"I've earned it"

You sent off the quarterly figures and took two chocolate digestives from the tin. This is the job that feels most innocent. Rewarding yourself for hard work is what sensible, self-respecting people are supposed to do, and a biscuit seems a modest prize.

Start with a finding about the thought itself. Cat Taylor, Thomas Webb and Paschal Sheeran, psychologists at Sheffield, studied the reasons people give themselves for eating something they'd intended not to. They collected six. People say that they deserve it, or that they're curious to try it. They tell themselves that this occasion is an exception, or that they'll make up for it later. The other two are that the food is simply there, and that it's irresistible. Deserving it came first on their list.

In a further experiment, they quietly prompted some volunteers to think in terms of such justifications, and then gave everyone what was described as a taste test with chocolate. The prompted volunteers ate more. The effect was strongest among the people who held the firmest intentions to limit what they ate.

That last finding is worth a moment. You'd expect good intentions to protect a person. What they seem to do is create a need for a good reason, and "I've earned it" is the best reason going. It arrives at the very moment you've achieved something, it sounds like self-respect, and it can't be argued with. The more serious you are about eating less sugar, the more work that little sentence does.

So it's worth looking at the reward on its own terms, as if it were a pay deal. These are my observations.

Look at who's awarding it. You're the worker, the employer and the judge of whether the work deserves a prize. Under that arrangement everything qualifies. Finishing the figures earns a biscuit, and so does getting through a dull meeting, doing the ironing, a long day or a short one that was annoying. You've never once turned yourself down for a reward.

Look at what the prize is. It's a biscuit costing a few pence, from a tin you can open at any time, and you could have had it without doing the figures. A reward has to be something you wouldn't otherwise get. The biscuit only feels like a prize because of the childhood code from chapter 2, in which sweets were scarce and adults controlled the supply. You control the supply now, and the tin is always full.

Look at how long it lasts. The lift is over in a few minutes. Three days of dread and a morning of concentration went into those figures, and they've been marked with something that was finished before the tea was cool enough to drink.

And look at what it says about the work. If every task needs a sweet at the end of it, that implies the work has no satisfaction of its own, as if you were a child being bribed through homework. I doubt that's how you see your working life. Finishing a hard thing feels good by itself, if it's given a moment. The biscuit tends to take that moment. You go straight from pressing send to the kettle, and the small glow of having done it gets eaten along with the digestive.

The honest objection is that it's harmless. It's two biscuits, and you did work hard. That's true of the biscuits taken alone. The problem is what the habit of rewarding does over time. It turns every effort into an occasion for sugar, which on a busy day means four or five occasions, and it replaces the satisfaction of finishing with a less satisfying substitute.

You do deserve something when you finish a hard piece of work. Chapter 15 suggests what that might be.