The role of joint commitment in intersubjectivity

Abstract

Since the beginning of the Nineteen-eighties, cognitive scientists have shown increasing interest in a range of phenomena, processes and capacities underlying human interaction, collectively referred to as intersubjectivity. The goal of this line of research is to give an account of the various forms of human interaction, and in particular of the affective, attentional and intentional determinants of joint activity. The main thesis we develop in the paper is that so far the authors interested in intersubjectivity have neglected, or at least undervalued, an important aspect of joint activity, that is, the essentially normative character of collective intentionality. Our approach to joint activity is mainly based on Margaret Gilbert’s theory of plural subjects. Gilbert’s general idea is that joint activities should be regarded as activities carried out by individuals who stand to one another in a special relation, called joint commitment, which has an intrinsically normative nature. As we shall try to show, the concept of a joint commitment is a powerful tool to explain certain specific features of joint activities. In the paper we first point out certain explanatory inadequacies of the current models of intersubjectivity, and contend that such inadequacies depend on failing to appreciate the fundamental role of normativity in collective intentionality. We briefly sketch Gilbert’s theory of plural subjects, and introduce the concept of a joint commitment, and then discuss some lines along which a psychology of plural subjects may be developed.

Full text

Enacting Intersubjectivity: A Cognitive and Social Perspective on the Study of Interactions
F. Morganti, A. Carassa, G. Riva (Eds.)
Amsterdam, IOS Press, 2008, pp. 187-201
13 The Role of Joint Commitment in
Intersubjectivity
Antonella CARASSA, Marco COLOMBETTI,
Francesca MORGANTI
Abstract. Since the beginning of the Nineteen-eighties, cognitive scientists have
shown increasing interest in a range of phenomena, processes and capacities
underlying human interaction, collectively referred to as intersubjectivity. The goal
of this line of research is to give an account of the various forms of human
interaction, and in particular of the affective, attentional and intentional
determinants of joint activity. The main thesis we develop in the paper is that so
far the authors interested in intersubjectivity have neglected, or at least
undervalued, an important aspect of joint activity, that is, the essentially normative
character of collective intentionality. Our approach to joint activity is mainly
based on Margaret Gilbert’s theory of plural subjects. Gilbert’s general idea is that
joint activities should be regarded as activities carried out by individuals who
stand to one another in a special relation, called joint commitment, which has an
intrinsically normative nature. As we shall try to show, the concept of a joint
commitment is a powerful tool to explain certain specific features of joint
activities. In the paper we first point out certain explanatory inadequacies of the
current models of intersubjectivity, and contend that such inadequacies depend on
failing to appreciate the fundamental role of normativity in collective
intentionality. We briefly sketch Gilbert’s theory of plural subjects, and introduce
the concept of a joint commitment, and then discuss some lines along which a
psychology of plural subjects may be developed.
Contents
13.1 Introduction....................................................................................................... 188
13.2 Intersubjectivity and deontic normativity .........................................................189
13.3 Joint commitment .............................................................................................191
13.4 Steps to a psychology of plural subjects........................................................... 193
13.5 Conclusions....................................................................................................... 199
13.6 Acknowledgments.............................................................................................200
13.7 References......................................................................................................... 200

