PSYCH 4320 / COGST 4310 / BioNB 4330

Consciousness and Free Will

Theme III

  Week 6: the Information Integration Theory, I

Week 6: the Information Integration Theory (IIT): a manifesto


the IIT vs. the NCC


"Increasingly refined neuroscientific tools are uncovering increasingly precise aspects of the neural correlates of consciousness (Koch, 2004). And yet, when it comes to explaining why experience blossoms in the cortex and not in the cerebellum, why certain stages of sleep are experientially underprivileged, or why some cortical areas endow our experience with colors and others with sound, we are still at a loss."

the photodiode vs. you example: the AMOUNT of information


"The first problem of consciousness reduces to this: when you distinguish between the screen being on or off, you have the subjective experience of seeing light or dark. The photodiode can also distinguish between the screen being on or off, but presumably it does not have a subjective experience of light and dark. What is the key difference between you and the photodiode?"

"The key is to realize how the many discriminations we can do, and the photodiode cannot, affect the MEANING of the discrimination at hand, the one between light and dark."

the camera vs. you example: the INTEGRATION of information


"Information — the ability to discriminate among a large number of alternatives — may thus be essential for consciousness. However, information always implies a point of view, and we need to be careful about what that point of view might be."

Consider a 1 megapixel digital camera, which can distinguish among 21,000,000 alternative states, corresponding to 1 million bits of information. [...] "Few would argue that the camera is conscious. What is the key difference between you and the camera?"

"According to the IIT, the difference has to do with integrated information. FROM THE POINT OF VIEW OF AN EXTERNAL OBSERVER, the camera may be considered as a single system with a repertoire of 21,000,000 states. [...] In reality, however, the chip is just a collection of 1 million independent photodiodes, each with a repertoire of two states. In other words, there is no intrinsic point of view associated with the camera chip as a whole. This is easy to see: if the sensor chip were cut into 1 million pieces each holding its individual photodiode, the performance of the camera would not change at all."

the integration of information and the "point of view" question


"By contrast, you discriminate among a vast repertoire of states as an integrated system, one that cannot be broken down into independent components each with its own separate repertoire. Phenomenologically, every experience is an integrated whole, one that means what it means by virtue of being one, and that is experienced from a single point of view."

[Unfortunately, in the above passage the focus on the intrinsic/extrinsic distinction is lost. Instead, we're offered a standard argument from the so-called "unity of consciousness", which is used to motivate the necessity for integration.]

Tononi (2008): p.220


"a system with this mechanism being in state 11 specifies that the PREVIOUS SYSTEM STATE x0 must have been either 11 or 10, rather than 00 or 01, corresponding to p = (0,0,1/2,1/2)."

"Since effective information is implicitly specified once a mechanism and state are specified, it can be considered to be an “INTRINSIC” property of a system. To calculate it explicitly, from an extrinsic perspective, one can perturb the system in all possible ways (i.e., try out all possible input states, corresponding to the maximum entropy distribution or potential repertoire) to obtain the forward repertoire of output states given the system’s mechanism."

p.221


"Finally, by measuring Phi values for all subsets of elements within a system, WE can determine which subsets form complexes."

— But does the system know it intrinsically?

"Specifically, a complex X is a set of elements that generate integrated information (Phi > 0) that is not fully contained in some larger set of higher Phi (Fig. 3). A complex, then, CAN BE PROPERLY CONSIDERED to form a single entity having its own, intrinsic “point of view” (as opposed to being treated as a single entity from an outside, extrinsic point of view)."

— Considered by whom? How does a complex know that it is not "fully contained in some larger one"?

p.229


"Note also that informational relationships, and thus the shape of the quale, are specified BOTH BY THE ELEMENTS THAT ARE FIRING AND BY THOSE THAT ARE NOT. This is natural considering that an element that does not fire will typically rule out some PREVIOUS STATES of affairs (those that would have made it fire), and thereby it will contribute to specifying the actual repertoire. Indeed, many silent elements can rule out, in combination, a vast number of previous states and thus be highly informative."

pp.230-231: how IIT accounts for various aspects of phenomenology


  1. modalities
  2. elementary vs. decomposable experiences (red apple / redness)
  3. homogeneous vs. composite experiences (sky / street)
  4. hierarchically organized experiences
  5. categorical vs. graded experiences
  6. similar and dissimilar experiences
  7. learning and refining of experiences
  8. where qualia are in a complex

the IIT: the identity claim and the question of existence


According to the IIT, consciousness is ONE AND THE SAME thing as integrated information. This IDENTITY, which is predicated on the phenomenological thought experiments at the origin of the IIT, has ontological consequences.

"I argue that such Phi-centric view is at least as valid as that of a universe dominated by mass, charge, and energy. In fact, it may be more valid, since to be highly conscious (to have high Phi) implies that there is something it is like to be you, whereas if you just have high mass, charge, or energy, there may be little or nothing it is like to be you. From this standpoint, it would seem that ENTITIES WITH HIGH PHI EXIST IN A STRONGER SENSE THAN ENTITIES OF HIGH MASS."

"Information that is not integrated, I have argued, is not associated with experience, and thus does not really exist as such: it can only be given a vicarious existence by a conscious observer who exploits it to achieve certain discriminations within his main complex. Indeed, the same “information” may produce very different consequences in different observers, so it only exists through them but not in and of itself."

the IIT: intrinsic vs. extrinsic perspectives


"Consciousness, as a fundamental property, is also an INTRINSIC property. This simply means that a complex generating integrated information is conscious in a certain way regardless of any extrinsic perspective."

"Another way to express this aspect of integrated information is to say that consciousness can be characterized extrinsically as a disposition or POTENTIALITY – in this case as the potential discriminations that a complex can do on its possible states, through all combinations of its mechanisms, yet from an intrinsic perspective it is undeniably ACTUAL."

the IIT: an important insight and a problem (p.234)


The insight:
"Consciousness is a way of being rather than a way of knowing."

The problem:
"According to the IIT, what constitutes a “state” of the system is not an arbitrary choice from an extrinsic perspective, but rather the spatiotemporal grain size at which the system can BEST generate information about its past: what is, is what can make a difference."

questions from Week 5, revisited


"The first-person exercise we have just conducted yields a minimal definition of the self as the perceptual egocenter of sensory consciousness and, BY EXTENSION, OF ALL AWARENESS."

What about bees? Nematodes?

Is completely self-less awareness possible? And if yes, what neural — or, better, COMPUTATIONAL — processes are necessary and sufficient for it?