Laws of Technological ProgressUniversity of Waterloo

December 7, 2009

J. Doyne FarmerSanta Fe Institute

from: A Short History of Technology, by T.K. Derry and Trevor I. Williams (1960). p.191.

skier

from: Life in Ancient Egypt, by Adolf Erman, p. 476

Egyptian sledge

from: Life in Ancient Egypt, by Adolf Erman, p. 464

Egyptian scales

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Outline• Why is technology an interesting topic?• Are there laws for technological evolution

and improvement in performance?• Can they be used to make useful forecasts?

– Which methods work best?– How can we use them to plan for the future?

• What causes such laws?

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Why am I interested in technology?

• Our understanding is pre-Linneus.• Role of technology in human culture and

well-being is huge and ever-expanding. • We can measure its performance, and study

how it changes with time.• Aspect of human culture that makes progress.

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from: Culture and Subjective Well-being, edited by Ed Diener and Eunkook M. Suh (2000)

Happiness through time

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What do I mean by technology?

• Lewis Mumford’s concept of technics– gadgets, artifacts, procedures, ideas, laws– a way of doing something

• Evolution of technology is in many respects similar to that of biological organisms.– Darwin: Evolution = descent with variation and

selection.

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Technological change is incremental

(though with punctuated equilibria)

from: “The Evolution of Technology,” by George Basalla (1988).

The heroic theory of invention

Newcomen’s steam engine

Hero’s steam engine (200 BC).

from: “The Evolution of Technology,” by George Basalla (1988).

Evolution of hammer

from: “The Evolution of Technology,” by George Basalla (1988).

SHIELD

THROWING STICK

BIRD CLUB

LAN

CE

MU

SHR

OO

MC

LUB

WADDYBOOMERANG

BOOMERANGLEANGLE WAR PICK

NEW CALEDONIA

AUSTRALIA

NEW CALEDONIA

AUST-

RALIA

boomerangs

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There is no good classification system for technologies

from: “The Evolution of Technology,” by George Basalla (1988).

Classification of machines?

• Early treatises on machines– Philo of Byzantium, 200 BC.– Hero of Alexandria, 62 AD., “Mechanics”,

“Book on the raising of heavy weights”• Five simple machines known to

Archimedes– Lever, wedge, screw, wheel and axle, pulley

Wheel and axle

wedgewedge

screwscrew

leverlever

pulley

The five simple machines

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What is a machine?

• Modern science is based on the mechanistic view, but there is no good definition of a machine.

• A machine is an assembly of matter capable of selectively altering other assemblies of matter.

• The key property of a machine is its ability to implement a functional constraint.

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Are there laws for technological progress?

Wright’s law(1936)

Thomas Paul Wright

Cost vs. cumulative production = power lawProgress depends on learning, proxied by production experience

Ford’s model T

Wright’s law only works when reducing cost is main objective

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Moore’s law(1965)

Originally a statement about density of transistorsWe will use to refer to the hypothesis that technological

performance improves exponentially with time

Gordon Moore

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Compatibility of wright and Moore(Sahal, 1987)

If production expands exponentially and costs drop exponentially, Wright’s law will hold.

Diversity of performance ratios

Performance curves for the EU 1980-1995 (IEA, 2000)

Progress ratios 108 cases, 22 field studies, electronics, machine tools, system components for electronic data processing, papermaking, aircraft, steel, apparel, and automobiles(Dutton and Thomas, 1984)

Alternative hypotheses

Goddard: Economy of scale (this year’s production is all that matters)

Sinclair, Klepper and Cohen (SKC) Both economy of scale (this year’s production) and learning (cumulative production) matter.

Nordhaus: Both exponential in time and power law in cumulative production.

Is technological progress

predictable?Joint work with Bela Nagy and Jessika Trancik

Testing for predictability through hindcasting

Pretend to be at a given time in the past

Use given method to forecast each future year

Repeat for all past dates

Score methods based on forecasting errors

Error analysis

Alpha:

Sinclair Wright laggedWright Moore Goddard 0.169 0.177 0.180 0.176 0.202

p-values for pairwise comparisons: Sinclair Wright laggedWright MooreWright 0.239 laggedWright 0.135 0.750 Moore 0.328 0.842 0.604 Goddard 0.000 0.003 0.009 0.002

Economic interpretation

Economy of scale alone is not a good predictor of cost.

Cumulative production is a good predictor.

It is possible to make useful forecasts of technological performance.

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Model of learningJoint work with James McNerney, Sid Redner, and Jessika Trancik

Sid RednerJames McNerney

Power law of practice

Improvement with practice in time to add two numbers(Blackburn, 1936)

Auerswald et al. Production recipe

Production costs are additive

Each operation is affected by d operations.

Innovation proceeds through a series of trials in which d operations omega_i are altered.

Design structure matrix for automobile brake system

Algorithm

Pick a component i

Randomly change its cost and all the costs of the d components that it affects.

If the total cost decreases, accept the change.

Constant out-degree

variable out-degree

Predictions of model

Rate of improvement depends on interconnectness of components, not on total number.

Variable interconnectness can cause punctuated equilibria in performance curve.

Better theory?Need to think in terms of a network of diverse technologies

like an autocatalytic set, e.g. metabolismtechnologies enable other technologies

Need to treat change as an evolutionary processTheory should be able to say why some technologies evolve faster than others

Summary

Very little is known about evolution of technology

not even a Linnean classification scheme

Technologies make predicable progressi.e. forecast is better than no forecast

No good theory for technological improvement

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