GROUP SELECTION AND THE LIMITS TO ALTRUISM

23 Pages·2000·0.06 MB·English

GROUP SELECTION AND THE LIMITS TO ALTRUISM
Paul H. Rubin
Department of Economics and School of Law
Emory University
Atlanta, GA 30322-2240
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Email: [email protected]
Keywords: evolution, altruism, morality, utilitarianism, Marxism, Rawls, fairness.
JEL D634
Synopsis:
Several evolutionary mechanisms have been identified in the literature that would
generate altruism in humans. The most powerful (except for kin selection) and most
controversial is group selection, as recently analyzed by Sober and D.S. Wilson. I do not
take a stand on the issue of the existence of group selection. Instead, I examine the level
of human altruism that could exist if group selection were an engine of human evolution.
For the Sober and Wilson mechanism to work, groups practicing altruism must grow
faster than other groups. I call altruistic behavior that would lead to faster growth
“efficient altruism.” This often consists of cooperation in a prisoner’s dilemma.
Altruistic acts such as helping a temporarily hungry or injured person would qualify as
efficient altruism. Efficient altruism would also require monitoring recipients to avoid
shirking. Utilitarianism would be an ethical system consistent with efficient altruism, but
Marxism or the Rawlsian system would not. Discussions of efficient altruism also help
understand intuitions about fairness. We perceive those behaviors as “fair” that are
consistent with efficient altruism. It is important to understand that, even if humans are
selected to be altruistic, the forms of altruism that might exist must be carefully
considered and circumscribed.
Introduction
A major debate in biology and in particular in the study of human evolution is the
extent and significance of group selection. Since the work of Williams (1966) it has
generally been thought that any form of group selection was impossible because free
riding within the group would eliminate the possibility. More recently, Sober and D.S.
Wilson (1998) have reignited the debate. They do not propose the old “good of the
species” form of group selection as advocated by Wynne-Edwards (1962) and discredited
by Williams (1966). Rather, they argue that in some circumstances groups containing
more altruists1 would grow faster than groups with fewer altruists, even though the
number of altruists within each type of group would decrease over time. If the groups
remain isolated, then the standard result would obtain, and the number of altruists in each
group and thus in the population would ultimately go to zero. However, if the groups
periodically split and reform, then the number of altruists in the population could
increase. They also argue that this mechanism would have been particularly important in
human evolution, and present some data indicating that human behavior is consistent
with their argument.2
I do not want to address the issue of group selection here. Rather, I am going to
assume for the purpose of argument that there is group selection of exactly the sort that
Sober and Wilson describe. I ask the question, What are the implications of group
selection for the analysis of human altruism? This is consistent with Alexander’s (1987,
p. 192) argument that “morality tends to mimic the effects of group selection.” Also, it
is well known that Darwin (1871) based his views of evolved morality on group
selection, although not of the sort discussed by Sober and Wilson.
The rationale for this examination is as follows: Analysts have identified several
individually based mechanisms for altruism. Some are: reciprocal altruism; kin selection;
the willingness of some to punish others for shirking, or for not punishing those who
refuse to punish shirkers (second degree punishment; Axelrod, 1997; Boyd and
Richerson, 1992; Hirshleifer and Martinez-Coll, 1988); assortment by degrees of
altruism, so that more altruistic persons interact with others with the same behaviors; and
asymmetric interaction, such as Maynard Smith’s (1982) “bourgeois” strategy, in which
the first player to arrive wins the resource.3 Hirshleifer (1999) has a particularly nice
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discussion of alternative mechanisms for evolution of cooperation, or altruism. But while
all of these mechanisms are plausible and all would generate some altruism, none are as
powerful at generating altruism among non-related individuals as is complete group
selection. Therefore, if we can determine the types of altruism that would be favored by
group selection, we can understand the limits of altruism. If some suggested form of
altruism is not compatible with group selection, then it is unlikely that humans have
evolved a preference for this behavior. Of course, the converse may not be true: if some
mechanism is consistent with group selection, this does not prove that this mechanism
exists unless we are confident that some form of group selection actually occurred or
unless we can identify some mechanism consistent with individual selection to generate
the behavior. Nonetheless, consideration of group selection will give us an “upper
bound” on the level and form of evolved human altruism.
