Using an experimental transmission design, we investigated the extent to which intentional information-sending creates anaccumulation of beneficial information, relative to transmission via inadvertent information.A small subset of an information providers search was transmitted to an information receiver, either selected by theinformation provider themselves (Intentional), or randomly sampled from their full search history (Inadvertent). A thirdcondition where information receivers were shown all of the information providers search attempts was included as acontrol.Intentional information-sending led to cumulative improvements that were comparable to receiving full information froma previous participants search, demonstrating that intentional information-sending had promoted cumulative cultural evo-lution. A follow-up study manipulated whether the sender also received feedback from the receiver which provided infor-mation about locations which had not been searched. No difference was found between these conditions, indicating thatfor this task, bidirectional communication did not further boost the effects of unidirectional intentional communication.