I am conducting a psycholinguistic experiment. Each trial consists of the subject responding to a word by pressing a button.The design of my experiment is as follows:
5 blocks of a 100 trials each (each trial is a response). In each block, 50 trials are Regular
and 50 are Random
. Response time (RT) is the dependent variable. This experiment is partly a learning experiment. I expect RTs to be faster in the Regular
condition because there is learning which allows for faster responses.
I therefore want to test the difference in mean response time (RT) between the two conditions of my experiment.I know that the model for the ANOVA would be something like
RTs ~ Type of Trial (`Regular` and `Random`) + ...
I have two related questions
Should I use
Trial
orBlock
as the other factor? (or both?) Normally I would compare mean RT for each condition across blocks, but it is possible that within blocks, there is already changes in RT between trials. So, isBlock
,Trial
or both my factor? (besides the condition factor).Since I expect variation across participants, should I include
Subject
as an Error variable in the model?
I am doing my analysis in R, in case anyone wants/can provide some advice in that format, but also general statistical advise is much appreciated.
Regular
andRandom
to change over time. Specifically, both trials will become faster as time progresses, but the decrease in RT forRandom
trials should be a linear decrease based on practice effect, whereas the decrease in RT forRegular
trials should be steeper because of the learning effect. Answering your second question, I want to test whether the differences in RT are different. So to answer your third question, there is indeed a difference between types of trials. The difference is in fact the experimental manipulation. $\endgroup$