Dr. Smith is exploring the concept of Stereotype Threat.
Explanation:
Stereotype Threat is a psychological effect, which indicates that a person's <em>behavior </em>can be <em>negatively affected</em> if this person is asked to specify if he or she belongs to a certain social group. If this social group is identified with a particular <em>stereotype</em>, the person’s behavior would be negatively affected by the stereotype threat.
Here women undergo a math test and their performance is being tested (<em>behavior</em>). They are asked to indicate their gender before the testing. According to the stereotype that Dr. Smith is researching, women are bed at math. Gender here indicates <em>belonging to the social group</em> (<u>women</u>) which is <em>identified with a stereotype</em> (<u>being bad at math</u>).