The utility of being vague.

I'm just getting to glance at the last few issue of Psychological Science, and find this gem, "In Praise of Vagueness" by Mishra et al., which they introduce as follows:

People are increasingly surrounded by devices that provide highly precise information. For instance, technologically advanced bathroom scales can now give measurements of weight, body fat, and hydration levels within two and even three decimal places. People can find out exactly how many calories they are eating, how much weight they can lift, and how many steps they walk in a typical day. The overarching belief exemplified by the use of such technologies could be summed up by the phrase, “If I can measure it, I can manage it.” In other words, people seem to believe that precise information increases their likelihood of performing better and meeting personal goals (e.g., improving physical strength or losing weight). People generally prefer precise information over vague information because precise information gives them a greater sense of security and confidence in their ability to predict unknown outcomes in their environment. Despite this preference, we have found that vague information sometimes serves people better than precise information does.

Why might individuals perform better when they receive vague information than when they receive precise information? We posit that vague information allows individuals leeway in interpretation so that they form expectancies in accordance with the outcomes that they desire. Further, we posit that these positive expectancies can give rise to favorable performance-related outcomes.

Their experiments examined the progress of people towards goals when they were given precise versus vague (error range given) feedback on that progress. Perhaps the most striking example was provided in the weight loss experiment whose participants gained, on average, one pound over the course of the experiment after being given precise feedback, those given vague feedback lost nearly four pounds. Here is their abstract:

Is the eternal quest for precise information always worthwhile? Our research suggests that, at times, vagueness has its merits. Previous research has demonstrated that people prefer precise information over vague information because it gives them a sense of security and makes their environments more predictable. However, we show that the fuzzy boundaries afforded by vague information can actually help individuals perform better than can precise information. We document these findings across two laboratory studies and one quasi–field study that involved different performance-related contexts (mental acuity, physical strength, and weight loss). We argue that the malleability of vague information allows people to interpret it in the manner they desire, so that they can generate positive response expectancies and, thereby, perform better. The rigidity of precise information discourages desirable interpretations. Hence, on certain occasions, precise information is not as helpful as vague information in boosting performance.