Head over to Brain Blogger for the 38th edition of the Brain Blogging Carnival.
There’s articles on ECT, Neurogenesis, self-improvement, self-awareness, meditation, and more.
If you're new here, you may want to subscribe to my RSS feed. Thanks for visiting!
…though it has left us many challenges.
Encephalon 49 is up, hosted by Marc over at Neuroscientifically Challenged.
Included is a great post on Mind Hacks bringing to light the need for not only the media to understand what brain imaging (particularly fMRI) can and can’t tell us, but scientists themselves too. I was pleased to find a succinct run-down of a paper I just finished reading and was going to write about. Go read Vaughan’s post instead. And then check out The Neurocritic’s post which discusses the same paper and then takes Science to task.
There’s a hell of a lot more so go check it out!
Some of my readers may be unfamiliar with Encephalon, so I highly recommend heading over to Sharp Brains for more.
In these last few posts I’ve been writing about Merlin Donald’s paper on the co-evolution of cognition and culture. The first two thirds of his paper, and so the overview in my last two posts, provide background for the main question the paper tries to address:
What is the cognitive element, missing in primates, that has enabled human beings to master so complex a social life?
Donald suggests that what’s missing may be the ability to mentally handle the vast intricacies humans deal with on a daily basis (and we do so mostly without being aware of it). He says that our current models of cognition focus mainly on short-term processes, and that little is known about the mechanisms for dealing with complex social interactions in the long-term. He points out that studies of neural activity have dealt with what goes on when there’s a reaction to an immediate stimulus, like neurons connected to your eye firing when you see a light flash. This kind of activity only lasts mere seconds at most. Studies have also dealt with short-term or working memory. This type of neural activity is self-maintaining (i.e., it doesn’t need a stimulus to keep it going, like the kind I mentioned just before would), and which can last for many more seconds (or even minutes). Finally, research has looked into long-term memory and found it to be more like an inactive storage, only truly coming into play when awareness is directed towards it, at which point it becomes activity in working memory.
But between the short-term and long-term is where he says we spend most of our mental life, in an
‘‘intermediate time zone”, within which many events and episodes are grasped and understood in terms of their implications for social relationships and future behavior.
He suggests that processing of events within an intermediate time zone could be handled by a “slow process.” This slow process can operate over longer time frames than working memory, though there is some overlap. It’s also active, maintaining control of our thoughts and behaviour while monitoring and withstanding potential interruptions. He argues that this kind of mental activity must take place, since there’s overwhelming evidence that our daily life involves relatively long thought processes. He gives the examples of conversations that last hours, and organised games.
But I wonder if the slow process is really just another way of describing processes that we already have a fair understanding of. Donald says that research into attention has focused on processes that occur from moment to moment, i.e., what happens when we attend to something happening right now. However in my (admittedly limited) understanding, activities such as long conversations and organised games involve continual feedback, which could exist as continually updated activity in working memory. I know that I can easily lose track of a conversation if I “drift off” for a few seconds; in other words there isn’t really an active process keeping track of what’s going on beyond a span of a few minutes.
And yet if I have a long conversation early in the day, even if I don’t think about it for a few more hours, later I find the subject matter of the conversation easier to recall than I otherwise would. For example, if I was talking about a relative I don’t often think about, I’ll be able to recall information about that relative more easily even hours after the conversation. Does this suggest that my memory of that relative exists as ongoing neural activity in a form which lasts longer than working memory supposedly can?
Could the processes of long-term memory consolidation explain the “slow process”? Again, in my limited understanding, long-term memory consolidation is a process which takes place over hours, days, and perhaps weeks. And the results seem to last much longer. Also, the process occurs when first learning something, but also when recalling a specific piece of information. I.e., when I find out the details of a friend’s latest fling I’ll probably think about other flings they’ve had in the past, and the memory of those distant events will be reconsolidated. Could it be that consolidation is the slow process, and that , for example, a conversation I had early in the day is more readily accessible later in the day because of the ongoing process of consolidation?
I’m still learning about these processes so I wouldn’t dare propose any firm conclusions, but it seems that the combination of the processes involved in attention and consolidation of memories may account for
the maintenance of something as complex and subtle as a very slow moving social scenario or mental plan, running in the deep background, enduring for many hours, and influencing a whole succession of actions and changes of strategy.
I’ll continue to scour the available research for answers, but if anyone has any at hand, I’d love to hear them.
Related entries:
