As human beings, we are particularly adept at discerning the emotions of others. Whether it’s our angry boss, saddened family members, or happy friends, we usually succeed at identifying emotional expressions in other people. These judgments let us adjust our behavior accordingly in complex social situations. It has allowed our species to avoid people who would do us harm, embrace people who need support, provide empathy to others, and bond with one another.
Overall, reading the emotions of the people around us has been (and continues to be) highly advantageous. Importantly, this vital social skill begins to develop at an early age. In fact, infants begin to show signs of detecting different emotions within the first year of life! So, how exactly do children come to understand different emotions? What information can they gather from emotional reactions and facial expressions at various ages? Although many questions on this topic remain, developmental psychologists have uncovered some interesting information about how emotion understanding develops across the first few years of life.
Infants as young as 4 months of age have been shown to discriminate between different emotions.1 That is, when infants are shown pictures of different facial expressions, they look at different emotions (such as joy and anger, or joy and neutral expressions) for different amounts of time. Since babies at this age aren’t capable of speaking yet, and their muscle movements are limited, looking at something for a longer amount of time is a baby’s way of showing interest or preference. Ultimately, the results of this study indicate that the babies recognized something was different about these images and preferred to look at the joyful one. However, this does not tell us whether they can draw any particular information from these different emotional displays.
By 5 months, many infants can discriminate between the vocal expressions of different emotions.2 In studies where infants are shown a single image of a face, but the voice changes from one emotional tone to another, babies begin looking at the image again directly after the voice changes. So, for example, if the baby is staring at a face while they hear a happy voice for a long time, eventually they will get bored and start to look elsewhere. Then, when the voice changes to a sad emotional tone, the babies begin looking back toward the face again. 5 month old infants show this reaction for happy, sad, and angry emotional tones. This tells us that at 5 months of age, babies are sensitive to changes in emotional tones of voice.
From this information, we can tell approximately when infants start to tell different facial expressions and emotional tones of voice apart. But when do they start to integrate this information in order to formulate a sense of emotional meaning across face and voice? To investigate this question, researchers have used something known as the “intermodal matching paradigm”. This involves showing babies 2 different video clips along with 1 audio clip. If the infants recognize that the emotion of the audio clip matches the emotion shown in one of the videos, the infant should spend more time looking at the matching video clip. In just such a paradigm, one group of researchers have found that by 5 months, babies look longer to the matching face when the emotions are happy, sad, and neutral, and the voice is in synchrony with the video.3 The same study also found that 7 month old infants are capable of looking more toward the matching face, even when the audio track is not in synchrony with the videos. This tells us that the 5 month old infants appear to rely heavily on synchrony to match emotional faces to voices, but 7 month olds are able to pick up on more subtle emotional information in order to match emotional faces and voices.
As babies get older and move into the second year after birth, they begin to see emotions as informative for recognizing someone else’s desires.4 To investigate this idea, another group of researchers showed toddlers an actor reacting to tasting different types of food (such as broccoli and goldfish). The experimenter would taste both foods and react happily to one type, and disgusted to the other. The children were then given both types of food, and the actor asked the child to give them one of the snacks. The researchers found that 14-month-olds would only provide the actor with whichever food they personally prefer, regardless of the actors reactions to the food. This means that when the actor showed disgust toward goldfish but happiness toward broccoli, the 14-month-olds would still give the actor goldfish when they asked for a snack. 18-month-olds, on the other hand, provide the actor with whichever food she expressed happiness toward (even when it was broccoli!). This indicates that by 18 months of age, children begin to recognize that emotions can be used to make inferences about another person’s preferences.
By the time they are 2 years old, children frequently talk about emotions.5 They are capable of labeling both positive and negative emotions such as “happy”, “sad”, and “angry”, and they use these labels to describe both how they are feeling, and how other people are feeling. By 3 years of age, many children are successful in labeling the emotions that a puppet portrays in brief vignettes, although there is a decent amount of variability between individual children.6 This skill is especially impressive, as puppets do not provide the facial cues that human beings frequently use to identify emotions. Therefore, 3-year-old children appear to be basing their accurate emotional judgments on just the vocal tone of the puppeteer and situational cues.
All in all, the first few years of life involve a significant amount of emotion learning. Babies begin exploring their world with little concept of social cues or situations, but by the time they are just 3 years old, they can correctly label and recognize emotions, as well as identify them in situations. This rapid development of emotion understanding serves to show just how incredible the early years of human development are, and how important emotions are to human beings.
1 La Barbera, J. D., Izard, C. E., Vietze, P., & Parisi, S. A. (1976). Four- and six-month-old infants’ visual responses to joy, anger, and neutral expressions. Child Development, 47, 535–538.
2 Walker-Andrews, A. S. & Lennon, E. (1991). Infants’ discrimination of vocal expressions: Contributions of auditory and visual information. Infant Behavior and Development, 14(2), 131–142.
3 Walker, A. S. (1982). Intermodal perception of expressive behaviors by human infants. Journal of Experimental Child Psychology, 33(3), 514–535.
4 Repacholi, B. M. & Gopnik, A. (1997). Early reasoning about desires: evidence from 14- and 18-month-olds. Developmental Psychology, 33(1), 12–21.
5 Wellman, H. M., Harris, P. L., Banerjee, M., & Sinclair, A. (1995). Early understanding of emotion: evidence from natural language. Cognition and Emotion, 9(2/3), 117–149.
6 Denham, S. A. (1986). Social Cognition, Prosocial Behavior, and Emotion in Preschoolers: Contextual Validation. Child Development, 57(1), 194–201.