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\title{The value of vulnerability: The transformative capacity of risky trust}

\author{
Luigino Bruni\thanks{Dipartimento di Scienze economiche, politiche e delle lingue
moderne, LUMSA, Via Pompeo Magno 22, 00192 Roma, Italy. E-mail:
l.bruni@lumsa.i.}
\and
Fabio Tufano\thanks{CeDEx, School of Economics, University of
Nottingham, University Park, Nottingham NG7 2RD, UK. E-mail:
fabio.tufano@nottingham.ac.uk.}
}

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\newcommand{\jhead}{Judgment and Decision Making, Vol.~12, No.~4}
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  \jdate \hfill Effect of trustor vulnerability on trustworthiness \qquad}
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\begin{onecolabstract}
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In an experimental gift-exchange game, we explore the
transformative capacity of vulnerable trust, which we define as
trusting untrustworthy players when their untrustworthiness is common
knowledge between co-players. In our experiment, there are two
treatments: the “Information” treatment and the “No-Information”
treatment in which we respectively disclose or not information about
trustees’ trustworthiness. Our laboratory evidence consistently
supports the transformative capacity of trustors’ vulnerable trust,
which generates higher transfers, more trustworthiness and increased
reciprocity by untrustworthy trustees.

\smallskip
\noindent
Keywords: experiment, gift-exchange game, organization, trust, vulnerability
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{\renewcommand{\thefootnote}{}

\footnotetext{

  Part of the research was done when Bruni and Tufano were at the
  University of Milano-Bicocca (Italy). The authors thank Irene
  Brundia for help and suggestions at the early stage of the design,
  and for lab assistance. We thank also Luca Stanca for his inputs and
  support especially in the initial phases of the study.  Research
  funding from the Center for Interdisciplinary Studies in Economics,
  Psychology and Social Sciences (University of Milano-Bicocca) is
  gratefully acknowledged.

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.}
}}

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\section{Introduction}

Behavioural and social scientists have been increasingly studying trust
and its properties (e.g., Balliet et al., 2013; Fehr, 2009; Johnson \&
Mislin, 2011). Still, much needs to be understood about trust,
particularly in non-enforceable, personalised interactions. The study
reported here investigates experimentally trustees' response when the
\textit{intentional} vulnerability of the trustor is both manifestly
salient and clearly dependent upon the trustee’s revealed
trustworthiness.

That trust – when not purely self-interested and instrumental –
involves vulnerability is acknowledged in the interdisciplinary
literature on trust (e.g., Rousseau et al., 1998; Schoorman et al.,
2007).  Vulnerability, however, is often interpreted only as
unintentional ``exposure'' to other people’s action or events,
normally due to lack of resources, rights, capabilities, empowerment
or freedom.\footnote{ On the concept of ``exposure'' see Pelligra
  (2007) and also Bruni (2012).}  The development of human wellbeing
and dignity is usually measured in terms of reduction or elimination
of this unintentional vulnerability.  At the same time, some
philosophers and social scientists claim also for a purposeful
vulnerability, related to the inherent fragility associated to good
life (e.g., Nussbaum, 1986).

Vulnerability pervades the most diverse social interactions (ranging
from education to management; from family to public life) whenever one
party, the trustor, intentionally entrust her “fate” to another party,
the trustee, who is free to behave in ways that may be beneficial but
even in ways that may be harmful for the trustor. This could be the
case, for instance, of a grassroots manager trusting a selfish young
footballer to play for the team in the cup final. The young footballer
may betray her trust and use the cup final to showcase his skills,
with little consideration of the team’s objectives; or, given his
history of selfish player and aware of the intentional vulnerability
of the manager’s trust, the footballer may change behaviour and
reciprocate her trust by playing to benefit the team.

Everyday life shows abundant evidence that without this purposeful,
intentional, vulnerability, human life does not flourish fully, and
organizations do not fulfil entirely their potential.

