To understand how self-reports and direct observations can yield different results, consider the example of eating. How much do you eat during a typical day? How many calories do you consume? Give a...

To understand how self-reports and direct observations can yield different results, consider the example of eating. How much do you eat during a typical day? How many calories do you consume? Give a rough estimate. Now spend a day actually recording what you eat and calculate the number of calories you consumed. Do the results match your estimate? Did measuring your consumption make you feel self-conscious about your eating behaviour? Is it possible your food choices changed because of this? When people are asked how much they normally eat, they are usually quite inaccurate. This is why a standard technique used to help people diet is to ask them to keep a record of their food consumption: many people are appalled at how many calories they ingested without being aware of it! Not surprisingly, being aware can itself cause changes in (eating) behaviour (reactivity). As a result, the choice between self-report and direct observation can be a complicated decision for a researcher.