The maintained assumption is that any “tastes” for altruism would have evolved
and we living humans would have those tastes that would have led to increased fitness of
our ancestors in the environment of evolutionary adaptatedness (EEA). We would
perceive these tastes as a sense of “right” or morality, but this feeling has evolved. (This
point is discussed in many places; see for example Ruse and E.O. Wilson, 1986.) Then
humans today can be no more altruistic than it would have paid to be if there was group
selection in the EEA because group selection sets the limits for altruism. This general
approach to political tastes is explained and amplified in Rubin (2000a).
The other point to note is that most agree that the EEA was an environment of
intense group competition. Predation by hominids on hominids or by humans on humans
was a very important factor in the EEA. Many analysts believe that this selection
pressure was responsible for the tremendous increase in intelligence and brain size as our
ancestors evolved from an ape like creature to become humans. Thus, in evolutionary
times, group size was important. That is, having more individuals in the group up to the
limit that could be supported by the existing technology at a given time was a positive
externality for each member. This is a consequence of the “balance of power” argument
that the purpose of sociality was defense against predators – primarily other hominids
(Alexander, 1987).
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Then there are circumstances in which transfers to some individuals would have
been in the group interest, and presumably in those circumstances the utility or well-
being of the recipients would have become an element in the utility functions of the
donors. The main point is that in situations where a low cost transfer could save the life
of the recipient and enable him to continue to participate in the group defense, or enable
her to reproduce other defenders, then transfers would have been desired. There are
probably two situations that would have been relevant in the EEA, and moreover which
are still relevant today (because we have tastes evolved in the EEA.) These are
temporary income shortfalls, which could lead to starvation, and illness or injury, which
could lead to death. Both are discussed below.
There is another mechanism, in addition to direct competition, that would have
favored more efficient preferences. Mobility between groups was often possible in the
EEA (as it is today.) Then groups with preferences for more efficient policies would
have been richer or more successful (or fit), and in many cases individuals would have
voluntarily chosen such groups. This raises the issue of cultural rather than biological
selection of preferences. The most useful models of such selection processes allow genes
and culture to interact; see Boyd and Richerson (1985). In their model, there is
evolutionary interaction between genes and culture. For example, if cultural norms in
some group favor some form of altruism, then individuals who most easily adapt to this
form of altruism will be more successful in that group. Cultural and genetic evolution
can reinforce each other. But in this paper I focus on the genetic part of the process.
The analysis here is positive, not normative. I ask what sorts of tastes humans
might have for altruism. In designing optimal policies (that is, in undertaking normative
analysis) it is possible to choose other policies that may not agree with these tastes.
However, decision-makers should be aware of the sorts of constraints under which they
operate. If policies are adopted that conflict with these evolved tastes, then there will be
some discontent with these policies, and they will be more expensive to implement.
There may also be pressure to change the policies. I will from time to time point out
situations where current policies agree with or conflict with evolved tastes.
GROUP SELECTION AND ALTRUISM PAGE 4
Efficient Altruism
The analysis of group selection leads to the notion of efficient altruism. In the
Sober and Wilson analysis, groups with altruists grow faster, and this explains the
survival of altruism in the population. But only some types of altruism would generate
this differential growth rate. Group selection is not an indiscriminate mechanism for
generating everything that is called or appears to be altruism, or for indiscriminate
“generosity.” Rather, some behaviors that some have called altruistic might actually lead
groups that practiced these behaviors (or that had many individuals practicing these
behaviors) to grow more slowly. For example, Binmore (1994, p. 259) argues that in a
“first best” world (a world with costless enforcement of social contracts) there would be
much more generosity than we actually observe. But the argument here is that natural
selection could not have generated preferences for such behavior in humans. I call
altruism that does lead to increased growth of groups with more such altruists (or that
would have done so in the EEA) “efficient altruism.”
The general example of such efficient altruism would be cooperation in some
variant of a prisoner’s dilemma game. The prisoner’s dilemma is the generic cooperate-
don’t cooperate game, where cooperation is efficient for the cooperators jointly in that it
leads to greater payoffs for both participants, but non-cooperation is the best strategy for
each player. Then some group in which more people played “cooperate” would have
greater income and wealth than some group where fewer individuals cooperated, and the
population in the more cooperative would grow more quickly. E.O. Wilson (1998, p.
252) relates morality to cooperation in a prisoner’s dilemma; see generally Binmore
(1994). Sober and Wilson (1998, Chapter 5) show that most or all societies enforce
“social norms.” One important function of such norms is to induce cooperation and
reciprocation – that is, to force a cooperative solution to a prisoner’s dilemma like game.
