The Effect of Touch on Emotion Recognition across Age Groups

In an examination of age differences in relation to emotion recognition, this experiment explored the effect of touch on participants’ accuracy in correctly identifying angry, disgusted, fearful, happy, neutral, and sad emotional faces. The experimental group was stroked with a paintbrush on their forearm while viewing the emotional face pictures. For exploratory purposes, young adult (N=18) and older adult (N=28) participants also viewed sketches of touching dyads. They reported their frequency of and comfort with observing, receiving, and performing the portrayed touch gestures. This study replicated previous findings that state older adults less accurately identify angry, fearful, and neutral faces. Touch was not found to be significant by itself but a non-significant trend between touch, age group, and gender provides some avenues for further investigation. The results of this experiment, when taken in the context of the current literature, fits within the neuropsychological model for understanding age differences in emotion recognition. Recommendations for future research focus on methodological improvements. TOUCH AND EMOTION RECOGNITION IN AGING 3 The Effect of Touch on Emotion Recognition across Age Groups Our sense of touch informs the human experience by influencing perception, communication, and health throughout our lives (Hertenstein & Weiss, 2011). New findings in a variety of fields suggest the effect of touch is even more pervasive than we currently understand (Coan, Schaefer, & Davidson, 2006; Olausson, Wessberg, Morrison, McGlone, & Vallbo, 2010; Papathanassoglou & Mpouzika, 2012). In a study where married women were threatened with an electric shock but given either their husband’s hand, an experimenter’s hand, or no hand at all, a noticeably lower arousal level and lower level of threat neural responses was found in the women who were given a hand to hold (Coan et. al, 2006). Providing physical contact was, in that experiment, a calming force. Other research shows patients in critical care experience a reduction in stress levels when nurses use interpersonal touch during their interactions (Papathanassoglou & Mpouzika, 2012). Recent studies on brain functioning have found that the parts of the brain that are responsible for emotional and social processing are affected by touch (e.g., Olausson et al., 2010). It appears from these findings that touch is a vital part of our social connections with the people around us on a neurologically based emotional level. The Role of Touch on Emotion Recognition Past research has demonstrated that touch affects our emotions but, until recently, little was know on the role touch places in emotion recognition. Research focused on event-related potentials (ERPs) has begun to explore this field. ERP is brain activity that occurs in response or in anticipation of an event (Luck, 2005). It has been found that the presence of a friend or a machine touching participants’ forearms during an emotional processing task positively influences ERP correlates that are associated with picture processing (Schirmer et al, 2011). This indicates that the brain activity found as a result of touch is related on a neurological level to TOUCH AND EMOTION RECOGNITION IN AGING 4 picture processing. Furthermore, the pattern of an ERP known as the late positivity component (LPC) indicates that the effect of touch on recognition is strongest when viewing emotional, rather than neutral, images (Schirmer et al, 2011). These findings are being continued in an ongoing ERP study where researchers are discovering a connection between touch, using a paintbrush on the forearm of participants, and early sensitivity to emotional faces (but not to neutral stimuli) in female participants (A. Schirmer, personal communication, August 7, 2012). From these findings, it appears that emotion stimuli are processed differently when touch is present and people are able to recognize emotional stimuli more accurately as a result; thus suggesting that touch triggers a socially beneficial increase in attention levels (Schirmer et al, 2011). Furthermore, the act of viewing another person while they are receiving touch activates multiple cortices, including the somatosensory cortex, usually associated with tactile perception (Keysers et al., 2004; Blakemore, Bristow, Bird, Frith, & Ward, 2005). Research has also found a significant connection between the somatosensory cortex and emotion recognition (Adolphs, Damasio, Tranel, Cooper, & Damasio, 2000; Pitcher, Garrido, Walsh, & Duchaine, 2008). The visual remapping of touch (VRT) is a theory that postulates that being touched while viewing another person being touched activates mirror responses in the brain that increase emotion recognition accuracy (Ladavas & Serino, 2010). A VRT study found that simultaneous touch occurring on an image and to the observer who is rating that image increases somatosensory activity, which resulted