Jonah Lehrer writes in praise of vagueness:
The problem with precision, though, is that it can often be discouraging. Let’s say you want to lose 10 pounds. After following a strict diet for a few days, you then decide to weigh yourself. The good news is that you have lost weight. The bad news is that you’ve only lost 4 pounds. While that represents progress, it probably feels pretty disappointing, since you’ve already worked hard and you’re not even half way to the goal. As a result, you might become a little less motivated, which means that you start to cheat on your diet. Before long, those pounds are back – you’ve been undermined by the precise feedback. The larger point is that the exactitude of the scale made it impossible to ignore the lack of success, which makes us more likely to surrender. And this is where vagueness comes in: when information is ambiguous we typically settle on more generous interpretations – Perhaps we’ve lost eight pounds! Perhaps we’re just retaining water! – which means that we stay motivated. In this sense, vagueness is a useful delusion, a nifty means of remaining committed to long-term goals. Reality is a deterrence.
Hang on — is it true that “when information is ambiguous we typically settle on more generous interpretations”? And is it true that “generous interpretations” mean that we “stay motivated”? I’m not sure I buy either of those completely unsupported assertions.
Let’s suppose that I do interpret generously: if all I know is that I’ve lost some weight but less than ten pounds of it, what’s to keep me from saying, “Hey, maybe I’ve lost eight or nine pounds, in which case this milkshake won’t set me back too far”? Why makes that assumption less likely that “I’m probably nearly at 10 pounds so I’ll push harder to get there”?
I don't buy Jonah Lehrer's argument either. It isn't the precise information that is the problem. The problem would be what the person receiving the information decides to do with it.
I think Mr. Lehrer's point is another spin on "don't measure the noise". But that is based on a vague understanding of his article which I haven't read. Hence, I generously assume that I am correct. And so I shall remain undeterred as I fire comments into the blogosphere.
The problem in his example is not too much precision but too little. Losing 5 pounds is too vaguely connected with any particular behavior so it's not very motivating.
If he had more and more precise information, e.g. Biking to work today instead of driving will burn X more calories. Eating salad instead of a burger at this meal will consume Y fewer calories. I have consumed Z calories so far this week and burned W calories. I think that sort of precision would be much more motivating than a vague, "you lost 3 pounds" at the end of the week.
People who closely monitor exactly what they're eating (or spending) for the first time often report that suddenly having that kind of precise data about what they're actually doing gives them more control over what they eat or what they spend.