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13.1 Introduction
Since the beginning of the Nineteen-eighties, cognitive scientists have shown
increasing interest in a range of phenomena, processes and capacities underlying
human interaction, collectively referred to as intersubjectivity. The view advocated
by these scientists is remarkably different from the one developed within the more
traditional Theory of Mind approaches, either in the “Theory Theory” or in the
“Simulation Theory” versions. Through the contributions of several authors [1-10]
a novel view of human interaction is being developed, that is compatible with
state-of-the-art knowledge on the phylogenesis and ontogenesis of interaction
capacities, with the analysis of human experience worked out by phenomeno-
logists, and with recent findings in the field of the neurosciences.
The goal of this line of research is to give an account of the various forms of
human interaction, and in particular of the affective, attentional and intentional
determinants of joint activity. Indeed, joint activity has long been a major issue for
the social sciences and for analythical philosophy. Broadly speaking, the relevant
theories can be classified in two groups: in the first group we have theories that
attempt to give a summative account of joint activity, reducing it to the same
building blocks underlying individual activity; the second group includes non-
summative theories, which claim that joint activity requires certain special types of
mental representations, often referred to as “collective intentionality” [11].
Most authors currently interested in intersubjectivity support some form of non-
summative account. Observational and experimental results on non-human
primates, human adults, and human children suggest that humans possess specific
mental capacities, which enable forms of joint activity that are precluded to other
primate species. A complete and coherent view of such capacities, however, is still
beyond the state of the art. In this paper we aim to give a contribution to the
construction of such a view. Our main thesis is that so far the authors interested in
intersubjectivity have neglected, or at least undervalued, an important aspect of
joint activity, that is, the essentially normative character of collective
intentionality.
Our approach to joint activity is mainly based on Margaret Gilbert’s theory of
plural subjects [12-15]. Gilbert’s general idea is that joint activities should be
regarded as activities carried out by plural subjects, which can be viewed as sets of
individual subjects who stand to one another in a special relation, named joint
commitment, that has an intrinsically normative nature. As we shall try to show,
the concept of a joint commitment is a powerful tool to explain certain specific
features of human joint activities.
This article is structured as follows. In Section 2 we point out certain
explanatory inadequacies of the current models of intersubjectivity, and contend
that such inadequacies depend on failing to appreciate the fundamental role of
normativity in collective intentionality. In Section 3 we briefly sketch Gilbert’s
theory of plural subjects, and introduce the concept of a joint commitment. In
Section 4 we discuss some lines along which a psychology of plural subjects may
be developed. Finally, in Section 5 we draw some conclusions and delineate some
directions for future research.

13.2 Intersubjectivity and deontic normativity
Since Trevarthen’s distinction between primary and secondary intersubjectivity
[1], it has become customary to differentiate among different types of
intersubjectivity. For example, Stern [16] distinguishes between interaffective,
interattentional, and interintentional sharing of experiences, and his distinction is
taken up by other autors, like for example Ingar Brink [17]. Gärdenfors [5]
advocates a similar position, but adds a fourth component, that is, representing the
beliefs and knowledge of others. In general, the different components of
intersubjectivity are taken to be stratified in levels, both from an evolutionary and
a developmental point of view.
One of the leading themes of this area of research is to characterise human
intersubjectivity with respect to the intersubjectivity of non-human primates,
singling out the developmental phases at which specifically human structures and
processes appear. Here we shall comment on a few works that we find
representative of this approach.
In a paper on “What makes human cognition unique,” Tomasello and Rakoczy
[18] compare the impact on human social cognition of two key developmental
moments, the first at about one year of age and the second at about four years. In
the authors’ terminology, the first ontogenetic step brings in shared intentionality,
that is, the childrens’ “ability to establish self-other equivalence, to take different
perspectives on things, and to reflect on and provide normative judgement on their
own cognitive activities” (p. 123). The second ontogenetic step, which comes after
several years of “continuous interaction, especially linguistic interaction, with
other persons” brings in collective intentionality, which ends up in the
“comprehension of cultural institutions based on collective beliefs and practices
such as money and marriage and government.” While it is obvious that the second
ontogenetic step is uniquely human, Tomasello and Rakoczy contend that a
fundamental qualitative difference between human and non-human primates is
already brought in by the first step, which sets the bases that make the second step
possible.
One important aspect whose emergence brings from the first to the second
developmental moment is normativity. Here we need to comment on this term,
because it is used with different meanings, one of which is essential to our
proposal. In the paper we are considering, the authors distinguish between original
and derived normativity (p. 127). Original normativity is in fact coextensive with
intentionality: every intentional state, as such, has conditions of satisfaction, and
can therefore succeed or fail [19]. An intentional action, for example, may achieve
or fail to achieve its purpose, and a belief may be true or false. Given that
intentional states are the same thing as (mental) representations, we call this kind
of normativity representational. Derived normativity has to do with the
collectively accepted functions of artefacts. A fork is for bringing solid food to
one’s mouth, a switch is to turn the light on and off, and so on: functions are
normative in the sense that they tell us how an artefact ought to be used. We call
this kind of normativity functional. Besides representational and functional
normativity, however, there is a third important kind of normativity, that we call
deontic. Deontic normativity has to do with obligations and rights, in particular
with directed obligations and rights, that is, the obligations and rights that a subject
has relative to other subjects. Deontic normativity is often believed to come about

