Friday, August 31, 2012

Jays in My Backyard

Western Scrub-Jay (©Ken R. Schneider)
Earlier this summer, I had the pleasure of watching two fledgling Western Scrub-Jays learn from consequences.  They were perched on my brush pile underneath my redwood when I spotted them, and clearly had left the nest not long before.  They were waiting impatiently for their parents, who stopped by regularly with food that got eagerly grabbed.  Meanwhile, they explored their surroundings.  One found a small yellow leaf, trapped it under one foot and pecked at it, as if checking whether it was good to eat (no).  It was discarded.  The other youngster poked around a bit too, also without success.  Still, it was a start on the path to independence.

One week later, I watched what was probably one of these youngsters in my yard again, this time foraging more actively, picking up dead grass stalks systematically.  Once again, its efforts did not appear to be crowned with success, but it was trying.

The adults are omnivorous, kind of like feathered bears:  They’ll go after anything that’s edible.  And they readily learn their way around minor obstacles.  Someone in my neighborhood feeds peanuts in the shell, and the birds come to particular flat fencepost stumps in my backyard to hold them down and peck them open with their all-purpose beaks.  I'm sure the youngsters will be up to that--someday.

Update:   I happened to catch a cool scrub jay post on animal expert Sophia Yin's blog (link here).  As she reports, two scientists published a 1999 Nature article on how jays learn from consequences when they store food like nuts in hidden "caches."  The nuts last a long time, but cached foods like waxworms don't.  It turns out that "the birds had to learn that food such as waxworms degrade after long intervals. A separate set of scrub jays whose rotten waxworms were secretly replaced with fresh ones after long intervals, never learned that waxworms go bad."  And they behaved accordingly, very differently from the jays that had learned otherwise.  The flexibility provided by learning--even if it's researcher-assisted and "unnatural"--helps the birds survive.

Tuesday, August 21, 2012

The Joy of Escape

Shelter, London Blitz (public domain)
I’m not talking about a trip to Hawaii here.  Escaping a big negative is a powerful reward, one that can be accompanied by powerful emotions.  My community’s "One Book" selection this year is Rebecca Solnitt’s A Paradise Built in Hell: The Extraordinary Communities that Arise in Disaster (which I thought was excellent, by the way; 2009, Viking).  Solnitt quotes a young woman describing her feelings of relief after making it to a shelter and surviving a bomb during the World War II London Blitz:  "It seems a terrible thing to say, when many people must have been killed and injured last night; but never in my whole life have I ever experienced such pure and flawless happiness" (p. 103).  She was not alone.

For most of us, the joys of escape come on a much smaller scale in less tragic circumstances.  When I read this passage, I flashed back to a sensation I’d experienced years ago.  I was a commuter cyclist for decades, but the statistics eventually caught up with me and I got hit by a car, fracturing my back as well as suffering many minor injuries.  The accident occurred during a stressful time in my life and, weirdly, even during the immediate aftermath, I had a feeling of liberation from those other problems.  I’d escaped from them--albeit not in a way I would have chosen--and could simply appreciate being taken care of and working on recovering. My bicycling had been punished pretty strongly by this powerful negative consequence, but when I recovered, I did eventually get back to it. 

Monday, August 13, 2012

Fun with Hummingbirds

Male Anna's (©Ken R. Schneider)

One of the delights of living in California is hosting hummingbirds year-round--including one of the most spectacular North American species, the Anna’s Hummingbird.  My brother took this picture of an adult male.

Last year I rescued a young, probably female Anna’s that hit a back window (despite the warning stickers).  She didn’t seem to  be injured, just stunned.  It was cold, so to help her recover--and keep her away from predators--I held her in my hand in the sun, while she stared at me and one wing quivered.  How could I reassure her?  I decided to take the opportunity to play a game that’s described in my book.  It entails rewarding an animal’s eyeblinks by giving unusually long eyeblinks in immediate response--a sort of communication, if you will.  My hummer didn’t blink much at first, but I took advantage of every blink.  Then she caught on, and within 3 minutes, every time I opened my eyes after my own blinks, she immediately blinked!  Great fun, and best of all, after 5 min, she lifted off, apparently back to normal.  What a magical experience. 

