I was reading this interesing report on some of Frank Tong’s recent work here. Tong’s work is regularly presented at the consciousness conferences I frequent and I have briefly mentioned it before. This recent study asked participants to imagine a certain image. Then these subjects were subjected to a binocular rivarly set up, which is where researchers present a different picture to each eye at the same time. What usually happens is that the person sees the two images switching back and forth. Some of Tong’s other works has focused on showing that we correlate the subject’s report of whcih they are seeing with their neural activity and thus learn to predict from looking at their brain what they are seeig. This is very exciting!
Anyway, in this research Tong shows that imagining one of the two simuli before having them presented influences which of the two you end up consciously seeing. In fact he is able to show that it has the same effect as being presented with a ‘dim’ image of the stimuli. The article points out that this might lead to an empirical way to quantify how strong an individual’s mental imagery is. Super interesting!! But I am interested in this as data for a theory of consciousness.
How do we explain this? Well, from the higher-order perspective it is easy to explain. A conscious mental state is, on this kind of view, consists in my being conscious of myself as bing in some first-order state. Presumably imagining is a conscious mental experience, and so would have to consist in my being conscious of myself as being in the first-order state that I am imagining. Presumably the disparity in first-person reports as to the presence of mental imagery is due to the varrying ability of persons to token this higher-order state in the absence of the firsrt-order sensory state. This also explain why it would be the case that presenting the subject with a dimly lit actual image works just as good as the subjects own imagined experience.
For some people it is easy to token the relevant higher-order state and they have very vivid mental imagery experience. Others have difficulty tokening these higher-order states and manage only to have ‘fleeting’ mental images. There is even a small group that denies to have this ability. I must confess to be one of these people. I have never been able to have vivid mental imagery. When I imagine a situation I usally find myself describing it like you might find in a book. Sometime I can manage vauge mental images, especially when laying down on the verge of sleeping, but when I am alert and awake it is very hard for me to do. Interestingly, I have good auditory ‘imagery’ experieince. I think that this may be due to me being a musician but that is just anecdotal evidence.
The preceeding discussion is all based on the assumption that imagining cannot happen unconsciously. The way I have explained it above has it as only being conscious. Is this a mistake? Rosenthal does not anywhere explicitly talk abou tthe imagination. I wonder if he thinks that we could imagine something unconsciously?
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