Piagetian Perspectives on Research with Deaf Subjects
In the preceding chapter, Hans Furth has offered a wide-ranging survey of studies of the cognitive abilities of deaf children and adolescents and concluded that there is considerable evidence for their general, underlying competence. Although group comparisons sometimes indicate that deaf subjects perform significantly below the hearing, the distributions are typically overlapping, as some deaf subjects perform better than the average hearing subjects, and some hearing subjects perform worse than the average deaf subjects. Clearly, deafness is not a sufficient cause for below-average performances. Moreover, there are a number of instances where there are no differences between deaf and hearing groups. This suggests that any shortcomings displayed by deaf subjects are likely to be due to some other factor than a general cognitive deficiency. Likely possibilities include the lack of incentives to perform well, insufficient experience or practice on the relevant tasks, incomplete understanding of the task requirements, and poor rapport with the examiner. Indeed, hearing subjects who grow up in impoverished circumstances also perform less well on a variety of cognitive tasks for some of these same reasons.