R help - Dec 2012 - confirming a formula for use with lmer

Hello,

I recently began using R and the lme4 package to carry out linear mixed 
effects analyses.

I am interested in the effects of variables 'prime','time', and
'mood'
on 'reaction_time' while taking into account the random effect 
'subjects.' I've read through documentation on lme4 and came up with
the
following formula for use with lmer:

reaction_time ~ (mood*prime*soa) + (1|subject)

Prime and soa were repeated measures within subjects, while mood was 
manipulated between subjects. As I understand it, however, this 
distinction does not affect how the formula should be written.

While I've done my background reading and think this formula is correct, 
I'd appreciate an expert with more experience than I to double check my 
work.

Thanks in advance for any help,

Matt



The information in this e-mail is intended only for the ...{{dropped:11}}

Matthew Panichello <panichem <at> nmr.mgh.harvard.edu> writes:
>
[snip]
> 
> I am interested in the effects of variables 'prime','time',
and 'mood'
> on 'reaction_time' while taking into account the random effect 
> 'subjects.' I've read through documentation on lme4 and came up
with the
> following formula for use with lmer:
> 
> reaction_time ~ (mood*prime*soa) + (1|subject)
> 
> Prime and soa were repeated measures within subjects, while mood was 
> manipulated between subjects. As I understand it, however, this 
> distinction does not affect how the formula should be written.
>
 
 [snip]

  This looks reasonable.  If 'prime' and 'soa' vary within
individuals,
you might want to consider (mood*prime*soa) + (prime*soa|subject):
see Schielzeth, Holger, and Wolfgang Forstmeier. 2009. ?Conclusions Beyond
Support: Overconfident Estimates in Mixed Models.? Behavioral Ecology 20 (2)
(March 1): 416?420. doi:10.1093/beheco/arn145.
http://beheco.oxfordjournals.org/content/20/2/416.

  Followups to r-sig-mixed-models at r-project.org.