NOTICE: Posting schedule is irregular. I hope to get back to a regular schedule as the day-job allows.

Monday, April 16, 2012

NEWS: More "Cracked" Science [Full link to blog for email clients.]

For the past several blogs we've been discussing a recent article by about five seemingly random factors that control our memory ( Today we will look at the effect of visual objects on memory, specifically with respect to the articles point number two: looking at the floor actually affects your memory.  From the article:

"Picture, in your mind, an elderly person who is desperately struggling to remember a name or event. He's got his hand on his chin, he's muttering to himself ("Was that Steve? No, Steve was in jail that year. Maybe Carl?"). Now let us ask you: Where is he looking?

Either at the floor or the ceiling -- almost as if he expects to find the answer written there. He may also just stare off into space -- anywhere, as long as he's not looking at you. Why?
It's faces."
 Again, while the article was correct, looking at faces does interfere with memory recall, in fact, it's a lot more complicated than that.  All visual items in our field of view affect our ability to recall.  This is due to the large amount of processing that occurs in the visual system which takes spots of light connects them into lines, the lines are connected in the shapes, and the shapes are connected into more complex objects.  An early study by the researchers Hubel and Wiesel found that there were cells in the visual cortex, which responded to lines in our field of view.  The neurons were organized into columns, and each column was sensitive to a bar of light (or an edge/dark line) with a particular orientation, or angle.  Columns for the left eye alternated with columns for the right eye, and these in turn alternated with different orientations or angles until all possible combinations were represented in the visual cortex.  This is the representation found in the area of cortex known as V1.  Association areas, brain areas which combined sensory information, contained neurons which responded to increasingly complex shapes, orientations, and even colors.  In the association area known as V4, are neurons which respond to complex objects in our environment, including faces.  It is rather amazing to think that there are cells in the brain, which respond only to the combination of features comprising a face: two eyes, a nose and a mouth - with or without facial hair.  The association areas in parietal lobe are heavily connected to the medial temporal lobe, and the memory centers therein.  It also appears that there are specific neurons in the hippocampus – the regional brain responsible for encoding and processing, memory – which also respond to features of a visual scene, such as background color or foreground shape.  Thus, what we encode and remember is not the whole scene but specific features – particularly faces.

Thus, it should not be surprising that our memory is sensitive to faces, and when we are attempting to recall items of memory, those faces that we see can interfere with the memory itself.  The more complete answer to the question of why a person looks at the floor at the ceiling or stares blankly into space, is that what they're doing is shutting out visual input.  It's easiest to do this by staring at something that does not have a lot of complex features.  You can get the same effect by simply de-focusing your eyes so that you do not see fine detail of your surroundings.  It's also why people who have to visualize in order to remember, like the computer technician who's trying to tell you what should be on your computer screen, often close their eyes when trying to remember.  It's not just the faces that interfere, but all of the visual input that conflicts with the information were trying to recall.

At the same time, other types of sensory information can also interfere with the process of recall.  While it may be possible to study for an exam with music playing, it's much harder to recall the information and take the exam with distraction.  However, this ties into something known as "state dependent learning."  Because all of our environment contributes to the context when memory is being encoded, quite frequently we need to re-create at least a portion of that context in order to recall.  A student who spends their time studying with TV, music and other dormitory distractions, can have a more difficult time recalling information during an exam.  At the same time a student who studies in a quiet, calm environment, such as a library performs much better in the similarly quiet environment of the examination classroom.  If this is true for auditory and visual distractions, it is even more so for the presence or absence of "recreational pharmaceuticals."

In the next blog we will look at the final "seemingly random factor" and finish this analysis of science in the news.  This past weekend was the RavenCon science fiction convention, and I hope to have a convention report for you to follow the current series.

Until then, keep looking up – or down – whatever it takes to help you remember!

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