TODAY we view TV documentaries about identical twins who, despite being
separated at birth, have had amazingly similar life experiences and grow up to
have similar IQs.
But when we think about what those twins imply, idle entertainment turns into
concern and anger. Must we believe that genes virtually determine IQ, and that
IQ differences between racial groups are caused by genetic differences? For
psychologists, there is a special cross to bear. The race and IQ debate has
created a paradox about nature versus nurture that appears insoluble.
Ever since the American military tested conscripts during the First World
War,…
