| HOME |
Evolution of direct reciprocity under uncertainty
can explain human generosity in one-shot encounters
Andrew W. Deltona, Max M. Krasnowa,et al.,
(* University of California)
PNAS (2011) vol.108 (32) p13335-13340;
published ahead of print July 25, 2011
Are humans too generous?
The discovery that subjects choose to incur costs to
allocate benefits to others in anonymous, one-shot economic
games has posed an unsolved challenge to models of economic
and evolutionary rationality.
Using agent-based simulations, we show that such generosity
is the necessary byproduct of selection on decision systems
for regulating dyadic reciprocity under conditions of uncertainty.
In deciding whether to engage in dyadic reciprocity,
these systems must balance
(i) the costs of mistaking a one-shot interaction
for a repeated interaction
(hence, risking a single chance of being exploited)
(ii) the far greater costs of mistaking a repeated interaction
for a one-shot interaction
(thereby precluding benefits from multiple future
This asymmetry builds organisms naturally selected to cooperate
even when exposed to cues that they are in one-shot interactions.
*dyadic (adj) ＜dyad (n)
= something that consists of two parts
(e.g.) the mother-child dyad
= a situation in which two people, countries, etc. provide
the same help or advantages to each other
(e.g.) from the standpoint of reciprocity
= to treat a person or situation as an opportunity
to gain an advantage for yourself
(e.g.) He exploited his father's name to get himself a job.
= to prevent something from happening or somebody from doing
(e.g.) Lack of time precludes any further discussion.
The evolution of generosity -“Welcome, stranger”
The human impulse to be kind to unknown individuals is not
the biological aberration it might seem
“The Economist” Jul 30th 2011
THE extraordinary success of Homo sapiens is a result
of four things: intelligence, language, an ability to
manipulate objects dexterously in order to make tools,
Over the decades the anthropological spotlight has shifted
from one to another of these as the prime mover of the package,
and thus the fundament of the human condition.
At the moment co-operation is the most fashionable subject
In particular, why are humans so willing to collaborate
with unrelated strangers, even to the point of risking being
cheated by people whose characters they cannot possibly know?
| HOME |