marginally significantp = .06
A significant two-way stage x sex interaction influencing infusions [F (1, 28) = 4.56, p < .05] and a marginally significant three-way strain x lever x sex interaction influencing lever pressing [F (1, 28) = 3.79, p = .06] indicated that escalation was sex dependent and that lever pressing varied as a function of the relationship between strain, lever, and sex.