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\title{It’s not fair: Folk intuitions about disadvantageous and advantageous inequity aversion}

\author{
Alex Shaw\thanks{Department of Psychology, University of Chicago, 5848
  University Ave., Chicago, IL, 60605. E-mail: ashaw1@uchicago.edu.}
\and
Shoham Choshen-Hillel\thanks{School of Business Administration, The Hebrew
University of Jerusalem.}
}

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\begin{onecolabstract}
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  People often object to inequity; they react negatively to receiving
  less than others (disadvantageous inequity aversion), and more than
  others (advantageous inequity aversion). Here we study people’s folk
  intuitions about inequity aversion: what do people infer about
  others’ fairness concerns, when they observe their reactions to
  disadvantageous or advantageous inequity? We hypothesized that,
  people would not intuitively regard disadvantageous inequity
  aversion by itself as being rooted in fairness, but they would
  regard advantageous inequity aversion by itself as being rooted in
  fairness. In four studies, we used vignettes describing inequity
  aversion of a made up alien species to assess people’s folk
  intuitions about inequity aversion. The studies supported our main
  hypothesis that disadvantageous inequity aversion, without
  advantageous inequity aversion, does not fit people’s folk
  conception of fairness. Instead, participants reported it to be
  rooted in envy.  According to these results, the claim that
  disadvantageous inequity aversion reveals a concern with fairness,
  does not readily accord with people’s intuitions. We connect these
  findings to other pieces of evidence in the literatures of
  behavioral economics, developmental psychology, and social
  psychology, indicating that lay people’s intuitions may be on the
  mark in this case. Specifically, unlike advantageous inequity
  aversion, disadvantageous inequity aversion need not be rooted in a
  sense of fairness.

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\smallskip
\noindent
Keywords: fairness, inequity aversion, envy, social comparison, equity
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{\renewcommand{\thefootnote}{}

\footnotetext{

  The authors would like to thank Laurie Santos for asking a question
  during the first author’s defense that inspired these
  experiments. The authors would also like to thank Jonathan Phillips
  and Joshua Knobe for valuable discussions about the studies in this
  manuscript, and Tal Eyal and Ilan Yaniv for helpful comments on an
  earlier draft.

Copyright: \copyright\ 2017.
The authors license this article under the terms of the
\href{http://creativecommons.org/licenses/by/3.0/}{Creative Commons
  Attribution 3.0 License.}
}}

\saythanks

\section{Introduction}

Fairness is a fundamental concern in people’s interactions influencing
many aspects of daily life, from how children share toys with
classmates to how legislators shape complex tax policies. Much of the
literature on these putative fairness concerns in psychology and
economics has focused on fairness being rooted in inequity aversion —
people’s negative response to unequal pay for equal work (for reviews,
see Adams, 1965; Bolton \& Ockenfels, 2000; Cook \& Hegtvedt, 1983;
Cooper \& Kagel, 2009; Damon, 1977; Fehr \& Schmidt, 1999; Hook \&
Cook, 1979; Lerner, 1974). This body of research has demonstrated that
people often respond negatively to receiving less than others (i.e.,
they experience disadvantageous inequity aversion, or DIA) as well as
to receiving more than others (i.e., they experience advantageous
inequity aversion, or AIA). Traditionally, each of these reactions,
DIA and AIA, have been argued to provide evidence for concern with
fairness (for reviews, see Brosnan \& de Waal, 2014; Smith \& Kim,
2007).

Whereas the literature has considered both of these concerns to be
connected to fairness, it has not asked whether these two putative
fairness concerns match people’s lay intuitions about what it means to
truly be concerned with fairness. Here we examine whether people
believe that DIA and AIA in isolation provide convincing evidence that
one is concerned with fairness, predicting people do believe the latter
is sufficient, but not the former. Given that the current literature
often connects DIA and AIA to fairness, it is interesting to know
whether people intuitively do the same or not. We start by reviewing
previous research on fairness and inequity aversion, and then focus on
people’s lay intuitions regarding these concepts. 

\subsection{Two types of inequity aversion}
Two broad classes of evidence have been used to demonstrate that
people are averse to inequity: their negative reactions to inequity
and their costly rejections of it. First, a large number of studies
have demonstrated that people respond negatively to being paid less
than others for similar work (DIA: Boyce, Brown \& Moore, 2010;
Goodman \& Friedman, 1971; Hook \& Cook, 1979; Lawler, 1968;
Loewenstein, Thompson \& Bazerman, 1989; Messick \& Sentis, 1985) and
also to being paid more than others (AIA: Sweeney, 1990; Sweeney \&
McFarlin, 2004). Second, in addition to reporting having negative
reactions to inequity, people will also pay costs to reduce it. People
avoid disadvantageous inequity by engaging in the costly rejections of
offers that place them in an unfavorable position (Bazerman,
Loewenstein \& White, 1992; Güth, Schmittberger \& Schwarze, 1982;
Roth, 1995; Weg \& Zwick, 1994). They also avoid advantageous inequity
by giving money to others in situations where they currently have more
than them (Camerer, 2003; Forsythe, Horowitz, Savin \& Sefton,
1994). These concerns with fairness can even lead people to waste
useable resources (Choshen-Hillel, Shaw \& Caruso, 2015;
Gordon-Hecker, Rosensaft-Eshel, Pittarello, Shalvi \& Bereby-Meyer, in
press; Shaw, 2013; Shaw \& Knobe, 2013; for review see Gordon-Hecker,
Choshen-Hillel, Shalvi \& Bereby-Meyer, in press).

Researchers have referred to AIA as unambiguous evidence that one is
concerned with fairness (why else would someone strive for equity, when
it hurts them? For an in depth answer to this question, see Shaw \&
Olson, 2012). Many authors further argue that DIA also provides
evidence that one is concerned with fairness (Adams, 1965; Andre \&
Baumard, 2011; Brosnan \& de Waal, 2014; Fehr \& Schmidt, 1999;
Forrester, 1997; Russell, 1930; Smith, 1991; Smith, Parrott, Ozer \&
Moniz, 1994). Indeed, rejections of unfavorable offers in the ultimatum
game, driven entirely by DIA, are the quintessential test in behavioral
economics for measuring fairness concerns (Halali, Bereby-Meyer \&
Ockenfels, 2013, for extensive reviews, see Camerer, 2003; Cooper \&
Kagel, 2009). Even if these researchers might agree that AIA is better
evidence in favor of someone being concerned with fairness, they still
regard manifestations of DIA by itself as evidence for people’s concern
with fairness (for review see, Smith \& Kim, 2007). 

In contrast to the traditional view of inequity aversion, some
researchers have argued that DIA by itself does not provide sufficient
evidence that one has a sense of fairness. According to this argument,
people’s negative response to having less than others is
over-determined — they could be motivated by either fairness or envy — and
so it is hard to know what is motivating them. This argument was made
prominent by Rawls (1971), who argued that calls for equality by those
who receive less can be motivated by resentment of the overall
injustice (i.e., unfairness) of the unequal situation, but also by
simple envy of others’ better outcomes. Such envy is focused on social
comparison, and consists of resentment to the other’s better outcome.
It is often unrelated to justice, but simply reflects one’s desire to
have what someone else has (Smith et al., 1994). Because both fairness
and envy lead to negative reactions to DIA in interpersonal situations,
it can be difficult to know if a person’s particular experience of DIA
reflects a concern based in fairness or social comparison, because
human beings have both concerns (Feather \& Sherman, 2002; Nichols,
2010; Shaw, 2016; Shaw \& Olson, 2012; Yamagishi et al., 2012). Any
individual instance of DIA could be motivated by a combination of
fairness and social comparison or it could be motivated by social
comparison in the absence of fairness. 

