dolphin cognition psych 1090 lecture 12. now, we ’ ve talked a lot about birds, nonhuman primates,...
Post on 20-Dec-2015
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TRANSCRIPT
Now, we’ve talked a lot about birds, nonhuman primates, even
insects…
but barely discussed cetaceans,
which are also large-brained, long-lived creatures
and for which lots of data exit
So we’re going to do a brief survey of these creatures;
we could take many lectures and barely get through the data
We’ll start with some of the two-way communication studies and end with what looks to be mirror
self-recognition
Dolphins had always held fascination for humans, even from
the time of the ancient Greeks
but it was really around the 1960s that researchers started studying
them scientifically
First looking at their natural whistles, learning that they had
sonar
And only a bit later was there the attempt to engage them in direct
communication studies with humans
Lilly was one of the first to engage in such work;
He trained dolphins to match number of and trains of sound bursts, interburst silences, and
latencies
He pretty much used standard operant techniques and fish
rewardsHis subjects were also able to
differentiate between one human’s voice and other humans’ comments or
corrections And he manage to train the
dolphins to produce a few human-like utterances
Unfortunately, Lilly became known more for LSD
experimentation and total deprivation studies
But his work set the state for a number of other intriguing studies
People like Karen Pryor trained dolphins to understand certain
signals
Not just the typical stuff of marine mammal shows, but signals such
as “invent”
For which the dolphins would do some entirely new behavior or
combination of behavior
Other researchers examined how dolphins might transfer information
to each other
How, for example, they could do particular jumps exactly in tandem
or transfer information about what was in their tank to another dolphin
in an adjoining tank
In the early 70s, the person who became most influential in dolphin
research was Louis Herman
Who looked at all the work being done with signing chimps and
computer-mediated communication between apes and
humansAnd decided to replicate the work
with dolphins
He worked in two modalities…hand signals and artificial whistles
His system was quite similar to that later adapted by Ron
Schusterman that we saw for Rocky, the sea lion
Basically, the animals learned to respond to a series of signals,
either auditory or gestural
And thus could be examined on how well they comprehended this
artificial language
So the dolphin would be given a set of signals that would mean
“flipper touch the ball” (i.e.,not the frisbee or the ring)
And it would swim to the ball in the pool, ignoring the ring and the
frisbee
and carry out the appropriate action
The animals were trained via operant techniques, with food
rewards…
Once they got the hang of the system, they began to learn new
symbols much more rapidly
Often simply by the use of mutual exclusivity, or “exclusion”
So if they were to learn the novel label “buoy”,
They would watch experimenters throw already known
objects/labels such as a frisbee and a ring into the tank,
And then be told to “fetch buoy”
They knew what a frisbee was and what a ring was…
So, by exclusion, they would fetch the buoy…
And thus make the connection between the novel sign and the
novel object
When Herman moved into production, life got much more
difficult
Mainly because he separated out production from comprehension
And didn’t use referential rewards,
first looking at just vocal reproduction
What he did was to get a good baseline of the vocalizations
already in his dolphins’ repertoire…
A critical important first step
Then he trained the dolphins so that they understood that they had to replicate whatever came
next
Nevertheless, it took over 1000 trials to get the dolphins to
replicate the sounds
And they ran into even more trouble when they tried to get the dolphins to associate these
soundsLearned in the total absence of a
referent,
with specific objects
What they did was to give the dolphin the sound along with the
object at first
They hoped the dolphin would make the association and produce the sound in the presence of the
objectBut the dolphin wasn’t getting the “replicate” signal, so it didn’t act
So then they tried giving the dolphin the replicate signal along
with the signal and the object
Which worked fine, except that the dolphin wasn’t really ‘labeling’ the
object
Just replicating as taught
So they tried fading out the signal they wanted the dolphin
to use as the label
So it heard “replicate this”, a less loud signal, and saw the object
Well, the dolphin was smart and knew it was supposed to replicate
exactly what it heard…
So, as you might imagine, it began to produce the imitated
signal in a softer and softer manner….
which was exactly the opposite of what Herman wanted
The humans finally figured out a kind of alternation system that
worked
But the training was painfully slow
Nevertheless, the animals did learn to use these signals with striking accuracy, if extremely
slowly
This work is in rather stark contrast to the paper we read by
Reiss and McCowan..
