What is this visual cliff phenomenon?

Robin Hill (bsrah@TWP.AC.NZ)
Fri, 3 Jul 1998 13:15:17 +1200

A reply to Harry and anyone else who is puzzled.

Seeings I kicked this discussion off, I guess I should respond to
Harry's question. The "visual cliff" phenomenon is known to
nearly anyone who studied psychology, and photographs of the
visual cliff appear in veirtually every Introductory Psychology
textbook that I've ever seen. The "visual cliff" involved the study
of perception in infants by Gibson & Walk in the very early 1960's.
The visual cliff consisted of two surfaces, both displaying the same
pattern (in most photgraphs it is a black and white chequered
pattern). Both surfaces were covered by a sheet of thick glass. One
surface was directly beneath the sheet of glass, while the second
surface was dropped several feet from the glass. Hence, there was a
cliff of several feet between the two surfaces, but was termed a
"visual cliff" since the thick glass was strong enough to support the
weight of a child, and there was no danger of falling down the cliff.

Infants between the ages of 6 and 14 months were placed on a center
board, between the two surfaces. Their mothers called to them from
the cliff side of the set-up. and from the shallow side successively.
Nearly all the infants refused to crawl out over the glass on the
deep side, but nearly all of them were quite happy to crawl across
the glass on the shallow side.

Basically, it was concluded from this that depth perception was
present in infants at a very early age.

If you consider the above, and then consider the posting by Jim
Mancuso, a few days ago, you will see that he too was interested by
this notion. But when he tried to replicate Gibson and Walk's study,
he was unable to get the same results.

Hope that explains it - it is quite hard to describe this expereiment
without a photograph of the apparatus. When you see a phot, it is
patently obvious what is going on...

Dr. Robin Hill

Principal Lecturer & Research Leader
Department of Business Studies
The Waikato Polytechnic
Private Bag 3036
Hamilton 2020
New Zealand

email: BSRAH@twp.ac.nz
Fax. NZ (07) 834-8802