While AIA and DIA are both present in adult humans, they need not
always co-occur. DIA has been found in capuchins, macaques,
chimpanzees, domestic dogs, crows, rats, and ravens (Brosnan \& de
Waal, 2003; Horowitz, 2012; Oberliessen et al., 2016; Range, Horn,
Viranyi \& Huber, 2009; Van Leeuwen, Zimmermann \& Davila Ross, 2011;
Takimoto, Kuroshima \& Fujita, 2010; Wascher \& Bugnyar, 2013; for
review, see Brosnan \& de Waal, 2014)\footnote{Although part of these
  negative reactions to receiving less may be focused on non-social
  expectations about expected rewards — that is, species might get
  upset merely at seeing a better possible reward (e.g., Brauer, Call,
  \& Tomasello, 2006, 2009) — there is evidence that several species
  show DIA selectively in social situations (Brosnan \& de Waal,
  2014).}. However, there is almost no evidence for advantageous
inequity aversion outside of human beings (with possibly the exception
of chimpanzees: Brosnan, Talbot, Ahlgren, Lambeth \& Schapiro,
2010). If both types of inequity aversion are focused on avoiding
inequity or unfairness, why would these species have one without the
other? Maybe, they care about fairness based in principles of equity,
but some other preference is preventing them from showing
dissatisfaction at advantageous inequity.  Alternatively, maybe these
negative reactions to receiving less are not rooted in a sense of
fairness, but instead in a sense of envy toward others’ better
results.

In addition to this evidence from comparative psychology, there is also
evidence from developmental psychology that demonstrates a person can
have DIA without AIA. Negative reactions to disadvantageous inequity
appear relatively early; 3- to 4-year-olds react negatively to
receiving less than others and make costly rejections of
disadvantageous unequal offers (Blake \& McAuliffe, 2011; LoBue,
Nishida, Chiong, DeLoache \& Haidt, 2011; Sheskin, Bloom \& Wynn, 2014;
Takagishi, Kameshima, Schug, Koizumi \& Yamagishi, 2010). Yet, it is
only at about the age of 7 or 8 that children show robust evidence of
AIA, and will sacrifice their own resources to avoid inequity between
themselves and others (Blake \& McAuliffe, 2011; Kogut, 2012; Shaw,
Choshen-Hillel \& Caruso, 2016; Shaw \& Olson, 2012; 2014). Why do
young children have one type of inequity aversion, but not the other?
Is their early DIA driven by concern for fairness, or rather with
social comparison rooted in envy? 

\subsection{Folk intuitions about inequity aversion and fairness}
The theoretical arguments and empirical findings reviewed here provide
some reason to question the connection between DIA and fairness. Here
we take no stand on the connection itself. Instead we suggest that
these findings prompt an interesting question about people’s folk
intuitions about fairness: do people think DIA or AIA in isolation
provide good evidence that an organism cares about fairness? For
example, if they heard about one of the non-human species mentioned
above, who show DIA but lack AIA, would they think that species is
driven by fairness concerns? We predict that the answer will be ‘no,’
that is, that lay people will assume that the organism in question is
not motivated by fairness. However, we predict that when an organism
has AIA, but lacks DIA, lay people will assume that the organism does
have a sense of fairness. We make these predictions because we expect
that lay people will intuitively understand that one needs a sense of
fairness to explain behavior rooted in AIA (why else would one be upset
at getting more than others), but DIA could be explained by either
fairness or envy. In the latter case, when they receive evidence that
the organism in question does not have AIA, they will take this as
evidence against a concern for fairness. We further predict that when
participants receive evidence that an organism is concerned with DIA,
but not AIA, they will assume that this organism is motivated by envy,
having ruled out the notion that this organism cares about fairness. 

We are interested in this question about people’s folk intuitions
because, as researchers, if we use terms like “fairness” in describing
lay people’s motivations, it would be informative to know if the words
we use are the same or radically different from lay conceptions. A
similar approach of understanding people’s folk intuitions about
psychological concepts has led to substantial progress in
understanding morality, intentional action, and free will (Knobe et
al., 2012; Knobe \& Nichols, 2013; Nahmias, Morris, Nadelhoffer \&
Turner, 2005; Nichols, 2004; Phillips \& Shaw, 2015). We hope to make
similar progress. If we were to find that DIA in isolation does not
accord with people’s intuitions about what it means to have a sense of
fairness, and continues to be referred to by researchers as tapping
into fairness, this will yield conceptual confusion. Of course, there
may be valid theoretical or empirical reasons to still consider DIA as
being about “fairness” even if this contradicts lay intuitions; we
return to this issue in the General Discussion.

\subsection{The Current Studies}

In the following studies, we attempt to assess people’s lay
intuitions about the putative relation between the two forms of
inequity aversion and fairness. We attempt to answer the question: is
having only one type of inequity aversion sufficient evidence for lay
people to conclude that an organism cares about fairness? Specifically,
we describe imaginary aliens who show evidence that they have either
only DIA (they get upset when they receive less than others, but not
more than others — i.e., just like non-human animals and young children)
or only AIA (they get upset when they receive more than others, but not
less than others). We then ask participants whether or not such a
species really cares about fairness. Referring to an alien species
allows us to minimize people’s projection of their knowledge about
animals or human beings onto our stimuli. Our main prediction was that
people would think that an organism that only had AIA would be said to
really care about fairness whereas an organism that only had DIA would
not be said to really care about fairness. We examine our prediction in
situations involving dissatisfaction with each type of inequity
aversion (Experiments 1 and 3) as well as situations involving costly
rejections based on DIA or AIA (Experiments 2 and 4). We further
predicted that people would think that a species with only DIA has envy
rather than fairness (Experiment 4).

\section{Experiment 1 }
The goal of the first experiment was to measure people’s folk intuitions
about a species that has only DIA or AIA. To examine participants’
beliefs, we told them about an alien species called the Knobies. We
told participants that Knobies do jobs like human beings and then
described the types of inequity to which this species responds.
Participants were randomly assigned to hear about Knobies who have DIA
but not AIA (DIA Condition) or who have AIA but not DIA (AIA
Condition). Participants were then asked whether or not they thought
this alien species truly cared about fairness. We predicted that people
would agree that the species in the AIA Condition cared about fairness
but would be less likely to agree that the species in the DIA Condition
cared about fairness. 

\subsection{Method}
\paragraph{Participants.} Participants were recruited online using the
Amazon Mechanical Turk website (Buhrmester, Kwang \& Gosling, 2011;
Horton, Rand \& Zeckhauser, 2011); participation was restricted to
participants from the United States. Participants in all experiments
earned 25 cents for completing the study (\~{}five minutes).
Participants who failed a comprehension test described below
(\textit{n} = 11) were excluded yielding a final sample of \textit{N} =
103 (77\% female, \textit{M} = 28.26 years old, \textit{SD} = 9.26) — the
pattern of results below remains the same if we include the
participants who failed the comprehension check. 

\begin{figure}[t]
\includegraphics[width=\columnwidth]{fig1.eps}
\caption*{Figure 1: Violin (density) plot of judgments about whether
  or not Knobies really care about fairness in Experiments 1 and 2, by
  condition. Experiment 1 involved evaluations of negative reactions
  to inequity, whereas Experiment 2 involved evaluations of costly
  rejections of inequity. The central dot shows the mean; the
  horizontal lines separate quartiles.}
\end{figure}

\paragraph{Procedures and Stimuli.} The task was presented online
using Qualtrics survey software. Participants read instructions
explaining that they would read a vignette and be asked to make a
judgment. They were also told they would be asked a comprehension
question. Participants were then randomly assigned to read one of the
following vignettes (in each set of brackets, the wording for the DIA
Condition appears first and the wording for the AIA Condition appears
second):
\begin{quote}
Imagine there is an alien species on another planet called Knobies.
Knobies work jobs very similar to human beings. Knobies get very upset
when they are paid [less/more] than someone else for doing the same
type and amount of work. However, they do not get upset when they are
paid [more/less] than others for doing the same type of and amount
work. Knobies claim that fairness is important to them.
\end{quote}
After the vignette, participants were all asked to rate their
disagreement or agreement with the following statement “Knobies really
care about fairness.” The scale ranged from 1 (strongly disagree) to 4
(neither agree nor disagree) to 7 (strongly agree). After making their
judgment, participants were taken to a new page without the vignette
and were asked the following comprehension question: “Which things make
the Knobies upset?” They could check as many of the following boxes:
“Getting paid less than others for doing the same work,” “getting paid
more than others for doing the same work,” or “neither of these upsets
the Knobies” Participants in the DIA Condition were expected to answer
“getting paid less” and participants in the AIA Condition, “getting
paid more.” Participants were then asked to explain why they made their
decision, and were finally asked to report their age and gender. 

