Planning Primates - A search for episodic foresight

Abstract: The ability to plan for future, not currently experienced, mental or physiological states has been regarded as unique to humans. When humans plan for such states it has been hypothesized that they make use of what has been known as episodic foresight. Episodic foresight is a part of the episodic cognitive system, which also includes episodic memory. The defining feature of this system is so-called autonoetic consciousness, which enables a phenomenal, first-person view on events that have happened or might happen. Autonoetic consciousness is constituted by sensorial simulations detached from current sensorial inputs; therefore, the episodic system provides humans with an "inner" sense, making it possible to mentally re- or pre-experience events. Humans who lack this ability (e.g., due to specific brain traumas) cannot remember any personla events, and similarly cannot plan for any future events involving their own person. The episodic system develops late in humans, around the age of three to five years. It is a non-trivial task to detect episodic foresight in non-linguistic creatures. However there exist a few behavioural criteria on what a non-linguistic episodic planner should be able to perform. This thesis includes three empirical studies on foresight in chimpanzees and orangutans. The first is an experimental study performed on both species in a series of four experiments. Its basic aim was to test the subject's ability to exercise self-control in the face of future tool use, and to investigate whether chimpanzees and orangutans are able to select unfamiliar tools for a familiar future task. Self-control is essential for planning, and arguably its essential for episodic planning. The ability to integrate novel features into a foresight is a strong indicator of episodic abilities. The study results are positive in favour of episodic foresights in apes. The second is a pilot study on one orangutan's ability to plan for a future physiological state that currently is satisfied. Again the results are positive. The third is an observational study on one chimpanzee. The results suggest that chimpanzees are capable of calmly planning for an event in which they will become agitated; further that they are able to manufacture tools for use in that future event. The question of episodic foresight in comparative cognition is highly contested. Therefore the thesis also includes two papers that respond to some of the criticisms. The final paper in the thesis speculates how episodic foresight might have influenced the evolution of language in humans, based on archaeological and paleoanthropological findings as interpreted from a cognitive view point. Its conclusion is that symbolic communication might have evolved as early as 2.6 million years ago in the so-called Oldowan culture.