Memory Superstar Eats Like a Bird

How has your memory been lately? You’ve been a little absent-minded, haven’t you? (Your keys are on the dining room table, right where you left them.)

If you don’t have a border collie to help you remember things, you may want to see if there are any Clark’s Nutcrackers in the neighborhood.

Clark's Nutcracker thinking about eating 30,000 pine nuts (photo: US Fish & Wildlife Service)

Clark’s Nutcrackers are medium-sized birds in the corvid family (the same family as jays, crows and ravens) that live in the Western United States and that rely on their memory to relocate stored food during the long winter months.  Every year, they can harvest more than 30,000 seeds from pine cones, which they then hide in thousands of separate places within a 15 mile or so radius.

Their memories for these locations are pretty incredible.  As one researcher, Brett Gibson, described it in a ScienceDaily1 article:

Nutcrackers are almost exclusively dependent upon cache recovery for their survival so if they don’t remember where they’ve made those caches, then they are in trouble. During winter, their cache locations are covered with snow so many of the small local features in the landscape during fall are no longer available to them. What’s clear is that they are using spatial memory to recover these caches. They are remembering these caches based on landmarks and other features of the terrain.

Another biologist, Russell Balda, who has studied Nutcrackers for a number of decades, is even more effusive in National Wildlife2 magazine:

How these birds find their caches looked like an incredible feat when we began studying them. We soon found out that the Clark’s nutcracker is the spatial memory superstar of the avian world, and possibly of the vertebrate world.

These two articles note that there is still some uncertainty about exactly how the Nutcracker is able to have such an astonishingly good memory. Regardless of how they do it, though, I think we all can be impressed by – and a little jealous of – these birds and their brains.

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1ScienceDaily, “Researcher Uncovering Mysteries Of Memory By Studying Clever Bird,” October 12, 2006.

2National Wildlife, “THE BIRD THAT NEVER FORGETS – The unassuming Clark’s nutcracker has one of the most remarkable memories in the animal kingdom,” October 1, 2000.

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A Reflection of Intelligence?

What is it that makes us most “human,” distinguishing us from other animals?

One common response is that we have a sense of self, an ability to recognize ourselves as being separate and distinct from other individuals. Thus, when I look in the mirror, I know that I am looking at myself and not a dashingly handsome stranger. You know this as well; when you gaze in the mirror, you realize that the incredibly attractive person peering back is you!

How about other animals? They don’t “get” mirrors, do they? When they look at mirrors, don’t they either stare blankly or, at best, act as if they have seen another animal? (Hey, what’s that other beast doing on my turf? I wonder if it’s friendly….) Right?

Wrong.

Increasingly, we are finding that the answer is that other animals know exactly who is staring back at them.

First, we found out that certain great apes, like chimpanzees, can recognize themselves in mirrors. Ok, we all know that primates are smart; I’ll buy that. Then, it was bottlenose dolphins. All right, Flipper was pretty darned smart, plus dolphins have those big melon-shaped heads. I suppose that makes sense. Next, Asian elephants. Really? That’s sounds a bit odd. They do have those big eyes, but still…. I guess if you say so. Most recently, birds. Hey, now, wait a minute!

That’s right, magpies are the newest – and only non-mammal – member of the mirror self-recognition club.

Magpies with colored stickers recognize themselves in the mirror (photo credit: Helmut Prior, Goethe University)

As published in PLoS Biology1, researcher Helmut Prior and his colleagues affixed a red, yellow or black mark to feathers on the throats of five magpies (the black marks were basically a “control”: since they were the same color as the surrounding feathers they were essentially invisible to the magpies, thereby allowing the researchers to see whether any magpie behavior during the tests was the result of feeling, rather than seeing, the marks). The colored spots were positioned so that they could not be seen by the magpies unless they were looking in a mirror. When the researchers added a mirror to the cage, certain of the magpies noticed the colored spots in the mirrors and displayed “mark-directed” behavior, swiping at the marks with their beaks or scratching at them with their feet, and then checking in the mirror to determine whether they had successfully removed them. The magpies did not attempt to remove the black spots, which they couldn’t see in the mirror. Here’s a YouTube video of one of the magpies during the testing:

Also, you can read nice summaries of the research and mirror self-recognition testing in ScienceNOW2 and NewScientist3 online magazines.

This research is particularly notable given the differences between the neural anatomy of birds and mammals. Science Daily4 describes the significance:

These findings not only indicate that non-mammalian species can engage in self-recognition behaviour, but they also show that self-recognition can occur in species without a neocortex. This area is thought to be crucial to self-recognition in mammals, and its absence in this case suggests that higher cognitive skills can develop independently along separate evolutionary lines.

Mammals and birds have developed vastly different brain structures, and future studies will be able to further examine how these structures converge to produce similar cognitive abilities.

So, the magpie, lacking a neorcortex area in its brain and with an evolutionary history that diverged from ours 300 million years ago, shares our ability to look into a mirror and see itself.

The point here is not that birds can think like humans – they undoubtedly think like birds. Rather, the lesson is that we need to be very careful in labeling ourselves as special, as having exclusive abilities and intellectual talents. The more we study other animals, the more have found – and the more we will continue to find – how much we have in common, how much we share. Increasingly, I think we will find that our claims regarding uniquely human abilities are just not true, that they are simply smoke and mirrors.

