studies on concept formation
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Studies on Concept Formation. Psych 1090 Lecture 2. The definition of ‘ concept ’ , like that of ‘ cognition ’. is rather flexible and involves many different types of behavior. So we are going to examine concept formation from the simplest to the most complex cases. - PowerPoint PPT PresentationTRANSCRIPT
Studies on Concept Formation
Psych 1090
Lecture 2
The definition of ‘concept’, like that of ‘cognition’
is rather flexible and involves many different
types of behavior
So we are going to examine concept formation from the
simplest to the most complex cases
And do it for a small (for the moment) variety of species
Concept formation, of at least some sort, is a very basic
phenomenon
Whether consciously or unconsciously, and organism must
distinguish, e.g., predator from prey/ friend-foe
food from not-food possible mates from non-mates
And, in any case, creatures must organize the big, confusing world
into some form of workable hierarchy
so that attention can be paid, shifted, directed, etc.
appropriately for survival
One big issue, that we mentioned last time,
is whether animals, lacking language, can form concepts
and, I said that they can…but now I’ll give some real data
We can split concept formation into three major categories….
object recognition
relational/abstract
what is or is not a key or a pencil
bigger/smaller; same/different
equivalence/transitive inference
A>B, B>C, C>D, D>E……B?D
We’ll hold off on concepts like same/different and transitive inference for
now…
There’s enough just on other areas of concept formation
for today’s lecture
But even the simplest level, object recognition isn’t really so
simple….
Think about the prototypical bird:
beak, feathers, wings, flight…
But what about
Some of these creatures have some bird-like
characteristics and are clearly not birds;
Others lack some of these bird-like characteristics and clearly
are birds
And, of course, what might be one important category to a
bird
Might be two to a human:
For a bird, the snakes are ‘functionally equivalent”
in that both are predators;
But for humans one is dangerous and one is not
And although humans can, for example, detect many variations in neighboring white-crowned sparrow
dialects,
To a bird in a given dialect, all the others are lumped
into the ‘foreign’ category,
And in different areas,
different parts of the songs (e.g., trills versus
introductory notes)
may be critical for recognition
So, one can train an animal like a pigeon to, for example, “categorize” all trees
But pigeons were less easily trained to form the category
“car”Something unnatural for it…
by pecking to picture of a few trees and not to a picture of a
bird
And pigeons completely failed when asked to categorize
one particular oak leaf from among a number of oak
leaves…
A discrimination not at all important to a pigeon
More recently, a number of researchers (e.g., Cerella,
Watanabe, etc.) showed that pigeons emphasize local cues
So they had considerable trouble distinguishing some,
but not others of the following….
Pigeons couldn’t distinguish intact versus
distorted cubes…
TTTTTT T T T T T T TTTTTTT T T T T T T
Pigeons could find the “T” in either picture,
but not the “H”
(Anim. Cogn. 2002)
And if given a regular triangle as the positively rewarded
choice, and then shown
Pigeons chose the trapezoid rather than
the occluded item
Suggesting that they chose on the basis of just the line
figure
More recently, Watanabe’s group showed that pigeons
can’t really discriminate scrambled from
unscrambled cartoon figure heads
At least until they got really scrambled
1x1 3x3 6x6 12x12
Could discriminate scrambled from
unscrambled pictures of pigeon heads
And Wasserman’s group argued that scrambling a line figure makes the task
more difficult for the pigeon
But pigeons seem to have a hierarchy of attention
So they may first look for curves versus straight edges
And then look for specific types of angles
And other studies suggest that motion is a critical
factor
Some researchers nevertheless argue that pigeons can be trained to do any kind of
discrimination,
But the point is that some discriminations are more
ethologically relevant
and that may be correct…
and thus are trained more easily
Other more subtle issues come up as well….
If you use video for birds, you have to use LCD projectors
Because their flicker-fusion rates differ from those of humans,
CRT screens are difficult to view
And what is true for a pigeon may not be true for another
type of bird…
Parrots go anorexic in an operant paradigm and stop responding
And some hummingbirds, who are win/shift foragers, have real
trouble w/ a win/stay operant paradigm
There’s the issue, too, of neighbor/stranger
discrimination in song sparrows…
And how at first some data showed it existed and other data
didn’t….
But the real issue was knowing the exact territorial boundary…
And, of course, most studies on categorization are done with
animals that categorize the world visually,
But pigeons and people would fail if the criteria were scents….
or subtle auditory cues…
much like humans…
And studies of polymorphous stimuli--
where a combination of attributes must be present for an
item to be judged as ‘correct’
Suggest that in pigeons the additive features should be
ecologically related for success
Remember our prototypic bird…if we assume wings AND
beaks,
X X
But if we assume wings AND flight,
X X
So, how do we go about dealing with
such issues?
