Eight Reasons to Doubt the Existence of a Geometric Module

Nora S. Newcombe

Temple University

When Sociobiology Met Cognitive Psychology Modular mind

Adaptive pressure works to select specific mental abilities Massive modularity Core knowledge

Innateness These evolutionarily-selected modules are

(naturally) innately specified

Swiss Army Knife Analogy “The Swiss Army knife is a flexible tool

[because] it is a bundle of tools, each well-designed for solving a different problem – scissors for cutting paper, corkscrew for opening wine, toothpick for cleaning teeth…..Similarly, the human mind … contains a large number of programs, each well-designed for solving a different adaptive problem: choosing a good mate, caring for children, foraging for food, avoiding predators, navigating a landscape, forming coalitions, trading, defending one’s family against aggression, and so on”—Leda Cosmides

Innately-Specified Modules Have Proliferated

Language acquisition Face processing Theory of mind Cheater detection Geometric module

What Do We Mean By Modularity? Modular cognitive systems are domain specific,

innately specified, hard wired, autonomous, and not assembled. Fodor (1983, p. 37)

Neural Specialization Does Not Entail Encapsulated Modularity

Brain areas generally need to ‘talk to’ one another to support a function

Case Study of the Geometric Module A representation of geometric information that

guides reorientation following disorientation That does NOT use nongeometric information

even when doing so would be advantageous

Hermer & Spelke (1996): Search Rates for Toddlers

White Room

F C

R N

F C

R N

C = CorrectN = Near

R = ReversalF = Far

.08

.49

.31

.12

.10

.39

.39

.12

Hermer & Spelke: Search Rates for Adults

White Room

F C

R N

F C

R N

C = CorrectN = Near

R = ReversalF = Far

0

.04

.96

0

.02

.41

.57

0

Language-as-Bridge Hypothesis Adults may have a further system of representation

that is uniquely human and that emerges over the course of development. This system may connect to many other systems of representation, regardless of their domain-specific content. Its operation may be governed by rules and principles allowing the arbitrary combination of information from distinct, domain-specific sources….The language faculty appears to have all the right properties to serve as this uniquely human combinatorial system of representation. --Hermer-Vazquez, Spelke & Katsnelson (1999, p. 34)

Support for Role of Language Transition to feature use at 6 years is

correlated with productive use of left and right

Training left and right leads to feature use Adults who do linguistic shadowing task

concurrently do not use features

Adaptive Combination Models Various sources of spatial information

Ego-referenced: response learning and path integration Allo-referenced: cue learning, place learning

Weighting depends on Salience Certainty and variability with which information is

encoded Validity

probabilities of finding objects given use of the information, derived from interaction with the environment

Weighting develops both in real time and in developmental time

Point 1: Evidence Against Encapsulation from Non-Human Animals Monkeys use colored

walls and large but not small features (a sensible choice given likely cue validity)

Other species Chickens Pigeons Fish

See Cheng & Newcombe, PBR 2005, for review

46 % 4.7 %

3.3 % 46 %

75 % 3.5 %

1.5 % 20 %

Without cue With cue

Point 2: Featural Cues Are Only Neglected in Tiny Rooms

-100

102030405060708090

100

Larger Room Small Room

Toddlers

3-4 Years

5 Years

6 Years

Adults

Cheng & Newcombe(Psychonomic Bulletin & Review, 2005)Note: Perfect Performance = 100

Point 3: Use of Features Varies for Several Reasons

Activity Active motion focuses spatial attention Active motion leads to remodeling of

hippocampal firing

Nature of landmarks More distal landmarks provide more useful and

ecologically valid information Larger landmarks may be more salient and

more likely to be stable

Room Within Room Studies Small waist-high

enclosure (Hermer-Spelke size) centered within “large” room (Learmonth et al. size)

Large room had one colored wall

Children stay within small enclosure

Learmonth, Newcombe, Sheridan & Jones (Developmental Science, 2008)

How the Data Fit An Adaptive Combination Model

Distal Action Target Proximal Age at SuccessFeature? Possible? to Feature?

Hermer-Spelke No No Yes 6 years

Learmonth Yes Yes Yes 18 monthset al. (earliest tested)

Study 1 Yes No No 6 years

Studies 2 & 3 Yes No Yes 4 years

How the Data Fit An Adaptive Combination Model

Distal Action Target Proximal Age at SuccessFeature? Possible? to Feature?

