Abstract: I give some examples of subliminal priming studies suggesting that subjective awareness may not be as functionally powerful as we might think. However these studies as well as most others in the field suffer from a methodological problem: in rendering stimuli unconscious we substantially lower the relevant signal strength, so subliminal priming effects are invariably weak. It is a problem for a whole field to rely on weak effects because null results are hard to interpret and positive results are subject to selection and publication bias. So I propose a new approach to address this problem. The key is to keep signal strength / perceptual sensitivity constant while manipulating subjective awareness, and to see how that affects cognitive functions. This is hard to achieve but I show preliminary data demonstrating how this could be done.
Unconscious activation of the cognitive control system in the human prefrontal cortex. Lau HC, Passingham RE. J Neurosci. 2007 May 23;27(21):5805-11.
Empirical support for higher-order theories of conscious awareness
Hakwan Lau and David Rosenthal
Attention to Intention http://www.fil.ion.ucl.ac.uk/~hclau/Lau_2004_Science.pdf
Subliminal stimuli in the near absence of attention influence top-down cognitive control.
Rahnev DA, Huang E, Lau H. Atten Percept Psychophys. 2012
Does response interference depend on the subjective visibility of flanker distractors?
Maniscalco B, Bang JW, Iravani L, Camps-Febrer F, Lau H. Atten Percept Psychophys. 2012
Attention induces conservative subjective biases in visual perception. Rahnev D, Maniscalco B, Graves T, Huang E, de Lange FP, Lau H. Nat Neurosci. 2011 Oct 23;14(12):1513-5
Direct injection of noise to the visual cortex decreases accuracy but increases decision confidence. Rahnev DA, Maniscalco B, Luber B, Lau H, Lisanby SH. J Neurophysiol. 2012 Mar;107(6):1556-63.