Last Night's Viewing: Horizon: The Creative Brain - How Insight Works, BBC2 Prisoners' Wives, BBC1

I sometimes wonder what our phrenology or phlogiston will turn out to be. There's bound to be one – a field of science that is all the rage for a time, but then turns out to be a bit of an embarrassment, even though it feints in the right kind of direction.

I sometimes wonder whether neural mapping might qualify, though mostly when I encounter it through the medium of popular-science programmes, which are always over-eager to pinpoint the location of a particular human trait or quality in some obscure convolution of the brain. In Horizon: The Creative Brain – How Insight Works, the quality in question was "ah-ha!", that light bulb moment at which a previously impenetrable conceptual murk suddenly disappears.

You may not be hugely surprised to find that "you need to think outside the box", a phrase now only used by those who've simply found a bigger box to put the original box in. You also need to use the right hemisphere of your brain –MRI studies and brain-teaser exercises having established that the neuronal wiring is different on one side of the brain than on the other.

The left has high bandwidth and short connections while the right sends longer connections snaking out into different regions of the brain. And if you feel that this is a rather vague rendition of a complex matter, I would reply that I can only work with what I'm given, and Horizon's narration was at times infuriating fudgy about the precise nature of the mechanisms involved.

Take, for example, its explanation of the finding that creative types turn out to have less white matter – the central wiring system of the brain – than the norm. This means that nerve traffic is slowed down and, I quote, "this cognitive slowdown... makes it more likely for ideas to connect with each other." Do "ideas" travel as discrete entities, then? And if they do, how do they "connect" with each other? Do they pull into some neural layby and compare notes? The explanation raises more questions than it actually answers.

But I suspect we're not meant to worry about actually understanding the mechanisms involved, only on taking in the consumer advice, which involved breaking your routines and exposing yourself to unexpected experiences. Oh, and any mundane activity that will stop those poker-up-the-ass frontal lobes from hogging the conversation and give the wacky guys back in the anterior superior temporal gyrus a chance to get a word in edgeways. I speak metaphorically, being no better than Horizon at the mind-twisting challenge of simplifying the mysteries of novel thought.

"Do you or any of your family have any known enemies?" a policeman asked Francesca at the beginning of the new series of Prisoners' Wives. Since Francesca is married to a notorious local crime boss and had just had her house petrol-bombed, the question seemed a touch unnecessary to me, but Francesca bore it with fortitude. She was much less calm when, after being pressed by her husband to deliver a peace overture to his chief rival, the chief rival's stomach suddenly exploded all over her, thanks to the heavy behind him with the sawn-off shotgun.

This rather dropped Francesca in it, though I suppose she could always have a crack at pleading marital coercion if she ever gets linked to the murder. Having husbands in jail turns out to be a very flexible basis for a drama series, by the way. Good actresses get a relatively rare chance to take the lion's share of the lines and you can mix in your long-term prisoners (narrative continuity) with new arrivals (narrative refreshment).

Francesca and Harriet are back and joined for this series by Kim and Aisling (husband charged with sexual abuse of a minor and father convicted of handling stolen goods respectively). It's popular, mainstream drama at its best, I'd say. Somebody's light bulbs went on.

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