In a now-famous experiment in the 1970s, mothers were asked to sit across from their seated infants, but instead of saying “hello”, smiling or cooing, the mothers were told to remain expressionless and unresponsive.
Their babies got very distressed very quickly.
As reported by developmental psychologist Edward Tronick in his 1978 paper: “The infant orients toward the mother and greets her. But when she fails to respond, he sobers and looks wary.
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