Influenced by the ideas of PERSON@1 , PERSON@2 developed this into a `` psychohydraulic '' model of the motivation of behavior , which tended towards group selectionist ideas , which were influential in the NUMBER@1 .

Building on the ideas of PERSON@1 , PERSON@2 developed this into a `` psychohydraulic '' explanation of the motivation of behavior , which tended towards group selectionist ideas , which were influential in the NUMBER@1 .
