Moral Guilt: An Agent-Based Model Analysis - Advances in Social Simulation - page 94

Moral Guilt: An Agent-Based Model Analysis

Benoit Gaudou 1 , 2 , Emiliano Lorini 1 , and Eunate Mayor 1

1 UMR 5505 CNRS IRIT, Toulouse, France
2 University of Toulouse, Toulouse, France
[e-mail],
{emiliano.lorini,eunate.mayor}@irit.fr

Abstract. In this article we analyze the influence of a concrete moral emotion
(i.e. moral guilt) on strategic decision making. We present a normal form Pris-
oner's Dilemma with a moral component. We assume that agents evaluate the
game's outcomes with respect to their ideality degree ( i.e . how much a given out-
come conforms to the player's moral values), based on two proposed notions on
ethical preferences: Harsanyi's and Rawls'. Based on such game, we construct
and agent-based model of moral guilt, where the intensity of an agent's guilt feel-
ing plays a determinant role in her course of action. Results for both constructions
of ideality are analyzed.

1 Introduction

Few aspects of human evolution have been more controversial that the explanation of
human ethics and morality. Especially when natural selection theory reached its peak, a
question started to be posed more and more often: is cooperation compatible with this
phenomena? Or is it so that only selfish behavior can survive under such circumstances?
And what about cooperation and other-regarding behavior?
According to Dawkins, all factors that lead to the evolving of instincts that favor
other-regarding behavior can be summarized into four main types: “We now have four
good Darwinian reasons for individuals to be altruistic, generous or 'moral' towards
each other. First, there is the special case of genetic kinship. Second, there is reciproca-
tion: the repayment of favors given, and the giving of favors in 'anticipation' of payback.
[...] [T]hird, the Darwinian benefit of acquiring a reputation for generosity and kindness.
And fourth, [...] there is the particular additional benefit of conspicuous generosity as
a way of buying unfakeably authentic advertising.”[11]. For Dawkins, through most
of our prehistory, humans lived under conditions that would have strongly favored the
evolution of other-regarding tendencies. The social side of our species, motivates that,
whether kin or not, individuals would tend to meet again and again throughout their
lives, favoring other-regarding behaviors.
Economic theories based in the self-regarding assumption have stated that, except for
sacrifice on behalf of others (what we call 'altruism'), the rest is just long-run material
self-interest, such theories abstract from reciprocity and other non-self-regarding mo-
tives which can guide individuals' behavior. Thus, although cooperation among purely
self-regarding agents in indefinitely repeated games with sufficiently low discount rate
is a widely accepted theoretical result, this narrow interpretation challenges observa-
tions of our everyday life. Indeed, there is compelling evidence that individuals adhere