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Neurological-psychological phenomenon first reported in 1972 by psychologists Frank Geldard and Carl Sherrick. The cutaneous rabbit is a manifestation of the brain's curious and largely unrecognized ability to represent temporal illusions in the same way it does spatial ones - by responding to events in what one may assume is a more "ordered" fashion to its biology, even when that response is observably incorrect. This simple experiment opens up the question of how the brain "represents" time, and whether it may be as unconnected to actual time as, say, the brain's "representation" of space or color is to those respective qualities (i.e., nothing in the brain is actually expanding to 35 feet - or 35 nanometers - or turning purple when one thinks of space or color).

The arm of the subject rests on a table, underneath synchronized mechanical "tappers". When a sequence is initiated, the machines deliver a series of taps in rhythm on certain points on the subject's arm - for example, three at one point on the wrist, then two at the elbow, and then two on a single point on the upper arm. Intervals between the stimuli could be anywhere between 50 and 200 milliseconds, so that any one sequence might last from less than one second to two or three seconds.

The effect as reported by the subject is rather astonishing: rather than "feeling" each of the taps where they occurred, subjects report an equidistant series of taps "hopping" up their arm in regular sequence, like a tiny rabbit bounding gleefully upon their nervous system. That is, they felt taps in between the areas that were actually being stimulated that altered the sequence in their brains. The question that occurs immediately is how the brain altered such a set of stimuli in such a short time as to not only respond to the taps spacially in a "false" manner, but how it reordered them temporally. How did the brain seemingly "know" that after a certain amount of taps on the wrist, there would be taps on the elbow, and then provide the "false" information in between the two to give the cutaneous rabbit effect in the proper place?

Daniel Dennett, professor of cognitive studies, presents two mainstream views in his field that purport to explain the phenomenon's workings. The first is the Orwellian, named for an idea outlined in that author's 1984: that a central authority (the Ministry of Truth in Orwell's book, or in this example, the brain)can revise memory itself by inserting false information into records and thus denying access to the "true" past. In the Orwellian model, the cutaneous rabbit's "phantom" taps are completely nonexistent and are inserted by the brain into memory after the sequence occurs, thus giving false reports from the experiment's subject.

The other view Dennett calls the Stalinesque, for the reign of terror of Josef Stalin in the Soviet Union, where entire false show trials, complete with manufactured evidence and testimony, were conducted by the central authority in order to manufacture history. Under this theory, the cutaneous rabbit is caused by the brain's actual "insertion" of taps into the sequence by providing false sensory information during the sequence itself, probably by expectation or reflex rather than precognition.

Dennett points out the major flaws in both these proposals. First, the dichotomy will never be resolved, as any truly effective Orwellian campaign mounted by the brain will be indistinguishable from a Stalinesque one (that is, if the brain has successfully revised your memory before you can provide output in response to stimulus, then the experiment will never be able to tell if the "false" response is due to a revised memory or an actual memory of a "false" experience). Second, both of the standard explanations unwittingly fall into a very old trap, that of Cartesian dualism. Although proponents of both theories would be shocked at the suggestion that they are anything but total materialists, both the Orwellian and Stalinesque models take for granted a sort of "theater" in which some ethereal "consciousness" views outside stimuli at a certain point in time. In the Orwellian model, this consciousness sees events on a movie screen and misremembers them, while in the Stalinesque model, the movie shown to consciousness is false. Dennett calls this assumption Cartesian materialism - the view that even though the brain is the mind, there is still some mysterious focal point wherein "consciousness" occurs, and that judgment on experience like the cutaneous rabbit must occur there, wherever and whenever "there" is.

Dennett proposes a new model, that of Multiple Drafts, where the memory is compared to an academic paper (handy, that, for the Distinguished Professor!) in constant revision from multiple sources. The experience of the "taps" reaches different points of the brain at different times: the shift in space of the taps over the arm is discriminated over time, as is the number of taps. Output from these differing parts of the brain interact with any number of other stimuli along a decentralized network. The simplifying assumption for the memory-oriented part of the brain is that they were distributed regularly along the space-time extent of the experience, creating the "cutaneous rabbit" after the taps (logically, of course, as the brain has no power to tell the future), when storing the experience in memory.

This is not Orwellianism: in fact, there is no single experience of the taps at all, simply an average of multiple experiences. This can be easily tested by having the subject in the same experiment hit a button directly after the subject experiences "two taps on the wrist" - even though the taps will be later revised to "move" along the arm in memory, the subject can still recognize them as they occur because of the brain's multitude of input/output channels.


For an analogous explanation of the "one-line-in, one-line-out" fallacy of Cartesian materialism, see neo-Laffer curve.

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