Four rats were trained to press a bar for food pellets and then were housed in operant chambers for 6 continuous days of choice-testing between obtaining pellets freely or by barpressing. There were two additional 3-day choice periods following more barpress training. It was found that (1) animals preferred to secure food by barpressing when initially placed in the choice situation and immediately following additional barpress training; (2) there was a subsequent decrease to very low levels of response-dependent food taken during choice testing; and (3) opening the chambers for daily maintenance during choice-testing caused a temporary increase in barpressing for food. Thus the previously reported stability of high rates of barpressing in the presence of free food is, at least in part, dependent upon short testing sessions.