Should we only use the prior literature as the basis for deriving new hypotheses?

"Reviewer 1 raises more troubling issue: the sense that this paper emerged from ad hoc observations [...] and the consequent lack of a coherent theoretical framework to drive the hypotheses."

I've just had the second set of angry rejections for a paper (the one that I blogged about here). Just as they did at the first journal I submitted it to - and despite the fact that, the second time, I'd watered it down as much as I possibly could - the reviewers hated the fact that the initial motivation for the paper came not from the previous literature, but from an idea that had occurred to me one day while I was watching a testing session.

I did start, the second time around, with a literature review that was a comprehensive as I could make it. I described how the majority of research into arousal (operationalised as levels of Autonomic Nervous System activity) has considered it in one of three different contexts. First, as a reflexive response - studying how external cues lead to a set of autonomic changes posited to optimise adaptive behavior by response preparation. Second, as periodic, oscillatory activity - from Circadian rhythms through to Respiratory Sinus Arrhythmia. And third, as sets of stochastic, random changes.

But then I went on to describe something that I'd noted, a while back, during testing - how, as I describe here, events that may have been initiated by a small increase in arousal might lead, in turn, to a chain of events that would each cause further increases in arousal. If true, this would make different predictions for what the time series of arousal should look like than if we conceptialise arousal as purely constituting reflexive, oscillatory and stochastic activity. And we tested these predictions, and observed patterns consistent with them.

The reviewers have are right to say that there isn't really a theory underlying the predictions that we're testing in the paper. But, in a sense, the reason that there isn't a theory is because this an area hasn't been looked at in much detail before. And we can't use 'we don't know anything about it yet' as a reason not to try to find out something!