YSM Issue 90.2

FEATURE
psychology
UNDERSTANDING COOPERATION
Theoretical model developed to explain human behavior
►BY CYNTHIA YUE
Four people work in a group, each given a sum of money. They
are asked if they wish to contribute some amount of money to the
public pot. The choices are thus made clear: either selflessly contribute
and allow the money to be evenly divided or selfishly keep
the money and share in the amount contributed by the others.
Such is the setup of a public goods game, which, like other game
theory-related concepts like a prisoner’s dilemma, provides insight
into inherent human behavior regarding cooperation and
selfishness. These games have inspired the research conducted at
Yale by Adam Bear, a fourth year Ph.D. candidate in Psychology,
and David Rand, an Associate Professor of Psychology, Economics,
and Management.
Basing their work on empirical data related to these games,
Bear and Rand have developed a theoretical game theory model
that explains that people who intuitively cooperate but can also
act selfishly succeed from an evolutionary perspective.
To create the model, Bear and Rand used MATLAB to construct
agent-based simulations consisting of virtual agents with
all permutations of behaviors, which interact with one another
in various environments through a computer system for several
generations. Afterward, they made mathematical calculations to
confirm the accuracy of their simulations.
“The idea of these simulations is they’re meant to model some
kind of evolution either over biological time or over cultural
time,” said Bear. “People who tend to do well when they play their
strategies are more likely to survive in the next generation than
people who do poorly, so these agents interact on a set of generations,
and once you do well, [you] tend to stay in the game; once
you do poorly, you tend to die out.”
The model itself takes several factors —such as type of thinking
and environment—into consideration.
With thinking, agents can either follow their intuition or use
deliberation. Bear describes intuition as a form of cognition that
uses heuristics—mental shortcuts—to get to answers quickly.
This way of thinking is efficient but may lead to errors in reasoning
due to its inability to reason through the details of the context
one is facing. On the other hand, deliberation allows agents
to take time to reason about the contexts and make more accurate
decisions. In the model, agents can strategize, choosing how
much intuition and deliberation to use.
The environment refers to the proportion of repeated to oneshot
interactions. Agents vary in how much they engage in
one-shot interactions and repeated interactions, in which they
may possibly establish a relationship.
From an evolutionary standpoint for which success seems built
on self-interest, Bear explains, “Say we’re in a repeated interaction:
it’s better if I’m nice to you if I’m going to see you again,” said Bear.
“But if I’m never going to see you again, say it’s a one-shot interaction
and no one else is seeing us…I’m better off being selfish if it
would cost me a lot to be nice to you.”
The conclusions of Bear and Rand’s model focused on environments
with more repeated interactions—as they more realistically
reflect the environment of the real world, according to Bear. He
described the best agent in their model: an agent that has a fast
cooperative response, but selfish response upon deliberation in
one-shot interactions.
Their research, however, received critiques from others working
in the field, particularly Kristian Myrseth, an Associate Professor
in Behavioral Science and Marketing at Trinity College Dublin,
and Conny Wollbrant, an Assistant Professor in Economics at the
University of Gothenburg. “The model makes this crucial claim
that evolution never favors strategies...where deliberation increases
your prosocial behavior,” Myrseth said.
Wollbrant added, “The problem is that we know today, we’re
fairly sure, that…people are often behaving prosocially, not for
strategic reasons, but because they feel that’s the right thing that
they should do.” These two researchers claim that the model does
not allow cases of inherent prosocial behavior to survive despite
the apparent evolution of people with such behavior existing in
the world today.
Nevertheless, according to Bear, he and Rand have continued
to work on additional versions of the model to make it more realistic
by incorporating how intuition and deliberation may not be
so black and white in terms of distinguishing the environment.
“There was this fun process of discovery in the model and
learning what the model was actually showing,” said Bear. “It’s
cool because you know you think when you model something,
maybe it’ll be obvious what you’re going to find, but actually, you
discover these interesting things that you didn’t necessarily anticipate
before modeling.”
IMAGE COURTESY OF REYNERMEDIA
►Agents who intuitively cooperate, but deliberate and defect to
selfish behavior in one-shot interactions, succeed evolutionarily.
34 Yale Scientific Magazine March 2017 www.yalescientific.org