There’s an interesting letter in this week’s edition of Nature from biologist Lewis Wolpert making the speculative but interesting claim that the development of causal belief may have been a key turning point in human evolution.
Wolpert is responding to a recent Nature essay critiquing the idea that closely related species will have evolved similar psychological processes, suggesting that it is shared selection pressures rather than genetic similarity that more greatly influences mental make up.
He responds by saying that we should focus on some of things that have uniquely evolved in humans rather than shared processes. He cites the ability to understand cause as a key example.
The feature that is peculiar to humans is their understanding about the causal interactions between physical objects (see, for example, L. Wolpert Six Impossible Things Before Breakfast; Faber, 2006). For example, children realize from an early age that one moving object can make another move on impact. It is this primitive concept of mechanics that is a crucial feature of causal belief, and that conferred an advantage in tool-making and the use of tools ‚Äî which, in turn, drove human evolution.
Animals, by contrast, have very limited causal beliefs, although they can learn to carry out complex tasks. According to Michael Tomasello (The Cultural Origins of Human Cognition; Harvard Univ. Press, 1999), only human primates understand the causal and intentional relations that hold among external entities. Tomasello illustrates this point for non-human primates with the claim that even though they might watch the wind shaking a branch until its fruit falls, they would never shake the branch themselves to obtain the fruit. Some primates are, nevertheless, at the edge of having causal understanding.
Once causal belief evolved in relation to tools and language, it was inevitable that people would want to understand the causes of all the events that might affect their lives ‚Äî such as illness, changes in climate and death itself. Once there was a concept of cause and effect, ignorance was no longer bliss, and this could have led to the development of religious beliefs.
Link to Wolpert’s letter in Nature.