Hello R-lang, I have a dataset consisting of observations of the binary variable ING (e.g. workin' vs working) from conversational speech. I am interested in the priming effect on this variable: to what extent does the most recent prior observation (the prime) affect the outcome of the current observation (the target)? To assess this, I am using the dependent variable of "rep" -- does the target have the same value (/in/ or /ing/) as the prime? I intend to use this as the response variable for logistic regression. Available predictors are prime.var (is the prime a token of /ing/ or /in/?), target.var (is the prime a token of /ing/ or /in/?), same.word (are prime and target the same lexical item?), same.gram (do prime and target have the same grammatical status?), log.lag (log2 of the distance in seconds between the prime and the target), and spkr.mean (the mean rate of /ing/ use by the speaker who produced the token). There are 4879 observations (prime/target pairs) from 90 different speakers who have very different mean rates of /ing/ use. The prime and the target are always from the same speaker.
So here's the problem: I can't figure out how to account for the fact that repetition of the variant is more likely as a matter of course (rather than as a matter of priming) when speakers have rates of /ing/ use near 0% or 100%. I am particularly interested in testing the hypothesis of an interaction between prime.var and spkr.mean: that for speakers who have low /in/ rates, /in/ is a stronger prime than /ing/, whereas for speakers who have low /ing/ rates, /ing/ is a stronger prime than /in/. If I include prime.var * spkr.mean in the model, though, the effect I am looking for is obscured by the trivial fact that speakers who use /ing/ a lot will naturally be likely to have another /ing/ target after an /ing/ prime, and speakers who use /in/ a lot will naturally be likely to have an /in/ target after an /in/ prime. What I'm trying to figure out is whether there is an interaction of prime.var and spkr.mean *beyond* what is expected just given that the prime and target share a bias. If anyone can make any suggestions for how to proceed here it would be much appreciated. Please let me know if there's anything I can clarify or add. Thanks! Meredith
