Conventionality and cognitive development: learning to think the right way.

There are many facts about the world that young children can discover for themselves. For instance, after a certain amount of experience in the world, children might discover that objects are solid, collide with one another, and are subject to the force of gravity. There is a correspondingly large body of facts that we cannot learn from direct observation and instead can be gleaned only from other human agents (Koenig & Harris, 2005). Some of these facts are naturally stipulated (or objective) but difficult for most people to ascertain. For instance, most of us have never seen a spleen and instead have relied on others’ reports to tell us where it is in the body, what it looks like, and what it does. Some other facts that we get from other people are overtly subjective. A medical professional might offer an opinion that the spleen is the most elegant organ in the human body. In these cases, the message tells us more about the communicator’s beliefs than something that is necessarily correct or true about world. The focus of this volume is a sort of middle ground between these two kinds of socially gleaned knowledge. We will refer to this middle ground as conventional knowledge. Conventional knowledge differs from naturally stipulated, objective knowledge in that there is no way to verify our beliefs independent of other people. Yet conventional knowledge is not subjective in the usual sense; it is supposed to be a truth about the world that can be evaluated as such. In conventional knowledge, the standard by which the truth