By means of a gift-exchange experiment, in this paper we study trustee’s
response to trustor’s intentional vulnerability and, consequently, the
transformative capacity of vulnerable trust, which we conceptualise as
the possibility that trusting untrustworthy individuals may change
their responses from untrustworthy responses to trustworthy ones. To
the best of our knowledge, no experiment has been conducted so far to
investigate the effects of trusting untrustworthy individuals, when
this specific vulnerability is common knowledge and is made salient by
its manifest intentionality. In what follows, we refer to the trustor’s
risk to be potentially betrayed by the trustee, who proved to be
untrustworthy (i.e., by sending back less than what received) in a
recent interaction with a third person, as trustor’s vulnerability. Our
general concern is: Does vulnerable trust increase trustees’ transfers?
Does it transform trustees’ attitudes by making their behaviour more
trustworthy and reciprocal? Our laboratory evidence says unambiguously
\textit{yes} to both questions. Intentional vulnerability of trust
shows sizeably increases in trustee’s transfers. Trustees’ behaviour
becomes also more trustworthy and reciprocal when vulnerability is made
salient. We discuss the policy implications of our results in
significant domains of social and economic life such as management and
education, where personalised interactions are characterised by
non-enforceable trust.

\section{Trust, Risk and Vulnerability}

Berg et al.\ (1995), Pillutla et al.\ (2003), Malhotra (2004) and
Strassmair (2009) dealt with issues similar to our own by explicitly
investigating in an experimental setting the role of trustors’ risk
exposure with regard to trustees’ behaviour.\footnote{ Cialdini (1993)
and Reagan (1971) dealt with risk and reciprocity, but the issue of
vulnerability was not part of their analysis.} These studies did not find
any significant effect of the trustor’s exposure on the trustee’s
behaviour. These results depend on critical features of the
experimental designs, which – we believe – were not purposely built to
investigate what we refer to as the transformative effect of
vulnerability on trustee’s behaviour.

In particular, in Berg et al.\ (1995) and Pillutla et al.\ (2003),
whenever trustors took higher risks by sending larger portions of their
endowment, they provided greater benefit to trustees as a consequence.
Thus, there is no possibility to know whether trustees reciprocated
because they valuated the risks trustors had undertaken, or for
distributional reasons – or for both.

Malhotra’s (2004) study is the closest to our own study, with a specific
acknowledgement of the role of the trustor’s risk. He found no significant
impact of the trustor’s risk on the trustee’s trustworthiness, which is
instead significantly affected by the benefit provided to them by the
trustor. In contrast with previous studies, Malhotra’s (2004)
experimental design maintained a clear separation between the effect of
the trustor’s risk and the trustee’s benefit, but still the trustor’s
intentional vulnerability was not manifestly salient and clearly
dependent upon the trustee’s revealed trustworthiness. In fact, in his
study the only dimension of risk exposure experimentally manipulated
was the variation in the material payoffs of the trustor’s outside
option. We claim that this strategy is not able to analyse the role of
trustor’s intentional vulnerability, i.e. the specific risk of being
betrayed inherent to trustor’s interaction with a given (untrustworthy)
trustee.

Strassmair (2009) studied the effect of trustors’ expected future
rewards on trustees’ reciprocal responses. To this aim, she
experimentally varied across treatments the probability for the trustee
to make a return transfer. In all her experimental treatments, the
probability of a return transfer was made common knowledge when
subjects were instructed. In Strassmair's (2009) ``low'' treatment, the
probability for the trustees of making their return transfer was 50\%;
in her ``high'' treatment, the respective probability was 80\%.
Therefore, in the low treatment the trustee were expected to perceive
the trustor as kinder than in the high treatment, ceteris paribus, and
therefore they were expected to return more in the former than in the
later treatment whenever asked to make a decision. The results,
however, did not show any significant difference across treatments: in
fact, trustees did not condition their transfers on trustors’ expected
future rewards. Therefore, she suggested that trustees are insensitive
to the specific risk faced by the trustors and, consequently, how risky
trustors’ trust was. But, again, also in Starssmair’s experiment the
specific dimension of intentional vulnerability was not salient enough,
due to the mediational role played by the probability of making a
return transfer, and did not depend upon the trustee’s revealed
trustworthiness.

In fact, the contribution of our paper is to explore the role of
\textit{intentional vulnerability}. The vulnerability of trust is
explained as a disposition of the trustor to accept the risk to be
\textit{intentionally} betrayed by the trustee (Baier, 1986). This
disposition emerges only in context of human relationships in which the
presence of people and their intentions – rather than other elements of
the decision context – explains the possibility to feel betrayed rather
than the mere possibility to be disappointed. 

