When foraging for nectar many insects exhibit flower constancy (a preference for flower species which they have previously visited) and frequently ignore rewarding flowers of other species. Darwin ...

In the natural world, many situations exist in which a percept remains constant in the presence of profound changes in the physical stimulus affecting the sensory receptors. Some of the most ...

Sigmund Freud had a nephew named Ernst with whom he would play peek-a-boo. Freud would hold a teddy bear at the edge of Ernst's crib and then drop it out of sight. Ever the scientist, Freud noticed ...