INTRODUCTION The herring gull chick begs for food by pecking at its mother’s beak. In a seminal experiment, Nobel-prizewinning ethologist Nikko Tinbergen and co-worker (Tinbergen & Perdeck, 1950) sought to discover the stimulus that maximized this response. This enterprise led to the remarkable discovery of the super-stimulus: an artificial stimulus that evokes a stronger response than the original, natural stimulus. For example, a white stick with three red annuli moving up and down produces a stronger pecking response than the head of the herring gull’s mother.