We're all aware of cute optical illusions. Some play tricks with our perception of color, size, or motion ... This particularly beautiful example plays with our perception of brightness - both turn out to be equally bright inside and out.
Optical illusions are an interesting tool to study how our brain puts together sensory input sent by the eye and there have been some major surprises and there have been revelations that address the question of how much of reality do we sample through our senses as we observe the world. To what degree are we sampling reality?
I stumbled across this example in a PNAS paper by Bruno Laeng and Tor Endestad of the University of Norway in Oslo. The illusion is well known, but they looked at something else - how the pupil responded.
If you look at something bright your pupils constrict to adjust to the new brightness level. This takes place in about a tenth of a second - reasonably fast on our level of perception - and it was thought to be a pure reflex that helps protect the retina from damage. Reflex mechanisms should be fast to prevent as much damage as possible and this one was thought to occur in in a few dedicated cells in lower brain structures.1 What is curious with this illusion is our pupils contract even though there is no real brightness - the reflex is in response to what we think we see rather than what really exists!
This is fantastic. Perceptual errors behave more liked learned phenomena and may be adaptations. Perhaps evolution has made us more adroit at encountering our environment.
A lot of visual information is ambivalent and noisy. Perhaps there is some contextual processing going on to construct a "reality" that is more useful. Maybe the reality our mind assembles is a bit better for our functioning that what really exists in nature.
The same goes for other senses - particularly hearing, but taste also comes to mind.2
As I am writing this it occurs to me that there are many other evolutionary tricks that help us to deal with how we relate to the environment. We read stories of animal athletes - cheetahs that can sprint to 70 mph, our cats and dogs that can make jumps that appear amazing - and sometimes think humans must be unathletic in the scheme of things. But we are amazingly good at endurance running. We probably evolved to this as our ancestors may have had to run down prey in order to get close enough to dispatch it, but whatever the reason we are wonderful aerobic machines.3
Many people report a "runner's high" after exertion. I find it around the sixty minute mark with my rowing and, if I make it that far the resulting rush is enough to encourage me to continue for as long as an extra half hour. It is a feeling of real euphoria.
It turns out the body under heavy aerobic load produces endocannabinoids which are substances that act as neurotransmitters. The name probably rings a bell - endocannabinoids are chemically very similar to the active ingredient in cannabis.
The runner's high is the real thing and the euphoria can be an excellent reward.
Recently it has been learned that a few mammals that are good aerobic athletes(humans and dogs) produce serious amounts of endocannabinoids during aerobic exercise while other mammals that aren't aerobic athletes (ferrets) don't. It may be we have evolved a reward system to encourage this type of activity - I know it is one of the few things that keeps me on the rowing machine for lengthy periods. Colleen is more geared towards bursts of power, but she notes that she loved the feeling of euphoria that came over her after an hour or so of intense training and the reward was enough to encourage her to go on for several hours more.
My niece Magi is a runner. A remarkable runner. She is a single mom with two very little kids and is struggling with raising them, working a couple of jobs and going to nursing school. A few years ago she took up running and found it came naturally. She's done several marathons and does respectable three hour times - not bad for someone who can't run every day and rarely more than an hour at a time and also lacks the money to get coaching - shoes are a major expense for her.
She lives in the Phoenix area and has always been comfortable in the mountains. A few races were in the back country and she found she really liked them. Also she learned that she's good with distance. Her quarter times on the Boston Marathon were all within a minute with the last quarter being the fastest. About a year ago she started trying the longer distances and did very well in several fifty mile runs.
With those under her belt it was time to get serious. Last Saturday she ran the Zane Grey - not a race for the faint of heart. Rather than writing about it, I'll print the email she sent and add a few images. Do read the links from the race director and another runner for more color... like
The course runs along the base of the Mogollon Rim, constantly dropping in and out of the little canyons and crossing multiple creeks and streams. The route is entirely single track trail and is extremely rugged. Despite a ton of work our volunteers have done on the course, entrants will have to navigate over or under fallen trees, through thick wickets of Manzanita bushes, and over very rocky terrain. There are also sections where the trail just disappears and route finding can be challenging. The middle section of the course, known as the “burn area” had the trees burned down from the Dude Fire in the early 90’s. Runners are exposed to the heat of the Arizona sun and have to travel as far as 11 miles between some aid stations. An unprepared runner can sometimes run out of fluids in these long hot stretches.
Not easy terrain down there. The Mogollon Rim is rough, tough and relentlessly difficult
with that, Magi's email:
A Very Simple Simple Pea Soup
° 2 tbl unsalted butter
° 1 diced medium sweet onion
° 1 clove garlic, sliced
° Kosher salt to taste
° 2 c thawed frozen sweet peas (fresh only if picked on the same day!!)
° 1/2 c lightly packed fresh tarragon leaves
° Melt butter over medium low heat. When it foams add onion, garlic and salt. Cover and cook until the onions are soft, but don't brown! Stir frequently - not a walk away and forget it stage
° Add a quart of water and bring to a boil. Add peas and tarragon and cook 'til tender - a few minutes
° take off heat, purée and strain.
° Reheat if necessary and serve. I like to garnish with a few whole raw peas and a bit of plain greek yogurt
After 80 or 90 minutes of hard rowing I'm soaking with perspiration and am in need of something cold with a lot of protein. Here is my current favorite - not vegan friendly though. "Shake" is tongue in cheek - I can make a quality milkshakes. Ask if you visit and we'll do one.
Berry Yogurt "Thickshake" with Nuts and Chocolate
° A good handful (about 100g) of slightly thawed frozen blueberrys or raspberries
° About 200g plain greek yogurt - I like to use 2%
° a half frozen banana - I remove the skins on very ripe bananas and tightly wrap them in plastic wrap and freeze. A great way to deal with ripe bananas
° 2% or whole milk. Start with 100g and adjust
° something sweet - maple syrup, honey, sugar
° 15 to 30g of dark chocolate broken into small bits
° 15 g broken pecans
° Blend banana, fruit, and about 50g of milk.
° Add the yogurt and milk as necessary to get a good enough consistency. Add sweetner if necessary
° Pour into a serving glass or bowl depending on thickness. Stir in pecans and chocolate