COLLECTIVE BEHAVIORare sifted as the crowd moves toward collaborative
action, usually involving a division of labor. To
explain decision making, he offers a simple equa-
tion in which the probability of a person beginning
to act (e.g., to loot) is a function of the product of
the net anticipated personal payoff for acting (e.g.,
equipment or liquor pilfered) and the probability
of group support in that action (e.g., bystanders
condoning or joining in the looting.)
Granovetter’s (1978) application of rational
decision theory focuses on the concept of thresh-
old. He assumes that each person, in a given situa-
tion, has a threshold number or percentage of
other people who must already be engaging in a
particular action before he or she will join in. Since
it can be less risky for the individual to engage in
collective behavior (riotous behavior, for exam-
ple) when many others are doing so than when few
are involved, the benefit-to-cost ratio improves as
participation increases. Based on the personal
importance of the action in question, individual
estimation of risk, and a host of other conditions,
individual thresholds will vary widely in any situa-
tion. Collective behavior cannot develop without
low-threshold individuals to get it started, and
development will stop when there is no one with
the threshold necessary for the next escalation
step. Collective behavior reaches an equilibrium,
which can be ascertained in advance from know-
ing the distribution of thresholds, when this point
is reached. Like Berk, Granovetter makes no effort
to explain what actions people will value. Further-
more, intuitively appealing as the theory may be,
operationalizing and measuring individual thresh-
olds may be, for all practical purposes, impossible.
MICRO-LEVEL INTERACTION THEORIESContagion Theories. Early interaction theories,
which lay more emphasis on what happens to
people in the context of a crowd or other collectivi-
ty than on the dispositions people bring to the
collectivity, stressed either the emergence of a
group mind or processes of imitation, suggestion,
or social contagion. Serge Moscovici (1985a, 1985b)
is a defender of these early views, stressing that
normal people suffer a lowering of intellectual
faculties, an intensification of emotional reactions,
and a disregard for personal profit in a crowd. The
fundamental crowd process is suggestion, emanat-
ing from charismatic leaders. During the twentieth
century, the breakdown of social ties has created
masses who form larger and larger crowds that are
controlled by a few national and international
leaders, creating an historically new politics or
appeal to the masses.Herbert Blumer (1939) developed a version of
the contagion approach that has been the start-
ing point for theories of collective behavior for
most American scholars. Blumer explains that the
fitting together of individual actions in most group
behavior is based on shared understandings un-
der the influence of custom, tradition, conven-
tions, rules, or institutional regulations. In con-
trast, collective behavior is group behavior that
arises spontaneously, and not under the guidance
of preestablished understandings, traditions, or
rules of any kind. If sociology in general studies
the social order, collective behavior consists of the
processes by which that order comes into exist-
ence. While coordination in publics and social
movements and involving more complex cognitive
processes called interpretation interaction, coordi-
nation in the crowd and other elementary forms of
collective behavior is accomplished through a proc-
ess of circular reaction. Circular reaction is a type of
interstimulation in which the response by others
to one individual’s expression of feeling simply
reproduces that feeling, thereby reinforcing the
first individual’s feeling, which in turn reinforces
the feelings of the others, setting in motion an
escalating spiral of emotion. Circular reaction be-
gins with individual restlessness, when people have a
blocked impulse to act. When many people share
such restlessness, and are already sensitized to one
another, circular reaction can set in and create a
process of social unrest in which the restless state is
mutually intensified into a state of milling. In
milling, people move or shift their attention aim-
lessly among each other, thereby becoming preoc-
cupied with each other and decreasingly respon-
sive to ordinary objects and events. In the state of
rapport, collective excitement readily takes over,
leading to a final stage of social contagion, the
‘‘relatively rapid, unwitting, and non-rational dis-
semination of a mood, impulse, or form of con-
duct.’’(Blumer 1939) Social unrest is also a prel-
ude to the formation of publics and social movements.
In the case of the public, the identification of an
issue rather than a mood or point of view converts
the interaction into discussion rather than circular
reaction. Social movements begin with circular