I was writing a comment back to the few readers that responded to the last post, part of which mentioned autobiographical memory, and then realized it was WAY too long for a comment and I might as well share it with everyone. So, here are a few more thoughts about the research on autobiographical memory:

In the comment section, @sheila asked some GREAT questions, the first of which was: How do scientists measure memories and trace them forward to deem them accurate or not? There are a bunch of ways that developmental scientists look at these things, some will seem pretty darn boring because it's not like you can ASK an infant if he remembers something. So, what researchers do is, for example, show a baby a shape one day and then test whether he "remembers" it a few days later by looking at his gaze and the extent to which it implies "recognition". Or they will teach an 18 month old a sequence of play events (hit this, then this, then pop goes the toy) and then test him at 2 years old and see if he knows how to re-enact that play sequence. Ta DA! Memory! If you look at the article I linked to in the last post, they give you a bunch of details (if you can't access it and are interested enough, leave a comment and I can send the pdf file).

Sheila also described the common experience of not being able to differentiate details of your childhood memories from stories or pictures that parents and other people tell you as you are growing up. This is indeed the norm in terms of how most people think of childhood memories. Interestingly, and not surprisingly, children DEVELOP the ability to remember in different ways. At first, young babies and children tend to "encode" small, concrete details about their world. Of course, that's because that's how they understand the world around them at that early stage of cognitive development — in concrete terms, not abstract. Also, their working memory capacity (the RAM of our minds) is so limited at this age that they can't keep much in mind at the same time for very long at all. As children grow, they are able to hold more in storage, to keep more things in the mind's RAM for longer periods of time. With that developmental progression comes older children's and adults' abilities to encode more "gist-like" or "fuzzy trace" memories. So, we as adults are more likely to remember episodes in terms of their general meaning to us, their emotional valance, and so on. Both children and adults "store" memories in both the more literal (e.g., details about a task, episode, etc.) and "gist-like"  (semantic, elaborate, "relational) styles, but young children rely much more on the former and adults more on the latter. (You guys don't want me to spout on about the fact that there actually is no "storage" per se in the brain, like a treasure chest that gets opened and shut; instead it's more about patterns of neural firings that scientists are still pretty in the dark about).

@Beth wondered in the comments whether early memories can be triggered by trauma; implicitly I thought she was also asking if more traumatic experiences are better remembered. Yes, to have ANY experience stick and become a lasting memory, there needs to be SOME level of emotion involved. There's a whole lot of cool neuroscience to back this claim up — but the summary is that you need certain parts of your more "primal, emotional" brain to be firing during an event to encode it into long-term memory. So it is indeed possible that those more emotionally-charged experiences are the ones you remember best. But also, those are the experiences that will be talked about most in your family oftentimes, which keeps those memory traces alive and these re-enactments, in turn, continue to strengthen those neural memory traces.

But there is also the extreme cases of emotional memories; these are the cases of post-traumatic stress disorder (PTSD). People with PTSD have experienced INSANELY traumatic things (abuse, war, etc.) and in some of these cases, their emotional centres OVER-fired and shut down the part of the brain that participates in storing information and forming memories during the trauma. As a result of this emotional flooding, these people often DON'T remember the traumatic events themselves (nice evolutionary survival mechanism, if you ask me). PTSD sufferers often have NO semantic memory (they can't actually remember WHAT happened), but they have EMOTIONAL traces still "stored." So, for example, a loud bang from a garbage truck can trigger seemingly irrational panic/anxiety attacks in a veteran who has experienced horrors in combat, but he won't know why because he won't be able to trace the memory back to the initial experience. (For more info, Joseph LeDoux has some exceptional research in this area).

@Cloud expressed something I think about almost daily right now, as I try to develop family traditions that my children will hopefully look back on with warmth and love throughout their lives: How WEIRD is it that a 2.5 year old (and many 3-5 year olds also) won't remember our vacations, holiday celebrations, or any other cool events, events that they can NOW remember? I think it IS strange. But also, we have to remember (hahahahaha… ugh) that just because most children won't retain coherent memories of these special events into adulthood, they still MATTER. These experiences still make up the foundation of who our children are, how they are developing, how secure, happy, anxious, angry, and so on they WILL become. We may not be able to retrieve a perfectly intact memory of our childhood vacations (I certainly can't), but those experiences nevertheless were the basis from which we learned how to share with other kids, swim safely, dance like lunatics, trust adults, stay clear of poison ivy, read with a watch light under the covers, try different types of foods, and so on. 

And now this post is getting away from me and I haven't even BEGUN to talk about all the ways in which our memories are biased, flawed, skewed, motivated by our current situation, mood, developmental stage and so on. There are boatloads of studies that show how bad we are at ACCURATELY encoding certain types of information. And who among us has not had the fight with a parent, sibling or partner who remembered a CRUCIAL event totally differently than we did? Memory is NOT an objective, factual trace laid onto our neural circuitry… that's what makes it so fascinating for so many psychologists to study and for so many therapists to delve more deeply into with their clients.

Are those experiences that we CAN'T remember from our childhood any less influential on the person we've become than the things we DO remember? What memories would you be/ are you sad that your child will not retain? (My mother, for example, is horrified that I don't remember the details of our trip to Italy when we were 12 years old. TWELVE?!?! How could I forget that gorgeous cathedral, that ice cream cone, that gilded br
idge?! She thinks I'm brain damaged. But the thing is, I DO remember the guy on the Spanish Steps who winked at me on his moped… 28 years later, and I remember him and that wink PERFECTLY.)

– Isabela