\subsection[Results and Discussion]{Results and Discussion}
We first conducted an independent samples \textit{t}{}-test on the
fairness measure, which revealed that participants thought the Knobies
who had only AIA (\textit{M} = 5.32, \textit{SD} = 1.86) cared about
fairness more so than those who had only DIA (\textit{M} = 3.48,
\textit{SD }= 1.67), \textit{t}(101) = 5.28, \textit{p} {\textless}
.001, \textit{d} = 1.05 (Figure 1). This result demonstrates that
people think that AIA in isolation is much more indicative of concern
for fairness than DIA in isolation.

We additionally conducted one-sample \textit{t}{}-tests, with 4
specified as the midpoint of the scale. This one-sample
\textit{t}{}-test revealed that participants in the AIA Condition were
above the midpoint in their agreement that Knobies have a sense of
fairness, \textit{t}(52) = 4.23, \textit{p} {\textless} .001. This
indicates that, on average, people agree that a species who has only
AIA, but not DIA, does really care about fairness. Participants in the
DIA Condition were significantly below the midpoint in their agreement
that Knobies have a sense of fairness, \textit{t}(49) = 2.20,
\textit{p} = .032. This result suggests that, on average, people
disagree that a species that possesses DIA, but not AIA, really cares
about fairness. Taken together, these results support our hypothesis
that participants think that having AIA alone indicates that a species
cares about fairness, but having DIA alone does not seem to provide
positive evidence that the organism cares about fairness. Indeed,
participants on average disagree with the idea that DIA alone is about
fairness. 

\section{Experiment 2}
Experiment 1 provided evidence that people find negative reactions to
receiving more than others (experiencing AIA) to be sufficient evidence
for fairness while they do not find getting upset about having less
than others (experiencing DIA) to provide such sufficient evidence. One
could argue that this difference stems from the different costs
associated with the two types of inequity aversion. Specifically,
showing aversion to receiving more is likely to be costly, because it
might result in redistribution that is unfavorable for the self
(restoring equity by eliminating one’s advantage). Having an aversion
to receiving less than others is likely to have the opposite effect,
resulting in potential benefit to the self, rather than cost.
Therefore, people might conclude that AIA but not DIA is sufficient
evidence for fairness, because the former involves the actor
potentially paying some cost to fulfill that preference whereas the
latter does not. In line with this idea, we know that costly rejections
of any type of inequity are rare in non-human animals. For example,
recent research suggests that capuchins may often be reluctant to make
costly rejections, even to avoid disadvantageous inequality (McAuliffe
et al., 2015). Perhaps people think that DIA is sufficient evidence to
presume that a species has a sense of fairness only when it involves
the agent taking some cost to express this preference (e.g., a costly
rejection of inequity). 

In Experiment 2, we investigate the same question as in Experiment 1,
but this time using a costly rejection paradigm. In the DIA condition,
participants were told that Knobies make costly rejections only when
they receive less than others, but not when they receive more than
others. In the AIA condition, participants were told that Knobies make
costly rejections only when they receive more than others, but not
when they receive less than others. In both conditions, the cost of
rejection was the same. We ran this costly rejection paradigm to
investigate whether or not a costly rejection of DIA, in the absence
of AIA, would be regarded as sufficient evidence that an organism
cares about fairness. If so, then we should see a smaller difference
between the DIA and AIA conditions in Experiment 2 and we should see
participants agreeing that DIA is sufficient for a species to truly
care about fairness. However, we expected the same pattern of results
as in Experiment 1, with DIA alone not being seen as sufficient for
agreeing that an organism cares about fairness and AIA alone being
sufficient.

Note that we developed a costly rejection paradigm that was not the
ultimatum game in order to eliminate any animus toward the other
recipient for creating the distribution in question — in a normal
ultimatum game one can respond negatively to the inequity, but also to
the intentions of the other player (Falk, Fehr, \& Fischbacher, 2008).

\subsection{Method}
\paragraph{Participants.} We recruited participants the same way as in
Experiment 1. Participants who failed a comprehension test (\textit{n}
= 10) were excluded yielding a final sample of \textit{N} = 101 (60.4\%
female, \textit{M} = 32.33 years old, \textit{SD} = 12.44) — the pattern
of results below remains the same if we include the participants who
failed the comprehension check. 

\paragraph{Procedures and Stimuli.} Participants were presented with a
scenario like the one used in Experiment 1 except that the Knobies’
inequity aversion involved costly rejections. Note that the rejection
made by the species involved the same sacrifice of personal resources
in both conditions (\$2), but different total resources. (See the
Appendix for another version of this study where we control for the
total amount of resources sacrificed, rather than the personal amount
sacrificed, obtaining the same results).  Participants were randomly
assigned to one of the following conditions:
\begin{quote}
DIA

Imagine there is an alien species on another planet called Knobies.
Knobies work jobs very similar to human beings. When Knobies are
presented with a decision in which (A) they can get \$2 but someone
else will get \$8 or (B) they can make sure both people get \$0, they
choose (B) making sure both people get zero because that is fair.
However, when they are presented with a decision in which (A) they can
get \$2, but someone else will get \$1 or (B) they can make sure both
people get \$0, they choose (A) to make sure they get \$2 and the other
person gets \$1. Knobies claim that fairness is important to them. 
\end{quote}

\begin{quote}
AIA

Imagine there is an alien species on another planet called Knobies.
Knobies work jobs very similar to human beings. When Knobies are
presented with a decision in which (A) they can get \$2 but someone
else will get \$1 or (B) they can make sure both people get \$0, they
choose (B) to make sure both people get zero because that is fair.
However, when they are presented with a decision in which (A) they can
get \$2, but someone else will get \$8 or (B) they can make sure both
people get \$0, they choose (A) to make sure they get \$2 and the other
person gets \$8. Knobies claim that fairness is important to them. 
\end{quote}

Participants were then asked if they agreed or disagreed that “Knobies
really care about fairness.” After making their judgment, participants
were taken to a new page without the vignette and were asked the
following comprehension question: “According to the scenario you read,
when Knobies are presented with a decision in which they can get \$2
but someone else will get \$1 or they can make sure both people get
\$0, what will they decide?” Participants in the DIA Condition were
expected to answer, “Make sure they get \$2 and someone else gets \$1”
and in the AIA Condition, “Make sure both get \$0.” Participants were
then asked to explain why they made their decision and to report their
age and gender. 

\subsection{Results }
Participants thought the Knobies who had only AIA cared more about
fairness (\textit{M} = 5.08, \textit{SD} = 1.91) than the Knobies who
had only DIA (\textit{M} = 3.30, \textit{SD} = 1.81) \textit{t}(99) =
4.81, \textit{p} {\textless} .001, \textit{d} = 0.96 (Figure 1). We
replicate the finding from the previous experiment that people think
AIA is much better evidence that one cares about fairness than DIA,
despite the fact that the Knobies in the currents vignettes sacrificed
the same number of resources in the name of DIA and AIA in the
respective conditions. 

