[R] lmer t value for 3 levels of fixed factor

[Obermeier Andrew]

Hello,

I just joined this list today, so am worried about proper protocol, but would like to post a question about lme4.

In Baayen, Davidson, and Bates (2008), Mixed-effects modeling with crossed random effects for subjects and items, the authors describe steps for a Latin Square Design (p. 402) in which they compare 3 levels of the experimental conditions. I am considering replicating this analysis for my dissertation, I would also like to investigate 3 levels of my factor, but wish to confirm how lme4 derives the t value. 

It is my understanding that t values can only be used to compare 2 means. For 3 levels, does lme4 do some kind of pairwise comparison?