It hasn't in anything we've seen so far.
Talking to himself about random objects? Dull neutral.
Talking to person about the Vaults? Dull neutral.
Talking to his wife? Dull neutral.
Talking to a dog? Dull neutral.
Talking to a guy with an awful name? Dull neutral.
The only time in any of the footage that they've shown so far the actually even slightly starts to show emotion is when a nuclear bomb is going off.