Specifically, Dr. Ball looked at sleep locations for new mothers and their infants and randomly
assigned women to one of three location
types — either those that facilitated mother - infant access (i.e.,
bed - sharing or putting the infant in a three - sided crib that was attached the parent
bed, much like an official Co-Sleeper) or those that did not (i.e., a standalone bassinette next to the mother's
bed).