Here the dolphins had a lot of control over what they wanted to
do
And they were actually given the choice of whether they wanted food, a toy, or interaction with
their trainers
By using an underwater keyboard system
Initially, Reiss would touch the
key
The dolphins heard a signal
And then something
appeared in the tank
The keyboard was then presented to the animals during
specific sessions
But they did not receive any specific training other than the demonstration of how it worked
The young males were extremely curious and explored it
Note that at least in this experiment, the older females
were not much interested
Which could be an important point
Herman’s subjects were older females
Too, Reiss’ young males often monopolized the keyboard
So, when we look at the results, we have to keep all that in mind…
We don’t know what would have happened had the experiment been done with just the adult
females
Or with females that weren’t actively involved with their calves
Or what Herman might have been able to do if he had had
young malesAnd, although my gut feeling is
that the training techniques were really the issue
That’s a hypothesis that needs testing very carefully
In any case, Reiss’ data were strikingly different from that of
Herman’s….
The dolphins started to reproduce the vocal signals after fewer than
20 exposures
And the productions were often made separately from the sample
The dolphins would produce the whistles BEFORE they hit the
appropriate key
Or when they were playing with the appropriate object in the absence
of the keyboard
Suggesting that they had easily made the connection between
whistle and object
The dolphins also remembered these whistles over a two year
period
And upon reintroduction of the keyboard, started using the
whistles immediately
Suggesting a strong association, at least, between the whistles and
the system
Of particular interest were the whistle combinations….
When the dolphins, while playing with both rings and
balls, took
+
Note frequency levels
And there was an 82% correlation between the
combination and combination play
Suggesting that this was a real association
But not one that was trained; it was a spontaneous combination
and spontaneous use
In fact, none of this was trained…
If nothing else, the data suggest something about the flexibility of vocal learning in
the species
Even if, like birds, this flexibility is more pronounced in youth
And, because there was no selective reinforcement of
particular aspects of the vocal behavior
We can see what is likely salient to the dolphins….
Frequency modulation, duration, harmonic structure
And, of course, it is fascinating to see parallels with respect to primacy and recency effects
The dolphins learning the beginning and ends first…
Much like humans and the birds that we’ve studied
Now, Reiss and McCowan are very careful not to claim full
referential communication here…
And rightfully so, given that the animals were not tested directly
on whether they could label
Nor on how well they might be able to transfer to really novel
balls or rings
And, of course, the study stopped (for lack of funding) well before the researchers could look at
more sophisticated sign combinations
For that, we have to look at some more studies by Herman
Here he stuck to the gestural communication trained with Ake
Basically, Ake had learned what Herman called a syntax
and what in a series of back-and-forth in-print arguments
Schusterman called rule-governed strings
which actually is a very important distinction…
Because syntax implies true correspondence with human
behaviorAnd the dolphins did not have
anything nearly as complex…e.g., no passives or past tense, etc..
But the dolphin did have to follow some fairly complex rules in deconstructing the gestural
strings she was given
So, for example, “hoop ball in” means
“put the ball inside the hoop”…
That is, in. object-dir. object-verb, in a recency pattern so that what is acted
on is closest to the verb
This pattern was chosen specifically to link the verb and
the object to be acted on
It also meant that the dolphin had to distinguish things like “hoop ball fetch” from “ball
hoop fetch”But in many cases there could be
no real reversal…you can’t put the hoop in the ball
But, instead of looking at that non-reversal issue as a
drawback,
Herman decided to use it as an advantage
to see what exactly his dolphin did or did not comprehend
and what types of errors she might make when given impossible
directions to carry out
Interestingly, when Schusterman did a similar study on a sea lion,
the sea lion pretty much did what is could with what it was given…
Often, tho’ not always, reinterpreting the commands so
as to do something related
It isn’t clear, of course, if the dolphins, who we will see, often
balked at an anomalous command
should be considered smarter than the sea lions…
The latter maybe should be given credit for their innovative
attempts to deal with something odd
Ake also had some modifiers, such as left and right
And the order there was also important, so that the modifier modified the term directly to its
right…
“pipe left ball fetch”
So, a dolphin being given anomalous phrases could have
quite a number of different thing ‘go wrong’…
Syntactic anomalies could be something like the verb in the
wrong place…
“over surfboard” or “ring over surfboard”….
