Post on 29-Jan-2016
Philip Ball
www.philipball.com
Utopia TheoryTowards a physics of
society
“The centre of politics has shifted…. The neoliberal thinking that has dominated the industrial world for nearly 30 years has led to a financial crisis, which in turn caused the global downturn…. Clearly, there can be no turning back to the failed and discredited politics of old. Instead, we need to use this time of emergency to aim for a different future and to get there by different means…. this is not a crisis of capitalism, but a crisis of a society and democracy that have failed to regulate the market.”
Neal Lawson & John Harris, New Statesman 9 March 2009
“Many of the problems our economy faces are the result of the use of misguided models. Unfortunately, too many [economic policy-makers] took the overly simplistic models of courses in the principles of economics (which typically assume perfect information) and assumed they could use them as a basis for economic policy… We need a new balance between market and government.”
Joseph Stiglitz, New Statesman 16 October 2008
Social Physics and the Complex Systems of Human Social Dynamics
N. Johnson, Two’s Company, Three Is Complexity (OneWorld, 2007) M. Buchanan, The Social Atom (Bloomsbury, 2007); Ubiquity (Weidenfeld & Nicolson, 2000) P. Ball, Critical Mass (Heinemann, 2004) C. Castellano & S. Fortunato, Rev. Mod. Phys. 81 (Jan-Mar 2009) J. H. Miller & S. E. Page, Complex Adaptive Systems (Princeton University Press, 2007) J. M. Epstein, Generative Social Science (Princeton University Press, 2006)
178
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179
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Nu
mb
er o
f d
eath
s
Year
Average
Average Number of deaths
Pro
bab
ilit
y o
f th
at d
eat
h c
ou
nt
Death statistics
1510501005000.000010.00010.010.0010.11Firm size (number of employees)
Fre
que
ncy
of f
irm
s o
f th
at s
ize
US firms in 1997
Axtell, Science 293, 1818 (2001)
Gaussian
Power law
110100100010,000110101010-2-4-6-8
Number of connections kPro
babi
lity
of h
avin
g k
conn
ectio
ns
Connections of pages on the WWW
Albert et al., Nature 401, 130 (1999).
Probability distribution of towns around London
1000100100.0010.010.1110100
Area (square km)
Nu
mb
er
of to
wn
s
Makse et al., Nature 377, 608 (1995).
Wealth distribution in the UK, 1996
1010010000.1110100Total net capital (thousands of pounds)
Cu
mu
lativ
e p
erce
nta
ge o
f pop
ula
tion
Pareto law
Statistics of fatal conflicts
Fatalities
Nu
mb
er
of c
on
flict
s
1000100101100100010,000100,0001 million10 millionL. F. Richardson, Statistics of Deadly Quarrels, eds Q. Wright & C. C. Lienau (Boxwood Press, Pittsburgh, 1960)
Statistics of fatal conflicts
Fatalities
Nu
mb
er
of c
on
flict
s
1000100101100100010,000100,0001 million10 millionN. Johnson et al., arxiv/physics/0506213
Queuing and task allocation
J. G. Oliveira & A.-L. Barabási,Nature 437, 1251 (2005)
Voting statistics in the Brazilian elections, 1998
Fraction of total votes
Nu
mb
er
of c
an
did
ate
s
0.00010.0010.010.10.00001Costa Filho et al., Phys. Rev. E 60, 1067 (1999).
Social power laws and self-organized criticalityG. K. Zipf, Human Behavior and the Principle of Least Effort (Addison-Wesley, Reading, MA, 1949)
Self-organized criticality and the sandpile0.10.010.0010.000111010010003210-4-3-2-10.00001-5
Size of avalanche
Pro
bab
ility
of a
vala
nch
eFluctuations at the critical point
Economic fluctuations
10010.01100.10.001-15-10-505101520-20Variation
-20-1001020-20-1001020ab S&P500
Gaussian
‘Fat-tailed’
The magnetism of voting
0.00010.0010.010.10.00001A. T. Bernardes et al., Eur. Phys. J. B 25, 123 (2002)
Opinion dynamics
K. Sznajd-Weron & J. Sznajd, Int. J. Mod. Phys. C 11, 1157 (2000)
The rules of opinion formation (Sznajd model)
W. Weidlich, Sociodynamics (Taylor & Francis, 2002)S. Galam et al., J. Math. Sociol. 9, 1 (1982)
“…there is an unbridgeable gap between the ‘behaviour’ of [subatomic particles] and those of the human beings who constitute the objects of study of social science... aside from pure physical reflexes, human behaviour cannot be understood without the concept of volition—the unpredictable capacity to change our minds up to the very last moment. By way of contrast, the elements of nature ‘behave’ as they do for reasons of which we know only one thing: the particles of physics do not ‘choose’ to behave as they do.”
