that shows overall preference strength. This scale places a positive value to right-handed actions and a negative value to left-handed actions. According to this scale there was a significant rise in frequency of right-handedness in bipedal reaching and a greater frequency overall in bipedal action. Contrarily there was little interaction in the bipedal tool use.The authors offer several mechanisms through which bipedalism may affect a particular hand preference. One view offered is that the quadrupeds, not habitually standing bipedally, are influenced by the greater specialization required in order to perform such manual actions. The authors keenly take note that this would not explain this experiments findings pertaining to the use of complex tools and the apparent lack of handedness associated with it. It is perplexing as to why no hand preference would be associated with reaching and not tool use. The authors recognize bipedalism as a trait that truly distinguishes man from other primates. They note several schools of thought concerning why handedness may have occurred evolutionarily. One such school of thought asserts that bipedalism is an evolutionary effect of tool use. That is primate ancestry may have realized the advantage of tool use and selection passed traits of handedness that in turn allow greater manual dexterity while standing bipedally. The cultural significance of this dexterity increase is evident in all aspects of human tool use. On the other hand one very much contradicting school of thought suggests that selection pressures in ancient primates may have been biased toward handedness due to feeding and postural support benefits.Regardless of untied evolutionary ends this experiment provides us with several useful conclusions: 1)posture significantly affects hand preference in tufted capuchin monkeys. 2)Tufted Capuchins exhibit a right-hand bias in the case of reaching but not in tool use. 3)The monkeys do exhib...