only with complex cultural products like legal systems, regulations, contracts and
the like. On the contrary, we shall defend the idea that a form of deontic
normativity is already there in every kind of joint activity, being a constitutive
component of collective intentionality. If this is the case, representational and
functional normativity, although essential for human cognition, are not sufficient
to account for the normativity of collective intentionality.
A second paper we want to discuss here is Brink and Gärdenfors’s work on
cooperation and communication in apes and humans [6]. The authors argue that
non-human primates are incapable of future-directed cooperation, which “concerns
new goals that lack fixed value” and “requires symbolic communication and
context-independent representations of means and goals” (p. 484). In this paper,
Brink and Gärdenfors remark that one of the key aspects of cooperation, that is, the
guarantee of proper compensation for one’s efforts, becomes hazardous with
future-directed cooperation. As the authors put it, “in the case of as yet imaginary
goals, compensation becomes much more of a venture than a safe strategy” (pp.
488-489).
Brink and Gärdenfors consider cooperation within a game-theoretical
framework. Much of their argument is based on the difficulty of developing
reliable expectations about the others’ behaviour; expectations are regarded as a
purely informational phenomenon, and there is little concern for the normative
component of interaction. Toward the end of the paper, the authors turn their
attention to aspects of cooperation that involve deontic normativity, like feelings of
shame and the expectation of sanctions from the rest of the group related to
defective behaviour. This line of thought, however, is not pursued to the point of
considering future-directed cooperation as a form of interaction intrinsically driven
by deontic normativity. As Brink and Gärdenfors remark, the core problem of
future-directed cooperation is that “it will be difficult to make estimates
concerning the behaviour of other agents on the basis of previous experience, since
the situation is new and unknown” (p. 499). We shall argue in the rest of this paper
that providing a sound basis for estimating the future behaviour of other agents is
the primary function of joint commitments.
Another relevant work is Gärdenfors’s article on the cognitive and
communicative demands of cooperation [4], where the author presents a table of
different forms of cooperation, at least three of which (“Commitment and
contract”, “Cooperation based on conventions”, “The cooperation of Homo
oeconomicus”; p. 20) seem to us to involve deontic normativity. Among the
demands of these forms of cooperation a special place is given to symbolic
communication, while the role of deontic normativity is ignored. For example, it is
said (p. 14) that “to promise something only means that you intend to do it. On the
other hand, when you commit yourself to a second person to do an action, you
intend to perform the action in the future, the other person wants you to do it and
intends to check that you do it, and there is joint belief concerning these intentions
and desires [20]. Unlike promises, commitments can thus not arise unless the
agents achieve joint beliefs and have anticipatory cognition.” Two criticisms can
be made to this position. The first is that promising creates obligations, and is not
limited to letting someone else know what one intends to do (see for example
[21]). The second is that committing to a second person to do an action cannot be
analysed only in terms of epistemic and volitional states like beliefs, desires, and
intentions. So, on the one hand to promising is committing oneself; on the other