Let’s look at the study on monkeys and
humans, Dépy et al. on the conjoined
search
Training was on marked items
[yellow vs. blue was color discrimination, not a bar]
The idea was to determine which 2 of 3 qualities,
color/shape/location, put a stimulus in C1 or C2
I did it by marking C1 as blue, except if blue, round,
and down; C2 as yellow, except for yellow, square
up
So I didn’t match the human subjects in the study, nor did I use the
experimenters’ prototype
Of course, I didn’t do it by seeing slides for 800
ms
I did it more like the baboons than the
humans
and being told if I were correct or not, either
But I would have gotten the prototype right
100%, like the baboons
And would matched them on Csl, too
So I’m not at all sure one can draw conclusions
as to how a particular species does a particular task
And, of course, animals will try to succeed however they
can…Studies on homing pigeons
suggest that they’ll use sight for local features or global features,
star navigation, smell, or magnetic currents
Depending upon what the experimenters knock out!
Thus issues of external validity
and particularly in a categorization task
are extremely important when determining whether an animal is competent or
not in any task,
My parrot, Alex, learned to identify a number of
objects with English labels
He could also generalize from a piece of an index card to a large 12’x18’ piece of paper
So we trained him on a set of items,
Differently sized pieces of paper, wood, rawhide, etc.
then tested him on variations of these things
But a separate issue is whether animals understand categorical
classes…..
Not just what is or is not “wood” or “green” or “square”
But that each of these attributes represented a different category
for the same object
That is, could an animal respond to “What color?”
versus “What shape?” versus “What matter?”
That is, could an animal understand a hierarchical
organization
in which various symbol represented different class labels
under which other classes could be categorized
Note that this task is not the same as the conditional
discrimination we saw last time
Remember….pick odd color if backed in white, odd shape if
backed in black….
Here an animal must
attend to a multivariant item
attend to the particular question
determine what attribute is targeted
determine which instance of many possible choices is correct (e.g., which of 7 colors or of 5 shapes…) and then encode that info into a vocal label
This is the kind of task that we gave to Alex
It differed from tasks given most chimps, for example, in that
it required reclassification of the same items at different times wrt different queries
it went further than testing transfer of symbol labels to new items
We trained him on a small subset of items in the lab
Then tested him on everything else
COLOR QUERIES
LABEL USED BY PARROTO
BJE
CT
S P
RE
SE
NT
ED
TO
TH
E P
AR
RO
T
K W H K W H K W H SHAPE OTHER
K
W
H
K
W
H
K
K
W
H
W
K
H
K
W
H
W
H
64
5
4
5
6
4
5
6
2
K,K
BCW
GH
RW
H
RWRW
K
U,W
U
U,W
4
8
5
4
5
6
5
7
5
BPW
BCW1
1
4K
U,H
SHAPE QUERIES: LABEL USED BY PARROT
OB
JEC
TS
PR
ES
EN
TE
D T
O T
HE
PA
RR
OT
K W H K W H COLOR OTHER
K
W
H
K
W
H
K
K
W
H
W
K
H
K
W
H
W
H
7
8
4
1
4
4
7
55
4
6
10
4
1
1
14
5
6
4
46
3W
3H,3BCW
3W
H,H
3K
CW
2CH
W
UCH
4CGW
UK,CK
4W
We did, of course, look at transfer as well…
NOVEL COLOR/SHAPE COMBINATIONSLABEL USED BY PARROT
WHAT COLOR ERRORS ERRORS
WHAT SHAPE
OB
JEC
TS
PR
ES
EN
TE
D T
O T
HE
PA
RR
OT
W
W
H
W
W
K
W
W
W
W
H
W
W
BW(2)
GW(2)
GH
RW
GyW
GyK
GyW
YW
BW
RW
YW
W(1)
W(1)
2CW(2)
2CW(2)
2CW
3CK
3CW(2)
4CW
5CW(2)
5CH
5CW
5CW(2)
2CH(1)
2W(1)
UW(1)
UW(1)
Now, this particular set of experiments did seem to rely on
‘language’,
but in reality it merely relied on the ability to understand symbols
and in principle could be done in an operant setting
First train an animal with a number of different symbols
Each of which represent a particular color or shape or
matter
Then train another set of symbols to represent ‘color’, ‘shape’, ‘matter’, maybe via a sorting
system
Then train the animal to pick one color symbol in the
presence of an object and the symbol for “color”
And likewise for “shape”
And then do transfer tests on novel items
“Language” just is easier
Now, one of the big issues that may not seem obvious so
far: The pigeon work is
almost exclusively done with slides or pictures
And the work with Alex was done exclusively with 3D
objects…
But does an animal understand that a photo is a
representation of a real-world item?
