studies on concept formation

140
Studies on Concept Formation Psych 1090 Lecture 2

Upload: tobias

Post on 05-Feb-2016

24 views

Category:

Documents


0 download

DESCRIPTION

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 Presentation

TRANSCRIPT

Page 1: Studies on Concept Formation

Studies on Concept Formation

Psych 1090

Lecture 2

Page 2: Studies on Concept Formation

The definition of ‘concept’, like that of ‘cognition’

is rather flexible and involves many different

types of behavior

Page 3: Studies on Concept Formation

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

Page 4: Studies on Concept Formation

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

Page 5: Studies on Concept Formation

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

Page 6: Studies on Concept Formation

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

Page 7: Studies on Concept Formation

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

Page 8: Studies on Concept Formation

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

Page 9: Studies on Concept Formation

But even the simplest level, object recognition isn’t really so

simple….

Think about the prototypical bird:

beak, feathers, wings, flight…

Page 10: Studies on Concept Formation

But what about

Page 11: Studies on Concept Formation

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

Page 12: Studies on Concept Formation

And, of course, what might be one important category to a

bird

Might be two to a human:

Page 13: Studies on Concept Formation

For a bird, the snakes are ‘functionally equivalent”

in that both are predators;

But for humans one is dangerous and one is not

Page 14: Studies on Concept Formation

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,

Page 15: Studies on Concept Formation

And in different areas,

different parts of the songs (e.g., trills versus

introductory notes)

may be critical for recognition

Page 16: Studies on Concept Formation

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

Page 17: Studies on Concept Formation

And pigeons completely failed when asked to categorize

one particular oak leaf from among a number of oak

leaves…

Page 18: Studies on Concept Formation

A discrimination not at all important to a pigeon

Page 19: Studies on Concept Formation

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….

Page 20: Studies on Concept Formation

Pigeons couldn’t distinguish intact versus

distorted cubes…

Page 21: Studies on Concept Formation

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)

Page 22: Studies on Concept Formation

And if given a regular triangle as the positively rewarded

choice, and then shown

Page 23: Studies on Concept Formation

Pigeons chose the trapezoid rather than

the occluded item

Suggesting that they chose on the basis of just the line

figure

Page 24: Studies on Concept Formation

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

Page 25: Studies on Concept Formation

1x1 3x3 6x6 12x12

Page 26: Studies on Concept Formation

 

Page 27: Studies on Concept Formation

Could discriminate scrambled from

unscrambled pictures of pigeon heads

Page 28: Studies on Concept Formation

And Wasserman’s group argued that scrambling a line figure makes the task

more difficult for the pigeon

Page 29: Studies on Concept Formation

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

Page 30: Studies on Concept Formation

And other studies suggest that motion is a critical

factor

Page 31: Studies on Concept Formation

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

Page 32: Studies on Concept Formation

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

Page 33: Studies on Concept Formation

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

Page 34: Studies on Concept Formation

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…

Page 35: Studies on Concept Formation

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…

Page 36: Studies on Concept Formation

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

Page 37: Studies on Concept Formation

Remember our prototypic bird…if we assume wings AND

beaks,

X X

Page 38: Studies on Concept Formation

But if we assume wings AND flight,

X X

Page 39: Studies on Concept Formation

So, how do we go about dealing with

such issues?

Page 40: Studies on Concept Formation

Let’s look at the study on monkeys and

humans, Dépy et al. on the conjoined

search

Page 41: Studies on Concept Formation

Training was on marked items

[yellow vs. blue was color discrimination, not a bar]

Page 42: Studies on Concept Formation

The idea was to determine which 2 of 3 qualities,

color/shape/location, put a stimulus in C1 or C2

Page 43: Studies on Concept Formation

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

Page 44: Studies on Concept Formation

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

Page 45: Studies on Concept Formation

But I would have gotten the prototype right

100%, like the baboons

And would matched them on Csl, too

Page 46: Studies on Concept Formation

So I’m not at all sure one can draw conclusions

as to how a particular species does a particular task

Page 47: Studies on Concept Formation

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!

Page 48: Studies on Concept Formation

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,

Page 49: Studies on Concept Formation

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

Page 50: Studies on Concept Formation

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

Page 51: Studies on Concept Formation
Page 52: Studies on Concept Formation

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

Page 53: Studies on Concept Formation

That is, could an animal respond to “What color?”

versus “What shape?” versus “What matter?”

Page 54: Studies on Concept Formation

That is, could an animal understand a hierarchical

organization

in which various symbol represented different class labels

under which other classes could be categorized

Page 55: Studies on Concept Formation

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….

Page 56: Studies on Concept Formation

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

Page 57: Studies on Concept Formation

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

Page 58: Studies on Concept Formation

We trained him on a small subset of items in the lab

Then tested him on everything else

Page 59: Studies on Concept Formation

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

Page 60: Studies on Concept Formation

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

Page 61: Studies on Concept Formation

We did, of course, look at transfer as well…

Page 62: Studies on Concept Formation

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)

Page 63: Studies on Concept Formation

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

Page 64: Studies on Concept Formation

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

Page 65: Studies on Concept Formation

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

Page 66: Studies on Concept Formation

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…

Page 67: Studies on Concept Formation

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?

