Eleven infant–mother dyads in Crete were videod during spontaneous interactions at home, from the second to the sixth month of life. Micro‐analysis was used to investigate‘coordination'and ‘non‐matching’ of facial expressions of emotion. ‘Emotional coordination’ was evaluated with four measures: matching of facial expressions, completion when one responded to the other with ‘pleasure’ or ‘interest’, synchrony by matching frequency of change or rhythm of emotional expressions, and attunement when shifts of emotional intensity of the two partners were in the same direction.‘Emotional non‐matching'was coded when neither the infant nor the mother showed interest in interacting with the other. In emotional coordination or non‐matching between mother and infant, who performed first was also recorded. We obtained evidence of emotional matching, synchrony, and attunement. Importantly, the probability of emotional non‐matching by the infant was higher than the probability of emotional matching and completion, indicating a tendency for thoughtful attention or playful rivalry in the responses of infants, who also initiated emotional matching, completion, and non‐matching more frequently than mothers. The probability of expression of emotional matching, completion, and non‐matching changed with age. Both mothers and infants act to obtain sympathetic complementarity of feelings and co‐operative inter‐synchrony of actions. Copyright © 2016 John Wiley & Sons, Ltd.