Response to: “Higher-order g versus blended variable models of mental ability: Comment on Hampshire, Highfield, Parkin, and Owen (2012)”

Highlight
• The authors respond to the comment of Ashton and colleagues.
• Brain imaging and performance data have different properties but relate to the same systems.
• A model of human abilities is best derived by combining brain imaging and performance data.

The comment by Ashton, Lee, and Visser (2014) seeks to find fault in the recent article ‘Fractionating Human Intelligence’ (Hampshire, Highfield, Parkin, & Owen, 2012). However, several of their key points are misleading and, more importantly, they fail completely to acknowledge the main novel contribution of the original article. More specifically, their comment focuses entirely on the behavioural data and makes no attempt to consider the relationship between the neuroimaging and behavioural results (Hampshire et.al, 2012). This is a major oversight, because the main point of the original article was an alternative perspective on the nature of Intelligence that considered how the factors of human ability reflect the manner in which the human brain is organised into specialised functional systems. Moreover, their argument for disregarding the imaging analyses is demonstrably weak. Here, we argue, that data from individual differences analyses and brain imaging analyses are complementary and must be considered together, because, whilst they relate to the same underlying cognitive systems, they have quite different properties. The weaknesses when analysing one set of data are complemented by the strengths when analysing the other. Consequently, by combining the two, it is possible to further constrain our understanding of the architecture of human cognition.