Comparison between the motoric constraints for Amer-Ind and ASL sign formation

Previous research has shown that Amer -Ind signals are more easily learned and remembered than their synonyms in American Sign Language. One possible reason is a difference in motoric complexity between the two systems. To test the hypothesis that such a difference exists, the positions and movements that constitute the 236 signals of Amer -Ind Code were compared with those of their synonyms in American Sign Language. It was found that the ASL signs were indeed more complex in terms of changes of hand orientation during production, the use of two hands rather than one, the number of different handshapes used, and the total amount of movement required. When the two systems were compared in terms of the normal development of finger, hand, and arm movements, it was found that more Amer -Ind signals than ASL signs are within the competence of infants at both the 6-month and 12-month levels. Relative to the motor coordination required to execute both systems, it was concluded that the Amer -Ind corpus is less complex than a matched group of ASL signs.