In this video, Columbia University neuroscientist Daphna Shohamy explains the science of memory to a kid, a teen, a college student, a grad student, and an expert. Along the way, she describes how her research is reshaping our understanding of what we remember, how, and where. From the transcript at Wired:
We're interested in the idea that memory is kind of a pervasive force that shapes all our behaviors. And we're trying to understand how different kinds of memory are organized in different structures of the brain. And then to understand how those different structures work together to orchestrate complex cognitive behaviors like decision-making or reasoning and thinking[…]
My work has actually kind of pushed against [the] distinction between memories that kind of are consciously accessible versus unconscious.
When you say that you don't necessarily look at implicit and explicit memory as anything different, if you were to take a step back, what would you define as implicit and explicit memory?
The best way to kind of think about that distinction really goes back historically to one of the most important discoveries in memory research. The patient was referred to famously as patient HM. The neurosurgeon went in and removed the tissue that happened to be right around the hippocampus on both the left side and the right side of HM's brain. But then they started noticing something odd in his behavior. He was not able to create new memories of the experiences he had after the surgery. And that led Brenda Milner and her colleagues to report that the hippocampus was very important for memory, but a one particular kind, these sort of explicit, or as now referred to them episodic memories. But the hippocampus was not necessary for learning skills like mirror tracing, things that you can't necessarily articulate but you just get better at over time.
And it really led to a couple of decades or more even of an enormous amount of very important work that kind of kept on breaking memory down further and further into different types. Episodic and semantic as both forms of explicit memory where episodic refers to memory for an event that happened like what you did yesterday morning and semantic refers to general knowledge about the world. Implicit memory is being broken down into a bunch of different kinds like skills or habits or conditioning. And when I started graduate school, many of us felt kind of the next question was really to understand how do we now understand how they work together.