Selective deficits in developmental cognitive neuropsychology: An introduction.

Traditionally, neuropsychologists have studied selective impairments in patients who suffered brain damage as adults. These selective impairments have revealed much about cognitive organization in normal brains (Shallice, 1988; Zeki, 1993) and have initiated major research programmes (Forde & Humphreys, 2002; Milner & Goodale, 1995; Shallice, 1988; Yin, 1969; Zeki, 1993). In addition, analysis of lesion location in patients with selective deficits has been critical for the localization of cognitive mechanisms (Broca, 1861; Milner & Goodale, 1995; Scoville & Milner, 1957). Although most documented selective impairments were caused by brain damage in adulthood, selective impairments can also result from developmental disorders. Rather than suffering damage to particular mature cognitive mechanisms, individuals with selective developmental disorders fail to develop certain cognitive mechanisms. A number of developmental disorders have been investigated using a cognitive neuropsychology approach (Baron-Cohen, Leslie, & Frith, 1985; Butterworth, 1999; Coltheart, Masterson, Byng, Prior, & Riddoch, 1983; Temple, 1989, 1997), and recent years have seen growing interest in selective developmental disorders (Blair, 2005; Duchaine & Nakayama, 2005; Klein, Cosmides, Murray, & Tooby, 2004; Nijboer, van Zandvoort, & de Haan, in press; Peretz & Hyde, 2003; Temple & Richardson, 2004). Selective developmental deficits have also generated considerable discussion in recent years (see Thomas & Karmiloff-Smith, 2002, and the commentaries), with some even suggesting that such deficits are unlikely to exist (Karmiloff-Smith, Scerif, & Ansari, 2003; Thomas & Karmiloff-Smith, 2002).