Monday, May 25, 2009

Time for more blogging! Warming up... You can't believe what you see...

I'm just now coming out of the end-of-semester fog.  I've been through three academic years so far as an assistant professor.  That's six semesters, five in which I've taught a course.  In all five of those semesters, I ran out of steam and could not keep up with all the things I'd have liked to have done in my areas of research, mentoring, teaching, and family.  In my opinion, 16 weeks is too long for a semester...I notice myself and my students beginning to burn out after 8 weeks. 

It's a pattern for me that I take on too much at the beginnings of semesters and then have to cast things aside as I get overwhelmed.  Before this semester I took a big leap into communicating with scientists on the internet, via blogging and discussions with a bunch of new friends on friendfeed.  As the semester engulfed me, I ended up casting aside blogging, but actually was able to maintain a lot of dialogue on friendfeed (e.g. in the Science 2.0 and The Life Scientists room).  So, even though I was disappointed to not keep up the blogging, I can look back and see that overall I made a huge amount of progress in terms of scientific communication and meeting (virtually) many great people around the globe.  I'm very happy with that, and I'm even happier that a couple of my graduate students came along with me.  They have made their own connections with other scientists and made substantial progress in open science and open scientific communication.

I've been excited for the last week or two to ramp up the blogs again.  In particular, I'm excited about a couple things.  One is to try out Research Blogging.  This was suggested to me by Michael Nielsen in a friendfeed thread in which I learned a lot, but which I started by spouting off way too ignorantly.  My apologies to Richard once again!  As I understand it, the service will allow me to write up blog reviews of specific research papers and then label my posts as suitable for listing in Research Blogging.  For me, it will be a step up from what I started doing this semester, which is trying to make a few notes on every paper that I add to citeulike.  You can see my citeulike RSS feed, with my comments added, on this Yahoo pipe.  It will be a lot more work to write what I think is a worthy blog report about a paper, but I'm excited about testing the waters.  The way citeulike is set up, I feel like my comments there are pretty much wasted as far as benefit to others goes.  In the future, I'm expecting my group to communicate more via citeulike (or another service) as a form of "journal watch."  But as it stands now, I'm pretty sure nobody reads the comments I add to my citeulike library.

The other thing that should be exciting is to write a guest blog for Lisa Green at NextBio.  We've talked about this a bit, and I think it may happen in the next few weeks.  What I will blog about that is worthy of a "guest blog," I don't know...but it should be a fun experience!

Finally, I needed some inspiration to come in here and start dusting off my blogs.  I had been a bit depressed at their dormancy, which was a postive feedback loop preventing me from blogging.  A blog warm-up idea came to me earlier tonight as I was staring at the ceiling fan.  I recalled something I'd noticed maybe 6-10 years ago in graduate school, which made me recall something else I'd noticed at the same time.  They're two "illusion" kind of things that I think are fun, and which I'm going to describe here without actually researching them scientifically.  Hopefully someone who knows something will pipe in and tell us something about them!

1. Blurry motion seems slower with peripheral vision


I first noticed this illusion when I was trying to make large graphs in Origin back in graduate school.  Whenever I made the mistaking of clicking on very large matrix plots, the graph would flash for like a minute before opening the graphing preferences window.  I would look aside in frustration each time.  And then I noticed that when I looked at the flashing graph (which was more like quick vertical scrolling of a dark patch), it seemed to scroll much slower in my peripheral vision.  A few years later, I noticed the same thing when looking at a ceiling fan, an experiment much easier to reproduce.

Here is the experiment you can try

Find a ceiling fan that's not too far away, and spinning at about 2 hertz.  When you look at it directly, if you're like me, the default image is to ignore the individual fan blades, and perceive a blur.  You can change the image dramatically by following an individual blade with your eyes.  For me, that motion seems "slower" than the blurry motion, but it's not the illusion I'm talking about here.  The illusion that I see is when you quickly switch from looking at the fan with your central vision and instead use your peripheral vision.  When doing that, the motion seems to slow down substantially.  For me, it is substantial and repeatable.

