Subject: reaction-time data From: Paul von Hippel -- Ohio State <pvh(at)CCRMA.STANFORD.EDU> Date: Sat, 13 May 2000 20:42:54 -0700I'm analyzing the results of an experiment in which listeners heard melodic fragments. After each fragment, they indicated (by typing) whether they thought the melody was more likely to continue upward (press "u") or downward (press "d"). The computer recorded boht their response and their response time. The response time data is really interesting. Many of the subjects grew faster and less variable as the experiment progressed -- of course, I expected that. What I didn't expect was that the response times for several subjects exhibited dependence between successive trials. For example, a couple of subjects tended to alternate short and long response times: for one trial they'd respond quickly, and for the next they'd respond slowly. I'm guessing that I've stumbled upon some effect that's well known in psychometrics. Have you ever heard of this kind of thing? Is there a book or article I should read on the common properties of reaction-time data? Or is there a psychometrics newsgroup that I should be posting this note to? Thanks for any pointers you can offer, Paul von Hippel Post-Doctoral Fellow School of Music Ohio State University 1866 College Road Columbus, OH 43210 614 292-7321 von-hippel.1(at)ohio-state.edu (You can also reach me by simply replying to this message. All my mail is forwarded to the same final destination.) http://music-cog.ohio-state.edu/~pvh