Hermer-Spelke No No Yes 6 years

Learmonth Yes Yes Yes 18 monthset al. (earliest tested)

Study 1 Yes No No 6 years

Studies 2 & 3 Yes No Yes 4 years

How the Data Fit An Adaptive Combination Model

Distal Action Target Proximal Age at SuccessFeature? Possible? to Feature?

Hermer-Spelke No No Yes 6 years

Learmonth Yes Yes Yes 18 monthset al. (earliest tested)

Study 1 Yes No No 6 years

Studies 2 & 3 Yes No Yes 4 years

Point 4: Featural Cue Use is Easy to Get When Lacking

Room within Room Switch-No Pen: 3 Years

67.71

20.83

4.177.29

0

10

20

30

40

50

60

70

80

90

100

Correct Opposite Near Far

Box Selection

% o

f possib

le in

sta

nces t

his

box

was s

ele

cte

d

1st 4 Trials2nd 4 Trials

Learmonth, Newcombe, Sheridan & Jones (Developmental Science, 2008)

Similar finding: Twyman, Spetch & Friedman, (Developmental Psychology, 2007)

F C

R N

.06

.33

.52

.10

Point 5: Spatial as Well as Verbal ShadowingReduces Feature Use in Adults

Ratliff & Newcombe, Cognitive Psychology, 2007Also--Hupbach et al., Spatial Cognition & Computation, 2007

Usual results with white room and with colored wall but no

concurrent task

*

Point 6: New Evidence from Conflict Paradigms When features are moved, subjects must

choose a location based either on features or on geometry

These paradigms reveal the fundamental similarity of human adults to children and non-human animals Ratliff & Newcombe, Psychological Science, 2008

Conflict Procedure “There are four hiding spots in this room, one at each corner”

“I will hide a pair of keys in the same place every time”

► 4 practice trials (target & landmark stable)► Leave the room► Brief delay ~ 2 minutes (drawing task)► While the participant waits outside, the

experimenter goes back into the room to move the landmark clockwise to the next adjacent wall

► Two conflict test trials

Conflict Procedure

Where are the keys?

A D

B C

Experiment 1N = 32 TRAINING (Between Subjects) TESTING

Direct Landmark

Indirect Landmark

E G

G L

E

G

G

L

Small room (4x6ft) n = 8

Small room (4x6ft) n = 8

Large room (8x12ft) n = 8

Large room (8x12ft) n = 8

(Landmark = L, Geometrically appropriate = G, and Error = E)

Adaptive Combination Predictions When forced to choose one cue over the other

(geometry vs. features), conflict test will result in a room size effect Distal landmarks are more valid in the larger room

Corners related to feature cues will be more likely to be chosen in the larger room

Geometric cues are more salient in the smaller room Geometric cues will be chosen most often in the smaller

room

Significant Room Size effect (p < 0.01) Geometric information guided reorientation in the small room Features guided reorientation in the larger room

LARGE ROOM TRAINING & TESTING

SMALL ROOM TRAINING & TESTING

E .43 (.06)

.19(.05)

.38(.06)

0

G

L G

E

.16 (.04)

.56 (.06)

.28(.06)

0 G

L G

(Landmark = L, Geometrically appropriate = G, and Error = E)

Results

Experiment 2 How does prior experience impact feature use in a

conflict situation? Replicates experiment 1 but switches room sizes

between training and testing Predictions:

Replicate no effect of landmark location (direct/indirect)

Training in the larger room will increase feature use among adults reorienting in the small room

Cross-experiment comparisons: Significant effect of training Feature use increased in small room testing from Exp. 1 (small

room training) to Exp. 2 (large room training)

(Landmark = L, Geometrically appropriate = G, and Error = E)

Results

E .10 (.04)

.81 (.04)

.10 (.04)

0 G

G

SMALL ROOM TRAINING/LARGE ROOM TESTING

L

LARGE ROOM TRAINING/ SMALL ROOM TESTING E

.03(.02)

.94(.03)

.03(.02)

0

G

L G

Conclusions Feature use is not associative:

No effect of feature location (direct vs. indirect) in Exp 1 or 2

Experience is important As expected, large room experience boosts feature use for the

small room test

Reorientation depends on process of combining weights associated with features and geometry Not simply relying on the most salient cue Although the conflict procedure does not allow direct

assessment of combination

Point 7: Geometric Information May Be a Special Case of Relative Information

The modularity position predicts failure to reorient in the absence of geometric information

Is reorientation a more general discrimination of relative quantity task?