These are the kind of errors a tired human trainer might
make, reverting to English in this case
Of course, the use of the term ‘syntax’ really needs to be
considered just a short-hand
It isn’t syntax like yours or mine
Now, Herman states that something like “surfboard basket tail-touch” is a syntactic error…
Because it uses a nonrelational verb in place of a relational one
But I would argue that this example is a semantic error
Because it hinges on the meaning of the verb
Not on its placement in the string of commands
Other semantic anomalies are things like “window through”…
like the above, a physical impossibility
Finally, Herman gave his animal lexical anomalies….
Something nonsensical was inserted into the string
The question was how would the dolphin respond to all these odd
requests?
The goal was to see if anything could be learned
about her information processing,
assuming that there might be patterns to the way she dealt
with these anomalies….
Would she just balk or be inventive?
Initial studies did show some patterns to her responses…
Thus, for example, she would totally reject a string with a
nonsense gesture in place of a verb
i.e…. “DUH, want do you want me to me do??”
And if given something like “frisbee over pipe”
She followed a similar rule that could be interpreted as “string
always start with verbs,
So ignore anything until you get a verb
Note that is was interpretations such as this that made
Schusterman argue for rule-governed behavior rather than
syntaxBecause one rule could
successfully be used in a number of different situations
Generally not true for syntax
And for a semantic anomaly, like ‘window through’,
She tended to carry out the verb on whatever was possible….
Again suggesting a strong primacy for the verb position
Now the difficult thing about Ake’s strings
were that she had to store the whole thing before she could
know what to do
And, for stuff like left-right, had to remember the order very
carefully
An odd bit of this was the pause to videotape only after an
anomaly;
Ake had to be able to use that information to clue her that
something was, indeed, weird about the previous trial
Why not videotape everything and analyze only what’s needed?
And, yeah, in 1993, video was expensive and difficult and
cameras were large…
But that kind of intrusiveness was therefore even more
telling..
So that is clearly one thing to think about in evaluating the
results
Too, when you look at the TTR, the MTTR and the TMTR normal
trials
That is, bring hoop to ball, or a right hoop to a ball or a hoop to
a left ball….
The success rates are not so good
And most errors were on the indirect object,
suggesting that Ake had a lot of trouble remembering the stuff at
the beginning of the string
Particularly if there were two of them and one wasn’t assigned L/R
In fact, although even the 40% is truly statistically above
chance
because you have to factor in choice of verb and choice of
direct object…
In reality that’s a bit wonky, because she almost never
goofed on the verb
And also was pretty good w/ the direct object (next to the verb)
but could mess up on the indirect object almost half the
time….
Of course, she had 11 choices, so again, statistically ok…
but clearly indicating memory issues
Memory might also explain the success when a stationary item
is involved….
Even if moved, most of these were always in the tank…
Whereas the moveable items, at least for all studies considered, might or might not be present
Thus, for example, it might be easier to code something
that is usually around
Even if its position varied across sessions, it stayed in
place, unlike the other items, for a given session
So, keeping this bit of info in mind, let’s look at the
anomalous stringsIf she were asked to move
something truly immovable…or likely immovable, like Phoenix…
She mostly balked…
Tho’ half the time w/ Phoenix she substituted something else…
And when given two verbs, she again rejected…seemed to respond with a “what AM I
supposed to do???”
The hardest were stationery to transportable
and she kinda made things up herself there
If given choices that were anomalous in a ‘logical’ way,
Like a stationary thing put in the midst of an otherwise OK string
She just ignored the weird part most of the time
Less so if it were at the end of too many items…
And she dumped stationary items when they didn’t make sense in an action sentence
that already had a transportable thing to be
acted onShe clearly knew what was impossible and rejected it
Or she did pieces that made sense
And she did seem to be very eager to reject strings that initially looked to require a
relational situation
But then tuned out to have a simple action verb
Herman argues for that rejection based on the processing of the
set
Giving an expectation of a specific type of verb
But sometimes, of course, she just used the verb on something in the string…
or something convenient…
It’s a bit difficult to analyze the data,
Given how badly the dolphin did on the TMTR and MTTR trials…
If I were doing a serious review, I’d crunch through and see if
there were statistically significant differences in
accuracy
Because that is exactly what is critical…
Not just what the dolphin did on the anomalous strings,
But how the errors compared to the error on the normal strings
with only 40% correct
And they never did that comparison
However, it is clear that the dolphin knew something about
the strings
But how the errors really related to memory or to a strong verb
recency effect
is not at all clear…
A separate issue is how the dolphins’ sonar system
interacts with its visual system
particularly in terms of dealing with object identification
What does it “see” when it uses its sonar?
