Children's perception of posed basic-emotion faces

Chapter 3 endnote 11, from How Emotions are Made: The Secret Life of the Brain by Lisa Feldman Barrett.
Some context is:

...psychologists James A. Russell and Sherri C. Widen showed that two- and three-year-old children, when shown basic emotion facial configurations, are not able to freely label them until they possess clearly differentiated concepts for “Anger,” “Sadness,” “Fear,” and so on. Such young children use words like “sad,” “mad,” and “scared” interchangeably, like adults who exhibit low emotional granularity.

A program of research from the noted affective scientist, James Russell, and his former student (now colleague) Sherri Widen, does not support the classical view.  Before two-year-olds know the words for multiple negative emotion categories, they can reliably distinguish only between positive and negative faces. Yet as children learn the meaning of words for other negative emotions, they become able to distinguish between categories of negative faces. By contrast, children with specific language impairment, who have difficulty naming faces, are much more likely to confuse emotions (e.g., sadness with anger) than their typically developing peers.

Russell & Widen find that toddlers start off with broad affective categories (feels good - feels bad) which then begin to narrow around the age of two, until they take on the structure of adult-like categories for anger, sadness, fear, happiness, disgust, and so on in middle school.  (This broad-to-fine process is similar for other categories that children learn, such as animals.) Children start off as low in granularity for their emotion concepts and then progressively become more granular as their conceptual system for emotion becomes more and more differentiated.

• Two-year-olds from the U.S. and Canada use emotion words like happy, sad and mad, but they use sad and mad interchangeably, as well as to refer to other unpleasant emotions like disgust and fear.
• By age three, they are using the word anger correctly (about 80% of the time, compared to happy at over 90% of the time).
• By age 4, they are using sad correctly (over 80% of the time), angry (90% of the time) but fear and surprise are still around 40% and disgust is around 10%.
• Surprise reaches 80% around age 6, fear never makes it past 65% at the age 9, and disgust is at 50% at age 9.

Words, rather than facial movements (i.e., expressions), drive emotion perception in children. Young children have an easier time matching a face to a word (a scowling face to the word “angry”) than they do matching two scowling faces to each other as examples of the category “anger.” This is consistent with the finding that words help 1-year-old children process objects.

In fact, young children have a difficult time categorizing even the most stereotyped facial poses.  They show what is called a “face inferiority effect.” For example, on a storytelling task, 3 and 4 year old children have a  more difficult time generating causes for facial expressions (a scowl) than for a word (anger) or for consequences (a scream).  The face inferiority effect is very robust across age groups in kids (3-10) and a variety of different experimental tasks. It's also similar to the context effects we see in emotion perception studies in adults.  When it comes to perceiving emotion in another person, almost everything trumps the face (a voice, a body, the surrounding context).  Even 5 month old infants rely more on vocal cues than faces when distinguishing positive and negative, and the ability to distinguish affect in visual cues alone develops later (on average, at 7 months of age) than for auditory cues (on average, at 5 months), although infants first learn to distinguish positive from negative with combined cues (4 months).

So, if you have trouble figuring out how someone is feeling by looking at his or her face, you are not alone.  And if you find it easy, you are probably, without knowing it, using the surrounding context, including the emotion words and concepts that are most accessible to you in that moment.  

Other studies

In a study of 17 infants at 7 months old, each infant viewed a single posed fear expression and a single posed anger expression while their electrical signal across the brain (EEG) was recorded continuously. The pattern of electrical signal differed between the fear and anger expressions, a finding that the authors interpreted to mean that the infant brain’s distinguished the perceptual features of the two faces, although more than that cannot be determined.

For children greater than 12 months, an experimental method is used called social referencing. Experimenters stage an event with an ambiguous outcome, such as crawling over a visual cliff, and a parent or adult experimenter provides a nonverbal cue to the infant who must categorize it to know how to act. Most of these experiments have parents pose facial expressions that differ in valence (happy vs. afraid, or happy vs. angry) or differ in arousal (happy vs. surprised), so these studies give evidence of infants’ affect concepts but not really of their emotion concepts.

Boone & Cunningham (1998) studied 4-, 5-, and 8-year-olds to investigate their ability to categorize happiness, sadness, anger and fear in the expressive body movements of dance. Five-year-olds could categorize fear and sadness above chance, but this could have been due to arousal alone, rather than emotion. Eight-year-olds and adults achieved better than chance for all categories.