Even primitive tribes don’t understand that relationship;
why would animals?
But that brings into question what kind of categories were the pigeons forming…
Did the categories have anything to do with real life?
Although Watanabe showed that pigeons could transfer food/not food discrimination
his work consistently used items that were familiar to the
subjects
from objects to pictures,
Some work by Spetch, that we won’t discuss in detail,
But they have a difficult time connecting 2D w/ 3D…
And so does Alex…
suggests that pigeons could associate pictures with real-
world situations and locations…
He initially called all pictures “four-corner paper”
And we’ve spent a lot of time working to try to train him on a separate category of “picture-
toy”
But what about nonhuman primates?
Are they easier to train in this respect than birds?
Savage-Rumbaugh and colleagues had to train
their chimps to associate objects and photographs
actually taping the photos to the objects
until the apes made the associations themselves
Note that in the baboon study on food vs nonfood
discriminations,
Bovet and Vauclair report first trial responses to novel items….
Such data are critical and often are omitted
On anything other than first trial responses,
and in many studies, like this,
learning can be involved,
we want to see what the animal knows before learning
occurs
Note that the baboons did need significant training to discriminate the pictures of
the apple versus the padlock,
even after being able to work almost immediately
with real 3D objects….
Such is not surprising,
And in terms of real correspondence,
given that young children without photo experience
respond similarly
children need to be at least 2.5 yrs old to see pictures as
representations of situations
Logically…a photo isn’t edible,
so why would one want to respond to it as an edible
item????
Why did the baboons do less well on whole photos
rather than cut-outs?
Cut-outs look more like the objects
whereas photos look more unreal
So, again, there are real issues of
external validity in determining
animal abilities
But so far we have looked only at concrete
concepts….
What about more abstract concepts?
Bigger/smaller?
And number?
These concepts are more difficult because they have to do not with individual items
But with the relation between or among items
And how that relationship might vary…
For relative concepts, such as bigger or smaller, or
lighter or darker,
Such was one of the problems when researchers
first looked at relational concepts in nonhumans
what is correct on one trial may be incorrect on
another
An animal in an operant paradigm is, for example, …
Grey is rewarded, and the animal learns to choose it after a number
of trials
trained to choose between two samples
The subject is then given a transfer test of the
following two choices:
Generally, the subject will initially hit the grey item, because that
was what was rewarded
If response to grey is extinguished, the subject will
learn to hit black…
And if switched back to white and grey, may have a bit of trouble going back to grey,
because that action was indeed extinguished
Eventually, it will learn the condition of when to hit and
when to avoid grey,
But the subject hasn’t really learned “darker than” as a
concept
Ethological studies, although not specifically designed to
contrast relative versus absolute concept learning in
animals,
nevertheless suggest that some avian species can respond to natural stimuli on a relative
basis
In the wild, eastern woodpewees (Contopus virens) may use the relative number of repetitions of a song type sung
by a conspecific
more reps = more aggression
to assess the ways in which the singer will engage in social
behavior (Smith, 1988)
Some species seem able to judge the relative size and motivational state of
competitors
and whether the ending frequency of a vocalization is relatively higher or lower than the starting frequency
(Morton, 1977, 1982)
by assessing the relative frequency (as measured in kHz) of their
vocalizations
Deeper pitch usually signals a larger and an angrier
animal,
And a lower ending frequency also generally signals
aggression
In the laboratory, great tits (Parus major),
respond to songs with intermediate numbers of notes
on a relative basis (Weary, 1989)
after being trained to respond differentially to songs with
either a large or a small number of notes,
Studies of optimal foraging also suggest
that birds base their feeding strategies on the relative amount of food they can
obtain per unit of time (see Kamil, 1988; Kamil & Roitblat,
1985)
But most of these studies cannot eliminate the
possibility that the animal is somehow learning about
the proper choice rather than
making relative judgments
One problem is that many animal subjects appear to
respond preferentially on an absolute basis
Or the task is set up so that the ecological relevance only makes
sense on an absolute basis
Hulse’s lab has shown that starlings (Sturnus vulgaris) can
be trained to discriminate ascending from descending
strings of notes
But the birds fall apart if the strings are transposed to a
different overall pitch
As we just saw, the pitch of a signal for a bird likely tells
something about the overall state of the signaller,
so shifting the absolute pitch changes the overall import of the
signal to such an extent
that the likelihood of responding to the fine-tuning may be
overwhelmed
And even if an animal is trained and tested
appropriately,
The animal might not be shifted to anything other than
exemplars that differ only slightly from those used in
training
If an animal is trained on a set of balls and tested even on a new set of differently
sized balls,
we still don’t know if the concept of bigger/smaller
has generalized to dumbbells and blocks….
