The 4 modes, active control systems

[From Chris Cherpas (970920.1523 PT)]

Have there been any speculations since Powers (1973) on the 4 modes?
- control
- automatic
- imagination
- passive observation

(Hope I got those right) Specifically:
1. Are there any order-specific interactions one might expect
   (e.g., you can't imagine intensities)?

2. Is there a control system for control what modes another
   control system is operating in?

3. Are there any parameters which might interact with
   modes (e.g., gain thresholds which might rule out
   or favor a control system's operating in a given mode
   -- possible word salad on this one).

Also, when one says a control system is "active" does
that mean it is getting a non-zero reference signal?

Best regards,
cc

[From Bill Powers (970921.0728 MDT)]

Chris Cherpas (970920.1523 PT)--

Have there been any speculations since Powers (1973) on the 4 modes?
- control
- automatic
- imagination
- passive observation

(Hope I got those right) Specifically:
1. Are there any order-specific interactions one might expect
  (e.g., you can't imagine intensities)?

That's one I've thought of. There doesn't seem to be any way to put the
environment into the imagination mode! And the wiring at the first level
doesn't seem to provide any way to feed the output directly back into the
input.

2. Is there a control system for control what modes another
  control system is operating in?

I suppose there has to be one. Can you think of any experiments that would
enable us to detect mode-switching?

3. Are there any parameters which might interact with
  modes (e.g., gain thresholds which might rule out
  or favor a control system's operating in a given mode
  -- possible word salad on this one).

Don't know.

Also, when one says a control system is "active" does
that mean it is getting a non-zero reference signal?

I think so. As I said to Marc Abrams yesterday, the nature of neural
signals says they can't go negative, so if you have an excitatory reference
signal and an inhibitory effect of the perceptual signal at the comparator,
a zero reference signal guarantees zero error for all magnitudes of
perceptual signal. The opposite arrangement (which seems to exist in the
brainstem) doesn't work this way. An inhibitory reference signal, when set
to zero, doesn't keep an excitatory perceptual signal from generating an
error signal. So "inverted comparators" can't be turned off except through
actively suppressing them with a large inhibitory reference signal, larger
than any perceptual signal that can occur. The phenomenon of decerebrate
rigidity shows this effect. If you chop a live cat's brain off at the
midbrain, all the reference signals in the brainstem presumably go to zero
-- and the result is full and active extension of all the limbs. Grisly
games these guys play, but the information should't be wasted once you've
wasted a cat to get it.

Best,

Bill P.