"The findings of these studies are significant for many reasons. They show that race-based bias already exists around the second half of a child's first year," said Dr Kang Lee, professor at University of Toronto in Canada.
"This challenges the popular view that race-based bias first emerges only during the preschool years," Lee said.
In the first study published in the journal Developmental Science, infants from 3 to 10 months of age watched a sequence of videos depicting female adults with a neutral facial expression.
Researchers found that infants at six to nine months of age looked longer at own-race faces when paired with happy music as opposed to with sad music.
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In contrast, six to nine-month-olds looked longer at other-race faces when paired with sad music compared to with happy music, researchers said.
In the second study published in the journal Child Development, researchers examined whether infants were biased to learn from own-race adults versus other-race adults.
Following the look, in some videos, an animal image appeared in the looked at location (a reliable gaze). In other videos, an animal image appeared at a non-looked-at location (an unreliable gaze).
Researchers found that six to eight-month-old infants followed the gaze of members of their own race more than they followed the gaze of other-race individuals.
This occurred when the faces were slightly unreliable, as they are in the natural environment. This result suggests that, under uncertainty, infants are biased to learn information from own-race adults as opposed to other-race adults, researchers said.