Psychology2016

Development across the Life Span 325

muscles that hold it in place mature. Until then the newborn is unable to shift what little
focus it has from close to far. Thus, newborns actually have a fixed distance for clear
vision of about 7–10 inches, which is the distance from the baby’s face to the mother ’s
face while nursing (Slater, 2000; von Hofsten et al., 2014).
Newborns also have visual preferences at birth, as discovered by researchers using
preferential looking, measures of the time that infants spent looking at certain visual
stimuli (Fantz, 1961). They found that infants prefer to look at complex patterns rather
than simple ones, three dimensions rather than two, and that the most preferred visual
stimulus was a human face. The fact that infants prefer human voices and human faces
(DeCasper & Fifer, 1980; DeCasper & Spence, 1986; Fantz, 1964; Maurer & Young, 1983;
Morii & Sakagami, 2015) makes it easier for them to form relationships with their care-
givers and to develop language later on. Infants’ preference for seeing things in three
dimensions suggests that they possess depth perception. The following classic experi-
ment provided evidence for that assumption.

Classic Studies in Psychology

The Visual Cliff

Eleanor Gibson and her fellow researcher, Michael Walk, wondered if infants could per-

ceive the world in three dimensions, and so they devised a way to test babies for depth

perception (Gibson & Walk, 1960). They built a special table (see Figure 8.6) that had a big

drop on one side. The surface of the table on both the top and the drop to the floor were

covered in a patterned tablecloth, so that the different size of the patterns would be a cue

for depth (remember, in size constancy, if something looks smaller, people assume it is

farther away from them). to Learning Objective 3.14. The whole table was then

covered by a clear glass top, so that a baby could safely be placed on or crawl across the

“deep” side.

Glass only

Deep side Shallow side

Glass over patterned surface

Floor pattern

seen through

glass

Figure 8.6 The Visual Cliff Experiment

In the visual cliff experiment, the table has both a shallow and a “deep” side, with glass covering the entire

table. When an infant looks down at the deep-appearing side, the squares in the design on the floor look

smaller than the ones on the shallow side, forming a visual cue for depth. Notice that this little girl seems to

be very reluctant to cross over the deep-appearing side of the table, gesturing to be picked up instead.