In the final section of their fascinating target article, Suddendorf & Corballis (S&C) propose that mental time travel has important implications for human culture: “Law, education, religion, and many other fundamental aspects of human culture are deeply dependant on our shared ability to reconstruct past and imagine future events” (sect. 6, para. 3). Yet, besides some informal speculation regarding stone tools and the use of fire (which, as the authors acknowledge, are “just-so stories”), the specific implications of mental time travel for human culture, and for research in the social sciences concerning cultural change, are left unexplored. It is important to distinguish between the capacity for culture and the contents of culture (Mesoudi et al. Reference Mesoudi, Whiten and Laland2006). While mental time travel potentially has implications for both, I focus here on the latter, that is, the effect of mental time travel on changes in the contents of human culture, such as law, education, and religion.

The existence of mental time travel, specifically regarding future events (i.e., foresight), has direct relevance to an ongoing debate concerning the validity of the theory of Darwinian cultural evolution. Recent years have seen a burgeoning interest in cultural evolution, the idea that human culture changes according to the same fundamental principles as do biological species, and that consequently many of the same tools, methods, theories, and concepts developed by evolutionary biologists can be adapted for use by cultural scientists to analyze cultural change (Aunger Reference Aunger2000; Henrich & McElreath Reference Henrich and McElreath2003; Mesoudi et al. Reference Mesoudi, Whiten and Laland2004; Reference Mesoudi, Whiten and Laland2006; Richerson & Boyd Reference Richerson and Boyd2005). Despite this growing movement, cultural evolution is still met with much hostility and opposition from many quarters, especially the social sciences most directly involved in the study of human culture, such as cultural anthropology and sociology. One of the most oft-cited criticisms of evolutionary approaches to human culture is that, whereas biological (gene-based) evolution is “blind” and undirected (Dawkins Reference Dawkins1996), culture is directed by conscious and intentional human agents who can use their capacity for foresight to guide cultural change towards specific goals (e.g., Benton Reference Benton, Rose and Rose2000; Bryant Reference Bryant2004; Carneiro Reference Carneiro1985; Chater Reference Chater, Hurley and Chater2005; Dasgupta Reference Dasgupta2004; Hallpike Reference Hallpike1986). For example, Benton (Reference Benton, Rose and Rose2000) criticizes Darwinian models of cultural change because “human agents act intentionally to produce anticipated outcomes: They are not ‘blind watchmakers’” (p. 216).

The initial reaction from advocates of Darwinian cultural evolution to such criticism was to deny that humans possessed foresight, and to argue that cultural change is just as blind as biological change (e.g., Campbell Reference Campbell1960; Rindos Reference Rindos1985; Simonton Reference Simonton1999). The existence of mental time travel, which, as S&C show, is supported by a rich body of evidence from neuropsychology and developmental, cognitive, and comparative psychology, appears to make this position untenable. Mental time travel allows people to simulate potential future scenarios in order to anticipate and plan for novel future events in a way that does not appear to have any parallel in biological evolution. Biologically evolved biases in learning can “predict” the future based on past regularities (Lorenz Reference Lorenz and Pribram1969; Mayr Reference Mayr and Plotkin1982), but biological evolution cannot actively simulate novel future events.

So does the existence of mental time travel invalidate the theory of Darwinian cultural evolution? Although it is possible, such a conclusion would be premature. First, it has yet to be established empirically that mental time travel has affected cultural change in a significant manner. This must be addressed not with just-so stories or vague talk of “intentional actors,” but by integrating the body of work from the behavioral and psychological sciences reviewed by S&C with evidence from the social sciences regarding actual cultural change. Existing studies (e.g., Basalla Reference Basalla1988) suggest that foresight plays little role in directing technological change, although such studies are relatively informal and do not make the important theoretical distinctions that follow from the work reviewed by S&C, such as between “semantic foresight” (i.e., script-like expectancies generated by semantic memory) and “episodic foresight” (i.e., forward-looking mental time travel). Future studies might simulate cultural change in computer-generated agents (Epstein & Axtell Reference Epstein and Axtell1996) who possess varying degrees of foresight, from “no foresight” to “semantic foresight” to “episodic foresight” to “omniscience,” along a “continuum of mindfulness” (Dennett & McKay Reference Dennett and McKay2006), and match the resulting cultural dynamics to actual historical, archaeological and sociological data. Lab-based experimental simulations of cultural transmission and cultural evolution (Mesoudi Reference Mesoudi2007) might test the extent to which the episodic memory system is used to maintain complex cultural traditions, while ethnographers might quantify the long-term accuracy and consequences of episodic foresight in traditional societies.

Second, even if it was established that mental time travel has significantly affected cultural change, this does not automatically invalidate Darwinian approaches to culture. Even though people can simulate future scenarios, there is no guarantee that this simulation will be accurate. As S&C note, “Mental time travel is of course not to be mistaken for clairvoyance” (sect. 4.5). The well-documented inaccuracies in episodic memory (Loftus Reference Loftus1996; Loftus & Ketcham Reference Loftus and Ketcham1994) suggest that episodic foresight is similarly biased and inaccurate. Indeed, some of these biases have already been identified, such as the planning fallacy (Kahneman & Tversky Reference Kahneman and Tversky1979) or hyperbolic discounting (Kirby Reference Kirby1997). Critics of cultural evolution commonly conflate this imperfect “human foresight” with the perfect “supernatural foresight” of an omniscient being. Biology is blind in the latter sense, but so is culture: There is no omniscient being with perfectly accurate supernatural foresight guiding cultural change. Unfortunately, most critics of cultural evolution do not make this distinction, and assume that any kind of foresight automatically invalidates Darwinian cultural evolution. Cultural evolution does not have to be identical in every respect to biological evolution, and evolutionary models of culture have already successfully incorporated phenomena not found in biological evolution, such as blending inheritance (Boyd & Richerson Reference Boyd and Richerson1985); perhaps the same can be done with mental time travel.

In summary, researchers who study culture would benefit from explicitly incorporating the theoretical distinctions identified by S&C into their work, while S&C's proposal would benefit from a more detailed consideration of evidence from the social sciences regarding actual cultural change.