And a *third* time to correct my editing errors in the previous reply . . .
Rich Ulrich wrote in message ...
>On Tue, 21 Dec 1999 09:34:53 +0800, "DIAMOND Mark" <[EMAIL PROTECTED]>
>wrote:
>Well, Mr Noname@noname, since I can't write to an address.
>And I will follow an example that I read lately and say that I don't
>feel kindly towards people who don't give a name and e-mailing
>address.
Point taken. My apologies for the lack of email address, although my name is
correct. Normally my signature file with a spam avoiding email address is
included. I do not know why it was not in this instance. Maybe an
interaction between Microsoft product reliablility and the inscrutable
workings of providence. University policy is to avoid putting email
addresses that can be extracted by spammers in the body of newsgroup
postings.
Mark R Diamond
Vision Research Laboratory
The University of Western Australia
no spam email: markd at psy dot uwa dot edu dot au
>I will have
>to say publicly that you did a lousy job of asking the question. Or,
>maybe it particularly looks that way because it is data from a lousy
>design.
Quite possibly. I shall try again.
(1) A prior experiment shows that a particular (special) subject who
engages in a temporal bisection experiment in which she is asked to say
whether a probe bar appeared early or late in temporal interval can do so
extremely accurately. That is, if the interval is, say 500 ms long, and a
probe stimulus is flashed 247ms after the appearance of the stimulus that
marks the beginning of the interval, then she will (with almost no errors)
say that the stimulus was probe stimulus was early. Similarly, if the probe
appears 253ms after the first stimulus, she will say that the probe was
late. That is, there is only a period of 3 ms either side of the true mid
point during which she makes any errors.
(2) Theory, and some other results, predicts that, for this subject, if her
attention is disturbed by an event that occurs in the first half of the
interval, then she will judge the midpoint of the interval to be later than
it really is. In other words, she will say that probes appearing up to 265
ms after the beginning of the interval were early, and
probes appearing after 271 ms will be judged to be late, putting the
subjective midpoint around 268 ms. However, the extent of the period over
which she makes errors may well change from 6 ms to something else.
A reversal of prediction occurs for conditions in which the disturbance
happens in the
latter half of the interval. Now, one expects the subjective midpoint to be
around 232 ms, and there is no guarantee that the the interval over which
the errors extend is the same as in the previous condition or the same as in
the control condition..
How does one go about testing the prediction that the two subjective
mid-points (as estimated by whatever method you suggest) are different from
one another?
