Re: reaction time ( was lacrosse 2)

Tony Beresford (
Tue, 06 Jul 1999 16:03:15 +0930

At 09:42 7/07/99 , James Nix wrote:

>        There's an interesting chapter in Paul Davies' "About Time"
>(Touchstone 96', Ch 13 "Experimenting with Time") on human reaction time.
>The message/impulse may only take .01 sec to get to the brain but to react
>takes a little longer. It also varies from person to person. Reaction time
>can be less in performing "automated" and repetitive tasks, and a .1
>reaction time is common.  The
>"now" we experience is estimated at .04 secs.  (Paul is at the University
>of Adelaide, maybe Tony can get him to add something to the discussion?)
I do know Paul Davies e-mail and snail mail addresses, but he is no longer directly connected with University of Adelaide, though still living here. He has never
been an exprimentalist.

When I did physics 1 ( 101 for North Americans) in 1960, The reaction time
experiment for hand eye system was an experiment we did. It served 2 purposes,
an exercise in processing measurements with simple statistics[ means, standard
deviations, SD of mean, and to show one about reaction time itself. From
memory my eye/hand reaction time was about 250 milliseconds. Last year in
a visit to Science Museum in Kensington,London, i tried ( and corrected)
 a similar experiment it was comming out more like 330 milliseconds. Shows the effect of 38 yearson the human physiology!
Tony Beresford

Of course for using a stopwatch for satellite tracking consistency (smaller
standard deviation) is more important than a smaller absolute value.
There is of course some systematic error because the start is by hand/eye
co-ordination and the the stop is by hand/ear co-ordination in my 
most used visual tracking technique.