Zeuxis

In his early work, which is the basis for his fame, Zeuxis painted a bowl of grapes that was so life-like that birds pecked at the fruit. In an attempt to expand his achievement to encompass, he painted a boy carrying a bunch of grapes. When birds immediately came to peck at the fruit, Zeuxis judged that he had failed.

Zeuxis judgment that he had failed in his latter work was based on the assumption that birds are less likely to peck at fruits when they see that a human being is holding them]

Source: GRE Barrons book