mod1 = lmer(accuracy ~ session + trialtype + group + session*trialtype +
session*group + session*group*trialtype + trialtype*group +
(1+trialtype|subject), data=data, REML=FALSE)

mod2 = lmer(accuracy ~ session + trialtype + group + session*trialtype +
session*group*trialtype + trialtype*group + (1+trialtype|subject),
data=data, REML=FALSE)

Data: data
Models:
mod1: accuracy ~ session + trialtype + group + session * trialtype +
mod1:     session * group + session * group * trialtype + trialtype *
mod1:     group + (1 + trialtype | subject)
mod2: accuracy ~ session + trialtype + group + session * trialtype +
mod2:     session * group * trialtype + trialtype * group + (1 + trialtype
|
mod2:     subject)
     Df    AIC    BIC  logLik deviance Chisq Chi Df Pr(>Chisq)
mod1 27 4026.4 4150.3 -1986.2   3972.4
mod2 27 4026.4 4150.3 -1986.2   3972.4     0      0          1