Emotional expression in deaf and hearing populations

The expression of emotion is a crucial part of everyday social interaction. This may be especially true of deaf populations. Studies show that the perception of emotions can differ between deaf and hearing people. On the one hand, sign language knowledge may contribute to more accurate identification of facial expressions (Goldstein & Feldman, 1996). On the other hand, deaf people can experience delays in emotional perception, as a result of delays in language exposure (Martins et al., 2019; Ziv et al., 2013). But no study to date has compared the production of emotional expressions by deaf and hearing adults. Our study is the first of its kind with the goal of determining specifically whether sign language knowledge and deaf experience lead to differences in the production of emotional expression of deaf and hearing individuals. We recruited 45 participants, representing three groups: (1) hearing non-signers (speaking), (2) hearing signers (in two conditions, signing and speaking), and (3) deaf signers (signing). The participants performed a language-related task eliciting emotional sentences in which the emotion and its expression were congruent. Our study is unique because we used facial tracking technology and machine learning techniques to describe and distinguish the four emotional conditions produced — sadness, happiness, anger and neutral. The results of the study show that deaf and hearing individuals differ in systematic ways, demonstrating that each group can be classified accurately based on their emotional expressions.