Today’s subject: the visual cliff. This pioneering experiement both looks cool and is a fun exploration into the development of depth perception in creatures great and small.
In 1960, E.J. Gibson and R.D. Walk set up this awesome looking contraption that makes it look like a surface completely drops off, when actually, it’s just an illusion made with shatterproof glass.
Then they put a variety of creatures on the contraption and tried to lure them to walk onto the glass with food or, like in the picture above, a teddy bear. They used rats, cats, babies, etc and discovered that all species tested can perceive and avoid a sharp drop by the time they take up independent locomotion, be it on day one in chicks, one month old rats, or six month old babies. Meaning that when a baby hits six months, it no longer just blindly crawls off of a cliff lured by the promise of a teddy bear.
There’s all kinds of fun stuff about whether or not the subjects were using visual cues, or a change in pattern, or a difference in how the floor feels to keep them from walking onto the glass, but really, the best thing about these studies is the pictures.