A recent study conducted by developmental scientists at Northwestern University has revealed new insights into infants' ability to learn from nonlinguistic signals. The research highlights the flexibility of human communication, showing that even infants as young as six months can interpret nonlinguistic signals for learning purposes.
Sandra Waxman, the senior author of the study, along with her colleagues, found that infants could harness these signals despite being in the early stages of language acquisition. "The study is significant because it helps us to understand what capacities the human mind is furnished with from the start and how infants use those capacities to identify important sources and signals for learning," Waxman stated.
The study demonstrated that cross-modal temporal synchrony—synchronized sound and movement—was crucial for infants to confer communicative status to novel tone signals. This finding was published in Nature Journal’s Scientific Reports.
Waxman, who holds the position of Louis W. Menk professor of psychology and directs the Infant and Child Development Center at Northwestern, collaborated with co-authors Brock Ferguson and Alexander LaTourrette on this research. Ferguson completed his Ph.D. at Northwestern, while LaTourrette is now an assistant professor of psychology at the University of Southern California.
In their experiment, researchers used sine-wave tone signals as a control because previous studies indicated that tones alone do not aid babies in categorization or other tasks. The study involved presenting six-month-old babies with animated videos featuring two non-human agents—a triangle and a circle—and assessing whether synchronized cues would allow infants to infuse tones with communicative status.
The researchers were surprised by their findings: babies were able to elevate signals to communication status when produced synchronously with an agent's motion. "Even in the third video where one agent sat like a bump on a log, and the other bounced and beeped, the exposure still helped assign meaning to the tone," Waxman explained.
"This is an important finding: When we provided cross-modal synchrony between the tones and the agents’ motions, infants spontaneously elevated tone signals to communicative status," she added.
This study marks a significant discovery about human capacity for communication without relying on fully developed linguistic systems. It also opens avenues for further research into how other communicative signals such as pointing or eye-gaze might benefit learning processes in infants.
Waxman noted that this work offers valuable insights into theories of language acquisition and holds potential for designing interventions for children facing developmental challenges. "This work offers valuable insights into theories of language acquisition. But equally important, it holds promise for designing effective interventions for infants and young children facing developmental delays and impairments," she said.