The role of attention and neural variability in awareness

We see things more clearly when we attend to them—right? It turns out that when task performance is equated, unattended stimuli are actually more subjectively visible than attended stimuli. I performed computational modeling work suggesting that this effect can be explained by attention-induced reductions in stimulus representation variability (Rahnev et al., 2011). This reduced variability in turn yields lower visibility and confidence according to a signal detection theory model.

A similar model can explain why transcranial magnetic stimulation (TMS) applied to primary visual cortex impairs visual task performance while simultaneously increasing confidence (Rahnev et al., 2012).

The fact that subjective visibility is artificially inflated under inattention suggests that observers might fail to appropriately downweight sensory evidence during inattention, even though it is computationally optimal to do so. This is in fact what we found (Morales et al., 2015).

References

Rahnev, D., Maniscalco, B., Graves, T., Huang, E., de Lange, F. P., & Lau, H. (2011). Attention induces conservative subjective biases in visual perception. Nature Neuroscience, 14(12), 1513–1515. https://doi.org/10.1038/nn.2948 [supplementary material]

Rahnev, D. A., Maniscalco, B., Luber, B., Lau, H., & Lisanby, S. H. (2012). Direct injection of noise to the visual cortex decreases accuracy but increases decision confidence. Journal of Neurophysiology, 107(6), 1556–1563. https://doi.org/10.1152/jn.00985.2011

Morales, J., Solovey, G., Maniscalco, B., Rahnev, D., de Lange, F. P., & Lau, H. (2015). Low attention impairs optimal incorporation of prior knowledge in perceptual decisions. Attention, Perception, and Psychophysics, 77(6), 2021–2036. https://doi.org/10.3758/s13414-015-0897-2 [supplementary material]