Cooperation: Examples
One example of efficient altruism would be cooperation in the purchase or
creation of public goods. In the EEA, many things that we think of as public goods
(roads, public buildings) would not have been meaningful. But law and order –
enforcement of rules – would have been a useful goal. Much of the discussion in Sober
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and Wilson and others of rule enforcement (punishment for rule violation) and second
level rule enforcement (punishment for not punishing rule violations) may be construed
as contribution to a public good. Thus, one form of altruism that may be favored in
human populations is providing institutions or mechanisms for enforcement of rules.
Rules and rule enforcement would lead to larger incomes or increased survival in groups,
and to exactly the sort of differential growth that is required in the Sober and Wilson
model. Rule enforcement in universal among humans (Brown, p. 138).
Cooperation in productive activities would also be an efficient form of altruism.
An example is group hunting. Indeed, Ridley (1996) indicates that big game was the first
public good. Cooperation would be to do one’s share even if the activity is dangerous;
shirking or non-cooperation would be to free ride and not do one’s assigned task. Then if
all cooperate the hunt will be more successful, so this is exactly a prisoner’s dilemma.
Groups with hunters who were more cooperative (or, more generally, workers who were
more cooperative) would grow faster than others, and so this form or altruism could
survive in the EEA in a Sober and Wilson process.
Similarly, if group conflict was an issue in the EEA – and most think that such
conflict has been an ongoing part of human and even prehuman existence – then
contributions to defense or offense would also have been a public good. The main form
of this public good would probably have been rewards to individuals, largely young
males, who participated in defense or in predation, and there seems to be much evidence
that such rewards are in fact forthcoming. Thus, while individuals may have participated
in defensive or offensive “military” activities for private motives, the reason that private
motives would have been available is because there were public rewards to such
participation. Cooperation by young males in offensive or defensive activities (or in their
contemporary surrogates, such as gangs or sports) is a form of altruism that would have
survived a group selection process.
Another form of altruism – one more consistent with the normal usage of the term
– would have been food sharing. Food sharing as a form of insurance could again have
been a form of efficient altruism. If one person is low on food today (perhaps because a
hunt was unsuccessful) he may die. If another shares his food, this will have desirable
effects on the group, since it will lead to a larger group size which is useful for protection
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(Alexander, 1987). The prisoner’s dilemma occurs because sharing in such
circumstances is efficient for both parties, but the party who first receives the transfer has
an incentive to shirk and not reciprocate. Reciprocal altruism (Trivers, 1971) can make
this policy privately as well as socially desirable, but in either case it would be an
efficient form or altruism. Binmore (1994) points out that reciprocal altruism is another
name for the notion in game theory that cooperative solutions can be reached in repeated
games – the so-called “folk theorem.” Moreover, some of the rules that the group might
efficiently enforce would be rules mandating sharing and reciprocation. A formal analysis
of this problem is in Binmore (1994, pp. 212-226). We would expect humans to agree to
share food, and food sharing is universal among humans: Brown, 1991, p. 138.
But it is important to note that such food sharing would be limited and would
occur only in well-defined circumstances. Sharing creates risks of shirking of two sorts.
One is not sharing when one is obliged to (the EEA equivalent of tax evasion). The other
is shirking in food seeking or production in order to free ride on those who do produce
and share (the EEA equivalent of welfare fraud). Kelly (1995, Chapter 5) discusses these
issues and shows that sharing, shirking, and detection of shirking all exist among hunter-
gatherers; see also Boehm (1999a). Then food sharing would not be efficient if the
recipient were lacking in food because of shirking. In the EEA, societies were relatively
small, and monitoring to reduce shirking would have been possible. Rubin (1982) stresses
the difficulty in monitoring shirking under current conditions as compared with
conditions in the EEA. Cosmides and Tooby (1992) point out that this issue still informs
debate on welfare and other contemporary sharing systems. Proponents of such programs
stress the random nature of poverty and the role of luck4; opponents stress shirking. Both
sides are trying to capitalize on evolved tastes for or against redistribution in particular
circumstances. The difficulty is in trying to design a system of transfers in a world where
monitoring of recipients to detect shirking is difficult. McGuire (1992) points out that
there are mental mechanisms for calculating the appropriate amount of moralistic
aggression associated with differing forms and degrees of shirking.