Thus, we consider the presence of people and their intentions as a
first necessary condition for the vulnerability of trust as we intend
it.  However, it does not constitute a sufficient condition to explain
the emergence and the role of intentional vulnerability. As also
Holton (2004) underlines, a person could choose to undertake actions
based on trust without taking the risk to be betrayed (e.g., when
interacting with an absolutely trustworthy person), that is, without
any particular vulnerability. This leads to what we consider a second
necessary condition for the vulnerability of trust: that is, the risk
of trusting depends on the trustee’s revealed level of
trustworthiness.

Upon maintaining the first condition in each and every experimental
treatment as in previous related studies (e.g., Blount, 2005; Falk et
al. 2008; Stanca et al.\ 2009; Stanca, 2010), we design our experiment
to explore the effect of the second condition once the trustee’s
revealed level of trustworthiness has been made manifestly salient. We
hypothesise that, when the second condition also holds, trustors’
\textit{vulnerability} may have a transformative effect on the
response of untrustworthy trustees.\footnote{For instance, we
  speculate that when the second condition holds trustors’
  vulnerability may prompt trustees to regard norms of altruism,
  reciprocity, and fairness as relevant for the circumstances they are
  in, and behave accordingly rather than following the norm of
  self-interest (e.g., Miller, 1999; Ratner \& Miller, 2001). However,
  it could also be the case that behaviour in line with norms of
  altruism, reciprocity and fairness is the intuitive behaviour
  triggered without deliberation (e.g., Rand, 2016, on cooperation as
  resulting from more intuitive or deliberative processes).} This is
what we investigate by means of our experiment as detailed below.

\section{Experimental Design and Procedures}

We employ a two-player symmetric gift-exchange game (Stanca et al.,
2009). Both players receive an initial endowment of 5 tokens each. In
line with the literature on trust (e.g., Bohnet, 2008), we refer to
the first mover as the trustor and the second mover as the trustee. In
Stage 1, the trustor decides how many of her 5 tokens (only integers
could be disposed) to send to the trustee. Then, the $x$ tokens sent
by the trustor are multiplied by 3 by the experimenter.  Therefore,
the trustee receives $3 x$. In Stage 2, the trustee decides how many
of his 5 tokens (only integers could be disposed) to send to the
trustor. Then, the $y$ tokens sent by the trustee are multiplied by 3
by the experimenter. Thus, the trustor receives $3 y$. In summary, the
trustor’s final payoff of the game is $5 - x + 3 y$, while the
trustee’s final payoff is $5 + 3 x - y$.

Within each experimental session, the game was played three times. We
refer to those three times as Game 1, 2 and 3, respectively. Players
learned about the games step by step.\ Players’ roles – namely either
trustor or trustee – were fixed across games. A stranger matching
protocol was in place: that is, Game 1--3 were each played with a
different co-player. Only in Stage 2 of Game 3 we applied a variant of
the strategy method similar to the one implemented in Fischbacher et
al.\ (2001): that is, the trustee in such a stage had to make a
\textit{set of six conditional decisions} (i.e., one per possible
number of tokens they could receive from the trustor they were paired
with) without knowing how many tokens the trustor actually sent. In all
other stages, the decision method was always applied entailing a
\textit{single} \textit{unconditional} \textit{decision} about how many
tokens from the initial endowment a player sent to their co-player.

One of the three games, 1--3, was randomly selected for payment. For
trustors, the single unconditional decision in the selected game was
used to determine the game payoffs relevant for payment. For trustees,
if either Game 1 or 2 was selected the single unconditional decision
was used to determine the game payoffs relevant for payment, whereas if
Game 3 was selected the conditional decision corresponding to their
trustor’s unconditional decision was used. Experimental earnings were
obtained by converting the payoffs of the selected game in euros
(exchange rate: 2 tokens = 1 euro), plus 5 euros as show-up fee.

There are two treatments in the experiment: the Information treatment
(I-treatment) and No-Information treatment (N-treatment). The
experimental manipulation between treatments is the disclosure or not
of information about the trustee’s choice in Game 1. In fact, in Game
2 and 3 of the I-treatment, trustors are informed whether their
co-player made either a “trustworthy” or an “trustworthy” choice in
Game 1, while trustees were made aware that their trustor co-players
were informed whether they made either a “trustworthy” or a
“trustworthy” choice in Game 1.  By contrast, in Game 2 and 3 of the
N-treatment, no information about Game 1 was disclosed. To effectively
and swiftly inform trustors about trustees’ revealed trustworthiness,
a trustee’s choice in Game 1 was labelled as “trustworthy” (vs.\
“untrustworthy”) if they sent to their co-player a number of token
larger than or equal to (vs.\ lower than) the tokens they
received. (The experimental instructions rather than ``trustworthy''
used the more neutral Italian term “equo” – or its negation – that
could be more closely translated in English with the word “fair”). The
two treatments were identical in all other respects.