Huttenlocher and Lourenco, 2007 Non-relative Cues

Non-geometric, Relative Cue

Multiple cues Area, spatial density, and number

Nominal versus ordinal scale “Cues which specify order along a magnitude

scale (more, less) may be more easily mapped onto spatial position (left, right) than two distinct unordered properties (red, blue) which are mapped separately onto spatial position” (Huttenlocher & Lourenco, 2007)

Why Might Relative Cues Be Easiest?

Since the initial claims of modularity were made from animal research…

Will mice replicate this pattern of results?

Is This Pattern True Across Species?

C57 mice – 4 per group

Non-geometric

Relative Cue

Non-geometric

Non-Relative

Non-geometric

Non-Relative

Results: AccuracyTwyman, Newcombe & Gould, J. Comparative Psychology, in press

Small - Large 81%

Yellow - Blue 69%

Dots - Gray 69%

Even though there is a trend for the relative cue group to be more accurate, there were no significant differences between groups

Results: Trials to CriterionTwyman, Newcombe & Gould, J. Comparative Psychology, in press

Small versus Large 12 trials (0.00)

Yellow versus Blue 38 trials (5.77)

Dot versus Gray 33 trials (6.81)

The small-large group learned the task significantly faster than either the yellow-blue or the dot-gray group.

Point 8: Use of Features is NOT Merely Associative One might have thought 7 points were enough

—but the modularity theorists have a comeback--

The Module Strikes Back Lee, Shusterman &

Spelke (2006) argue that—

Search behavior following disorientation depends on two distinct processes: a modular reorientation process…and an associative process that directly links landmarks to locations (p. 581)

Return of the Jedi Problems with Lee et al.

Small moveable landmarks Defining quite small area

Alternative way to test the two step hypothesis Use of colored wall in an octagon with

alternating short and long sides to discriminate among 3 all white corners

The Octagonal Space

BD

A

C

Photo of the Octagon

Starting with An All-White Octagon

Questions Can children use geometry in a more complex figure?

YES if total GC choices > 50% Can children use geometry in a figure without an axis of

principal symmetry? YES if total GC choices > 50%

Methodologically, have children been successfully disoriented? YES if correct choice NOT > average of other

GC choices

Data from All-White OctagonNewcombe et al., Developmental Science, in press

0

50

100

2yr

3yr

TotalGCChance 0

50

100

2yr

3yr

PC

MeanGC

At left, we see that both 2- and 3-year-old children were reliably greater than chance in choosing geometrically correct corners

At right, we see a slight and non-reliable ability to choose the correct corner from among the 4 geometrically correct corners

Data from Octagon with Colored WallNewcombe et al., Developmental Science, in press

0

50

100

3yr

5yr

TotalGCChance 0

50

100

3yr

5yr

PC

MeanGC

At left, we see that both 3- and 5year-old children were reliably greater than chance in choosing geometrically correct corners

At right, we now see a reliable ability to choose the correct corner from among the 4 geometrically correct corners

What About the Targets in All-White Corners?

Correct choices reliably greater than average of other GC corners 35% versus 14% at 3 years 38% versus 10% at 5 years

These data show that young children do in fact use features to reorient

Can Children Use Features ALONE?Newcombe et al., Developmental Science, in press

XX

XX XX

On these 2 conditions, children averaged 50%, reliably greater than chance (33%)

In this condition, children averaged 64%, reliably greater than chance (50%)

Three Hiding Boxes Two Hiding Boxes

Specific Conclusions Strong evidence for coding of geometric information Little evidence for an encapsulated geometric module or

the role of language in puncturing it Good evidence that different types of spatial information

are routinely (though not invariably) combined Combination process depends on

Cue salience Encoding variability and certainty Acquiring information on cue validity through action

and experience

General Conclusion We can analyze

spatial navigation and orientation as an evolved mental skill without postulating Encapsulated

modularity Highly specific

innate endowment