Additionally, a one-sample \textit{t}{}-test reveals that participants
in the AIA Condition responded at above the midpoint to the fairness
measure (4), \textit{t}(50) = 4.04, \textit{p} {\textless} .001,
indicating that they agreed that a species with only AIA cares about
fairness. Participants in the DIA Condition responded below the
midpoint on the fairness measure, \textit{t}(49) = 2.74, \textit{p} =
.009, indicating that participants disagree that a species with only
DIA cares about fairness. 

\subsection{Discussion}
Again, we found that AIA by itself is enough to evidence that a species
truly cares about fairness, while DIA by itself is not. Furthermore,
this experiment demonstrates that even costly rejections in the name of
DIA are not sufficient evidence that an organism cares about fairness
if that organism does not exhibit AIA.

\section{Experiment 3}
If our first two experiments do in fact tap into participants’
intuitions about DIA and AIA, then why would the idea that DIA is
sufficient for concluding that an organism has fairness seem somewhat
plausible? One reason for this discrepancy might be that people
misapply what they know about human beings to other species. People
know that human beings express both DIA and care about fairness, and
may therefore use this knowledge about human beings and assume that if
a species has DIA, then that species also has other related fairness
concerns (e.g., concerns with unfairness when they are third parties).
In Experiments 1 and 2 we explicitly specified that the species who had
DIA, lacked AIA. What would happen if we just told people about a
species with DIA without specifying that the species lacked AIA? 

We attempt to answer this question in Experiment 3 by either
specifying or not that a species lacks DIA or AIA. The Specified
conditions provide a replication of Experiment 1, in which we
specified that the species that had DIA lacked AIA and that the
species who had AIA lacked DIA. In the Non-Specified conditions,
participants are told only that Knobies have DIA or AIA and are not
told that they lack AIA or DIA. We expected that the specified
conditions would replicate the pattern of results of our previous
experiments, but that the non-specified conditions would indicate more
correspondence between fairness evaluations of DIA and AIA because the
participants would simply assume that a species that has one type of
inequity aversion would also have the other. Thus, when they hear that
an organism has DIA, they would assume it cares about fairness, unless
we specified that it lacks some fairness relevant concern.

\subsection{Method}
\paragraph{Participants.} Participants were recruited as before.
Participants who failed a comprehension test (\textit{n} = 15) were
excluded, yielding a final sample of \textit{N} = 208 (70\% female,
\textit{M} = 28.5 years old, \textit{SD} = 8.5) — all results below
remain the same if we include the participants who failed the
comprehension check. 

\paragraph{Procedures and Stimuli.} Participants were randomly
assigned to one condition in a 2 Inequity Type (DIA or AIA) x 2
Specification (Specified or Not Specified) between participants
design.  The scenarios for the DIA and AIA Specified conditions were
exact replications of the DIA and AIA conditions from Experiment
1. The scenarios in the DIA and AIA Not Specified conditions were
similar to the DIA and AIA conditions in Experiment 1, except that the
sentence “However, they do not get upset when they are paid
[more/less] than others for doing the same type of and amount work”
was deleted. That is, the information that made it clear that the
Knobies did not possess either AIA or DIA was excised. Participants
answered the same fairness measure from previous experiments in all
conditions: they were asked if they agreed or disagreed with the
statement “Knobies really care about fairness” (Fairness Measure). We
also added a new fairness measure: participants were asked if they
agreed or disagreed with the statement “Knobies likely get upset when
they see that others are paid unequally for equal work” (Fairness
Third Party Measure). This measure was added to assess people’s
perception of more objective fairness concerns in third party cases,
where they are not one of the potential recipients (e.g., Hook \&
Cook, 1979; Shaw \& Knobe, 2013). We assumed the new measure would
accord with the original fairness measure, but wanted to verify that
the two overlapped.

In all conditions, participants were asked a comprehension question
similar to Experiment 1, “According to the vignette you read, does
getting paid more or less than others make Knobies upset?” They then
could answer with a yes or a no. Participants were finally asked to
explain why they made their decision and to report their age and
gender. 

\subsection{Results}

\begin{figure}[t]
\includegraphics[width=\columnwidth]{fig2.eps}
\caption*{Figure 2: Violin plot of judgments about whether or not
  Knobies really care about fairness in Experiment 3, by condition. In
  the “specified” conditions we specified that species had one type of
  inequity aversion but lacked the other (e.g., in AIA specified, they
  had AIA but lacked DIA). In the “non-specified” conditions we did
  not specify that they lacked a type of inequity aversion.}
\end{figure}

\paragraph{Fairness Measure.} We first conducted a 2 Inequity type
(DIA or AIA) x 2 Specification (Specified or Not Specified) ANOVA on
the fairness measure, which revealed a main effect of Inequity Type,
such that participants in the DIA Conditions saw the Knobies as less
fair (\textit{M} = 4.83, \textit{SD} = 2.21) than participants in the
AIA Conditions (\textit{M} = 5.81, \textit{SD} = 1.69), \textit{F}(1,204) = 19.79, \textit{p} {\textless} .001, $\eta_p^2$ = .088, which
replicates our previous results. We also found a main effect of
Specification, \textit{F}(1,204) = 83.60, \textit{p} {\textless}
.001, $\eta_p^2$ = .291. This result indicates that participants
thought the Knobies were less fair when we specified they lacked one
aspect of inequity (\textit{M} = 4.25, \textit{SD} = 2.26) than when
we did not specify this (\textit{M} = 6.32, \textit{SD} =
1.06). However, there was also an Inequity Type by Specification
interaction, \textit{F}(1,204) = 21.06, \textit{p} {\textless} .001,
$\eta_p^2$ = .094 (Figure 2).

To follow up on this interaction, we conducted planned contrast
\textit{t}{}-tests that compared the DIA Specified Condition to our
other three conditions. We found that participants rated the fairness
of the Knobies significantly lower in the DIA Specified Condition
(\textit{M} = 3.27, \textit{SD} = 2.06) than in the DIA Not Specified
Condition (\textit{M} = 6.33, \textit{SD} = 0.97, \textit{t}(72.02) =
9.74, \textit{p} {\textless} .001), and AIA Specified Condition
(\textit{M} = 5.29, \textit{SD} = 2.0, \textit{t}(99) = 4.99,
\textit{p} {\textless} .001). Participants also rated fairness lower in
the AIA Specified Condition than in the AIA Not Specified Condition
(\textit{M} = 6.30, \textit{SD} = 1.15, \textit{t}(75.47) = 3.11,
\textit{p} = .003). The fact that participants thought that a species
who had AIA but lacked DIA cared less about fairness than a species
with AIA, with no lack of DIA specified, indicates that people think
that DIA does provide some evidence for a concern with fairness. There
was no difference between the ratings of fairness in the DIA Not
Specified and the AIA Not Specified conditions (\textit{t}(105) =
0.153, \textit{p} = .88). That is, when we did not specify that the
organism lacked one of the types on inequity aversion, there were no
longer any differences between the fairness ratings for the organism
that displayed DIA and the organism that displayed AIA. 

We additionally conducted one-sample \textit{t}{}-tests on the fairness
measures, with 4 specified as the midpoint of the scale (where
participants neither agreed nor disagreed). Participants responded at
above the midpoint on the fairness measure in the AIA Specified
(\textit{t}(48) = 4.50, \textit{p} {\textless} .001), AIA Not
Specified (\textit{t}(52) = 14.53, \textit{p} {\textless} .001) and DIA
Not Specified Condition (\textit{t}(53) = 17.65, \textit{p} {\textless}
.001). In the DIA Specified Condition, participants responded at below
the midpoint on the fairness measure (\textit{t}(51) = 2.56, \textit{p}
= .013). We again replicate the fact that people, on average, disagree
with the notion that DIA alone is sufficient evidence for fairness. 