The experiment started with instructions read aloud by the experimenters
to set ground rules. Then, subjects were led step by step by
computerized instructions in z-Tree (Fischbacher, 2007). After going
through Games 1--3, subjects learned the game randomly selected for
payment, their choice, their opponent’s choice and their earnings. The
experiment ended with a standard background questionnaire.

Two-hundred eight students (of whom 59.62 percent enrolled in
undergraduate degrees) drawn from a range of academic disciplines
(with Business and Economics summing up respectively to 50.96 percent
and 17.79 percent of the whole sample) participated in our experiment,
which took place at the Experimental Economics Laboratory of the
University of Milano-Bicocca (Italy) and lasted on average one hour.
Subjects were paid individually and anonymously at the end of each
experimental session.\footnote{ All subjects received the total sum of
  the actual earnings from the experiment as described in the main
  text plus a € 5.00 show-up fee. Total payments ranged between € 5.00
  and € 15.00 with an average payment equal to € 9.40 (standard
  deviation of € 3.12).}

\section{Predictions}

\begin{table*}[t]\centering
\caption*{Table 1: Summary statistics of token transfers by treatment, game and
type of player.}
\begin{tabular}{lcccc}\toprule
 & Game 1 & Game 2 & Game 3 & \\
 & Mean (s.d.) & Mean (s.d.) & Mean (s.d.) & N \\\midrule
\textbf{N-treatment} & & & & \\
Trustor's transfer & 3.077 (1.702) & 3.192 (1.783) & 2.135 (1.961) & 52\\
Trustee's transfer & 1.885 (1.843) & 1.885 (1.916) & 1.474 (0.996) & 52\\\midrule
\textbf{I-treatment} & & & & \\
Trustor's transfer & 2.846 (1.564) & 2.365 (1.794) & 2.731 (2.097) & 52\\
Trustee's transfer & 1.712 (1.730) & 1.981 (1.873) & 1.962 (1.108) & 52\\\bottomrule
\mc{5}{p{4in}}{Note: In Game 3, the raw data for calculating the mean and
standard deviation for the trustee’s transfer were obtained by
averaging the individual transfers elicited by the strategy method.}
\end{tabular}
\end{table*}

The present study focuses on the behavioural implications of the
vulnerability of trust. To explore those implications, it is necessary
to concentrate the attention on the trustee. Therefore, in what
follows, the predictions are stated with regard to trustees’
behaviour.

Upon assuming that players are purely self-interested and this is
common knowledge, the trustee who is at the game terminal node will
always send zero tokens to the trustor. By backward induction, the
trustor will rationally choose to not send any token to the
trustee. Therefore, the standard equilibrium prediction is that both
players will send zero tokens. However, we do not expect many players
to behave this way.

More importantly in the present case, if trustee’s preferences show
concerns for the vulnerability of trust, the amount of tokens sent
back by them should be higher when the trustor’s vulnerability is
salient.

\paragraph{Hypothesis 1.} If trustees’ preferences present concerns
for the vulnerability of trust, they will transfer more tokens in the
I-treatment than in the N-treatment.

In the I-treatment, higher transfers of tokens by trustees do not imply
per se a higher share of trustworthy choices and, consequently, of trustworthy
players. In other words, when vulnerability is salient, it is
conceivable that trustees’ behavioural strategies could imply more
generous but not yet fair transfers, which would leave unchanged the
share of trustworthy players. Hence, a second hypothesis follows:

\paragraph{Hypothesis 2.} If trustees’ preferences show concerns for the
vulnerability of trust, the share of trustworthy trustees is larger in
the I-treatment (``trustworthy'' in the sense defined above).

Irrespective of how trust vulnerability affects the level of return
transfers and the share of trustworthy people, its transformative
capacity may also affect the reciprocity attitudes of trustees. In
fact, both an increase in the return transfer levels and a higher
share of trustworthy people may result simply from an upward shift of
trustees’ behavioural strategies. By contrast, a change in the
trustees’ reciprocity attitudes would require a different association
between trustors' and trustees’ transfers, or in other words, a change in
the slope of trustees' \textit{return function}, the amount returned
as a function of the amount received.