Does sonar give it an overall global perception?
Or, like the many blind men examining the elephant
does sonar give the animal a handle on some particular,
distinctive feature?
Early studies by Herman and his lab suggested that dolphins could examine an object via
sonar
and then, in a two-choice test,
correctly identify the object via vision, and vice-versa—
but couldn’t explain how it was done
The argument of using raw acoustic cues plus associative
learning wouldn’t hold
because Herman used first-trial data
But the objects used were distinctive enough that
information about single aspects could have been
sufficient
And the dolphin could, with only two distinctive choices
have actually not even looked closely at the 2nd choice,
Just choosing it only if the first choice wasn’t really correct
In contrast, if the sample had, say, a distinctive bump
and now the two choices both had that distinctive bump and
that’s all that the dolphin checked out…
then, whether it vacillated between the two or chose as soon as it located the bump…
The results would be at chance,
even if one of the choices resembled the sample a little
bit more overall
If however the dolphin went for overall shape, performance would be consistently high
So another set of experiments was done specifically to check
exactly to what the dolphin attended…
Did it care about a class feature such as a bump
or a global feature such as symmetry?
And if it had three instead of two choices
Then we could see if the animal actually paid some attention to anything other than that first
choice
Or if it at least searched in a ordered type of way
In the first experiment, they gave the dolphin three
alternative choices
All of which differed in global shape but did have local
matching featuresThey could then test just how the
subject reacted
In the next experiment, they added a ‘none of the above’
choice
Which, if the animal were working on global features, it
should generally choose
Of course, that choice could also be used if the animal were simply too confused to choose anything
else
The tasks were various combinations of sonar-vision
Although it would have been interesting, too, just to do a sonar
or a vision task to see if these differed by themselves
Maybe something is special about knowing you need to switch
modes?
First the dolphin was trained with baseline objects…things like flower pots and gratings…
She would get to examine them by sonar
Then choose between two visual items and then three
items
And was gradually introduced to some training PVC items as
well
so she wouldn’t freak when she was given such different
things during testing
And, again, went from a 2 item to a 3 item choice of
response
Now she was given a bunch of new samples mixed with old
baselines
And sometimes the choices were all mostly new stuff or
sometimes baselines mixed in
So that there were full or partial transfer tests
She was right over 90% on all types of tests, so the sonar-vision
order was reversed…
Now she saw the object and had to choose using sonar…
First with baseline and two choices, then moving up to
complexity as before
Again, she was accurate over 90% of the time, even though
the samples and the choices had some overlapping features…
Such data suggested that she was looking at the object
globally, not locally…
And her search strategy was pretty regular, too….
She pretty much checked the right, stopped if it was a
match;
If not, went on to C, stopping if it was a match and going on if
it wasn’t….
And then hitting L if that’s what was left
Note that this is somewhat different from pigeons who will
focus on local cues….
Remember, if given something like
But what would have happened had none of the objects been an
exact match?
So she was first given objects as samples and taught to use a
“NA” paddle if no exact match was there
But, of course, this kinda set the stage for whatever came next
She seemed to need a bit more training on going from
vision to sonar this time, getting only one out of four
trials correct
But eventually understood that she had to have an exact match
Which, again, predisposed her choices for later
She was then given some samples that had only local
features in common with the possible choices
Now, if she were using global cues, she should hit the NA
paddle on those trials
to say that nothing really matched
She was still pretty good, but her accuracy dropped to about 75% on the “missing objects”
And, interestingly, her errors were to objects that shared at least half of the features of the
sampleSuggesting that she could be
confused, at least a bit
But there was a preponderance of global
matches or NAs
Which could have been an effect of being rewarded for “If
it’s not exact, hit NA” type training
It also seemed a bit odd that the NA paddle was always to the left, even if to the FAR left…
Because if the dolphin just kept going when she didn’t find a match right away,
Then the NA paddle was just the last thing on her list, no matter
what
Even if it wasn’t an object in a box
In a sense, it didn’t matter, because it meant that the
dolphin was searching for that exact match
But what would it have done w/ an empty box in the last
position?Or yet another bum choice?
Would it have dithered?