\renewcommand{\baselinestretch}{1.05} \large\normalsize % for fixing spaces

\paragraph{Fairness Third Party Measure.} In line with our
expectations, the results from the Fairness Third Party Measure showed
the same pattern as we found for the Fairness Measure. The two
measures were highly correlated \textit{r}(208) = .64, \textit{p}
{\textless} .001. We conducted a 2 inequity type (DIA or AIA) by 2
specification (Specified or Not Specified) ANOVA on the Fairness Third
Party Measure (in which participants were asked to make predictions
about whether the Knobies cared about fairness when they were third
parties), which revealed a main effect of specification,
\textit{F}(1,204) = 53.62, \textit{p} {\textless} .001, $\eta_p^2$ =
.208. This result indicates that participants thought the species was
less likely to show third party concerns with fairness when we
specified they lacked one aspect of inequity aversion (\textit{M} =
4.65, \textit{SD} = 1.80) than when we did not specify this
(\textit{M} = 6.06, \textit{SD} = 1.04). We also found a main effect
of condition, such that participants in the DIA Conditions were
thought to have less of a third party fairness concern (\textit{M} =
4.94, \textit{SD} = 1.84) than participants in the AIA conditions
(\textit{M} = 5.81, \textit{SD} = 1.21), \textit{F}(1,204) = 22.12,
\textit{p} {\textless} .001, $\eta_p^2$ = .098.  However, this main
effect was primarily driven by a large Inequity by Specification
interaction, \textit{F}(1,204) = 13.73, \textit{p} {\textless} .001,
$\eta_p^2$ = .063.

To follow up on this interaction we conducted planned contrast
\textit{t}{}-tests that compared the DIA Specified Condition to our
other three conditions. We found that participants rated the fairness
significantly lower in this condition (\textit{M} = 3.88, \textit{SD} =
1.83) than in the DIA Not Specified Condition (\textit{M} = 5.96,
\textit{SD} = 1.14, \textit{t}(85.16) = 6.97, \textit{p} {\textless}
.001) and AIA Specified (\textit{M} = 5.47, \textit{SD} = 1.37
\textit{t}(94.24) = 4.94, \textit{p} {\textless} .001). Participants
also rated fairness lower in the AIA Specified Condition than in the
AIA Not Specified Condition (\textit{t}(83.47) = 2.92, \textit{p} =
.005). This result indicates that participants found DIA as providing
some evidence for a concern with fairness, because when they were told
that a species had AIA but lacked DIA they thought they were a bit less
likely to care about third party fairness considerations than when they
were told the species had AIA, but were not told that it lacked DIA.
There was no difference between DIA Not Specified and AIA Not Specified
conditions, (\textit{t}(105) = 0.93, \textit{p} = .35).

We additionally conducted one-sample \textit{t}{}-tests on the Fairness
Third Party Measure, with 4 specified as the midpoint of the scale
(where participants neither agreed nor disagreed). Participants
responded at above the midpoint on the Fairness Third Party measure in
the AIA Specified (\textit{t}(48) = 7.50, \textit{p} {\textless} .001),
AIA Not Specified (\textit{t}(52) = 16.87, \textit{p} {\textless} .001)
and DIA Not Specified conditions (\textit{t}(53) = 12.56, \textit{p}
{\textless} .001). Participants in the DIA Specified Condition were not
different from the midpoint (\textit{t}(51) = .45, \textit{p} = .65),
suggesting that participants do not think DIA is sufficient evidence to
think a species will show third party fairness concerns. Thus, we see
that our findings with the fairness measure are replicated with the
Fairness Third Party measure. 

\renewcommand{\baselinestretch}{1.00} \large\normalsize

\subsection{Discussion}
The results of Study 3 suggest that, in the absence of information
regarding a species’ lack of AIA or DIA, people do think that both DIA
and AIA signal that a species cares about fairness. However, this
seems to be happening because people infer that, when a species has
DIA, then it will have corresponding concerns with
fairness. Specifically, our third party inequity aversion measure
demonstrated that people thought that the species will become upset
when others are paid unequally (i.e., evidence third party fairness
concerns) if they are told only that the species has DIA as long as we
did not specify that the species with DIA lacked AIA. When most people
hear about a new finding in non-human animals showing DIA they are
basically in this DIA Not Specified Condition — the findings that are
often reported and emphasized are that the species has DIA and there
is often less mention of (or less conclusive proof for the fact) that
the species lacks AIA.  Thus, it is not surprising that people think
that these findings are about fairness. However, as we noted in the
introduction, multiple lines of research have indicated that there are
several non-human animals that possess DIA, but have no AIA reaction
(for a review, see Brosnan \& de Waal, 2014). Of course, the absence
of evidence is not the evidence of absence and researchers may
continue to look for evidence of AIA in non-human animals. However,
our results indicate that many lay people will simply assume that such
species with DIA have related fairness concerns until they are
provided with evidence that the species lacks AIA.

We also found that participants think that a species that has AIA but
lacks DIA (i.e., AIA Specified Condition) is less concerned with
fairness than a species that has AIA, but where we have not specified a
lack of DIA. Because fairness concerns are often tied to concerns with
equity (i.e., Adams, 1965), it seems plausible that telling
participants that someone lacks an equity concern (either DIA or AIA)
should make them think that organism is less concerned with fairness
than if they think that the organism has both concerns. It is notable
that AIA by itself still seems sufficient for many to agree that the
organism is motivated by fairness whereas DIA by itself is not. 

\section{Experiment 4}
In Experiment 4, we attempt to replicate our findings from Experiment 3
using a different paradigm (costly rejection paradigm from Experiment
2) and, importantly, answer a new question: if DIA alone is not
regarded as being really about fairness, then what do people think is
driving Knobies’ reactions when a species has DIA, but lacks AIA?
According to our explanation above, in these cases participants may
infer that people’s reactions are actually driven by envy based in
social comparison (Festinger, 1954). We know that envy exists in many
facets of human life. Therefore, when people respond negatively to
inequality that disadvantage themselves, this reaction is
over-determined — it could be fairness that is driving their judgment,
but it could just as easily be envy (Nichols, 2010; Shaw \& Olson,
2012). 

Therefore, we predict that when we specify that a species in question
does not show AIA, but does show DIA, participants will no longer
think the species has a sense of fairness and will correspondingly
view DIA as evidence for envy. We test this prediction in Experiment 4
using a design similar to the previous experiments, except we added a
measure of envy. We expected that participants would think the Knobies
lack fairness and that their behavior is better explained by envy than
fairness when they are said to have DIA, but lack AIA.

\subsection{Method}
\paragraph{Participants.} Participants were recruited as in previous
experiments and included 203 participants (68\% female, \textit{M} =
29.5 years old, \textit{SD }= 8.5). We decided before running this
study that we would now include all participants in this study to avoid
any selection issues (only including the most attentive participants,
as we did in the previous studies). The exclusion of the participants
who failed the comprehension check does not change the reported pattern
of results.

\begin{figure*}[t]
\includegraphics[width=\columnwidth]{fig3a.eps}\hspace{5mm}%
\includegraphics[width=\columnwidth]{fig3b.eps}
\caption*{Figure 3: Violin plots of judgments about whether or not
  Knobies have a sense of fairness, and whether they feel envy, in
  Experiment 4, by measure and condition. In the “specified”
  conditions we specified that species had one type of inequity
  aversion but lacked the other (e.g., in AIA specified, they had AIA
  but lacked DIA). In the non-specified conditions we did not specify
  that they lacked a type of inequity aversion.}
\end{figure*}

\paragraph{Procedures and Stimuli.} Participants were randomly
assigned to a condition in a 2 Inequity Type (DIA or AIA) x 2
Specification (Specified or Not Specified) between-participants design.
The scenarios for the DIA and AIA Specified conditions were exact
replications of the DIA and AIA conditions from Experiment 2 — they thus
utilized the costly rejection paradigm. The scenarios for the DIA and
AIA Not Specified conditions were also the same, except that we deleted
the sentence specifying that the Knobies did not have the other type of
inequity aversion. For all conditions, we added an additional measure
of envy. In addition to being asked if they agreed or disagreed with
the statement “Knobies really care about fairness” (fairness measure)
they were also asked if they agreed or disagreed with the statement
“Knobies have a sense of envy” (envy measure). The scales for both
measures ranged from 1 (strongly disagree) to 7 (strongly agree).
Because the Fairness Measure and Fairness Third Party Measure from
Experiment 3 were correlated and were similarly affected by our
manipulations, we dropped the Fairness Third Party Measure in
Experiment 4.

