Infant‐directed song potentiates infants’ selective attention to adults’ mouths over the first year of life

Abstract

The mechanisms by which infant‐directed (ID) speech and song support language development in infancy are poorly understood, with most prior investigations focused on the auditory components of these signals. However, the visual components of ID communication are also of fundamental importance for language learning: over the first year of life, infants’ visual attention to caregivers’ faces during ID speech switches from a focus on the eyes to a focus on the mouth, which provides synchronous visual cues that support speech and language development. Caregivers’ facial displays during ID song are highly effective for sustaining infants’ attention. Here we investigate if ID song specifically enhances infants’ attention to caregivers’ mouths. 299 typically developing infants watched clips of female actors engaging them with ID song and speech longitudinally at six time points from 3 to 12 months of age while eye‐tracking data was collected. Infants’ mouth‐looking significantly increased over the first year of life with a significantly greater increase during ID song versus speech. This difference was early‐emerging (evident in the first 6 months of age) and sustained over the first year. Follow‐up analyses indicated specific properties inherent to ID song (e.g., slower tempo, reduced rhythmic variability) in part contribute to infants’ increased mouth‐looking, with effects increasing with age. The exaggerated and expressive facial features that naturally accompany ID song may make it a particularly effective context for modulating infants’ visual attention and supporting speech and language development in both typically developing infants and those with or at risk for communication challenges. A video abstract of this article can be viewed at https://youtu.be/SZ8xQW8h93A.Research Highlights Infants’ visual attention to adults’ mouths during infant‐directed speech has been found to support speech and language development. Infant‐directed (ID) song promotes mouth‐looking by infants to a greater extent than does ID speech across the first year of life. Features characteristic of ID song such as slower tempo, increased rhythmicity, increased audiovisual synchrony, and increased positive affect, all increase infants’ attention to the mouth. The effects of song on infants’ attention to the mouth are more prominent during the second half of the first year of life.

The role of talking faces in infant language learning: Mind the gap between screen-based settings and real-life communicative interactions

“…Given that 6-months of age is also the stage where infants' endogenous control starts to emerge [63], it would allow them to exert top-down control to specific subparts of a speaker's face, and voluntarily deploy more of their attention into the speaker's mouth. Indeed, the onset of this mouth preference has been confirmed to emerge at around 6-8 months of age by more recent studies [64]- [71] and seems to present its peak around 18 months of age [67], [72]. This disposition to look towards speakers' mouths remains present in the second year [73], [74] and slowly diminishes during later childhood, with 5-year-old children showing instead a balanced attention between the talker's eyes and mouth when perceiving native speech [67], [75], [76].…”

“…This is a different situation as compared to what happens in most of the studies that have examined the role of talking faces for language learning during infancy using screen-based tasks. Indeed, in virtually all these studies (including some work from the co-authors), non-contingent face-stimuli appear often exaggerated in size, and presented against a rather neutral background, with no or very few distractors on a computer screen (e.g., [62], [64], [66], [67], [69], [72], [74], [82]. Here, we argue that these presentation characteristics could lead to a distortion of the perceptual saliency of talking faces and their role in guiding infants' attention and language processing and learning.…”

The Role of Talking Faces in Infant Language Learning: Mind the Gap between Screen-Based Settings and Real-Life Communicative Interactions

“…Given that 6 months of age is also the stage where infants’ endogenous control starts to emerge [ 68 , 69 ], this would allow them to exert top-down control to specific subparts of a speaker’s face and voluntarily deploy more of their attention into the speaker’s mouth. Indeed, the onset of this mouth preference has been confirmed to emerge at around 6–8 months of age by more recent studies [ 44 , 45 , 46 , 47 , 70 , 71 , 72 , 73 ] and seems to present its peak at around 18 months of age [ 46 , 74 ]. This disposition to look toward speakers’ mouths remains present in the second year [ 75 , 76 ] and slowly diminishes during later childhood, with 5-year-old children typically showing balanced attention between the talker’s eyes and mouth when perceiving native speech [ 46 , 77 , 78 ].…”

“…This is a different situation compared to what has happened in most studies examining the role of talking faces for infant language learning using screen-based tasks. Indeed, in virtually all these studies (including some work from the authors), non-contingent face stimuli have often appeared exaggerated in size and presented against a rather neutral background with no or very few distractors on a computer screen (e.g., [ 42 , 44 , 46 , 70 , 72 , 74 , 76 , 84 ]). These presentation characteristics could lead to a distortion in the perceptual saliency of talking faces and their role in guiding infants’ attention and language processing and learning.…”

Music, a piece of many puzzles in developmental science

“…(2023) report findings from low‐income preschoolers on a music‐based self‐regulation intervention, while Alviar et al. (2023) explore the impact of infant‐directed (ID) song on infants’ attention to caregivers’ mouths in support of language development.…”