In all likelihood, there is a kernel of truth to the "what is beautiful is good" stereotype; that is, attractive people are often more warm and socially skilled than less attractive people. According to the authors, this is probably because attractive people

a. are treated differently than unattractive people.
b. have higher self-esteem than unattractive people.
c. are more introverted than attractive people.
d. compensate by emphasizing their intelligence.