\paragraph{Hypothesis 3.} Assuming concerns for the vulnerability of trust,
the slope of untrustworthy trustees’ return function is higher in the
I-treatment.

\section{Results}

\begin{figure*}[t]
\includegraphics[width=\columnwidth]{fig1n.eps}\hspace{5mm}%
\includegraphics[width=\columnwidth]{fig1i.eps}
\caption*{Figure 1: Tokens sent back in the N-treatment (left panel) and
I-treatment (right panel) from Game 3 (strategy method).}
\end{figure*}

Table 1 reports summary statistics by treatment, game and type of
players. First of all, both trustors and trustees transfer on average
non-zero amounts of tokens to their co-player. In Game 1 of the
N-treatment (vs.\ I-treatment), trustors sent on average
3.077 (vs.\ 2.846) tokens to their respective co-players;
trustees responded by sending back on average 1.885 (vs.\ 
1.712), which are still positive but lower than what full reciprocity
would imply. A set of t-tests and Wilcoxon rank-sum tests (p-values
{\textgreater} 0.40) demonstrate that there is no statistically
significant difference in Game 1 between the average amounts sent by
trustor (vs.\ trustee) across treatments, showing a
successful random assignment of subjects in treatments and roles.

Game 2 of the N-treatment was a close replica of the previous game
outcomes. On average, trustors transferred 3.192 tokens to their
co-players who responded by sending back 1.885 tokens. In the
I-treatment a slight change in the average behaviour was reported in
Game 2: trustors and trustees transferred 2.365 and 1.981 tokens,
respectively.

Game 3 presents a different overall picture. In the N-treatment
(vs.\ I-treatment), trustors transferred on average 2.135
(vs.\ 2.731) tokens to trustees who in turn sent back 1.474
(vs.\ 1.962) tokens.

So far it is worth noticing that Game 1 was designed to identify
trustees’ trustworthiness; Game 2 was designed to provide subjects
with a first experience of the environment we aim to study, while
adopting a more intuitive choice mode with a single unconditional
decision. 

By eliciting the entire set of conditional decisions, Game 3 was
designed to efficiently provide the relevant information to fully test
the hypotheses stated in the previous section, concerning the effect
of vulnerability. Hence, following the approach by Fischbacher et al.\
(2001), we now focus our analysis largely on the set of trustees’
conditional decisions from Game 3.\footnote{Game 2 did not provide
  sufficient data for a test of the effect of vulnerability. The
  critical cases are those in which the trustee was not trustworthy in
  Game 1, yet, despite this, the trustor transferred 4 or 5
  tokens. There were only 20 such cases, 13 in the N-treatment and 7
  in the I-treatment. When the trustor transferred less than 4, as we
  shall see, information had little effect, as the trustor was not so
  obviously vulnerable.} Game 3, in using the strategy method,
required trustees to indicate how they would respond \textit{if} the
trustor were vulnerable in this test. Thus, every trustor provided a
response to this hypothetical case.

Figure 1 shows the individual Game 3 return functions (amount returned
as a function of the amount transferred by the trustor) for the
trustees who were not trustworthy in Game 1, separately for the
N-treatment and I-treatment. It is apparent that the mean trustee
return function (dashed lines, with circular points) was a roughly
linear function of the amount transferred up to about 3 tokens, at
which point the trustee response start to become sensitive to the
information condition. In particular, trustees returned more when they
knew that the trustor was vulnerable, that is, the trustor transferred
4 or 5 tokens despite knowing that the trustee was not trustworthy
(Hypothesis 1).

In Figure 1, red lines indicate that the intercept of the linear model
for each trustee was greater than 4 (as explained shortly). It is
apparent that many more trustees reciprocated in full (i.e., in a way
that would count as ``trustworthy'') in the I-treatment than in the
N-treatment (Hypothesis 2, for transfers of 4 or 5, $p=.026$,
one-tailed Wilcoxon test on the number of trustworthy responses [0, 1,
or 2]).

To test the main hypotheses of interest (Hypotheses 1 and 3), we fit a
straight line to the each trustee's return function. Two parameters of
this fit were of interest: the intercept when the trustor transferred
5 tokens, and the slope of the line. The intercept assesses the
response when the trustor was most vulnerable. The slope assesses the
sensitivity of the trustor's response to the amount transferred by the
trustor. Of particular interest were the responses of the 56 trustees
who were not trustworthy in Game 1.

