The power of the positive: revisiting weak coherence in autism spectrum disorders.

This paper reexamines Frith's original concept of weak coherence, its historical origins, recent reformulations, and alternative accounts. We suggest that the key notion of reduced global integration of information, which Frith proposed to underlie the assets in local processing, has been neglected in recent accounts of autism spectrum disorders (ASD). In fact, most paradigms used to test weak coherence conflate global and local processing, often placing them in direct trade-off, so that it is not possible to tell whether patterns of performance in ASD reflect reduced global processing, increased local processing, or both. We review the literature from typical development and ASD that may be pertinent to this distinction and examine some data from our own studies. Only once tasks are devised that measure separately the effects of reduced global processing and increased local processing will it be possible to test the on-line and developmental relations between these two aspects of "weak coherence". Some preliminary ideas about these relationships are discussed, and suggestions are made for why disentangling two possibly independent dimensions of weak coherence may be timely and productive.