The cognitive gadgets hypothesis suggests that distinctively human cognitive mechanisms – including theory of mind, imitation, and language – are like slingshots, hour glasses and spinning wheels; they are products of cultural evolution. After a little logical geography, locating the cognitive gadgets proposal relative to high church evolutionary psychology and cultural evolutionary theory, I will give a flavour of the evidence from comparative and developmental psychology and cognitive neuroscience. This evidence suggests that distinctively human cognitive mechanisms are built in the course of ontogeny through social interaction. The ‘parts’ and construction engines are supplied in our genetic starter kit, but this kit doesn’t contain anything fancy. Instead of domain-specific cognitive modules, we genetically inherit temperamental and attentional biases, and high-capacity, domain-general mechanisms of learning and memory. If the cognitive gadgets hypothesis is correct, the mental processes that make human lives so different from those of other animals are more agile and more fragile than is typically assumed.