By "executive" I mean "carrying out". That is, without some executive (in this sense) mechanism, the signal associated with constricting the iris won't do anything. The overt behavior won't happen. You'll be left with just the neural chain reactions in the brain.
Something has to translate (so to speak) between the IP-supported-by-just-enough-hardware-to-accomplish-it and the bodily function which is not merely IP.
There's no reason to expect consciousing to be any different.
Just as with regulating body temperature or heartbeat or anything else you can think of that the body does, something has to "carry out" the task based upon the output, or there is no behavior beyond the background logic, the entire purpose of which (of course) is to drive the behavior.
The notion of an "executive" function is a bit of a misunderstanding of brain function. An illusion created by a good match between our will as we perceive it and our actions. I'll use a Hebbian type model to help explain. It matches well with an evolutionary hierarchy, as well as specific experiments, memory issues, etc. There's actually a quiet huge body of empirical data, from false memories to brain probe responses, spanning neuroscience, psychology, illusions, etc., that I'll be glossing over without addressing here.
When we learned that stimulating a particular neuron could fire a specific memory, action, etc., we thought maybe memory was stored somehow in these neurons. But other experiments demonstrated a distributed memory system.
Here's the mechanistic Hebbian model. Consider a pair of metronomes with randomly timed common cycles. If these metronomes are placed on a movable base, they will self sync up similar to neurons. Now consider a group of these distributed between springs, instead of a solid base. Thus the degree they will self sync is determined by the tension in the springs. Some of these metronomes will be tied to sensory input, while others are tied to output actions. No fundamental difference in these at the mechanistic level. A sensory activation corresponds to an increase in a metronomes frequency, after which the metronomes begin self syncing again. We need one more set of very simple rules. When two metronomes are simultaneously activated the spring tension between them begins to increase. When the frequency of two metronomes don't match, the spring tensions between them begin to relax. Now let's implant a basic experiential memory.
An experience simply consist of some subset of metronomes being activated, increasing their frequency. Some of the activations corresponds to different types of senses. The changes in spring tensions corresponds to a memory of that distribution of sensory input. Now, in spite of the memory being distributed in the spring tensions, an activation of one of the associated metronomes will by the same self syncing behavior reactivate the entire subset associated with that memory. The same self syncing behavior, in combination with experientially induced variations in which ones will sync with others, induces a self organization of past experience. This compacts our memories as efficiently as possible, and effectively associates similar memories. Efficiency can be increased by grouping input types effectively.
Now for consciousness it has to be hierarchal. Most simply described as another subset of metronomes which, instead of being tied to sensory or body state, have inputs defined by the state of other metronomes. I'm jumping the gun a little calling this consciousness, but not too much. Now we can begin self organizing, not only the experiential data, but also the data that ties our experiences together.
[Executive]
Now let's try to define what an "executive" function is. Since experiential data can be accessed or triggered by any of the metronomes associated with that experience, action, choice, etc., there exist no singular "executive" for that experiential data. Any of the associated metronomes can work as well for that or similar experiential data. Thus "executive" functions are as distributed as the memories themselves. This leads to an associative capacity on a massive scale, well beyond what you are explicitly aware of. Traditionally labeled the subconcious mind. It's often used by mentalist such as Derren Brown to make you believe you made a choice that was actually made for you. Even brain research shows that with scans, your choices can be known before you know what your choice is going to be yourself. Thus you perceive your choice as an executive action, when in fact is is only an after the fact event.
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I skipped over the distinctions between consciousness, instincts, and responses that merely evolve in a manner with a limited similarity to evolution, as it was more depth than needed. Our core emotional system plays the role of an adaptive advancement of instincts, but lacks the rigidness of instincts. Our attention, which most people associate with consciousness, can draw on previous experience to play out expectations we have yet to experience, to predefine future action potentials. Essentially creating experiences to learn from prior to the actual experience. We also mirror other peoples behaviors and emotions within us to gain experiential data we don't have personal experience of. Self proclaimed psychics call this being psychic. In reality it's being human.
Hopefully this 'toy' model will help some think about the issue of consciousness more realistically. Trying to get a sense of it from the raw math is generally problematic. Often our mathematical models fall short when even a modicum of self organization and chaotic behavior is involved.
