Preferences= individual wants, which can be inspired by different sources, and which don’t
change much in the short run. People who act according to their preferences are self-interested,
and this include everything that an individual perceives as important. The external world, which
is characterized by uncertainty, also affects the way people express their preferences. Because
of uncertainty, people may not be able to predict whether an instrument/behavior they adopt
relates to the outcome they value, thus the effectiveness of behavioral instruments is only
imperfectly known. Beliefs is what we call the hunches an individual has concerning the efficacy
of a given instrument for obtaining smth. Acting in accord with both one’s preferences and one’s
belief is called “instrumental rationality”. Taking all this into account, a rational individual is one
who combines his beliefs about the external environment and preferences about things in said
environment in a consistent manner. The rational choice approach is a form of “methodological
individualism”, that is the individual is taken as unit of analysis, while collectives do not have
minds and cannot be said to have beliefs and preferences.
Example relating to economics. We have four classes of actors. Consumers have to choose
how to spend their money so as to achieve maximum contentment/utility. Producers must
determine how to combine productive inputs so as to maximize profit. Workers aim at having
purchasing power and leisure time. Investors are providers of capital and seek long-term
financial return. Descriptive accuracy is not the point of these assumptions, instead the point is
explanation.
Two properties that capture the notion of rationality as ordering things in terms of preference:
comparability/completeness and transitivity. Alternatives are comparable (and the preference
relation is complete) if for any two possible alternatives (x and y), either xPiy, yPix, or xIiy. The
relation is transitive if for any three possible alternatives (x, y and z), if xPiy and yPiz, then xPiz.
If i’s preferences satisfy comparability and transitivity, then i is said to possess a preference
ordering. And if preferences permit rational choice, they are ordering principles. A caveat is that
for choices to be rational they must make sense to the choosers, in the sense that we cannot
get “don’t-know” answers. Transitivity requires consistency, which can be violated when
comparisons are difficult, when little is at stake, or when answers aren’t likely to make a big
difference. Lastly, rationality is seen as consisting of maximizing behavior.
Conditions under which individuals operate: if one knows what will happen, he operates under
conditions of certainty; if one is not very confident about what will happen but still has an idea of
the possibilities their likelihoods, he operates under conditions of risk; if the relationship between
actions and outcomes is completely imprecise, one is operating under conditions of uncertainty.
Whenever we don’t operate under certainty, we need to assign a numerical value to each
outcome, the “utility number”. Utility numbers reflect the relative value associated with each
outcome. The rule to make a rational choice is called Principle of Expected Utility: the sum of
the utility of all the outcomes that could result from an action, weighted by the likelihood that
each outcome will happen.
, Chapter 3
In groups, a problem called “preference diversity” can arise, meaning it’s difficult to arrive at a
collective action. Round-robin tournament= each alternative is pitted against each other
alternative and, if one is preferred by a majority to all the others, it’s declared the group choice.
In the book example, we use round-robin tournament because unanimity and first-preference
majority rule can fail when preferences are too heterogeneous. Another problem is that group
preference relation can be intransitive. A constitutional scheme that can help solve this is the
agenda procedure.
Chapter 4
Group preferences can be divided into “strong” and “weak”, where weak ones involve some
degree of indifference between certain options.
Condorcet’s Paradox= when each individual has complete and transitive preferences but the
group doesn’t. These are called “cyclical majorities”, where each alternative is ranked first by
exactly one person, second by one person, and third by one person. This produces a “forward
cycle”, that is c P b P a P c. If we have only three groups with only strong preferences, as in the
book example, we will get a “Condorcet winner” most of the time. However things get more
complicated if we increase the number of individuals (n) or of alternatives (m). We want to
derive a probability that gives the likelihood of a maj.rule preference cycle, and we write this as
Pr(m,n). The formula is Pr(m,n)= # of problem preference configurations / (m!)ⁿ. The numerator
is the number of societies with cycling group preferences, for example for m=3 and n=3 the
number will be 12. The denominator gives the total number of possible societies computed as
follows: with m alternatives, any individual in the group may choose any one of m x (m-1) x
(m-2) x … x 3 x 2 x 1 different ways to order his preferences over the alternatives. E.g. for
m=n=3, it’s (3x2x1)³. As the result approaches 1.0, it becomes more and more likely that there
will be preference cycles among majorities. In such cases we cannot rely on majority rule to
produce a coherent sense of what the group wants. However, we assumed independence
among individuals, while real societies are characterized more by interdependence, e.g.
individuals can choose to join groups when they have preferences in common with other
members. As long as either n or (especially) m is large, the odds of majority preference cycling
is large enough to be of concern. As for the “divide the dollars” game, author claims it produces
cyclical majorities, as no distribution is preferred by a majority to every other distribution, and
thus there’s no Condorcet winner. Even if a perfectly fair distribution can arise, it is vulnerable to
majority coalitions of individuals ganging up on an excluded member. The maj.coalitions that
arise, too, are vulnerable as there’s always a distribution preferred by at least two members and
new coalitions that can arise to defeat an existing one. To put it in textbook words: “any
proposed distribution is open to amendment as different majorities jostle with one another for
advantage; final outcomes are extremely sensitive to other institutional features of the group
decision-making setting”. In distributive politics, therefore, the only way to avoid preference
cycles is to impose anti-majoritarian restrictions.
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