in more accurate facial fear recognition (Maister, Tsiakkas, & Tsakiris, 2013). Based on these findings, somatosensory activity seems to be strongly associated with both touch and emotion recognition. These results, in combination with the ERP findings, strongly suggest that touch is connected to emotion recognition on a neurological level. TOUCH AND EMOTION RECOGNITION IN AGING 5 Age Differences in Emotion Recognition Emotion recognition research has been exploring age differences, in addition to touch differences. Previous research on emotion recognition and aging has found young adults perform better than older adults on emotion recognition tasks (e.g., Isaacowitz et al., 2007; Murphy & Isaacowitz, 2010; see Isaacowitz & Stanley, 2011 for a review). Young adults are generally better at accurately identifying emotions but that the trend varies across different tasks (Isaacowitz et al., 2007). Still, over-arching trends with specific emotions can be found. In a literature review of the field Isaacowitz & Stanley (2011) explain the following: 1) Older adults are generally worse at identifying fearful and sad faces, 2) Young adults also sometimes more accurately identify angry and neutral faces, 3) Though still sometimes following the trend that young adults are better at emotion recognition, happiness and surprise often result in more conflicting and smaller age differences, and 4) Going against the general trend, older adults are often equally accurate or more accurate than young adults at identifying disgust (Isaacowitz & Stanley, 2011). Existing research indicates that age differences in emotion recognition are different depending on the emotion of the stimuli. Age differences in emotion recognition have been well established and explored, but researchers have been unsuccessful in identifying their source. Previous studies have failed to account for any age related deficit in emotion recognition as a byproduct of larger cognitive and perceptual changes in older adults (Keightley, Winocur, Burianova, Hongwanishkul, & Grady, 2006; Sullivan & Ruffman 2004). This has led researchers to investigate other areas related to emotion recognition that might be the cause of age differences. Research has identified differences in where young and older participants hold their gaze (e.g., Isaacowitz, Wadlinger, Goren, & Wilson, 2006; Sullivan, Ruffman, Hutton, 2007; Wong, Cronin-Golomb, & TOUCH AND EMOTION RECOGNITION IN AGING 6 Neargarder, 2005). It is possible that older adults are simply not looking at advantageous regions of the face to accurately recognize emotions. For example, when rating emotional faces accurately, young adults tend look more at the eyes, an emotionally expressive facial feature, than at the mouth, where there is less emotional information; but, older adults are more likely to look at the mouth during emotion recognition tasks (Sullivan et al., 2007). Though this concept is highly relevant, it is not the focus of this study. To date none of these tactic-based findings have fully explicated the cause of age differences during emotion recognition tasks. Another approach to exploring age differences in emotion recognition is to use different mechanisms in an attempt to improve the accuracy of older adults. Context has been shown to be a key factor in reducing age differences and explaining age related deficits (e.g., Colonia-Willner 1998; Hess, 2005). These studies have found that providing participants with more contextual information in experimental situations helps older adults to perform better, often significantly decreasing age related differences previously found. It has also been theorized that experiments designed to be more similar to everyday life would result in older and younger adults performing at the same level of accuracy in emotion recognition tasks (Isaacowitz & Stanley, 2011). A recent study (Noh & Isaacowitz, 2012) explored the possibility that providing emotional context would improve the accuracy of older adults by providing more realistic emotion recognition tasks. Participants rated faces on bodies displaying the same emotion (congruent), a different emotion (incongruent), or a neutral expression. Older adults’ performed more accurately with the use of congruent emotional context between the displayed facial expressions and body expressions. Context research suggests that older adults may be affected more by the addition of aiding mechanisms. In the current study, we attempt to improve the accuracy of participants through a different aiding mechanism, touch. TOUCH AND EMOTION RECOGNITION IN AGING 7 Why Investigate Touch? All the research about touch and its relation to emotion recognition indicates that touch is very important to social and emotional life; yet, little has been done to explore how tactile experiences may influence older adults. While conducting the current study, new research on touch, aging and the somatosensory cortex was found. In an fMRI study, older adults processed a simple stimul