Not only does Botox ameliorate frown lines, but it also seems to impair the ability to recognize angry or sad situations.
I thought this experiment was especially interesting because I wouldn't have expected something like Botox to affect how someone understands emotions. I can see how facial expressions might help us process what we're feeling, but it seems like a pretty big jump to say they're actually necessary for understanding an emotion. Someone who can't physically make a certain expression can still recognize that emotion in other people. I think the results show that facial movements play some role in how we process emotions, but I'm not sure they prove that our understanding of emotions depends on those movements.