Robert Heilbroner
Feedback in social interactions
A rare example of ‘turning the dial’ experimentally: M. J. Salganik et al., Science 311, 854 (2006)
The ‘Broken Windows’ effect: K. Keizer et al., Science 322, 1681 (2008)
Attraction and repulsion in human interaction
D. Helbing & P. Molnar, Phys. Rev. E 51, 4282 (1995)
Interacting walkers in a corridor
D. Helbing et al., Environment & Planning B, 28, 361 (2001).
http://www.helbing.org/Pedestrians/Corridor.html
Interacting walkers in a panic
D. Helbing et al., Nature 407, 487 (2000).http://angel.elte.hu/~panic/
Interacting walkers at the Notting Hill Carnival
M. Batty et al., Urban Studies 40, 1573 (2003).
Interacting walkers at the Notting Hill Carnival
M. Batty et al., Urban Studies 40, 1573 (2003).
The formation of human trailsD. Helbing et al., Nature 388, 47 (1997)
The formation of human trails
The formation of human trails
The formation of human trails
Modelling traffic
D. Helbing, Rev. Mod. Phys. 73, 1067 (2001)B. S. Kerner, The Physics of Traffic (Springer, 2004)
Phantom traffic jams?
Time
Dis
tanc
e al
ong
road
Phasetransitions
Density
Vapour
Open road
Liquid
Congested
Solid
Jam
*
*
*
*
Why do societies segregate?
T. C. Schelling, Micromotives and Macrobehavior (W. W. Norton, New York, 1978)
0 10 20 30 40 50
0
10
20
30
40
50
0 10 20 30 40 50
0
10
20
30
40
50
Alliance formation
Alliance 1SunAT&TPrimeIBM
≈ UNIX International(+IBM)
Alliance 2DECHewlett-PackardApolloIntergraphSGI
≈ Open Software Foundation
(-IBM)
R. Axelrod et al., Management Sci. 41, 1493 (1995)R. Axelrod & D. S. Bennett, Brit. J. Polit. Sci. 23, 211 (1993)
ABCD ABCD
Firm growth
R. Axtell, Working Paper No. 3, Brookings Institution, Washington (1999)
100150200250200400600
200150100502004006008001000TimeTimea b
Num
ber
of f
irm
s
Firm turnover
1510501005000.000010.00010.010.0010.11a b10,000,0001,000,000100,00010,0001,0001001101001,00010,000100,0001,000,000Firm size (number of employees)Firm size (number of employees)
Fre
quen
cy o
f fi
rms
of th
at s
ize
Simulated distributionfrom agent-based model
R. Axtell, Science 293, 1818 (2001)
10,000,0001,000,000100,00010,0001,0001001101001,00010,000100,0001,000,000Firm size (number of employees)Num
ber
of f
irm
s
Game theory
e.g. the Minority Game: D. Challet, M. Marsili & Y.-C. Zhang, Minority Games (Oxford University Press, 2005)
Econophysics
R. N. Mantegna & H. E. Stanley, Introduction to Econophysics (Cambridge University Press, 2000)
J. L. McCauley, Dynamics of Markets (Cambridge University Press, 2004)
J. D. Farmer & J. Geanakoplos, arxiv:0803.2996
Thomas Hobbes(1588-1679)
The first ‘social physicist’?
Leviathan (1651)
John Stuart Mill(1806-73)
Auguste Comte(1798-1857)
Pierre-Simon Laplace(1749-1827)
The emergence of social physics