Not quite. The endless interaction of social and biological relations; one might say (metaphorically but not too inaccurately) that "Psychology" is the overlap of politics and neurology. But in answer to the question, "What is the subject which psychology explains?" the only answer is that there exists no such "X"? We can study social relations (history, remembering that the present is history). We can study the brain (though not wholly in abstraction from the entire organism). We can sort of study the overlap, and we call that overlap psychology. Because we can only "sort of" study it we get a bunch of more or less accurate rules-of-thumb with all the inadequacies of such rules.
(And these rough rules of thumb, though having no particular scientific interest, *do* have a definite pragmatic utility at times -- which is why I pay $15 of my own money, in addition to what insurance pays, twice a month to talk to a therapist [Ph.D in psychology].)
Beyond these useful rules of thumb we get various ghillies and ghosties and things that go boomp in the night such as "the ego," "the unconscious," "hysteria," "neurosis," "psychosis" (as opposed to psychotic symptoms, which do have a fairly precise definition but do not explain anything), "memory," etc. To all of these ghillies and ghosties one can apply the same critique that Marx applies to "Providence" in the *Poverty of Philosophy*:
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Thus *Providence* is the locomotive which makes the whole of M. Proudhon's economic baggage move better than his pure and volatilised reason. He has devoted to Providence a whole chapter, which follows the one on taxes.
Providence, providential aim, this is the great word used today to explain the movement of history. In fact, this word explains nothing. It is at most a rhetorical form, one of the various ways of paraphrasing the facts.
(Chapter II, "The Metaphysics of Political Economy," near the end of "Sixth Observation." P. 104 in the Progress Pub. ed.)
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You ask, "what used to be called psychology is biology and/or chemistry alone?" But this is absurd, and my original post made enough use of "social" to make it clear that I thought no such thing. But there is one sense, of course, in which that would be tautological. When you try to construe the preceding sentence, electro-chemical changes occur in your brain. That is trivial, like most tautologies, but like all tautologies, also true. And some thoughts, particularly some sense perceptions and some "emotions," can be triggered by purely mechanical stimulation of the brain; that too is interesting but mostly trivial.
To put it another way, banishing psychology eliminates many false solutions but does not in itself produce any true solutions.
And to go back to the original post, Showalter herself obviously would not recognize a "psychological cause" if jumped out and said boo! Her explanations are hopelessly incoherent.
Carrol