How do infants perceive scrambled face?: A near-infrared spectroscopic study

Area of Science:

• Neuroscience
• Developmental Psychology
• Biomedical Engineering

Background:

• Face perception is crucial for social development.
• Understanding early face processing aids in identifying developmental trajectories.
• Hemispheric specialization in the infant brain is an area of active research.

Purpose of the Study:

• To investigate hemispheric differences in brain activity in response to canonical and scrambled faces in infants and adults.
• To compare face perception mechanisms between infants and adults using a novel NIRS approach.
• To explore developmental changes in right hemisphere dominance for face recognition.

Main Methods:

• Utilized near-infrared spectroscopy (NIRS) to measure changes in oxygenated hemoglobin (oxy-Hb), deoxygenated hemoglobin (deoxy-Hb), and total hemoglobin (total-Hb).
• Employed a newly developed, infant-friendly NIRS probe for awake recordings.
• Presented canonical and scrambled face stimuli to 7- to 8-month-old infants and adults.

Main Results:

• Infants showed greater total-Hb in the right hemisphere for canonical faces compared to scrambled faces, indicating right hemisphere dominance.
• Adults exhibited increased oxy-Hb and total-Hb in the right hemisphere for canonical faces.
• Both age groups demonstrated greater right hemisphere engagement for canonical face stimuli, though adult responses were more modest than infant responses.

Conclusions:

• The findings suggest right hemisphere dominance for canonical face perception is present early in development (by 7-8 months) and persists into adulthood.
• This study provides novel data on infant responses to scrambled faces and highlights developmental shifts in face processing.
• Acknowledges potential methodological and physiological factors influencing inter-group comparisons, necessitating cautious interpretation of adult-infant differences.