srep45722 >
might be a good exercise some of the readers less familiar with PCT modelling, and in a second message (the one to which you were responding), I said that this was why I posted the link in the first place.

Martin,

As a newcomer I would like to take the challenge. It is though quite demanding challenge for me because in addition
that kind of research is not familiar to me. Anyway I try to give some preliminary comments about it. Hopefully someone continues and corrects mine.

Of course the first thing that took my attention was the assumption that we plan our movements beforehand. The control
of the movement then means control against that prevailing plan. As if when reaching to a point we would draw straight line in our mind and the tried to control that our hand remains on that line. From PCT point of view we have a perception of our hand position
and the target position and their distance. Also we have a reference value for that perception according to which the distance should be zero. This error between perception and reference causes lower ECUs do what they use to do in this kind of situations.
So there is in a way a plan, a practiced plan but it is not “drawn” in the moment of task instruction.

Actually if the “controlled variable” is the distance between the hand and the target then there does not seem to
be much difference between the cases of point or bar as a target? There is anyway one point in the bar where the distance is shortest and that point is the “natural” target for the movement. So Why the differences in the results of the research?

What I did not understand is the figure 4.C. Why the hand force curve does not follow the perturbation (disturbance?)
curve?

Eetu