[R] GLMM with lme4 and octopus behaviour

[Samaritan]

Hi all,

First time poster and a relatively new R user, I'm beginning analysis for my
masters degree. I'm doing a bit of work on octopus behaviour, and while it's
been fascinating, the stats behind it are a bit beyond my grasp at the
moment. I was hoping that somebody with more experience my be able to look
at my example and offer their wisdom, much to my appreciation :-)

At the most basic level, I'm testing the effect of sleep deprivation on
various behaviours (e.g. amount of time spent awake, amount of time spend
expressing difference textures, patterns, colours etc). I take a video
sample of each octopus every hour for 72 hours and score their behaviour in
Jwatcher.

I'm using GLMM so that I can nest Individual as a random factor within Time,
which I'm told will reduce the problem of making repeated measures (is this
effectively blocking by time and by octopus?). Currently my model looks like
this:

octopus.lmer<-lmer(awake~as.factor(Treatment)+Sex+Weight+(1|Time/Octopus))

where "Treatment" is "0" or "1" representing sleep-deprived or
sleep-allowed. When I try to fit the model I get the following error
messages:

Error: length(f1) == length(f2) is not TRUE
In addition: Warning messages:
1: In Octopus:Time :
  numerical expression has 190 elements: only the first used
2: In Octopus:Time :
  numerical expression has 190 elements: only the first used

This is the point at which I become lost. What does this mean? Clearly I'm
not doing something right, perhaps in my data preparation? So far as I can
see the length of each of the variables is the same (although I'm no certain
as to what f1 and f2 refer to).

If anyone could offer me some kind of advice about this I would appreciate
it very, VERY much. Both of my supervisors have no experience with R and so
have kind of washed their hands, so I'm alone in this and your expertise
would be a big help.

Dean


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