\subsection{Results} 
\paragraph{Fairness Measure.} We first conducted a 2 Inequity type
(DIA or AIA) x 2-Specification (Specified or Not Specified) ANOVA on
the fairness measure, which revealed a main effect of Inequity Type,
such that participants in the DIA Conditions were seen as less fair
(\textit{M} = 4.44, \textit{SD} = 1.99) than participants in the AIA
Conditions (\textit{M} = 5.19, \textit{SD} = 1.86), \textit{F}(1,199) = 8.57, \textit{p} = .004, $\eta_p^2$ = .041, again replicating
our previous effects. We also found a main effect of Specification,
\textit{F}(1,199) = 9.16, \textit{p} = .003, $\eta_p^2$ = .044. This
result indicates that participants thought the species was less
concerned for fairness when we specified that it lacked one aspect of
inequity (\textit{M} = 4.41, \textit{SD} = 2.03) than when we did not
specify this (\textit{M} = 5.21, \textit{SD} = 1.82). However, this
main effect was primarily driven by an Inequity Type by Specification
interaction, \textit{F}(1,199) = 17.91, \textit{p} {\textless} .001,
$\eta_p^2$ = .083 (Figure 3). To follow up on this interaction, we
conducted planned contrast \textit{t}{}-tests that compared the DIA
Specified Condition to the other three conditions. We found that
participants rated the fairness significantly lower in this condition
(\textit{M} = 3.52, \textit{SD} = 1.94) than in the DIA Not Specified
Condition (\textit{M} = 5.37, \textit{SD} = 1.59, \textit{t}(97.94) =
5.32, \textit{p} {\textless} .001), AIA Not Specified (\textit{M} =
5.04, \textit{SD} = 2.03, \textit{t}(101) = 3.89, \textit{p}
{\textless} .001), and AIA Specified (\textit{M} = 5.35, \textit{SD} =
1.68, \textit{t}(99) = 5.06, \textit{p} {\textless} .001). There were
no differences between the other conditions, all \textit{p}’s
{\textgreater} .41. Note that here we did not replicate the difference
between the AIA Specified and AIA Not Specified Conditions that was
found in Experiment 3. This could be because of the different
paradigms used in Experiment 3 and 4. Still, we believe that receiving
some evidence that an organism does not care about equity (even
disadvantageous inequity) should slightly reduce people’s attributions
of fairness.

We additionally conducted one-sample \textit{t}{}-tests on the fairness
measure, with 4 being the midpoint of the scale (where participants
neither agreed nor disagreed). Participants responded at above the
midpoint on the fairness measure in the AIA Specified (\textit{t}(48) =
5.62, \textit{p} {\textless} .001), AIA Not Specified (\textit{t}(50) =
3.66, \textit{p} = .001) and DIA Not Specified Condition
(\textit{t}(48) = 6.17, \textit{p} {\textless} .001). In the DIA
Specified Condition, participants were marginally below the midpoint on
the fairness measure (\textit{t}(51) = 1.79, \textit{p} = .08). We
again replicate the finding that, on average, people thought that AIA
alone indicated that a species would care about fairness, but did not
think this was true for a species who only possessed DIA. 

\paragraph{Envy Measure.} Next, we conducted a 2 Inequity Type (DIA or
AIA) by 2 Specification (Specified or Not Specified) ANOVA on the Envy
Measure. There was a main effect of Inequity Type, such that Knobies
in the DIA Conditions were thought to have more envy (\textit{M} =
4.36, \textit{SD} = 1.73) than Knobies in the AIA conditions
(\textit{M} = 2.96, 1.74), \textit{F}(1,204) = 41.03, \textit{p}
{\textless} .001, $\eta_p^2$ = .171. There was no main effect of
Specification, \textit{F}(1,204) = 1.54, \textit{p} = .22,
$\eta_p^2$ = .008. There was also an Inequity Type by Specification
interaction, \textit{F}(1,204) = 45.72, \textit{p} {\textless} .001,
$\eta_p^2$ = .187 (Figure 3).

\begin{table*}[t]\centering
\caption*{Table 1: Summary of participants’ fairness evaluations in
  the DIA and AIA specified conditions from Experiments 1--4 along
  with the scenario type used in each study and any additional
  measures or conditions. All t values are significant at $p<.001$.}
\begin{tabular}{lC{1in}cccc@{\quad}L{1.75in}}\toprule
Exp & Scenario Type & DIA Specified & AIA Specified & t & d & Conditions; Other Measures \\\midrule
Exp 1 & Reactions to inequality & 3.48 (1.67) & 5.32 (1.86) & 5.28 & 1.05 & Only Specified Conditions \\
Exp 2 & Rejections of inequality & 3.30 (1.81) & 5.08 (1.91) & 4.81 & 0.96 & Only Specified Conditions \\
Exp 3 & Reaction to inequality & 3.27 (2.06) & 5.29 (2.00) & 4.99 & 0.99 & Specified and Non-Specified;\newline Third Party Fairness Measure \\
Exp 4 & Rejections of inequality & 3.52 (1.94) & 5.35 (1.68) & 5.06 & 1.00 & Specified and Non-Specified;\newline Envy Measure \\\bottomrule
\end{tabular}
\end{table*}

To follow up on this interaction, we conducted planned contrast
\textit{t}{}-tests that compared the DIA Specified Condition to the
other three conditions. We found that participants rated the envy
significantly higher in this condition (\textit{M} = 4.96, \textit{SD}
= 1.66) than in the DIA Not Specified Condition (\textit{M} = 3.75,
\textit{SD} = 1.60, \textit{t}(101) = 3.79, \textit{p} {\textless}
.001), AIA Not Specified (\textit{M} = 3.82, \textit{SD} = 1.77 ,
\textit{t}(101) = 3.42, \textit{p} {\textless} .001), and AIA Specified (\textit{M} =
2.06, \textit{SD} = 1.16, \textit{t}(93.19) = 10.48, \textit{p}
{\textless} .001). Participants rated envy lower in the AIA Specified
Condition than in the DIA Not Specified Condition (\textit{t}(89.72) =
5.90, \textit{p} {\textless} .001) and the AIA Not Specified Condition
(t(86.62) = 5.90, p {\textless} .001). There was no difference between
DIA Not Specified and AIA Not Specified, (\textit{t}(100) = 0.23,
\textit{p} = 0.82). These results indicate participants thought that
the Knobies cared more about envy in the DIA Specified Condition than
in the other conditions and that they thought that the Knobies cared
less about envy in the AIA Specified Condition than in all other
conditions.

