The Effect of Training on Haptic Classification of Facial Expressions of Emotion in 2D Displays by Sighted and Blind Observers
Haptics , Face Perception , Blindness , Learning , Facial expressions of emotion , 2D raised-line drawings
Abstract The current study evaluated the effects of training on the haptic classification of culturally universal facial expressions of emotion as depicted in simple 2D raised-line drawings. Blindfolded sighted (N = 60) and blind (N = 4) participants participated in Experiments 1 and 3, respectively. A small vision control study (N = 12) was also conducted (Experiment 2) to compare haptic versus visual learning patterns. A hybrid learning paradigm consisting of pre/post- and old/new-training procedures was used to address the nature of the underlying learning process in terms of token-specific learning and/or generalization. During the Pre-Training phase, participants were tested on their ability to classify facial expressions of emotion using the set with which they would be subsequently trained. During the Post-Training phase, they were tested with the training set (Old) intermixed with a completely novel set (New). For sighted observers, visual classification was more accurate than haptic classification; in addition, two of the three adventitiously blind individuals tended to be at least as accurate as the sighted haptic group. All three groups showed similar learning patterns across the learning stages of the experiment: accuracy improved substantially with training; however, while classification accuracy for the Old set remained high during the Post-Training test stage, learning effects for novel (New) drawings were reduced, if present at all. These results imply that learning by the sighted was largely token-specific for both haptic and visual classification. Additional results from a limited number of blind subjects tentatively suggest that the accuracy with which facial expressions of emotion are classified is not impaired when visual loss occurs later in life.