hand, there is more to commitment than achieving joint beliefs and having
anticipatory cognition.
In a series of important works, Hannes Rakoczy investigates the children’s
ability to construct and exploit social reality. In [22] the author interprets young
children’s pretend play as examples of cooperative activities involving the
collective definition of fragments of social reality (understood along the lines of
Searle’s account [23]). Rakoczy’s interpretation of pretend play comes very close
to the concept of joint commitment that we shall discuss in the following sections:
in Rakoczy’s words, “a we-intention essentially involves some basic form of
commitment to acting together, analogous to the individual commitment of actors
in solitary actions, but different in that not only my own desires and intentions
provide reasons for further intentions and actions, but now the collaborator’s
actions and intentions provide reasons for me to act accordingly in the course of
the joint action” (p. 120). Still it seems to us that the deontic nature of joint
commitment is not fully appreciated. As a consequence, commitments are
regarded, somewhat vaguely, as “quite minimally involving an appreciation of
normative inferential (reason giving) relations between collaborators’ and own
actions and the willingness to respect these relations in the pursuit of acting
together successfully” (p. 120). We believe that the best way to characterise such
“normative inferential (reason giving) relations” is to regard them as deontic
relationships (i.e., directed obligations, rights, and entitlements) generated by joint
commitments.
The discussion we have carried out so far suggests that deontic normativity may
indeed be a fundamental component of human interaction. If this is the case, we
believe, theories of intersubjectivity will have to grant deontic normativity the
room it deserves. In the rest of this paper we shall try to give an initial contribution
in this direction, starting from a concise introduction to Gilbert’s concept of a
plural subject.
13.3 Joint commitment
Gilbert’s theory of joint activities is centred on the concept of a plural subject and
to the strictly related normative notion of a joint commitment. The importance of
normative concepts in general, and of commitment in particular, for understanding
human interactions has been recognised long ago. For example, in their pioneering
book Winograd and Flores [24] wanted “to counteract the forgetfulness of
commitment that pervades much of the discussion (both theoretical and
commonplace) about language” (p. 76). In argumentation theory, commitment-
based models have been proposed and discussed since the concept of a
commitment store was introduced by Hamblin [25] and later developed by Walton
and Krabbe [26]. Very recently, John Searle [27] has advocated a view of human
language in which deontic normativity is regarded as a basic constitutive
component, side by side with representative power and syntactic compositionality.
In the current landscape, Gilbert’s theory is unique in placing deontic
normativity at the very heart of collective intentionality. Gilbert’s idea is that all
genuinely collective phenomena (like joint activities, collective beliefs, group
feelings, social conventions, and so on) involve a normative component, called
joint commitment, that turns the set of interacting subjects into a plural subject.

The idea of a “plural subject” may sound metaphysically suspicious, but in fact it
is nothing more than a group of individuals bound by a joint commitment. In turn,
for a group of individuals to be bound by a joint commitment it is necessary and
sufficient for them to entertain certain mental representations.
What it means for a group of individuals to be jointly committed to doing X (or
believing X, or feeling X, and so on) is explained by Gilbert in several books and
papers (see in particular [13], Part III; [14], Chapter 4; and [15], Chapter 7). Below
we briefly describe the main features of this important concept.
A subject may be individually committed to do X, for example as a result of a
personal decision: such a decision may be rescinded, but until this does not happen
the subject is committed to do X. Being committed to do X is a reason (although
not a sufficient cause) for the subject to do X; however, in the individual case the
subject is the only “owner” of the commitment, and can rescind the commitment as
he or she pleases.
Contrary to individual commitments, a joint commitment is a commitment of
two or more subjects, which we shall call parties of the joint commitment, to
engage in a common enterprise as a single body. Taken together, a number of
subjects jointly committed to do X form a plural subject of doing X. The main
difference between individual and joint commitments is that joint commitments are
not separately “owned” by their parties, but they are, so to speak, collectively
owned by all parties at the same time.
Joint commitments may arise as a result of an agreement. However, explicit
agreements are not necessary: according to Gilbert, what is necessary and
sufficient to create a joint commitment, and thus to set up a plural subject, is that it
is common knowledge of all parties that every party is ready to engage in some
joint enterprise. Such common knowledge may derive from explicit agreements,
but also from less structured communicative exchanges and, in many cases, from
shared understanding of a culturally meaningful context.
Let us consider a few examples. Ann may say to Bob, “I’m going for a walk,
would you like to come?” If Bob answers, “Yes, sure!”, then it will be common
knowledge of Ann and Bob that they are both ready to engage in a walk together,
and this suffices to create a joint commitment to have a walk together. In certain
situations, like for example a dinner party, it will be common knowledge of all
participants (without the need of specific communicative exchanges) that all
parties are ready to carry out certain kinds of joint activities, like chatting or
dancing, with the other participants. Indeed, joint commitments are much more
common in human interaction than one may think. Even an apparently unilateral
promise, like Bob saying to Ann “I promise to come visit tomorrow evening,” if
accepted by the Ann creates a joint commitment, because while Bob is now
obliged to do what he promised, Ann is obliged to stay at home and welcome Bob.
For our current purpose, the main feature of joint commitments is that they
generate deontic relationships, like directed obligations and the correlative rights
and entitlements. (A directed obligation is an obligation that a subject, the debtor
of the obligation, owes to another subject, the creditor of the obligation. Every
directed obligation brings about a correlative right of the creditor to the debtor.) If
n subjects are jointly committed to do something, then every subject is obligated to
all other subjects to do his or her part of the joint activity, and has the right that all
other subjects do their parts. It is characteristic of joint commitments that all such
obligations are created simultaneously, and are interdependent in the sense that if

