[From Bruce Abbott (951007.0935 EST)]
Bill Powers (951007.1500 MDT) --
Having written three pages in response to your posts about the MSH
effect, I perceive that what I'm trying to do here is futile. You are
presenting conventional data obtained in the conventional way to show
that this is a good way to find out about behavior. I have a million
reasons why it is not a good way to find out about behavior, but every
one of them will be met by a counterargument that will satisfy you.
What I should really be doing is asking you what is wrong with this
study and all the others, in contrast with PCT. I am never going to find
a criticism that will change your mind.
My experience on CSG-L over the past year has done something to me: as I
read conventional studies with their conventional conclusions about the
factors that "cause" or "control" behavior, I can see, as I could not
before, what is wrong with these studies and with the conclusions drawn from
them. This change has occurred because I've been persistent in asking
questions where I either do not understand or have not been convinced of the
answer given, and because I have been willing to listen to -- and evaluate
-- the answers with an open if critical mind.
Yes, I am presenting conventional data in the conventional way, because we
currently disagree as to its value in a science of behavior. I know that
you have asserted that such methods are not appropriate; I am arguing not
that they are the best way to proceed but that they can provide useful
information so long as their limitations are recognized (as, unfortunately,
in psychology they often are not). I am also arguing that sometimes they
are the only available option.
I have a million
reasons why it is not a good way to find out about behavior, but every
one of them will be met by a counterargument that will satisfy you.
I wonder whether you are really talking about me here or yourself. As I was
not given the chance to provide such counterarguments, I can only conclude
that you were able to think of them yourself. You say you have a million
reasons and yet you fail to provide even one. Perhaps you believe that your
reasons are just not convincing enough to present.
What I should really be doing is asking you what is wrong with this
study and all the others, in contrast with PCT. I am never going to find
a criticism that will change your mind.
The question is somewhat poorly framed, as a study is just a bit of
empirical research and thus cannot be contrasted with PCT, which is a
theory. Perhaps you mean by this to ask what is wrong with the study when
evaluated in light of PCT. For starters, it uses a group-based methodology
that can tell one little about how MSH affects an individual bird, whether
it interferes with the perceptual input function, the comparator process,
the error signal, the output function, the overall gain of the system, or
its loop propagation speed, or some combination of the above. The
differences in group means could arise because MSH affects some birds and
not others, or different birds in different ways, or because each bird is
affected in similar ways to a similar degree. In reply I would agree but
note that a finding of no effect of MSH would at least tell us that the
control systems involved in attachment behavior are not measurably affected
by this biochemical. The cited study shows that MSH can affect this system
in at least some birds and provides both the time-course and the
dose-response curve for this effect. A properly framed PCT-based study
could probably tell us a great deal about how MSH produces its effect, and
this in turn might help us to understand at least one role of this
biochemical system in the brain.
Perhaps a second problem of the study from the PCT viewpoint is that it
tends to promote a lineal cause-effect view of behavior. Given the
widespread failure of psychologists to appreciate the implications of the
closed loop (as evidenced by, for example, attempting to trace cause and
effect around the loop stepwise), this may be of some concern. I myself
have no difficulty thinking in terms of cause-and-effect as, for example,
when describing the action of the control system in response to a
disturbance acting on its controlled perceptual variable, nor do I have any
problem with conceiving of MSH as causing changes in the parameters of the
attachment control system. The important thing, it seems to me, is to
recognize that such influences are mediated by the dynamic process involving
a closed loop as opposed to some direct influence of X (e.g., MSH) on Y
(e.g., distress vocalizations). Observed changes may reflect changes in the
dynamic balance of the system rather than a direct effect of the manipulation.
I get a sense from your previously asked questions that my use of such terms
as "separation anxiety," "distress," and so on were not to your liking,
perhaps because they appear to involve a somewhat anthropomorphic
interpretation of the observations. If this is true then you are thinking
like a true behaviorist. It would be possible to couch the observations in
more neutral terms (you seem to prefer "peeping," although this fails to
convey the differences between ordinary peeping and what I've labeled
"distress vocalizations," which are strikingly apparent to anyone who has
had the opportunity to experience both). We can never know what the chick
is actually experiencing (indeed, we can only guess at what other _people_
experience), but one can draw clear inferences about the nature of these
actions and their functions, and these inferences are capable of
experimental test.
Speaking of tests, the Test for the controlled variable has been conducted
in this situation; what the birds are ordinarily doing is keeping a
preferred distance from the mother hen and broodmates. After brief
separation the preferred distance becomes zero for a short time; the
previously separated bird maintains direct physical contact with the mother
or with the other chicks. I'm speculating, but it is possible that this
change from visual contact to physical contact being required in order to
reduce error to near zero may be mediated by increased levels of MSH. It
has been suggested that MSH is released whenever there is a perception of
personal danger. By the way, MSH stands for "melatonin stimulating
hormone," after its function in the periphery where it stimulates the
production of skin pigmentation.
I'd really like to have been able to read those three pages of reply you
decided not to post. I wouldn't bother to pose the problem if I didn't want
to consider your reply. I also wonder whether in your scheme of things
there is any room for the possiblity that on some issues you might need to
reconsider your own position.
Regards,
Bruce