“…Although by no means a comprehensive review, we identified several cocaine and amphetamine conditioned place preference studies that used a biased apparatus and paired the drug with the less preferred chamber as was done in the present study. In these studies, cocaine increased the time spent in the CS+ chamber by an average of approximately 15 s/min (posttest − pretest: 7 s/min low and 27 s/min high), while failing to produce an absolute preference for the CS+ chamber, at least based on the data available in the manuscripts (average time in CS+ chamber: 30 s/min, 27 s/min low and 33 s/min high; Bardo et al, 1986 ; Spyraki et al, 1987 ; Yates et al, 2021 ; Nedelescu et al, 2022 ; Philogene-Khalid et al, 2022 ). Amphetamine similarly increased the time spent in the CS+ chamber (posttest − pretest = 17 s, low = 13 s, high = 23 s) however, it was not possible to determine whether amphetamine produced an absolute or relative preference in these studies (Spyraki et al, 1982 ; Gilbert and Cooper, 1983 ; Decker et al, 2018 ).…”