Page 68: Studies on Concept Formation

But that brings into question what kind of categories were the pigeons forming…

Did the categories have anything to do with real life?

Page 69: Studies on Concept Formation

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,

Page 70: Studies on Concept Formation

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…

Page 71: Studies on Concept Formation

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”

Page 72: Studies on Concept Formation

But what about nonhuman primates?

Are they easier to train in this respect than birds?

Page 73: Studies on Concept Formation

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

Page 74: Studies on Concept Formation

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

Page 75: Studies on Concept Formation

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

Page 76: Studies on Concept Formation

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….

Page 77: Studies on Concept Formation

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

Page 78: Studies on Concept Formation

Logically…a photo isn’t edible,

so why would one want to respond to it as an edible

item????

Page 79: Studies on Concept Formation

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

Page 80: Studies on Concept Formation

So, again, there are real issues of

external validity in determining

animal abilities

Page 81: Studies on Concept Formation

But so far we have looked only at concrete

concepts….

What about more abstract concepts?

Bigger/smaller?

And number?

Page 82: Studies on Concept Formation

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…

Page 83: Studies on Concept Formation

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

Page 84: Studies on Concept Formation

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

Page 85: Studies on Concept Formation

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

Page 86: Studies on Concept Formation

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

Page 87: Studies on Concept Formation

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

Page 88: Studies on Concept Formation

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

Page 89: Studies on Concept Formation

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)

Page 90: Studies on Concept Formation

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

Page 91: Studies on Concept Formation

Deeper pitch usually signals a larger and an angrier

animal,

And a lower ending frequency also generally signals

aggression

Page 92: Studies on Concept Formation

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,

Page 93: Studies on Concept Formation

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)

Page 94: Studies on Concept Formation

But most of these studies cannot eliminate the

possibility that the animal is somehow learning about

the proper choice rather than

making relative judgments

Page 95: Studies on Concept Formation

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

Page 96: Studies on Concept Formation

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

Page 97: Studies on Concept Formation

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

Page 98: Studies on Concept Formation

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

Page 99: Studies on Concept Formation

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….

Page 100: Studies on Concept Formation

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

Page 101: Studies on Concept Formation

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

Page 102: Studies on Concept Formation
Page 103: Studies on Concept Formation

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

Page 104: Studies on Concept Formation

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….

Page 105: Studies on Concept Formation

Even if subjects discriminate a specific amount, such as ‘threeness” when given a

variety of choices

Page 106: Studies on Concept Formation

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”….

Page 107: Studies on Concept Formation

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

Page 108: Studies on Concept Formation

““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

Page 109: Studies on Concept Formation

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….

Page 110: Studies on Concept Formation

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)

Page 111: Studies on Concept Formation

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…..

Page 112: Studies on Concept Formation

So, let’s talk about numerical competence in avian species… …

Page 113: Studies on Concept Formation

Some of the most elegant studies with avian species was done by Koehler…..

Look at the work historically….

Page 114: Studies on Concept Formation
Page 115: Studies on Concept Formation
Page 116: Studies on Concept Formation

Koehler and his colleagues transferred this behavior across

modalities….

Flashes of light

Notes on a flute

Page 117: Studies on Concept Formation

Related work on humans…..

What happens when there isn’t time to count?

Page 118: Studies on Concept Formation
Page 119: Studies on Concept Formation
Page 120: Studies on Concept Formation
Page 121: Studies on Concept Formation
Page 122: Studies on Concept Formation

Researchers found that humans bottomed out at about the same

level as the pigeons–-

about 4about 4

Page 123: Studies on Concept Formation

So, how might these studies relate to counting,

or at least precise number recognition?

Page 124: Studies on Concept Formation

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?

Page 125: Studies on Concept Formation

What could Alex really doafter some training?

Page 126: Studies on Concept Formation
Page 127: Studies on Concept Formation
Page 128: Studies on Concept Formation

Now, note that Alex is not the only animal that has number concepts….

Matsuzawa has shown that chimpanzees can label

quantities up to 8

Page 129: Studies on Concept Formation
Page 130: Studies on Concept Formation
Page 131: Studies on Concept Formation

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

Page 132: Studies on Concept Formation
Page 133: Studies on Concept Formation

Other aspects of Alex’s number have to wait til our

class on number concepts…

Page 134: Studies on Concept Formation

Given that parrots and primates evolutionary history dates from

the dinosaurs….

Number concepts are likely to be relatively widespread across

species

Page 135: Studies on Concept Formation

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

Page 136: Studies on Concept Formation

So, we’ve found that animals seem to have some pretty decent

understanding of concepts…

Page 137: Studies on Concept Formation

But I hope what came through was that the

critical issue in determining these

abilities

has to do with experimental design

Page 138: Studies on Concept Formation

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

Page 139: Studies on Concept Formation

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

Page 140: Studies on Concept Formation

Sci-Am show on number work in chimps and rhesus