The cultural transmission of causally (ir)relevant actions in the laboratory: Does modelling or verbal instruction lead to greater copying fidelity?

This study examines the fidelity with which adults vs. children transmit a set of actions within diffusion chains (generations 1 to 3). The set consisted of causally relevant and causally irrelevant actions. Half of the adult and half of the child chains transmitted the actions via demonstration (next participant saw the previous perform the actions on video); the other half transmitted them verbally (next participant listened to audio file the previous participant describe his/her actions). We measured whether the actions were retained (i.e. re-produced by each next participant in the chain).