People who claim to have been abducted by space aliens seem to invariably describe a very similar picture. Space aliens are described as having large heads, big eyes, gray skin, smooth features and small mouths.

Psychologist Frederick Malmstrom, currently a visiting scholar at the U.S. Air Force Academy, believes that these 'visions' of space aliens are actually the image of the prototypical female face that is hardwired into every baby human's brain. When Malmstrom altered a picture of a woman in a way consistent with the characteristics of a newborn's vision (astigmatism and a shallow focal plane), the result looked very much like a big-eyed alien.

(x-posted at my site)