Discovery of the Fourth Dimension: Mental Time Travel and Human Evolution

This article considers the role of mental time travel in human evolution. A central thesis is that other primates, although having memory and expectation, do not possess the same ability to live in the past or in the future. The first half of this paper argues that reconstructive access to the past (i.e. episodic memory) is dependent on other advanced cognitive capabilities (e.g. self-awareness and meta-representation) and focuses on the results of recent `theory of mind' research in order to evaluate the thesis. Mental simulation is the proposed underlying mechanism for the development of both mindreading and mental time travel. The second half contrasts flexible awareness of possible futures with other forms of `anticipatory behaviour' and reviews evidence about how far other primates may think ahead. The phylogenetic history of mental time travel and its adaptive and exaptive relationships to other features are discussed. Mental access to the fourth dimension is essential for many of the distinctive characteristics of our species.