Expectation creates something out of nothing: The role of attention in iconic memory reconsidered

- Consciousness is shaped both by sensory data and by attention and expectations.
- The independence of iconic memory (IM) from attention has been recently questioned.
- We contribute to the debate by measuring subjective visibility.
- We demonstrate that expectation creates illusory content that overwrites valid IM content.
- We show that there is still phenomenal consciousness, even when attention is diverted.

Conscious experience is modulated by attention and expectation, yet is believed to be independent of attention. The experiments on iconic memory (IM) are usually taken as support for this claim. However, a recent experiment demonstrated that when attention is diverted away from the IM letter display subjects fail to see the absence of IM letters. Here we contribute to the ongoing debate by overcoming experimental shortcomings of this previous experiment, by measuring subjective visibility and by testing the effect of the post-cue. We were able to replicate these earlier findings and extend them by demonstrating that subjects who do not realize the absence of letters perceive illusory letters. This result means that there is still phenomenal consciousness, even when attention is diverted. Expectation creates illusory content that overwrites valid IM content. Taken together these findings suggest that the present experimental paradigm is not appropriate to make claims about IM content.