Age-Related Changes in Detecting Happiness: Discriminating Between Enjoyment and Nonenjoyment Smiles Gillian Slessor, Lynden K. Miles, Rebecca Bull, and Louise H. Phillips University of Aberdeen The present study investigated age-related changes in the ability to discriminate between distinctions in the emotion underlying enjoyment and nonenjoyment smiles, both when making explicit decisions about feelings of happiness and when making social judgments of approachability. No age differences were found in the ability to discriminate between these two types of smile. However, older adults demonstrated a greater bias toward reporting that any smiling individual was feeling happy. Older adults were also more likely to choose to approach an individual who was displaying a nonenjoyment smile. Implications of these findings for older adults’ interpersonal functioning are discussed. Keywords: smiles, aging, positivity bias, emotion Many studies report evidence of age-related impairments in emotion recognition, predominantly when recognizing facial ex- pressions of anger, fear, and sadness. Compared with the findings for negative emotions, age-related declines in happiness perception are rarely significant and are of substantially smaller effect size (see Issacowitz et al., 2007; Ruffman, Henry, Livingstone, & Phillips, 2008, for reviews). Relatively spared perception of pos- itive compared with negative expressions may be linked to more general biases in processing positive information in old age (Wil- liams et al., 2006). According to the socioemotional selectivity theory (SST; Carstensen, Fung, & Charles, 2003), when time is perceived to be limited, as in older age, individuals focus on optimizing positive emotions and avoiding negative interactions. This may link to an age-related improvement in emotion regula- tion, with older adults exhibiting a positivity bias both when attending to and recalling emotional material (Leighland, Schulz, & Janowsky, 2004; Mather & Carstensen, 2003). In studies investigating age differences in the ability to recog- nize positive facial expressions (i.e., smiles), researchers have asked participants to decide which of six basic emotions (anger, fear, sadness, disgust, surprise, or happiness) a smiling individual is portraying. In studies with this task, at least one of the age groups shows ceiling effects (Issacowitz et al., 2007), thereby limiting the potential to detect age-related differences in happiness perception. It is thus important to use measures that provide more sensitive indices of the recognition of positive emotion to inves- tigate age differences in the perception of happiness. We address this issue in the present research by using stimuli that portray subtle but socially meaningful differences in smile physiognomy. These differences pertain to the underlying emotional experience of an individual, detection of which has been argued to be critical to effective social interaction (Johnston, Miles, & Macrae, in press; Miles, 2009; Miles & Johnston, 2007; Owren & Bachorowski, 2001). This approach provides a means to assess sensitivity to functional distinctions in emotional meaning between positive expressions rather than treating all smiles as a single generic expression. It has been argued that morphological distinctions can be made between smiles related to an underlying experience of positive emotion (i.e., enjoyment smiles) and smile-like social signals unrelated to internal emotional states (i.e., nonenjoyment smiles) by examining the muscles involved in their production (e.g., Ekman, 2001; Frank, 2002; Frank, Ekman, & Friesen, 1993). The contraction of the zygomatic major muscles lifts the corners of the mouth obliquely upward into the typical smile shape. However unlike nonenjoyment smiles, enjoyment smiles also involve the contraction of the orbicularis oculi muscles, which produce changes to the eye region (Ekman, Davidson, & Friesen, 1990), including narrowed eyes, wrinkles around the outer corners, and lowered eyebrows (see Frank, 2002, for an overview). These differences provide a reliable source by which perceivers can detect the emotional state of a smiling individual. Younger adults are sensitive to differences in emotional mean- ing between deliberately posed nonenjoyment smiles and sponta- neously expressed enjoyment smiles, categorizing more of the latter as reflecting genuine feelings of happiness when judging static images, video displays, and real-life interactions (Frank, Ekman, & Friesen, 1993; Miles & Johnston, 2007; Scherer & Ceschi, 2000). Younger participants also differentiate between enjoyment and nonenjoyment smiles when making more implicit judgments (Frank et al., 1993; Mehu, Little, & Dunbar, 2007; Peace, Miles, & Johnston, 2006). Because these smiles have very different social meanings, the ability to distinguish between them is important for effective interpersonal functioning (Ekman, 2001). Boraston, Corden, Miles, Skuse, and Blakemore (2008) found that autistic individuals who had the most difficulty differentiating between smiles also had the greatest impairments in social inter- Gillian Slessor, Lynden K. Miles, Rebecca Bull, and Louise H. Phillips, School of Psychology, University of Aberdeen, Aberdeen, Scotland, United Kingdom. This research was supported by the Carnegie Trust. Correspondence concerning this article should be addressed to Gillian Slessor, School of Psychology, College of Life Sciences and Medicine, Aberdeen University, Aberdeen, AB24 2UB, Scotland, United Kingdom. E-mail: gillian.slessor@abdn.ac.uk Psychology and Aging © 2010 American Psychological Association 2010, Vol. 25, No. 1, 246 –250 0882-7974/10/$12.00 DOI: 10.1037/a0018248 246