Researchers from Uppsala University and Karolinska Institutet have revealed that infants at 5 months of age exhibit distinct preferences for faces or non-social objects, and this inclination is largely influenced by genetic factors. The study, involving over 500 infant twins, utilized an infant-friendly eye tracker to measure gaze, finding that genetic differences played a significant role in determining these early visual preferences.
Ana Maria Portugal, Postdoctoral Researcher and lead author, emphasizes that even before infants can actively engage with their environment, they shape their perceptual experiences through a predisposition to focus on social or non-social stimuli. The study challenges the assumption that family environment strongly influences these preferences at such an early stage in life.
Importantly, the research indicates that infants who showed a preference for faces at 5 months of age demonstrated a connection with having a larger vocabulary in their second year of life. This association suggests a link between early-looking preferences and later developmental milestones.
Portugal notes that the differences in infants' looking behavior can impact the parent-child interaction, as an infant's gaze at faces signals cues to others and may influence parental behavior. However, she highlights that a preference for non-social objects is also crucial for cognitive development.
The study, conducted as part of the Babytwins Study Sweden (BATSS) research project, observed that genetically identical twins displayed more similar looking preferences compared to fraternal twins. This suggests a stronger genetic influence on these preferences, as identical twins share 100% of their genes, while fraternal twins share only about 50%.
In addition to exploring the link between visual preferences and language development, the researchers investigated whether these preferences could predict behaviors associated with autism later in childhood. Surprisingly, the study found no strong association between face preference in infants and social communication abilities in later childhood.
Terje Falck-Ytter, Professor at the Department of Psychology at Uppsala University and principal investigator in the BATSS study, highlights that the genetic factors influencing facial preference are distinct from those involved in eye contact. This intriguing finding suggests that fundamental social behaviors, such as looking at faces and eyes, have different genetic and evolutionary foundations.
Source: Uppsala University