[Fred Nickols (2015.11.26.1057)]
Thanks, Martin. I understand that the 11 levels are hypotheses. As Bill wrote in Making Sense of Behavior, %26#8220;Don%26#8217;t take these levels I propose too seriously.
%26#8221; p. 135. What did seem serious is the notion of a hierarchy, whatever the levels might eventually prove to be. So, as Bill also wrote, the 11 levels are %26#8220;a useful starting point.%26#8221;;
All I%26#8217;m trying to do is clarify intensity as Bill proposed it and, if possible, come up with a commonplace, everyday illustration or example for my one-pager. In reading what Bill had to say it struck me that we don%26#8217;t have words to describe intensity at Level 1. We can talk about the intensity of a particular sensation but, as Bruce Abbott pointed out, that%26#8217;s not the same thing as intensity at Level 1.
As for the lowest level of the hierarchy, I suspect there are two. The first is the lowest level of whi
ch we can be aware; the second is the lowest of which we are not consciously aware. Which of those is lower or higher in the hierarchy I haven%26#8217;t a clue.
From: Martin Taylor [mailto:firstname.lastname@example.org]
Sent: Thursday, November 26, 2015 10:37 AM
Subject: Re: Clarifying Intensity vs Sensation
[Martin Taylor 2015.11.26.10.05]
[From Bruce Abbott (2015.11.26.0910 EST)]
[Fred Nickols (2015.11.26.0808)] –
I need to clarify my understanding of intensity vs sensation. I%26#8217;ll use the coffee example.
Whether the coffee feels hot or tastes sweet is at the sensation level. How hot or how sweet is a matter of intensity.
Do I have that correct?
In B:CP sensations are defined as vectors whose multiple inputs are first-order perceptions, which Bill labeled intensities. He speculated that intensity signals reaching %26#8220;the sensory nuclei of the spine and brainstem,%26#8221; if consciously experienced, would be experienced as sensations. Intensity signals from different kinds of sources, when reaching the same groups of second-order input functions, would result in a single complex sensation (my words) comprising, for example, taste, smell, texture, temperature (Bill references the taste of a steak).
Ever since I first learned about PCT and joined the precursor of CSGnet, I’ve been mildly concerned about the scientific validity, as opposed to the conceptual logic, of these very l
ow levels of the hierarchy. In my previous life as a student of sensory perception (audition, vision, and touch), it had seemed that everything starts with a differential, whether across space or time. You simply don’t sense the intensity of a sound, patch of the visible field, or touch/pressure. You sense how it changes over time and how it differs from one place to another. That, I believe, is the lowest level.
When you perceive an intensity, it’s never absolute – even the intensity of something like velocity, which does seem to be the output of very low-level visual processing. If the intensity of something remains physically unchanged, the perception of it seems, at least in the cases of which I am aware, to decline. I mention velocity specifically, because I did a tracking study of it long ago, for rotary velocity. In that study, the logarithm of the velocity required to maintain a constant perceived velocity increased linearly with the square root of time o
n task over a 10 minute run.
I haven’t thought that this, or indeed any of the details of Bill’s subjectively derived hierarchy, matters for PCT. As Bill has said, the true structure of the hierarchy is a subject for experiment probably far in the future, as is the question of whether the structure is a true hierarchy or something else. A hierarchy works pretty well in experiments, but until it is experimentally compared with other possibilities, it is impossible to say whether it is what actually happens in a brain with trillions of interconnections. Personally, Given that level of brain complexity, I doubt that the hierarchy can be better than a gross sketch of some salient features of what goes on in the brain. It’s probably a good sketch, but that’s only my subjective opinion until there is evidence that I don’t expect to be available in my lifetime.
What matters for PCT is the principle that different kinds of perception of great complexity can be built from simple components, and that at each level of complexity, a hierarchic system allows for those perceptions to be controlled. However, when you start delving into the details, I think you should start with what seems to be understood from experiments and observations rather than subjective impressions and conclusions that seem to be logical, drawn from those subjective impressions. And one of those things seems to be that the bottom of the perceptual hierarchy has to do with rates of change in space and time, not absolute values.
I%26#8217;m not sure I%26#8217;ve answered your question, because it seems to me that Bill%26#8217;s %26#8220;sensations%26#8221; differ from the ordinary meaning of the term. Your example treats sensations in the normal way, as qualities associated with specific senses (taste = sweet, temperature = hot) and intensities as amplitudes of those sensations. But no combination of intensity inputs, it seems to me, will give rise to sweetness or to the experience of heat, despite being called %26#8220;sensations%26#8221; in Bill%26#8217;s hierarchy.
I can understand, however, how combinations of qualitatively different sensations at various intensities would give rise to a complex experience such as is experienced when eating a hot, juicy filet magnon.