Answer: Social referencing
Explanation: The concept of learning or emulating people especially adults within the environment by infants could be regarded as social referencing. Infants often try to reproduce actions they watch their elders, guardians or parents perform. The concept of social referencing could involves how infants apply what they've seen their parents do to respond or react to similar situations or occurrences within their environment. The positive expression or reaction exhibited by Phyllis's brother encouraged the consumption of the delicacy by the infant. A negative expression might have had a negative impact and hindered the infant's desire to consume the food.