THE DEVELOPMENT OF INDEPENDENT MUSCULAR CONTROL OF SEPARATE EYELIDS IN TWO RACIAL GROUPS, EUROPEAN AND POLYNESIAN

The ability to control separate eyelids independently (‘the voluntary winking ability’) is studied in 527 subjects of European stock and in 262 Polynesians, with the following results: (1) In both groups, there is a significant correlation between voluntary winking ability and age. (2) Winking ability of the males is not significantly greater than that of the females. (3) In children under 10 years of age, the incidence of non‐winking is significantly higher than in the remaining subjects. (4) In the European group, but not in the Polynesian, the incidence of those who could wink both eyes readily and with approximately equal facility is significantly lower in those who are 10 years and under, than in subjects over 10. (5) In those subjects of European stock who could wink one eye only or could wink one eye more easily than the other, a preponderance of the use of the left eye for winking is found. This is mainly due to the preference for winking the left eye which is seen in those who are under 10 years. However, in the Polynesians there is no significant difference between the frequency of winking each eye.