Dr. Roberts studies how best to assess individual differences in traits such as impulsiveness and sociability. Which specialty area does her research best represent?

The specialty area that Dr. Roberts' research best represent is that of personality psychology.

Explanation:

The personality of any given person is a culmination of a number of traits and attributes that the person possesses. These traits and attributes are not just physical (external) but are also mental (internal). The study of these traits to compare between two distinct traits like that of impulsiveness and sociability can be termed under the knowledge discipline of personality psychology.