In the Mood for Memory

It's January and I just started a new quarter at UCSD, so I'm going to make a fresh attempt to make a habit of posting when I learn something especially interesting. Maybe, if this works, I'll even do a "Coolest Cog Sci Fact of the Week" sort of thing or something.

So, to begin with, I'm taking a class called "Learning, Memory and Attention." In her first lecture Dr. Sarah Creel (my professor) told us the most interesting thing about memory. She was giving us a few scientifically informed study tips, like study a little bit at a time and be sure that you understand the concepts well enough to explain them to your grandmother and caffeine and exercise help consolidate memory, etc., when she mentioned that it is important to study in the same state of mind that you will be in when you take the test. In other words, memory is functionally dependent on your brain state.

Here's her illustration (note: stories and concrete examples are amazing ways to make a concept memorable). A friend of hers, lets call her Carly, was an undergrad at Berkeley taking calculus. Carly was also on crack. When she studied she was on crack, when she went to class she was on crack, when she took tests she was on crack. Carly got an A in calculus. At this point Dr. Creel made sure to disclaim that "This isn't a drug endorsement, and crack doesn't make you smarter." Over the summer Carly got clean and when she came back in the fall she took the next calculus class in the series. Carlys new teacher gave her a test to see how much of the material from the previous class she had retained. She got an F. The sober Carly couldn't remember the things that the drugged Carly had learned. So, Dr. Creel said, the moral of the story is that you should make it easy on yourself by studying AND testing sober.

Great story, but I am much more interested in the implications this has on the nature of my own identity than improving my memory. Think about it. This memory principle applies to our brain states in general (i.e. our overall mood and neurochemical activity) rather than specifically just drug-induced brain states. In practice this means that, for example, when I am depressed I most easily remember episodes and information that I encountered during past periods of depression (by depression I mean a mood, not clinical depression). We've all experienced how our moods seem to feed themselves, but just think about it in terms of identity. Identity is essentially composed from a series of key memories about the experiences that we have had and what we have made them mean about the world. If I am building a definition of myself (to a certain degree) from my own memories, then my understanding of who I am when I am depressed is significantly different from who I think I am when I am happy or calm simply because I am constructing my identity from a different set of memories.

Now, I'm definitely no expert, and I haven't done any experiments to investigate this further (yet), but I have a few theories (or rather, informed intuitions) about the nature of self and identity. There are a ton of real-life illustrations of how a 'person' can behave as though he/she is actually a series of distinctly different people (generally speaking, in terms of personality traits and behavior). Obvious examples are people with Multiple-Personalities Disorder and people who are bipolar, but the same principle can be seen in perfectly functional, well-adjusted, 'normal' people. For example, a woman uses significantly different behaviors and cognitive strategies (she assumes an entirely different role) when she is interacting with her child than she does when she is interacting with her husband. Our culture and our immediate context (our social role and mood)help us filter out memories that aren't appropriate or are inconsistent (in terms of our social context). I definitely need to do a whole lot more thinking (and maybe some research) about this, but if any of you have any thoughts on the subject, please do share them.