Why has Nadine Dorries' decided to appear on I'm a Celebrity? She claims it's to get her message across to millions of people MPs can't reach. Others mention vanity and ''40,000. In the long tradition of seeing what we want to see in any event, I suspect some cognitive biases are at work:

1. Neglect of base rates. Nadine isn't the first MP to apear on a reality show. Lembit Opik was on I'm a Celebrity two years ago.His career has not conspicuously thrived since. And George Galloway's appearance on CBB achieved the astonishing feat of making him look an even bigger arse than we thought. If Ms Dorries were a good Bayesian - and something makes me think she might not be - she'd attach a low prior probability to her chances of success. And two things mean she she's probably overweighting the posterior probability too...

2. Projection bias (pdf). People are bad at foreseeing their future tastes, exagerrating the degree to which they'll resemble their present tastes. I fear hope that Ms Dorries is doing this. She might now believe she can cope with having buckets of cockroaches tipped over her or having to eat kangaroo's bollocks. But when she actually has to do so, she might think otherwise.

3. Optimism bias. Even in the improbable event that Ms Dorries does a fantastic job in the jungle, does she really think this will come across? She seems to be forgetting that TV shows are edited. If she spends 95% of her time speaking eloquently on abortion and being a great team player and the other 5% whining and looking dog-rough, which 5% will be broadcast?

I suspect, therefore, that what we're seeing here is further corroboration that MPs are surprisingly bad at making judgments about probability.