The Dictionary of Human Geography

G

game theory A theory of interdependent
decision-making. Individuals (‘players’)
choose their actions (‘strategies’) with limited
or zero knowledge of those of the other players,
but with knowledge of the ‘payoffs’ (costs and
benefits) of different joint outcomes. The the-
ory was taken up by von Neumann and
Morgenstern inTheory of games and economic
behaviour(1944) and has been extensively
developed and applied in economics and
other social sciences, notably political science
and sociology. In geographya pioneering
study was that by Gould (1963), which showed
how African farmers’ agricultural strategies
could be modelled as ‘a game against nature’,
with the farmers gaining different benefits
depending on what they produced and what
weathernaturechose to throw at them.
Game theory tries to deduce theequilibrium
strategies of players under rational decision-
making. Games may be non-co-operative
(where each player only considers their own
benefits and costs) or allow co-operation be-
tween the players. A classic example where
individualrational choiceleads to collective
sub-optimality is theprisoner’s dilemma.A
geographical example of a simple competitive,
two-person, zero-sum game is the model of two
ice-cream sellers on a linear beach, with a uni-
formly distributed population of consumers. If
consumers buy from the nearest seller, then the
rational seller strategy is to locate back-to-back
in the centre of the beach – any other location
gives an advantage to the other seller (see
hotelling model). Yet, from the consumers’
angle, this is sub-optimal. They would benefit
more if the sellers located one-third from the
two ends of the beach, so that consumers had to
walk less. (Of course, this assumes that both
sellers have identical prices for identical prod-
ucts: seehotelling model.) Much of the later
theory has concerned how non-co-operative
games can lead to non-zero-sum payoffs under
various assumptions, and this work (starting
with John Nash’s work in the early 1950s) lies
behind much of the moderntheoryof eco-
nomicmarketsand bargaining.
Game theory has been applied to problems
of interregionalexternalities, where actions
in one region are interdependent with those in
another, as inwater resourcedevelopment,

pollutionstrategies and environmental pol-

icy, and in economic policies within a federal

state such as the USA or an economic union

such as the European Union. It has also been

extended to dynamic games, where learning

takes place and sequences of choices are

made and where there may be ‘leaders’ and

‘followers’ (the Stackelberg game), as in

federal–local policies. However, most of these

studies are by economists, and, aseconomic

geographyhas increasingly lost contact with

much of recent economics, few geographers

have pursued these developments. lwh

Suggested reading

Gould (1963).

garden city A relatively spacious and small,

self-contained planned settlement. Originally

conceived by Ebenezer Howard (1850–1928),

the concept was adopted by the British

Garden City Movement, which he founded.

It formed the basis for two settlements –

Letchworth (1903) and Welwyn (1920) – in

Hertfordshire: both are now much larger than

Howard originally envisaged (c.32,000 people

on a 6,000 acre [2,430 ha] site). The idea of

low-density, relatively small, high-quality

settlements characterized by their ‘greenness’

was adopted in a number of countries during

the twentieth century, as part of a planning

ideology based oncommunity (cf.neigh-

bourhood unit): indeed, the garden city

movement was the precursor in the UK of

the Town and Country Planning Association,

which remains a powerful pressure group. The

general concept was transferred to other coun-

tries and influenced the planning of numerous

new settlements – such as Canberra – andnew

townmovements, as in the USA. rj

Suggested reading

Hall and Ward (1998).

gated communities While associated with

the large US urban regions (Blakely and

Snyder, 1997), gated communities are increas-

ingly global in their distribution (Webster,

Glasze and Frantz, 2002). They are residential

enclaves demarcated physically by walls,

fences and secured gateways, which are often

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