I have a problem with my mixed effects model where I found that both subjective evaluations of my stimuli (valence - positive or negative and self-relevance - highly self-relevant or not self-relevant) are highly correlated with one another. Theoretically this is not too surprising but poses a problem in my model. Thus can I take out one of these two variables in my model? When I run the model on solely one of the two variables, I obtain more or less the same t-values of my significant interactions. I also have age as a categorical variable and two dimensional continuous variables in my model. My dependent variable is response times.