a1 Department of Experimental Psychology, University of Cambridge, Cambridge, CB2 3EB, United Kingdom. [email protected] [email protected] [email protected] [email protected] www.psychol.cam.ac.uk/ccl/
Although the mental time travel (MTT) hypothesis provides a rich, conceptual framework, the absence of clear, empirically tractable, behavioural criteria for determining the capacity for MTT restricts its usefulness in comparative research. Examples of empirical criteria for evaluating MTT in animals are given. We also question the authors' evaluation of semantic foresight and their even-handedness in assessing human and nonhuman behaviour.