We also conducted one-sample \textit{t}{}-tests on the envy measure,
where 4 specified the midpoint of the scale. Participants responded at
below the midpoint on the envy measure in the AIA Specified Condition
(\textit{t}(48) = 11.68, \textit{p} {\textless} .001). That is,
participants disagreed that a species that had AIA, but lacked DIA, had
envy. Participants were not different from the midpoint in the AIA Not
Specified Condition (\textit{t}(50) = 0.71, \textit{p} = .48) or the
DIA Not Specified Condition (\textit{t}(50) = 1.10, \textit{p} = .28).
Importantly, in the DIA Specified Condition, participants were above
the midpoint point on the envy measure (\textit{t}(51) = 4.34,
\textit{p} {\textless} .001).

\paragraph{Envy-fairness correlation.} The ratings of fairness and envy
were strongly negatively correlated with one another across all
conditions \textit{r}(203) = --.423, \textit{p} {\textless} .001,
meaning that the more participants attributed fairness, the less likely
they were to think that the organism had envy. This correlation held
even when partialing out inequity type, specification, and their
interaction, \textit{r}(198) = --0.33, \textit{p} {\textless} .001.
Thus, even within condition, participants who thought the species was
more motivated by envy were less likely to think that they were
motivated by fairness. 

\subsection{Discussion }
In Experiment 4, we replicated most of our findings from Experiment 3
using a different scenario (costly rejections), finding again that
participants think that DIA by itself is not sufficient evidence for
fairness when you make it clear that the species lacks AIA (though see
our discussion about AIA Specified and AIA Not Specified). Indeed,
Table 1 summarizes this effect across the four experiments.  However,
when participants see evidence of DIA and are not told that the
species lacks AIA, they do assume the species has a sense of
fairness. In all cases, participants think that AIA by itself is
sufficient evidence for fairness. We also extended our results and
found that people form inferences about envy. Participants thought
that a species was “really envious” (at above the midpoint on envy)
only when it was specified that the species had DIA, but lacked
AIA. These results suggest that when a species lacks AIA and has DIA,
participants think this species is better described as envious rather
than fair. We found that participants strongly disagreed that a
species who had AIA but lacked DIA had a sense of envy.

One possible explanation of the pattern of results in the fairness and
envy conditions is causal discounting (Morris \& Larrick, 1995):
participants judge DIA to not be motived by fairness, they then give
more weight to another factor that could motivate that behavior —
envy, or vice versa. While this effect is certainly possible, our
findings at least suggest that people do not conceive of the
relationship between fairness and envy as completely hydraulic — e.g.,
a decrease in envy need not correspond to an increase in
fairness. Specifically, participants in the AIA Specified, AIA Not
Specified, and DIA Not Specified conditions all gave similar fairness
evaluations, but they gave different evaluations of envy. While AIA
and DIA Not Specified were about at the midpoint in attributions of
envy, AIA Specified was significantly below this midpoint. This fact
demonstrates that participants did not balance their envy attributions
and their fairness evaluations completely.

The envy results are also informative because they help us deal with
an alternative account of participants’ responses to the fairness
measure.  One possible concern is that, when participants were asked
whether a species that exhibited DIA in the absence of AIA “really
cared about fairness,” they said that the species did not care about
fairness not because they thought it did not care about fairness at
all, but because it was not the most ideal form of fairness. For
example, Japanese people might encounter sushi at an American
supermarket and say: “That is not sushi!” They do not really mean that
the product on sale is not sushi, but that it does not fit their
minimal threshold for what they think sushi should be. The envy data
provide some reason to doubt such an account. Indeed, in Experiment 4
we found that not only do participants deny that DIA alone is
motivated by fairness, they also think it is motivated by envy. An
account based on people not wanting to endorse a non-ideal form of
fairness does not make this predication. Indeed, the person who would
deny that the sushi in the supermarket is sushi would presumably not
agree it is a taco, or any other type of food. Thus, we believe that
participants actually thought that DIA by itself does not, on its own,
correspond to fairness.

\section{General Discussion}
The results of Experiments 1--4 provide support for our prediction
that advantageous inequity aversion (AIA), but not disadvantageous
inequity aversion (DIA), meets people’s common sense intuitions about
what it means to have a concern with fairness. Our results demonstrate
that when participants imagine an alien species that behaves
like some non-human animals (and young children), reacting negatively to
disadvantageous but not to advantageous allocations, they do not view
such a species as having a sense of fairness (Experiment 1 and
3). They do, however, think that a species cares about fairness if it
is concerned with advantageous, but not with disadvantageous
allocations.  We replicated this pattern of results in a situation
where participants were told about a species that engaged in costly
rejections of only disadvantageous or advantageous inequity. We found
that participants disagreed, on average, that a species that responded
negatively only to disadvantageous inequity had a sense of fairness,
yet they agreed that a species that only reacted negatively to
advantageous inequity had a sense of fairness.

Our findings may also explain why people often find aversion to
disadvantageous inequity to be convincing and sufficient evidence for
fairness: when we told participants in Experiments 3 and 4 about a
species with DIA and did not make it clear that this species did not
have advantageous inequity aversion, participants assumed that the
species did care about fairness. We also found that, while
disadvantageous inequity is not necessary or sufficient for
participants to agree that an organism cares about fairness, it is not
irrelevant to fairness concerns: participants were a bit less likely
to agree that a species cared about fairness when they were told that
the organism did not respond negatively to disadvantageous inequity
(in Experiment 3, but not in Experiment 4). Finally, we showed that,
whereas participants did not interpret having DIA alone as sufficient
evidence for concern about fairness, they did interpret this as
sufficient evidence for envy (Experiment 4).

Our results suggest that what the literature refers to as DIA does not
accord with people’s folk intuitions about what it means to actually
care about fairness. Canonical evidence used to demonstrate a concern
with fairness (i.e., the prominent example of costly rejections as in
the ultimatum game), does not, by itself, fully capture people’s idea
of what it means to care about fairness. These results on people’s lay
intuitions of course do not mean that DIA is never motivated by
concerns with fairness. However, they do indicate that people are much
less likely to see DIA alone as motivated by fairness. 

\subsection{The relationship between folk intuitions about fairness and
research on fairness }
Of course, people’s intuitions are not reason enough to stop referring
to DIA as being connected to fairness. Although we think there are
reasons that researchers should be interested in knowing whether or not
DIA corresponds with people’s lay intuitions, the researchers are more
interested in understanding how these putative concerns influence
people’s behavior and judgments, not if they happen to correspond to
people’s lay intuitions. Indeed, DIA should still be conceptualized as
part of the fairness concept, along with AIA, if there are theoretical
reasons or empirical justifications for considering them as one unified
system.

However, there are pieces of evidence in the literature indicating
that lay people’s intuitions may be on the mark in this case – AIA and
DIA seem to involve different psychological mechanisms.  Indeed, the
two types of inequity aversion have different developmental
trajectories (Blake \& McAuliffe, 2011; LoBue et al.\ 2011; Shaw et
al., 2016; Sheskin et al., 2014; Takimoto, et al., 2010) and are
differentially prevalent across cultures (Blake et al., 2015). The two
respond differently to observational cues; people are more likely to
reject an allocation that gives them more than others (AIA), when they
are being publicly watched; yet their likelihood to reject an
allocation that gives them less than others (DIA) is not affected by
being watched (Bolton \& Zwick, 1995; Franzen \& Pointner, 2012;
Hoffman, McCabe, Shachat \& Smith, 1994; Hoffman, McCabe \& Smith,
1996; Kurzban, 2001; Shaw et al., 2014). Further, AIA and DIA respond
differently to competition; when people compete with others, they want
to have more than others (show less AIA) and do not want to have less
than them (they show more DIA) (Fershtman, Gneezy \& List, 2012; Shaw,
DeScioli \& Olson, 2012). Finally, the two respond differently to
agency; when people have a sense of agency in creating an allocation,
they are more likely to show aversion to having more than others
(AIA), but less likely to show aversion to having less than others
(DIA) (Andreoni \& Bernheim, 2009; Choshen-Hillel et al., 2015;
Choshen-Hillel, Shaw \& Caruso, 2017; Choshen-Hillel \& Yaniv, 2011,
2012; Shaw et al., 2016). Thus, taken together, existent findings from
the literature provide theoretical reasons for believing that DIA and
AIA may actually not be part of one unified concern with “equity” or
fairness.