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1Prior, H., Schwarz, A., & Güntürkün, O. (2008). Mirror-Induced Behavior in the Magpie (Pica pica): Evidence of Self-Recognition PLoS Biology, 6 (8) DOI: 10.1371/journal.pbio.0060202.

2ScienceNOW, “The Magpie in the Mirror,” August 19, 2008.

3NewScientist, “Mirror test shows magpies aren’t so bird-brained,” August 19, 2008.

4ScienceDaily, “Mirror Self-Recognition In Magpie Birds,” August 19, 2008.

Improbable Pigeons

I have bad news for you – a pigeon can probably outperform you in the area of probability and statistics.  Yes, that’s right, a pigeon.

The Problem:

Consider the classic “Monty Hall” problem, named after the original host of the Let’s Make a Deal game show:

Suppose you’re on a game show and are given the choice of three doors. Behind one door is a car; behind the others, goats. The car and the goats were placed randomly behind the doors before the show. Before opening the door you’ve picked, the host, who knows what’s behind the doors, must open one of the remaining doors and make you an offer. Accordingly, he opens a door, reveals a goat, and asks you whether you want to stay with your first choice or switch to the last remaining door.

Assuming you want a car and not a playful goat, should you stick with your first choice or go for the remaining door?

The Answer:

This may sound counterintuitive (unless you’re a pigeon), but you actually have twice the chance of winning the car if you change your selection and pick the remaining door.  Why is this?  Well, the relevant Wikipedia1 entry includes the following table, which shows the three possible arrangements of one car and two goats behind three doors and the result of switching or staying after initially picking Door 1 in each case:

Door 1 Door 2 Door 3 Result if switching Result if staying
Car Goat Goat Goat Car
Goat Car Goat Car Goat
Goat Goat Car Car Goat

As shown above, a player who stays with the initial Door 1 choice wins in only one out of three of these equally likely possibilities, while a player who switches wins in two out of three.

How Do People Perform?

In a word, poorly.

Most people will stay with their initial choice or, at best, express no preference either way. In one high profile case, Marilyn Vos Savant (she of the world’s highest IQ) published the answer to the puzzle in Parade magazine and approximately 10,000 readers, including nearly 1,000 with Ph.D.’s, wrote in to vehemently claim she was wrong. The New York Times2 published a fuller explanation of the Monty Hall problem as well as an entertaining account of the Vos Savant incident and how a large number of mathematicians and other well-educated people refused to accept the correct answer, even after being shown multiple proofs of its accuracy.

How Do Pigeons Perform?

Much better!

As published in the Journal of Comparative Psychology3, researchers Walter Herbranson and Julia Schroeder designed a series of experiments in which six pigeons were tested to see how well they would do at solving the Monty Hall problem, and how their performance would compare to that of university undergraduate students. Discover Magazine’s Not Exactly Rocket Science4 blog describes the experiments and the results:

Each pigeon was faced with three lit keys, one of which could be pecked for food. At the first peck, all three keys switched off and after a second, two came back on including the bird’s first choice. The computer, playing the part of Monty Hall, had selected one of the unpecked keys to deactivate. If the pigeon pecked the right key of the remaining two, it earned some grain. On the first day of testing, the pigeons switched on just a third of the trials. But after a month, all six birds switched almost every time, earning virtually the maximum grainy reward.

Every tasty reward would reinforce the pigeon’s behaviour, so if it got a meal twice as often when it switched, you’d expect it to soon learn to switch. Hebranson and Schroder demonstrated this with a cunning variant of the Monty Hall Dilemma, where the best strategy would be to stick every time. With these altered probabilities, the pigeons eventually learned the topsy-turvy tactic.

It may seem obvious that one should choose the strategy that would yield the most frequent rewards and even the dimmest pigeon should pick up the right tactic after a month of training. But try telling that to students. Hebranson and Schroder presented 13 students with a similar set-up to the pigeons. There were limited instructions and no framing storyline – just three lit keys and a goal to earn as many points as possible. They had to work out what was going on through trial and error and they had 200 goes at guessing the right key over the course of a month.

At first, they were equally likely to switch or stay. By the final trial, they were still only switching on two thirds of the trials. They had edged towards the right strategy but they were a long way from the ideal approach of the pigeons. And by the end of the study, they were showing no signs of further improvement.

In their article, Herbranson and Schroeder summarized the results even more succinctly: “The surprising implication is that pigeons seem to solve the puzzle, arriving at the optimal solution while most humans do not.”

Conclusion

While we will accept the view of the researchers that this doesn’t prove that pigeons are smarter than humans, we still think that, if you ever have a chance to appear on Let’s Make a Deal, you should consider bringing a real bird rather than a friend dressed up in a giant bird costume.

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1Wikipedia, Monty Hall Problem, visited on June 27, 2011.

2The New York Times, “Behind Monty Hall’s Doors: Puzzle, Debate and Answer?,” July 21, 1991.

3Herbranson WT, Schroeder J. Are birds smarter than mathematicians? Pigeons (Columba livia) perform optimally on a version of the Monty Hall Dilemma. J Comp Psychol. 2010 Feb;124(1):1-13.

4Discover Magazine, Not Exactly Rocket Science Blog, “Pigeons outperform humans at the Monty Hall Dilemma,” April 2, 2010.

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