Juvenile Anna's (public domain)
Having a hummingbird feeder lets me enjoy behavior-watching as well as beauty.  I get to laugh at hummingbirds learning to find the nectar.  (Sometimes they try in what seems like every possible place before they succeed.)  When I take the feeder in for cleaning and refilling, I see hummers fly to where they’ve learned it should be, casting about fruitlessly before buzzing off.  Talk about well-learned habits!  And I breathlessly witness frequent dominance battles over access to this prime resource.  In most U.S. hummingbirds, females are larger than males, and my own feeder tends to be dominated by one of them.  I still get to enjoy the beautiful magenta iridescence on the throat "gorget," though, because adult female Anna’s have them.  Maybe the hummer I rescued has developed one by now, attracted a mate, and raised little ones of her own.  

Wednesday, August 8, 2012

Genes, Behavioral Economics, and Dinner

As many are well aware, obesity in the United States has reached "epidemic" proportions (Centers for Disease Control), with about two-thirds of us overweight.  Helpful consequence-based approaches are discussed in my book.  But wouldn’t it be easier just to pop a pill that would reduce appetite? 

The drug rimonabant did just that, first for animals, and then in human clinical trials.  It was on the market as a prescription drug only briefly, though:  As you might have guessed, it was too good to be true, and came with problematic side effects.  But suppose we could better understand how it works?  And how it interacts with some of the relevant genes? 

A particular genetic strain of rats is primed for obesity, and has been used for decades as a model for related human problems, such as diabetes and high blood pressure.  These rats still don’t necessarily become obese, they’re just more likely to.  Erin Rasmussen and colleagues, for example, studied these rats working for sucrose pellets--table sugar.  They showed that when the schedule of reinforcement became lean enough (that is, required a lot more work per sucrose pellet), these rats worked no harder and earned no more rewards than normal rats.  As always, nature-and-nurture systems offer lots of interactions and flexibility.

It’s probably obvious that increasing the amount of work to get a consequence is similar to increasing its price--making the economic demand likely to decrease.  If it’s something we can’t live without, though, like water in a desert, we’ll do whatever we need to:  Demand is "inelastic" in that case.  My own demand level for premium breakfast cereals is seriously elastic:  I don’t buy one unless it’s on sale!  It's simply not a powerful enough reward to overcome a high price.  Mathematical relations let scientists compare demand levels and degree of elasticity in precise ways.

In a follow-up article that appeared this year in the journal Physiology and Behavior, Rasmussen and colleagues checked out the effects of rimonabant on food reward value and elasticity in the normal and "obese" variants of this rat strain.  Sucrose was again the reward, and these nuggets of pure sugar are usually as desirable to rats as they are to us.  The schedule of reinforcement was a "fixed ratio," which means it was work-based:  just 1 lever press per pellet at first, then 15, 30, 50, 90, 150, and 300 (whew).  At the lower prices (lower ratio values), the overweight rats worked harder and earned significantly more sweet rewards than the normal ones, as we might expect.  But, when the going got tough, as in the earlier study, all the rats behaved similarly:  The obese rats were no longer working more and eating more.  Now add the appetite-reducing drug, with its known effects on neurophysiology.  Not surprisingly, all the rats stopped working as hard as they had before:  Sucrose wasn’t as rewarding.  Mathematically, elasticity increased for both groups.

What a great example of interdisciplinary work, including behavioral economics, neuroscience, schedules of reinforcement, reward value, genetics, and more.  Research like this helps us understand how all these factors interact, and may lead to practical applications in preventing and treating obesity. 

Meanwhile, check out the effective consequence-based methods that already exist if you want to work on your weight.  David Freedman's recent articles offer a good, accessible introduction (for example, here).