Dissociative theories of consciousness want to dissociate phenomenal consciousness and access consciousness, or functional consciousness. They wish to argue that ‘phenomenology overflows access’. In other words, they state that while we only have limited attentional resources available, we perceive the whole world.
For example, whenever you look outside, your attention is focused on a few items in your focal area. But phenomenally, you experience the entire world. This is supported by evidence from a classic psychology experiment conducted by George Sperling in 1960. As it turns out, if you show participants a brief display of a letter matrix composed of 9–12 letters, they can only report on a few letters through free recall.
But if they are cued with a tone indicating the row of the matrix, participants were able to recall most of the matrix, instead of only a small part of it.
Source: Cohen, M.A. and Dennett, D.C. (2011) ‘Consciousness cannot be separated from function’, Trends in Cognitive Sciences, 15(8), pp. 358–364. Available at: https://doi.org/10.1016/j.tics.2011.06.008.
Sperling, G. (1960) ‘The information available in brief visual presentations. Psychological Monographs: General and Applied, 74, 1-29’, Psychological Monographs: General and Applied, 74. Available at: https://doi.org/10.1037/h0093759.