Young children copy cumulative technological design in the absence of action information.

The ratchet effect - the accumulation of beneficial changes in cultural products beyond a level that individuals could reach on their own - is a topic of increasing interest. It is currently debated which social learning mechanisms allow for the generation and transmission of cumulative culture. This study focused on transmission, investigating whether 4- to 6-year-old children were able to copy cumulative technological design and whether they could do so without action information (emulation). We adapted the spaghetti tower task, previously used to test for accumulation of culture in human adults. A baseline condition established that the demonstrated tower design was beyond the innovation skills of individual children this age and so represented a culture-dependent product for them. There were 2 demonstration conditions: a full demonstration (actions plus (end-)results) and an endstate- demonstration (end-results only). Children in both demonstration conditions built taller towers than those in the baseline. Crucially, in both demonstration conditions some children also copied the demonstrated tower. We provide the first evidence that young children learn from, and that some of them even copy, cumulative technological design, and that - in line with some adult studies - action information is not always necessary to transmit culture-dependent traits.