I couldn't resist checking into this a bit on wikipedia, and I found something called "flicker fusion threshold" in this wikipedia article on peripheral vision.  In the flicker fusion article, it is said, "so flicker can be sensed in peripheral vision at higher frequencies than in foveal vision."  Given this, I wonder if the effect I am seeing has to do with some part of the visual system normalizing a given flicker relative to the maximum possible perceived flicker?  The fan produces a constant rate of flicker...but it is a larger percentage of the fastest possible flicker when looked at with foveal vision?

2.  I think you can hear individual splashes in the roar of a waterfall.
(Photo by Ant J on Flickr.)
This is an experiment I can't replicate easily now that I live in Albuquerque.  We do have waterfalls in the mountains, but it's nothing like when I lived in Ithaca, NY during graduate school.  Almost every day, I would cross the bridge over the waterfall at the end of Beebe Lake.  This was on my way between Clark Hall (the physics building) and A-Lot, the parking lot the bus dropped off at. I would often stop and stare at the falling water. I noticed one day that if I followed with my eyes a particular part of the broken stream from the lake to the point at which it hit the rocks, I could audibly hear it "splash" within the "blurry" roar of the waterfall.

Here is the experiment you can try

If you have access to a waterfall, this experiment isn't too difficult to try.  As I mentioned above in item 1, you can track the blades of a ceiling fan with your eyes, and this is the same thing you need to do with the waterfall.  Track a "patch" of water all the way from the point at which it starts falling to when it hits the rocks or water below.  Keep doing this repeatedly in a cycle, and you should "hear" the individual splashes--or at least I do.  It's also fascinating to just look at the water as it breaks into pieces on the way down.

I just attempted 30 seconds of lazy google research for this phenomenon and was not successful at uncovering a wikipedia article to give insight into this effect.  I am 50% sure it's an auditory illusion, and the other 50% of me thinks, "why not...maybe the sound isn't as 'blurry' as it seems?"  It would be possible to check this with an objective audio/visual recording system.

3. The Blue Field Entoptic Effect -- Mystery Solved!

Also known as Scheerer's phenomenon.  As opposed to the above two illusions, this one I now know what it is.  I first noticed it on airplanes when flying in a really bright sky.  In Albuquerque, we have bright blue skies frequently, and I can see the effect.  According to wikipedia, most people can see what I see in these conditions: counteless point-like bright white things that travel in squiggly paths in the field of vision.  It turns out that these are white blood cells flowing through the capillaries that cover the non-foveal parts of the retina.  On a blue background (e.g. the sky), those capillaries produce very dark lines all across the field of vision--due to red blood cells absorbing blue light very well.  Somewhere in the visual processing system, these dark lines are "edited" out, so we don't perceive them.  However, when a white blood cell travels through, it is mostly transparent, and the increased light is perceived as a tiny white thing in the field of view (which it is, I guess).  One of the most fascinating things to me is that it allows you to actually visualize your own blood cells flowing.  According to the article, some doctors have tried to leverage this as a diagnostic technique.

How to try out the experiment:

This one is easy.  Wait for a nice sunny day.  Pick a big blue patch of the sky and stare at it for a couple minutes.  Keep your attention focused on looking for bright dots appearing and traveling in squiggly paths.  You won't be able to follow individual ones, but by trying to use your peripheral vision,  you can see hundreds or thousands of them.  They are quite different than "floaters."  They are smaller (point-like), quicker, and more fleeting.

4. The McCollough Effect -- An amazing optical illusion

I'm including this one because I realized that I ended up having a common theme of "can you believe your eyes?"  The answer is "no!" apparently.  So, I'm including this final, amazing illusion that is well worth trying out.

How to try out the experiment:

If you have 10 minutes, you should go try out this optical illusion: The McCollough Effect.  Spend the 5 minutes they recommend and then test it out for yourself.  You can read a description of it on wikipedia.  I found this illusion mind boggling, because for me it persisted for DAYS after I'd spent the five minutes training whatever part of my visual system that is being trained.  Just an amazing demonstration of an ability to unwillingly and semi-permanently "program" part of your brain (or visual system at least) just by staring at some images for a few minutes.

1 comment:

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