Originally published in slightly
different form on January 12, 2011 at
PsychologyToday.com.
There are three
interesting studies in the news right now. The first
is about Chaser, a border collie who’s been rigorously trained to remember the
names of all 1022 of her toys, and can differentiate between the verbs “to
nose,” “to paw,” and “to take.” She learned to do this in a series of 4-hour
sessions, taking place over a period of three years, using a ball as a reward
for making a successful match between a word and a toy, or a word and an
action.
Some in the media, and
even in the scientific community, have touted Chaser’s abilities as evidence
that she has a rudimentary capacity to understand human language, and that her
linguistic abilities are on a par with those of a 3-year old child.
Most animals—dogs and
humans included—process salient features of their environments by making
internal representations of them. This is pretty simple stuff. We look at an
object but our eyes don’t really see it, they just provide raw sensory data,
which is translated by the visual circuitry in our brains into a
representation, or mental image, of that object. Dogs are clearly able to do
this, otherwise they wouldn’t be able to dream or catch Frisbees (or perhaps
dream of catching Frisbees).
However, when get into the
realm of what words “mean,” we’re entering the territory of representations of
representations. This means that for Chaser’s abilities to rise to the level of
a 3-year old child’s linguistic skills, she would have to be able to understand
words in a more abstract fashion, not just as verbal cues. She would also have
to be able to use words herself, do so in novel and inventive ways, and
differentiate between nouns, adjectives, pronouns, verbs, etc., and use them
all with a fair amount of grammatical precision. Don’t get me wrong, I think Chaser is very, very smart. But she’s not that smart!
Chaser’s basic ability to
respond to verbal cues, relative to her prey drive (toys are prey objects, after
all), isn’t unusual. Dogs, like wolves, are social predators, so they’re
constantly reading us for social cues. They do this so casually and so often
that many times we’re unaware of what’s going on. So, to me, what’s most
interesting about Chaser isn’t that she can respond to auditory cues, but the
staggering number of them she apparently has stored in her memory banks. And even her owners can’t remember the names of all her toys; they have to
rely on a list!
Meanwhile, another study,
from UCSD, suggests that babies differentiate between words that relate to
pictures of objects and those that don’t in much the same way that adults do. The researchers used MEG
(which measures magnetic fields in the brain) and fMRI machines to estimate brain
activity in 12 to 18-month old infants when they were shown pictures of
familiar objects then heard words that were either a match or a mismatch to the
name of the object. (Interestingly one of the tests involved showing the
infants a picture of a ball followed by the word ball, versus a picture of a
ball followed by the word dog.)
The brains of the infants
lit up in certain areas when the word matched the picture. And the same parts
of the brain lit up when human adults were given the same tests. Plus, these
parts of the brain weren’t those normally associated with language, such as the
Broca’s and Wernicke’s areas. In fact, a much older part of the brain—the
cerebellum, which controls attention, and motor skills—also lit up.
The third study may seem
totally unrelated, but I think it can tell us something about how Chaser
learned the names of so many toys, and also why matching words to objects seems
to involve the cerebellum in human infants and adults. In this study, researchers at Princeton
University tested two groups of students for their ability to retain printed information
based on how difficult a font, or typeface, was to read. One group was given
a homework assignment printed with either a Comic Sans or Bodoni/Italic font,
printed at 60% grayscale, while a second group was given the same assignment
printed with the easy-to-read Arial font, printed in pure black. Oddly enough, the first group did
substantially better on retention.
The researchers write, “It
is not the difficulty, per se, that leads to [learning] improvements but rather
the fact that the intervention engages processes that support learning.”
What might those processes
be?
The researchers say that
“pinning down the precise mechanism [is] quite challenging.” But in a recent blog article here, I wrote about dopamine circuits in the brain, and how
they’re not really “reward circuits,” as they’re often referred to, but
attentional pathways. And that what they seem to reward is paying attention to
changing patterns in the environment.
From that article: “We’re
now discovering that the real purpose of dopamine is to help motivate us to
gather new information about the outside world quickly and efficiently. In fact
dopamine is released during negative experiences as well as positive ones. (The
puppy who gets his nose scratched by the cat doesn’t need further lessons to
reinforce the “no-chasing-the-cat” rule; he learns that instantaneously, with a
single swipe of the cat’s paw.) This adds further importance to the idea that
learning is not as much about pairing behaviors with their consequences as it
is about paying close attention to salient changes in our environment: the
bigger the changes, the more dopamine is released.”
Could simple pattern
recognition explain Chaser’s amazing abilities?
I think so. Chaser is a
border collie. (So was Ricoh, who knew the names of over 200 toys and other objects.) And
border collies aren’t bred for their linguistic abilities but for their herding
skills. In other words, language is not a prerequisite for herding sheep but
pattern recognition (which is an evolutionary pre-cursor to language)
is.
I said earlier that in the
study done on how infants discriminate between word/object pairs that match and
those that don’t, one of the areas in the brain that lit up was the cerebellum,
which is operational during motor control as well as during attentional tasks.
And if dopamine is designed to make us pay attention to changing patterns in
our environment, then it makes sense that the cerebellum—which controls or facilitates attention and motor skills—might
also be involved in the cognitive process of finding words and objects that
match up, while ignoring those that don’t. This would also explain how the
students who had to expend more energy reading the more difficult fonts in
their homework printouts retained the information better than those whose
homework was easier to read.
I also said that dog
owners are often unaware of how easily and how often dogs read our social cues
(i.e., pick up on our patterns).
Just as an example, years ago my dog
Freddie and I would go on long walks in Central Park during off-leash hours,
and he would often do his business (#2) while we were there. If I got distracted while he was in the process of elimination I would sometimes be
unable to find where he’d left his “present,” which left me perplexed
and frustrated.
Fred, meanwhile, would usually
be off sniffing around, or looking for other dogs to meet or squirrels to
stalk. Sometimes, as I stopped and looked around, baggie in hand, I would say,
mostly to myself, “Fred, where did you do your business?” And for some reason, one I can’t
exactly figure out, he would almost invariably stop what he was doing, come
back over to the spot, and sniff his own poop. And he never did this on his
own. He only did it when I was frustrated and began talking to him.
I didn’t train Fred to do
this. There were no external rewards (though I always thanked him for helping me out). And perhaps more
importantly, he didn’t look at me or reference me; he never gave any outward
signal that he “understood” my words. And yet he always, always went back to his
spot and sniffed it when I asked him to.
So, is Fred’s behavior an
example of a capacity to understand human language, a facility for pattern
recognition, or something else entirely?
What do you think?
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