Everyone loves a good evolutionary puzzle. Why do we have appendices? Why do we dream? Why do we blush? At first glance, memory would not seem to be in this category. It's clearly useful to remember stuff, after all—to know where to find food, to remember your mistakes so you don't repeat them, to recall who's friendly and who's fierce. In fact, though, certain aspects of memory—when you hold them up to the light—turn out to be quite puzzling indeed.

My guests today are Dr. Ali Boyle and Dr. Johannes Mahr. Ali is a philosopher at the London School of Economics (LSE); Johannes is a philosopher at York University, in Toronto. Both have written extensively about the functions of memory, and, in particular, about the functions of episodic memory—that capacity for calling up specific events and experiences from our own lives.

Here, Ali, Johannes and I lay out the textbook taxonomy of memory, and discuss how episodic memory has drawn the lion's share of philosophical interest. We pick apart the relationship between episodic memory and another major type of long-term memory, semantic memory. We sketch a range of different accounts of the evolved functions of episodic memory, including Johannes's proposal that episodic memory serves communication and Ali's proposal that it fuels semantic memory. And, finally, we consider what this all means for our understanding of memory in children and in animals. Along the way, we touch on Highly Superior Autobiographical Memory, infantile amnesia, evidential systems in language, imagination, "simulationist" theories of episodic memory, what it feels like to remember, collective memory, the hippocampus, cryptomnesia, and the cow's digestive system as a metaphor for memory.

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Notes

4:30 – For a broad orientation to memory research in the cognitive sciences, see here. For a broad orientation to the philosophy of memory, see here.

13:00 – See here for Dr. Boyle's paper on the "impure phenomenology" of episodic memory.

16:30 – For more on the idea of "WEIRD"-ness and the "WEIRD problem" in psychology, see our previous audio essay and our recent episode on childhood across cultures.

20:00 – For more on metaphors for memory in the cognitive sciences, see here (in which an apparently different "cow stomach" metaphor for memory is discussed). Note that cows do not, in fact, have four stomachs, but rather a single stomach with four distinct chambers.

24:00 – For an overview of the cognitive neuroscience of episodic memory, see here.

31:30 – For a discussion of the commonsense "mnemonic view" of episodic memory, see Dr. Boyle's recent article.

37:00 – For one influential articulation of a "simulationist" account of episodic memory, see here.

40:00 – For the proposal by Dr. Mahr and his colleague that episodic memory is for communication, see here and here.

45:00 – For more on evidential systems in language, see here and here.

48:00 – For the study by Dr. Mahr and colleagues on source memory in children, see here.

51:30 – For Dr. Boyle's proposal that episodic memory is for semantic memory, see here. For another of Dr. Boyle's discussions of the functions of episodic memory, see here.

1:02:00 – For more of Dr. Mahr's ideas about the cultural evolution of the "epistemic tag" that distinguishes episodic memory, see here.

1:03:00 – Partially digested stomach contents are sometimes known as "chyme."

1:07:00 – A news story about recent findings on infantile amnesia.

1:08:00 – A recent review article about Highly Superior Autobiographical Memory.

1:12:00 – An empirical study on the phenomenology of "cryptomnesia."

1:15:00 – For a recent discussion of episodic memory in animals, see this paper by Dr. Boyle and a colleague. Examples of Dr. Boyle's other work on memory in animals are here and here.

Recommendations

The Memory Palace (blog)

The Invention of Tomorrow, by Thomas Suddendorf, Jonathan Redshaw, & Adam Bulley (see also our episode featuring this book)

Searching for Memory, by Daniel Schacter

The Enigma of Reason, by Hugo Mercier & Dan Sperber

Many Minds is a project of the Diverse Intelligences Summer Institute, which is made possible by a generous grant from the John Templeton Foundation to Indiana University. The show is hosted and produced by Kensy Cooperrider, with help from Assistant Producer Urte Laukaityte and with creative support from DISI Directors Erica Cartmill and Jacob Foster. Our artwork is by Ben Oldroyd.

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Jack Reacher (2012) and Once (2007)