[From Rick Marken (960328.2130)]
Richard Thurman (960321.0959) --
How about if you describe what would be necessary to replicate
and extend this [Robertson and Glines (R/G)] study. And I will try to
gin up a version (in HyperCard or something) that we could use in
some joint research.
I think a HyperCard replication of the R/G study would be a great idea.
I'd put four solid squares (1,2,3,4) in a row on the screen. The subject's
goal is to press keys to keep the squares filled. When a square is
emptied, it can be filled again if the subject presses the correct key
(from among four possibilities -- say H,J,K and L). The mapping of keys
to squares might be 1-K, 2-H, 3-L, 4-J. If square 1 is emptied, then
the subject can fill it by pressing key K. Of course, the subject must
learn the mapping of keys to squares in order to be able to do this quickly
each time a square becomes empty.
The time that a square remains empty affects the "score" displayed on the
screen. At the start of the experiment the score starts at some big value,
say 5000. Each "tick" of time that a sqaure remains empty subtracts from
the score. The subject's job in the experiment is to stop the downward
movement of the score.
A fixed time after subject has pressed the key that fills the empty square,
another square becomes empty. The squares are emptied in some sequence, say
1,3,4,2,1,3,4,2,... So once the subject has learned the mapping of keys to
squares she might learn that the squares are emptied in a sequence. Once the
subject learns the sequence, it should be possible to respond to the next
emptying more quickly than before. So we should see the subject achieve better
control of the decrease in the score once she has learned the sequence.
Finally, R/G gave the subject a way to stop the decline in the score
completely. This was done by making it possible for the subject to prevent
a square from emptying by pressing a key _before_ the next square in the
sequence emptied; so the subject had to anticipate the sequence in which
the squares _would_ empty and produce the anticipated sequence in the
correct rhythm. So, if, ordinarily, the next square in the sequence would
be emptied 2 seconds after pressing a key to fill the previous key, a press
of the correct key within this 2 second period would prevent the next square
from being emptied.
This last perception (of an anticipated rhythmic sequence) is very hard to
learn, I think. It might make things a little easier if the computer made
a beep about a second before the next square in a sequence is emptied (if
the subject doesn't press the correct key in anticipation).
The computer should keep track of the time between key presses (inter-
keypress intervaIs; IKIs). When these IKIs are plotted as a function
of time you should see plateaus when the subject masters the 1) key/square
mapping (longest IKIs) 2) the square emptying sequence (shorter ITIs) and
3) anticipation of the sequence (shortest IKIs). These plateaus should
be separated by periods of random duration IKIs.
Ok, gentlemen, start your programming engines;-)
Best
Rick