Monday, 24 February 2014

Psychologists use baby-cam to study infants' exposure to faces

An infant sporting the baby-cam, worn upside down to ensure the camera
was level with the eyebrows. Image reproduced with permission of N. Sugden.
What does the world look like from a baby's perspective? In the first research of its kind, psychologists in Canada have analysed hours of video footage taken from small cameras worn by babies on their heads. Nicole Sugden and her colleagues were particularly interested in the babies' exposure to faces, to find out whether the kind of faces they were exposed to might explain a developmental process known as "perceptual narrowing". In the context of face recognition, this is the finding that babies gradually lose their ability to distinguish between other-race faces and other-species faces.

The researchers recruited the parents of 14 1-month-olds and 16 3-month-olds. There was an even mix of girl and boy babies, and the families were of a variety of ethnic backgrounds including Caucasian, Southeast Asian, and Black-Caucasian. For a two-week period the parents were asked to place the smiley faced camera, attached to a headband, onto their baby's head whenever he or she was awake.

In total, the researchers obtained nearly 20 hours of footage from the 1-month-olds and over 25 hours footage from the 3-month-olds. This difference reflects the fact that the older babies were awake an average of 9 hours a day, while the younger babies were awake an average of 7 hours daily. The footage was varied, taking in the home environment and outdoors, including situations where adults were playing with their babies but also many other contexts such as riding in a stroller, at parent groups, and out at a restaurant.

Sugden and her team found evidence the babies experienced "massive" exposure to faces, accounting for 25 per cent of their waking lives. They also found a dramatic bias towards babies being exposed to own-race faces - 96 per cent of all faces matched this category. This is despite the fact that the research was conducted in Toronto, a multicultural metropolitan city with a diverse population. The researchers said this overwhelming exposure to own-race faces could be responsible for the fact that by three-months of age, babies already show a preference for looking at own-race faces. By six months they are already starting to lose their ability to distinguish other-race faces.

The baby-cam footage also revealed that the babies were overwhelmingly exposed to female faces (accounting for 70 per cent of all face exposure) - which likely explains babies' usual preference for female faces - and to adult-age faces (accounting for 81 per cent of all face exposure).

This research did not directly address whether the experiences of individual babies led to specific changes in their perceptual abilities and preferences. However, the findings are compatible with this idea. "This study is the first to document the quantity and quality of infants' natural daily face exposure from the infants perspective," the researchers said, "and offers strong support for the idea that experience drives the development of the face processing system."

_________________________________ ResearchBlogging.org

Sugden NA, Mohamed-Ali MI, and Moulson MC (2014). I spy with my little eye: Typical, daily exposure to faces documented from a first-person infant perspective. Developmental psychobiology, 56 (2), 249-61 PMID: 24285109

Post written by Christian Jarrett (@psych_writer) for the BPS Research Digest.

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