Do We Think in Inner Speech?

We often "think" things silently to ourselves -- have the conscious experience of having a certain thought. We also silently "say" things to ourselves in inner speech. Here's the question: Is the latter a species of the former? Does conscious thinking sometimes take place IN inner speech? Or is inner speech more of an epiphenomenon, something that transpires more as a consequence of the thought than as the medium of thought itself? Peter Carruthers has recently argued the former.

Although there's plenty that's appealing in Carruthers' view, one type of case gives me (as it were) second thoughts. Russ Hurlburt and I were running an "experience sampling" experiment with a subject named Melanie. (I've mentioned this experiment in other posts.) We gave Melanie a random beeper. When the beeper went off, she was to note her "inner experience", as best she could ascertain it, at the last undisturbed moment prior to the beep.

In the sample I have in mind, Melanie was backing her car out of the driveway, saying to herself, silently in inner speech, "Why can't I..." when the beeper interrupted her. When we interviewed her about this experience shortly thereafter, she reported having a sense, at the time immediately prior to the beep, that the full content of her thought was this: "Why can't I remember about the parking brake?", and that thought was already completely there in her experience at the time of the beep, though not completely expressed in inner speech.

Let's set aside concerns about the accuracy of self-reports in such conditions (concerns I take quite seriously), and just consider her report on its (plausible) face. It seems, indeed, that we often have an unarticulated sense of what we're about to say -- in either inner or outer speech -- before we say it. No?

Sometimes this sense is only very rough and inchoate; but in other cases -- as perhaps in Melanie's case here -- it's fairly specific and developed. In the latter sort of case, it seems, then, plausible to say that the thought is complete before the speech is complete -- that there's a kind of thoughtless inertia sometimes in speech, inner or outer. But if the thought is complete before the inner speech is complete, then the inner speech can't be the medium of the thought, can it?