one of the parties fails to fulfill one of his or her obligations, then the joint
commitment is violated. What exactly this amounts to depends on a variety of
circumstances, including the number of members of the plural subject. In
particular, in the case of two parties the violation of an obligation by one of them
rescinds the joint commitment.
According to Gilbert, every genuine case of joint activity is an activity carried
out by a plural subject, and thus involves joint commitments. It is important to
understand that such commitments are not imposed to the parties from the outside,
but are “internal” to the joint activity. For example, when a group of people engage
in a game, we do not need to assume that there is some external source of
obligations that compels the participants to follow the rules of the game: rather,
engaging in a game together is by itself a source of obligations.
Our brief presentation of plural subjects and joint commitments raises a number
of important issues: What is the function of joint commitment? To what kind of
things can people jointly commit? What kinds of joint commitments are involved
in joint activities? What kinds of cognitive processes underlie joint commitment?
How do people make and maintain joint commitments? Since what age are humans
able to participate in joint commitments? Some of these questions are logical, in
the sense that they concern the function and structure of joint commitments, and
some are psychological, in the sense that they directly concern human mental
capacities. In the two following sections we shall submit some initial answers to
the previous questions.
13.4 Steps to a psychology of plural subjects
13.4.1 The function of joint commitments
At least since Aristotle, we understand human beings as rational animals. If we
construe the concept of a reason broadly enough, humans are not the only rational
species on Earth. But, based on the experimental evidence collected so far, it is
generally accepted that humans are the only species that can deploy a very specific
type of rationality, that is, the ability to plan their future. Given that anticipatory
planning is one of the distinctive features of Homo sapiens [28], it is not surprising
that so much attention has been devoted to it by scholars of disciplines like
cognitive psychology, philosophy of mind, economy, and artificial intelligence.
The function of future-directed intentions, or prior intentions in Searle’s
terminology [19], has been analysed, among the others, by Michael Bratman [29],
who stresses their characteristic role of coordinating practical reasoning. Indeed
future-directed intentions, organised into complex plans, allow human subjects to
reason within stable tracks directed to specific purposes, thus avoiding the risk of
being mislead by fluctuating motivations.
From an analysis of current literature, it seems that most authors do not find it
problematic to extend the stabilising function of intentions from individual to joint
action: even the most complex forms of cooperation are assumed to require
nothing more than the ability to share nested intentions and beliefs. At present,
some authors are starting to see that this is not sufficient. For example, introducing
contracts as a sophisticated form of human cooperation, Gärdenfors [5] states that
“If we agree that I shall deliver a hen tomorrow in exchange for the axe you have

