Transparency of one-handed Amer-Ind hand signals to nonfamiliar viewers

Thirty non-brain-damaged adults viewed 104 videotaped Amer-Ind hand signals. The majority of these hand signals were produced with one hand; 60 originally one-handed gestures and 31 left-hand adaptations of two-handed gestures were included in the data analyses. Nineteen subjects were between the ages of 20 and 30 years (younger group), and 11 subjects were between the ages of 50 and 69 years (older group). After viewing each hand signal twice in succession, the subjects wrote at least one word for that signal's meaning. The mean percentage of one-handed signals correctly identified was 48.2%; these signals varied widely in transparency (0% to 100%). The left-hand adaptations were significantly lower in transparency than the originally one-handed signals. The younger and older subjects did not differ in the mean percentage of one-handed signals they identified correctly (49.0% and 46.4%, respectively). However, some individual hand signals were easier for the younger subjects to identify; the opposite was also true.