Claiming evidence from non-evidence: a reply to Morton and Harper.

Morton and Harper (2007) argue that research presented in support of a bilingual advantage in the development of executive control has been confounded with social class, the actual mechanism for group differences. As evidence, they report a study in which a small group of monolingual and bilingual 6- and 7-year-olds performed similarly on a Simon task. The present paper points to weaknesses in their experimental design, analysis, and logic that together undermine their criticism of the conclusion that bilingualism is responsible for the reported group differences.