Cognitive complexity is defined here as the capacity for abstract thought, analogical reasoning, cognitive fluidity, innovative thought, complex goal-directed actions, flexibility in problem-solving, multi-tasking, task switching, response inhibition and planning over long distances or time. Some of these attributes are archaeologically recognizable in transformative technologies such as heat treatment of rocks and ochre, and the manufacture of compound adhesives and paints. Advanced executive functions of the brain are also required for remote capture during snaring, which is implied by circumstantial archaeological evidence. Some technologies seem good indicators of complex cognition and the emphasis here is on making the connection, but this does not mean that cognition necessarily drove innovation in the past any more than it does today. The recursive relationships between cognition, social behaviour and technology mean that change cannot be attributed to a single stimulus.