Attention-sensitive signalling by 7- to 20-month-old infants in a comparative perspective

Area of Science:

• Developmental Psychology
• Pragmatics
• Evolutionary Linguistics

Background:

• Attention-sensitive signalling is a pragmatic skill where signallers adapt communication to the recipient's attentional state.
• Understanding its development in infants is key to language acquisition and evolutionary history.

Purpose of the Study:

• To provide comprehensive evidence for the onset and development of attention-sensitive signalling in human infants aged 7–20 months.
• To investigate the influence of maternal factors (visual attention, infant-directed speech, tactile contact) on infant signalling adjustments.
• To explore the significance of these skills for language acquisition and evolutionary origins.

Main Methods:

• Studied 30 mother-infant dyads across three developmental periods: 7–10, 11–14, and 15–20 months.
• Observed interactions in naturalistic settings.
• Classified infant signals by sensory modality and analyzed proportions relative to maternal visual attention, infant-directed speech, and tactile contact.

Main Results:

• Maternal visual attention and infant-directed speech significantly influenced the onset and development of infants' communicative adjustments.
• Infants first inhibited silent-visual signals (unimodal adjustment) towards inattentive mothers before deploying audible or contact signals (cross-modal adjustment).
• Maternal infant-directed speech facilitated unimodal adjustment, preference for oral over gestural signals, and audio-visual signal combinations. Breakdowns in maternal attention increased audible-oral signals.

Conclusions:

• Attention-sensitive signalling emerges and develops significantly between 7 and 20 months in human infants.
• Maternal scaffolding, particularly through infant-directed speech, plays a crucial role in developing these pragmatic skills.
• The findings suggest a link between shared attentional resources in parent-infant interactions and the evolution of modern language.