In the Brain Club (our research group's journal club) yesterday, Tetsuro Ishikwa, (Ph. D student) introduced Shurger et al. (2009). Their research reported that reproducibility distinguishes conscious from nonconscious neural representations.
I found the idea quite interesting. When we see an object, the conscious percept remains basically the same, no matter how often we may observe it. The unconscious cognitive processes associated, however, might be quite variable, corresponding to the heterogeneous multiple processes that makes our cognition robust.
Take the particular example of an apple. The visual image of an apple is basically the same, if we look at a particular apple from a certain angle and under specific lighting conditions. The significance attributed to the apple, however, might be different from time to time, depending on one's mood, memory, feelings, and the context in which the fruit is presented.
The picture emerges that conscious perception corresponds to the invariable in perception, while there is much variability in the related unconscious processes. It is the co-existence and co-dynamics of two processes of distinguished nature that makes human cognition robust and evolvable.