["To gain insight into the potential impact of plain tobacco packaging policy, two experiments were undertaken to test whether 'prototype' plain compared with branded UK cigarette pack stimuli would differentially elicit instrumental tobacco-seeking in a nominal Pavlovian to instrumental transfer (PIT) procedure.", 'Two experiments were undertaken at the University of Bristol UK, with a convenience sample of adult smokers (experiment 1, n\u2009=\u200923, experiment 2, n\u2009=\u2009121).', 'In both experiments, smokers were trained on a concurrent choice procedure in which two responses earned points for cigarettes and chocolate, respectively, before images of branded and plain packs were tested for capacity to elicit the tobacco-seeking response in extinction. The primary outcome was percentage choice of the tobacco- over the chocolate-seeking response in plain pack, branded pack and no-stimulus conditions.', 'Both experiments found that branded packs primed a greater percentage of tobacco-seeking (overall mean\u2009=\u200962%) than plain packs (overall mean\u2009=\u200953%) and the no-stimulus condition (overall mean\u2009=\u200952%; Ps\u2009≤\u20090.01, ŋp (2) s\u2009≥\u20090.16), and that there was no difference in percentage tobacco-seeking between plain packs and the no-stimulus condition (Ps\u2009≥\u20090.17, ŋp (2) s\u2009≤\u20090.04). Plain tobacco packs showed an overall 9% reduction in the priming of a tobacco choice response compared to branded tobacco packs.'] Do plain cigarette packs exert Pavlovian to instrumental transfer of control over tobacco-seeking?