Jim rolls his head on his neck, a silent oh please.

'I'm not a performing monkey, sweetheart. And I was referring to rate of learning, in any case. If I can match what you know of astrophysics and maths - my thirty-five years against your thousands - who's the real winner?'

He doesn't sound confrontational, or arrogant, or as if he cares about winning. Vaguely amused, if anything.