Judi James analysed footage taken of the family's Christmas Day outing to St Mary Magdalene in Sandringham, Norfolk.
Kate was dressed in a chic dark green coat and hat while Charlotte, 7, wore a buttoned burgundy coat and stockings. Prince William and Prince George, 9, matched in navy suits and light blue ties while Prince Louis, 4, looked smart in a navy buttoned coat with a black collar.
Photos showed the family during their walk, with Prince Louis holding onto his mother's hand while George and Charlotte strolled alongside their parents.
Speaking to The Mirror, Judi said it appeared the royals were taking a "hands-off" approach with their parenting, evident through a number of "intentional gestures".
"William and Kate showed off their children with the usual signals of pride and it was clear they are now becoming 'hands-off' parents as their children grow in confidence," she told the publication.
"Charlotte was pulling ahead as they walked towards the church and George has gone from being the rather shy-looking boy holding his father's hand to the older brother keeping an eye on and showing nurturing and directional signals towards four-year-old Louis.
Judi added that George "mirrored" his father and was protective towards his younger brother.
"One of the sweetest and most poignant body language signals was the sight of George using touch, chat and bending rituals to signal he is now in the role of protector and 'keeping-an-eye-on' monitor for his younger brother Louis," she said.
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