T tests confirmed the apparent results of Figure 2. The mean intercept
was higher in the I-treatment (3.29) than the N-treatment (2.25,
$t=1.97$, $p=.027$ one tailed), and the slope was also higher (.62
vs.\ .40, $t=1.88$, $p=.032$ one tailed). The fact that the slope was
higher casts doubt on an interpretation in terms of increased altruism
alone: the result depends on the vulnerability resulting from a large
transfer from the trustor. It represents an effect of vulnerability on
reciprocity.

However, we found that both intercept and slope were also strongly
affected by individual differences in the trustees' general willingness
to return, as measured by their amount returned in Game 2. (Game 1 did
not provide additional information; in regression models, its
contribution was not significant once Game 2 was included.) The amount
returned in Game 2 correlated .70 with the intercept and .52 with the
slope, within the trustees who were untrustworthy in Game 1. The Game
2 returns were thus nuisance variables, which contributed extraneous
variance to the t tests just reported. They represented pre-existing
individual differences in trustworthiness.

To reduce the effect of this extraneous variance, we regressed slope
and intercept on information treatment and Game 2 returns, for the
trustees who were not trustworthy in Game 1. The regression
coefficient for the effect of information treatment on intercept was
1.16 ($p=.001$ one tailed), and the coefficient for the effect on
slope was 0.24 ($p=.010$ one tailed). For trustees who were
trustworthy in Game 1, information condition had no effect on slope or
intercept.

In sum, the results support the hypothesis that previously
untrustworthy trustees are more likely to reciprocate high transfers
when they know that the trustor knows that they were previously
untrustworthy than when they do not know.

\section{Concluding remarks}

Our experiment has consistently shown across treatments that when
trustors’ vulnerability is linked to the trustee’s revealed
trustworthiness and is made salient by providing relevant information
to the players, trustees do change their behaviour by increasing the
amount of tokens transferred. In those circumstances, both trustworthy
and untrustworthy trustees make more generous transfers, and the
degrees of trustworthiness and reciprocity of trustees’ behaviour
rise.  Thus, the transformative nature of vulnerable trust finds
consistent support as shown by its capacity of generating higher, more
trustworthy and reciprocal transfers by trustees. Vulnerability has
shown a transformative capacity.

Our empirical regularities may serve as additional “exhibits” (Sugden,
2003) to be viewed – from a theoretical standpoint – through the lens
of intention-based theories, which model other-regarding preferences
in the form of reciprocity towards co-players (Rabin, 1993; Dufwenberg
\& Kirchsteiger, 2004) or aversion to guilt resulting from unfulfilled
expectations (Battigalli \& Dufwenberg,
2007).\footnote{Intention-based models of aversion to guilt may
  encompass complementary evidence as, for instance, the one reported
  by Butler et al.\ (2016), who link individuals’ cheating notions to
  guilt aversion, and trust.}

Furthermore, it is easy to envision relevant fields where our results
may suggest policy implications and, in general, reflections and
suggestions. For instance, a manager adopting subsidiarity management
should intervene in team decisions only for activities that would be
worse without her \textit{subsidiary} intervention (Melé, 2004). For
subsidiarity management to work, it is essential that team members
experience managers’ genuine, vulnerable trust. Manager should then
avoid trying to control or ``contractualise'' the entire process to
prevent possible abuse of trust. A key issue in subsidiarity
management is the resilience after a crisis due to betrayal of trust
when untrustworthiness is known to the organization, which wants to
keep its culture of trust. Our results support the effectiveness of
subsidiarity and the importance of giving new trust to team members
who appeared to be untrustworthy.

Subsidiarity is essential also in education, where teachers have to
create an environment of genuine trust in order to elicit
responsibility and freedom. Trusting children, youngsters, and adults
with a past of untrustworthiness is a key factor on which the success
of the education process hinges. Our results suggest that making
salient trustors’ (i.e., teacher or social worker) vulnerability may
produce a truly transformative effect on trustees (Horsburgh, 1960).

Finally, we hope that our study will stimulate replications and
further research to accumulate systematic knowledge on trust in
non-enforceable, personalised interactions, and may promote trust as
behavioural disposition, as social norms (e.g., Baron, 1998; Dunning
et al., 2014), in organisations and beyond.

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\end{hangparas}

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