A teacher believes that one group of children is very bright and the second group is below average in ability. Actually, the groups are identical but the first group progresses more rapidly than the second. This demonstrates

The self-fulfilling prophecy occurs when expectations about someone's behavior influence that person's actions in ways that confirm the original expectations. The teacher's belief about student ability subtly changed their behavior toward each group, causing the 'bright' group to perform better despite equal initial ability.