This experiment measured physiological responses in different testing conditions to assess whether individuals viewed a difficult test as challenging (when resources are seen as adequate for successful task completion) or threatening (when resources are seen as inadequate for successful task completion). Whereas challenges tend to decrease systemic vascular resistance and increase cardiac output, threat tends to increase vascular resistance but produce minimal change in cardiac output. To examine these physiological responses to task demands, the researchers had male and female undergraduates complete a difficult math test that was described as typically producing gender differences (invoking stereotype threat for women) or no gender differences (control). Compared with baseline measures collected before the test was introduced, women under stereotype threat exhibited physiological responses consistent with threat, but women who believed that the test was unbiased showed patterns consistent with challenge. In contrast, men exhibited challenge patterns when the test was described as biased (i.e., when the test supposedly favored males), but they showed threat responses when the test was unbiased. These findings suggest that stereotype threat can lead women to view math-related tests as posing a threat in that available resources would be insufficient for success. However, the elimination of stereotype threat apparently allowed women to view their resources as adequate to the task, producing physiological responses that typically assist in producing optimal performance. Men showed benefits when they believed their gender was favored on the test (stereotype lift), but showed responses consistent with threat when this supposed advantage was explicitly negated.