In addition to food sharing, assistance to the ill, hurt or injured who would be
expected to recover would have been an efficient form of altruism. This is because
someone hurt or injured could, upon recovery, again become a useful member of the
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band. Injury was probably much more common in the EEA than today; injury has been
falling steadily in historic times, and is lower now than even in our own recent past.
Methods of production in the EEA, such as hunting, would have been particularly prone
to injury. Even today many view medical care as a “necessity” and are opposed to
treating medical care as simply another expenditure item; this may be because such a
taste for treating medical care as different could have evolved in the EEA. Moreover, the
nature of care in the EEA was probably such that shirking in the form of consumption of
additional care would not have been an alternative. This may be why people today think
in terms of the amount of medical care “needed” without realizing that the amount of care
consumed can be increased if costs are reduced.
None of these forms of altruism would have supported providing food or other
resources to a non-productive individual who was not expected to become productive, or
to a shirker who was expected to continue to shirk. That is, altruism might have
supported transfers to a temporarily unlucky individual or to an individual who was
temporarily incapacitated through illness or injury. But it would not have supported
transfers to someone who would be expected to remain unproductive. (Kin selection
mechanisms might have induced family members to provide some support, for example,
to the elderly, and there is evidence that children support aged and unproductive parents
in hunter gatherer societies, as long as such support does not lead to excessive
deprivation for children or grandchildren.) Continual transfers to non-productive
individuals would have been a drain on a band and would have reduced the ability to
compete with other bands in the EEA. Boehm (1999a; 1999b) indicates that among
hunter-gatherers older individuals who cannot walk are often killed or abandoned.
Westermarck (1912) has a lengthy discussion of this issue in Volume 1, Chapter 17, and
discusses the killing of certain sick persons as well. Binmore (1994, p. 259) asks why it
is that people seem to feel less empathy towards schizophrenic homeless persons. These
attitudes and behaviors are consistent with the argument here.
There is substantial evidence that in hunter-gatherer societies, there was what has
been called an “egalitarian ethic.” (Boehm, 1993, 1999b; Knauft, 1991; Wiessner, 1996.)
This might seem to imply that we have inherited from our hunter-gatherer ancestors a
desire for income transfers and equality of outcome. But careful reading of Boehm
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(especially 1999b) indicates that what was actually involved was a desire not to be
dominated; this is consistent with Knauft’s analysis, although Knauft does not state this
as directly as does Boehm. That is, individuals who expected to be the lower ranked
members of any hierarchy banded together to prevent potential higher ranked members
from actually forming a hierarchy. Food sharing (especially of meat) was virtually
universal in such societies, but care is taken not to use such sharing to provide excess
status or power to successful hunters (Wiessner, 1996). There is no evidence that
potentially dominant members wanted to eliminate hierarchies. Rather, individuals
wanted to avoid being dominated. Humans still have such preferences. For example,
Buchanan and Tullock (1965) provide a theory of constitutions based on this desire.
Bentham, Yes; Marx and Rawls, No
Three standard philosophical systems that discuss the optimal moral stance for
society are utilitarianism (Bentham, 1781/1988), Marxism (Marx, 1888) or, more
generally socialism, and the Rawlsian system (Rawls, 1971). Utilitarianism is roughly
consistent with the form of altruism that would occur under group selection; the Rawls
“difference principle” is not, nor is a communist or socialist system.
My analysis here is obviously sketchy and uninformed by academic discussions
of moral theory. However, Posner (1999) indicates that such discussions are not very
fruitful anyway. E.O. Wilson (1998) argues that moral philosophy is not generally based
on empirical biological knowledge. Alexander (1987, p. 145-165) discusses the
relationship between moral philosophy and biology as viewed by moral philosophers. He
concludes that in general moral philosophers have not paid adequate attention to biology,
and have not taken account of biological knowledge. Earlier, Westermarck (1932) had
reached a similar conclusion regarding an earlier generation of moral philosophers.
There is also a body of literature by biological informed writers applying
biological knowledge to moral discourse. Westermarck (1912, 1932) was an early
scholar working in this vein, although his writing is impaired by the limited knowledge of
biology available when he was writing; for example, he commonly writes of things
“useful for the species.” Westermarck does sometimes refer to natural selection (as in the
famous discussion of incest avoidance based on youthful propinquity: Westermarck,