One of the advantages of working with a talking
parrot is that one can train it to tell you, for example,
“What color bigger/smaller?” for familiar
itemsSo that it can be tested on objects it has never before
seen
We could use objects larger or smaller, novel
objects, objects of the same size
and see if he could respond with
“none”, and also ask about what
matter was bigger or smaller, all
without additional training
Another issue about abstract concepts is that a subject has
to learn to reclassify items
So it may know that these things are all blocks,
But now it has to distinguish sets of three from six
if it wants to show number concepts
What constitutes numerical What constitutes numerical competence?competence?
Number can be a descriptive categoryNumber can be a descriptive category
chose one set from competing chose one set from competing arraysarrays chose with respect to chose with respect to “more”/”less”“more”/”less” match-to-sample with respect to match-to-sample with respect to quantityquantity respond to one sequential series of respond to one sequential series of eventsevents
Most of these do not involve exact Most of these do not involve exact number….number….
Even if subjects discriminate a specific amount, such as ‘threeness” when given a
variety of choices
The subjectsThe subjects
may have only a recognition of may have only a recognition of patternpattern
may be responding to mass or may be responding to mass or contourcontour
may be responding to brightness or may be responding to brightness or densitydensity
may actually be “subitizing”….may actually be “subitizing”….
SubitizingSubitizing
is a perceptual mechanismis a perceptual mechanism
generally depends on canonical generally depends on canonical arraysarrays
-- think dice, dominoesthink dice, dominoes
is used when time constraints is used when time constraints existexist is usually approximate for is usually approximate for larger quantitieslarger quantities
-- but can be sequential-- but can be sequential
““Counting” is a different matter:Counting” is a different matter:
Produce a standard sequence of number Produce a standard sequence of number tagstags Apply a unique tag to each item to be Apply a unique tag to each item to be counted counted
know that the last number tag used tells know that the last number tag used tells the quantity of interestthe quantity of interest
If arrays are not canonical, subitizing is If arrays are not canonical, subitizing is thought to occur for quantities thought to occur for quantities 4 and 4 and
counting for quantity > 4counting for quantity > 4
Numerical research in animals has a long history….
Current thinking suggests that humans and animals share processes that involve subitizing….
Various proposals exist for the mechanisms involved….e.g., object files, accumulators….
Several studies have begun to approach number competence in, e.g., monkeys and pigeons by
examining ordering of quantities
matching symbols with numbers of actions (yielding approximate values)
examining more vs. less after adding or subtracting items (yielding approximate values)
Most researchers argue that true counting can exist only with language ….even for humans…
And, of course, most animals do not have language….
However, a few apes, dolphins, and parrots have acquired elements of human communication systems, including number labels…..
So, let’s talk about numerical competence in avian species… …
Some of the most elegant studies with avian species was done by Koehler…..
Look at the work historically….
Koehler and his colleagues transferred this behavior across
modalities….
Flashes of light
Notes on a flute
Related work on humans…..
What happens when there isn’t time to count?
Researchers found that humans bottomed out at about the same
level as the pigeons–-
about 4about 4
So, how might these studies relate to counting,
or at least precise number recognition?
Geshwind showed that humans use different brain areas for labeling versus match-to-sample
Premack found that his chimpanzees had more difficulty labeling quantities than performing match-to-sample with number
Alex was already labeling shapes as 3- or 4-corner: was it a general gestalt, or maybe something more?
What could Alex really doafter some training?
Now, note that Alex is not the only animal that has number concepts….
Matsuzawa has shown that chimpanzees can label
quantities up to 8
Number used by Number used by AlexAlex
Num
ber
of
ob
ject
sN
um
ber
of
ob
ject
s1 2 3 4 5 6
1
2
3
4
5
6
7
8
6
9
7
1
2
1
1
1 1
4
1
1
8
Other aspects of Alex’s number have to wait til our
class on number concepts…
Given that parrots and primates evolutionary history dates from
the dinosaurs….
Number concepts are likely to be relatively widespread across
species
Maybe numerical competence involves giving the subject the appropriate
tools to express latent abilities….
Certainly, enculturation is important, given evidence from untrained humans in
Peru
So, we’ve found that animals seem to have some pretty decent
understanding of concepts…
But I hope what came through was that the
critical issue in determining these
abilities
has to do with experimental design
The more the experimenter looked at the design through
the eyes of the animal,
The more likely was the animal to succeed on the
task
I’ve emphasized my own work, because that’s the easiest material for me to
present
But researchers working with other animals have, as we’ve
seen, also found striking abilities
Sci-Am show on number work in chimps and rhesus