given me now, I believe that you believe that I will deliver the hen and you believe
that I believe that our agreement will then be fulfilled, etc. Furthermore, a contract
depends on the possibility of future sanctions and thus on anticipatory cognition: If
I don’t deliver the hen, you or the society will punish me for breaching the
agreement” (p. 20). There is an attempt, here, to reduce deontic normativity to the
expectation of punishment, and thus to a purely epistemic phenomenon (a future-
directed belief). However, even before we ask ourselves whether this reduction is
psychologically plausible, we face a conceptual problem here, because the very
concept of a punishment is deontic. Indeed a punishment is more than just a cost
imposed to the subject by someone else: it is a cost rightly imposed to the subject
by someone else.
In our view joint commitments play, in the case of collective activities, a
stabilising role analogous to that played by future-directed intentions in the case of
individual actions. Joint commitments achieve this function by creating directed
obligations, thus decoupling future actions from possibly fluctuating motivations.
Consider the following example: by entering a suitable joint commitment, Ann and
Bob may form a plural subject of mutual care. While the joint commitment is in
force, Ann and Bob will be obliged to carry out appropriate actions, like proving
support to each other in difficult situations, and so on. Given the joint
commitment, it is not important whether Ann or Bob are continually motivated to
support each other: the reason for doing so is now an obligation created by the
joint commitment.
13.4.2 The structure of joint commitments
To what kind of things can people jointly commit? Or, in other words, what can be
the content of a joint commitment?
The most obvious examples of joint commitments concern joint activities. For
example, by jointly committing to have a walk together, Ann and Bob create
obligations concerning their future behaviour. But Margaret Gilbert argues that
joint commitments are more general: for example, for a group of people to
entertain a collective belief means that the group constitutes a plural subject of
believing something. A joint commitment to believe, say, that all men are created
equal, will carry out its function in much the same way as a joint commitment to
do something together: that is, by creating directed obligations to perform
appropriate actions, which will be determined case by case in a context-sensitive
way. In the “all men are created equal” case, for example, every party of the plural
subject is obliged to act accordingly, by treating every person with equity, by
reacting to blatant discriminations, and so on.
An important feature of Gilbert’s non-summative treatment (see for example
[13], Chapter 14) is that a plural subject may collectively believe that p even if not
all the parties (indeed, in extreme cases, none of them) believes that p. The point
with collective belief is not what individuals actually believe, but what are their
obligations given their joint commitment to believe something.
Given the significance of affective states in intersubjectivity, it is important to
understand whether people can create plural subject of feeling something. This
seems to be the case when, for example, a team is proud of a remarkable
achievement, or a group of people are sorry for a distressing event occurred to a
common friend: statements like “We are proud of being the first to land on Mars”

or “We are so sorry your house burnt to ashes” reveal that the feeling of pride or
sorrow is attributed to a plural subject. Analogously to the case of collective
beliefs, a joint commitment to feeling something will carry out its function by
creating obligations to perform appropriate actions, independently of the fact that
the parties actually have the relevant feeling.
Recently, Margaret Gilbert suggested that also joint attention is a plural subject
phenomenon [30]. The idea is that joint attention is best “understood in terms of a
joint commitment to attend as a body to some particular in the environment of the
parties” (p. 7). According to Gilbert, joint attention requires mutual recognition,
which in turn presupposes common knowledge of co-presence. Joint commitments
thus appear to be a pervasive aspect of intersubjectivity.
From the point of view of a theory of intersubjectivity, it is necessary to
understand the relationships between joint commitments and psychological states.
In Table 1 we propose a systematic view of all such states. We first classify
psychological states into affective, attentional, and intentional states. Here the term
“intentional” is to be understood as a synonym of “representational,” in line with
the philosophical theory of intentionality: perceptions, beliefs, desires, and
intentions are all examples of intentional states. We consider purely affective and
attentional states as psychological states of a single individual: a distinction
between individual and interpersonal states can be drawn only for intentional
states, because interpersonality is achieved through representations.
Intentional states are classified as individual or interpersonal. Examples of
individual intentional states are intending to do something (in the future),
intentionally doing something (right now), perceiving something, desiring
something, and so on. Interpersonal intentional states are, by definition, those
intentional states of a subject whose content involves psychological states of other
subjects.
There are basically three ways in which a psychological state of an individual
may become interpersonal. The first way is through perception: a subject may
directly perceive an affective, attentional, or intentional state of another subject.
Indeed, the possibility of directly perceiving psychological states of another
subject (inclusive of intentional states) is an important tenet of current theories of
intersubjectivity (see for example [31]).
The second way in which a psychological state may become interpersonal is
through sharing: a shared state, in our terminology, is a state that is “out in the
open” (to adopt the felicitous expression used by Gilbert to describe situations of
common knowledge [13]) but to which there is no joint commitment. Again, the
shared state may be affective, attentional, or intentional. As an example of a shared
attentional state that involves no joint commitment consider two criminals trying
to kill each other and standing a few meters apart, with the only gun at their
disposal lying on the ground right between the two of them. In this situation there
is shared attention to the other and to the gun, but of course the two criminals do
not form a plural subject of paying attention to the other and to the gun.
Finally, a psychological state may be interpersonal by being joint (or collective).
By this we mean that the relevant subjects are jointly committed to entertaining
such a state. As we have already remarked, the content of a joint commitment may
be any affective, attentional, or intentional state.