Folk intuitions in these experiments accord with a recent argument
proposed by Shaw and Olson (2012), whereby DIA can be motivated by
social comparison and envy, rather than a concern with fairness. The
reason is that equity is usually the best thing that one can hope for
when one is disadvantaged, and so one settles for equity despite that
fact that one might actually be happier if one could have more than
another person. That is, although DIA or social comparison often leads
to “Keeping up with the Joneses,” people may be even happier to be way
ahead of the Joneses rather than equal to them (Frank, 1985). Thus,
many seemingly negative reactions to inequity or unfairness may be
motivated by simple envy. Our results demonstrate that this
theoretical conception of DIA appears to accord with lay people’s
notions of fairness, providing evidence that there may be some face
validity to such an account. What does this theoretical account of DIA
predict that would not be predicted by a view of DIA that imagines it
to be rooted in concerns with equity or fairness?

If disadvantageous inequity aversion is often the result of social
comparison or envy, then it should be possible to find that
individuals will sometimes pay costs to make sure they have relatively
more than others, even when this increases inequity. Indeed, people
appear to be “equity averse” in many domains — striving to make sure
that they have more than others (Frank, 1985; Loewenstein et al.,
1989; Shaw et al., 2012; Sheskin et al., 2014; Veblen, 1922). If such
negative reactions to having less than others were really focused only
on a concern with equity per se, then one should not observe such
results.

A related final question is how human beings developed, either
ontogenetically or phylogenetically, AIA and related third party
fairness concerns. Specifically, is DIA an essential ingredient in
developing AIA? Although we find that people will attribute fairness
to an organism that lacks DIA, but has AIA, DIA might actually be a
necessary step in the development of AIA or third party fairness
concerns. Some authors have argued that DIA might be a pre-requisite
for developing other fairness concerns (e.g., Brosnan,
2013).\footnote{This does not mean that DIA is a simple form of
  fairness, a “proto-fairness concern” or a “1\textsuperscript{st}
  order fairness concern” (Brosnan \& de Waal, 2014). Indeed, having
  eyes may be a pre-requisite for developing color vision, but that
  does not make eyes a proto-color vision or “1\textsuperscript{st}
  order color vision”. Indeed, the majority of species that have eyes
  do not have color vision. Similarly, the fact that most species who
  have DIA lack AIA, may suggest that DIA is a prerequisite for later
  developing fairness concerns, but that does not make DIA itself a
  fairness concern.} Indeed, it might be telling that no
known species have AIA but not DIA. DIA might be an important
stepping stone to reaching AIA, especially if the distributor in
question understands that others experience DIA. That is, developing
AIA may require that others react negatively to DIA and that the
distributor has the perspective taking capabilities to understand
these others will react negatively (Shaw, 2013, 2016; Takagishi, et
al., 2010). This idea is consistent with two broad accounts of how AIA
develops. One account is that people experience AIA and are motivated
to be fair to avoid hurting others’ feelings (e.g., Adams, 1965).
Another account is that people experience AIA in order to avoid
condemnation from others (Andreoni, \& Bernheim, 2009) for being
partial (Shaw, 2013). Both of these accounts suggest that AIA will be
more likely to develop when recipients react negatively to inequity
and the distributor appreciates this fact.

\subsection{Conclusion}
We have demonstrated that DIA, without AIA, is not regarded by lay
people as being motived by fairness and instead appears to be more
related to envy and social comparison. These lay intuitions appear
consistent with some recent empirical findings that suggest that DIA
and AIA may be separate psychological entities, with different
behavioral, comparative and developmental trajectories. We suggest that
the literature on fairness might benefit from a careful consideration
of the relations of DIA, AIA and fairness. 

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% \break
\end{hangparas}

\bigskip\bigskip

\section*{Appendix: Supplemental study}

Our supplemental study replicates Experiment 2 in a situation where
the total number of resources distributed is equal (\$10) — our
Experiment 2 equated the amount sacrificed by the decision maker,
which meant that the total number of resources differed between
conditions.

\subsection{Method}

\paragraph{Participants.}
We recruited participants the same way as in Experiment 1.
Participants who failed a comprehension test (\textit{n} = 12) were
excluded yielding a final sample of \textit{N} = 100 (58\% female,
\textit{M} = 32 years old, \textit{SD} = 11.5) — the pattern of results
remain the same if we include the participants who failed the
comprehension check. 

\paragraph{Procedures and Stimuli.} Participants were presented with a
scenario similar to the one used in Experiment 1 except that now the
Knobies’ inequity aversion involved costly rejections. Participants
were randomly assigned to one of the following conditions:

\begin{quote}
DIA 

Imagine there is an alien species on another planet called Knobies.
Knobies work jobs very similar to human beings. When Knobies are
presented with a decision in which (A) they can get \$1 but someone
else will get \$9 or (B) they can make sure both people get \$0, they
choose (B) making sure both people get zero because that is fair.
However, when they are presented with a decision in which (A) they can
get \$9, but someone else will get \$1 or (B) they can make sure both
people get \$0, they choose (A) to make sure they get \$9 and the other
person gets \$1. Knobies claim that fairness is important to them. 
\end{quote}

\begin{quote}
AIA 

Imagine there is an alien species on another planet called Knobies.
Knobies work jobs very similar to human beings. When Knobies are
presented with a decision in which (A) they can get \$9 but someone
else will get \$1 or (B) they can make sure both people get \$0, they
choose (B) to make sure both people get zero because that is fair.
However, when they are presented with a decision in which (A) they can
get \$1, but someone else will get \$9 or (B) they can make sure both
people get \$0, they choose (A) to make sure they get \$1 and the other
person gets \$9. Knobies claim that fairness is important to them. 
\end{quote}

Participants were then asked if they agreed or disagreed that “Knobies
really care about fairness,” using the same scale from Experiment 1.
After making their judgment, participants were taken to a new page
without the vignette and were asked the following comprehension
question: “According to the scenario you read, when Knobies are
presented with a decision in which they can get \$9 but someone else
will get \$1 or they can make sure both people get \$0, what will they
decide?” Participants in the DIA Condition should have answered “Make
sure they get \$9 and someone else gets \$1” and participants in the
AIA Condition should have answered, “Make sure both get \$0.”
Participants were then asked to explain why they made their decision
and to report their age and gender. 

\subsection{Results and Discussion}

Participants thought the Knobies who had only AIA (\textit{M} = 4.88,
\textit{SD} = 1.83) cared about fairness more so than those who had
only DIA (\textit{M} = 2.72, \textit{SD} = 1.65), \textit{t}(98) =
6.20, \textit{p} {\textless} .001, \textit{d} = 1.24.

Participants in the AIA Condition responded at above the midpoint (4)
on the fairness measure, as indicated by a one-sample
\textit{t}{}-test, \textit{ t}(49) = 3.41, \textit{p} = .001. As in
Experiment 1, we find that AIA alone is sufficient evidence that a
species cares about fairness. Participants in the DIA Condition
responded below the midpoint (4) on the fairness measure,
\textit{t}(49) = 5.47, \textit{p} {\textless} .001. Thus we again
replicate the finding that people tend to disagree with the notion
that DIA alone evidences fairness.

These results, taken together with the results from Experiment 2,
suggest that costly rejections of disadvantageous inequity are not
sufficient for people to think that a species has a sense of
fairness.  Instead, people only thought the Knobies had a sense of
fairness when they made costly rejections of advantageous inequity.

\end{document}