It does seem as tho’ the dolphin did choose in terms of
overall shape
But I’m not convinced that the latter experiments made the data
any more convincing
For the latter part, she seemed to be trained
What is extremely interesting is that the dolphin does transfer from sonar to visual and back
That data tell us a lot about how the sonar capacity must work…
Ecologically, the global features are critically important
So the data do not seem all that surprising;
And some data for humans who have been trained to
use sonar like canes suggest that, over time,
they learn to integrate the information to ‘see’ via the sonar
So, if all these data aren’t enough to impress you that something is going on in the
dolphin brain
there are now the studies on mirror self-recognition,
which suggest some level of self-awareness
MSR (mirror self recognition) is a rare trait in animals
Although part of the problem is that testing nonhumans is really
tricky
because the standard test is very difficult to administer
In the standard test, you put the subject in front of the
mirror
And first watch for self-exploratory behavior of bits of the body that
can’t be seen otherwise…
Like looking inside one’s mouth
In the second part of the task
You surreptitiously mark the individual with a sticker
or some water paint or such
And then see, if subsequently shown the mirror, if the subject
investigates the mark on its own body
Problems arise because nonhumans often don’t have
hands
or like birds can see most of their bodies without mirrors
or like elephants and birds don’t seem to care if they’ve got gunk
on their bodies
And, of course, there’s a big question as to whether having
MSRReally does mean that an animal has self-awareness
An old paper by Robert Epstein basically trained pigeons to
react appropriately
So surface behavior matched
But the birds probably had no idea about what they were
doing, at least in that experiment
So what about other animals?
So far, apes succeed and monkeys fail; parrots are a toss
up
Reiss and Marino studied two dolphins that had been in pools with reflective glass walls for some part of each
yearThus the first part of the usual
study was not possible….
The animals would have been habituated to seeing themselves
Thus they were unlikely to react by exploring bits of their bodies
they couldn’t otherwise see
when now given a mirror
Of course, this situation also meant that they probably had a pretty good idea of what they
looked like
So anything that changed could, theoretically, be noticed
immediately
To control for just handling the animals, mark sessions were balanced with sham sessions
The animals felt something happen, but nothing was left on
them
Self-directed included anything that could be mark- or sham-
directed,
such that the animal positioned himself at the mirror and then
produced orienting or repetitive motions
So that the area of interest was visible in the mirrored surface
Exploratory behavior is self-directed, but not with respect to
the mark or sham-mark
These involve viewing other areas not generally able to be
seen without the mirror
And that occurred at the mirror
Social behavior is what occurs when a dolphin meets
another dolphin….familiar or stranger…
either aggressive or affiliative
but clearly to “another” creature
Suggesting that the mirror image wasn’t interpreted as of oneself
Reiss and Marino did a number of different markings
Of particular interest were those sham markings done before and
after the real marks
because the dolphins treated these differently from each other
In all cases, the animals spent more time in front of the
mirrored surfaces when marked than when sham-marked
Interestingly, during the early sham- marks
One animal checked itself out once and then ignored the situation
But after it had been marked and had explored the markings
When then sham-marked it went to look for a mark
So he checked himself out, looked for a mark, and if none
was there, went away
Essentially reacting as if to say, “I felt something, that often
means a mark….”
“I’d better go check it out and see what it’s like”….
Then “Oh, it’s not there, so fuggetaboudit”
Which also shows quite a bit about some level of self-
awareness
And, the dolphin chose the most reflective surface,
Using a black-backed wall if the mirror wasn’t present
I asked Reiss about the initial marking, because if the early sham-marked animal didn’t spend time near the mirror
why would they suddenly start when really marked?
Sham-marked animals skimmed by at first, didn’t see anything
and left
Marked animals skimmed by, saw something and the first
time they did,
Became hooked and kept looking
Should have been clearer in the article as written
So, dolphins, like apes, do show MSR
But, unlike apes, don’t care about marks on another animal
and what that means for full consciousness is unclear
but does show self-awareness
What is also of interest are the ‘contingency checking’ (CC)
behavior patterns from the earlier study
Pan, unlike the two dolphins who did show MSF, had mirrors only for
a few days
And did more and more CC as time went on…
Possibly the long exposure of the two MSR dolphins provided
time enough so that
CC could develop into MSR
That does not happen with monkeys, who habituate and then
ignore the mirror and fail MSR