affective attentional intentional
individual subject A intends to do X, does X (intentionally), perceives X, believes X,
desires X, etc.
affective attentional intentional
perceived
subject A
perceives that
subject B has
emotion X
subject A
perceives that
subject B attends
to object X
subject A
perceives that
subject B intends
to do X, etc.
shared
it is out in the
open for subjects
A and B that one
of them (or both
of them) has
emotion E
it is out in the open
for subjects A and
B that one of them
(or both of them)
attend to object X
it is out in the
open for subjects
A and B that one
of them (or both
of them) intends
to do X, etc.
subject A
has
emotion X
subject A
attends to
object X
interpersonal
joint
A and B are jointly
committed to
have emotion X
(as a body)
A and B are jointly
committed to
attend to object X
(as a body)
A and B are
jointly committed
to intend X, do X,
etc. (as a body)
Table 1. A classification of psychological states.
Only some intersubjective processes involve shared intentional states, and an
even smaller fraction involve joint intentional states. Among these, however, we
find a very significant category of intersubjective processes, that is, joint activities
which, in particular, presuppose joint intentions. It is important not to confuse our
distinction between shared and joint psychological states with other kinds of
distinctions, like for example the one between coordination, collaboration, and
cooperation. All types of joint activities involve some kind of dependency between
the actions performed by the different parties as part of the joint activity. The
difference between coordination, collaboration, and cooperation concerns what we
could call degree of coupling: while in the case of coordination, typically based on
a loosely synchronised execution of individual plans, coupling is kept to a
minimum, cooperation involves a very high degree of coupling, achieved through
the collective execution of a common plan. However, all such types of joint
activities involve joint commitments, even if their contents will be different for
different kinds of joint activities. Suppose for example that Ann and Bob decide to
have dinner together at Bob’s apartment at 8 pm. As both of them are very busy,
they will separately buy some ready-made food: Ann will get the entrées and the
wine, and Bob will take care of the main course. Ann and Bob are now bound by a
joint commitment that generates at least the following obligations: that Ann gets
the entrées and the wine, goes to Bob’s apartment around 8 pm, and then has
dinner with Bob; that Bob gets the main course, will be at his apartment around 8
pm, and then has dinner with Ann. The first part of the joint activity, when Ann
and Bob separately get the food, has a very low degree of coupling; in spite of this,
however, there is a genuine joint commitment binding Ann and Bob to act as
agreed.

13.4.3 Cognitive requirements
A plural subject is a group of people bound by a joint commitment. In turn, the
members of the group are bound by a joint commitment if, and only if, they have
certain psychological states. But what kind of psychological states are involved?
As we have remarked in Section 2, many authors agree that some form of
commitment is essential at least for the most complex types of joint activity. There
is, however, no attempt to explain what it takes for a subject to commit to a course
of action.
Given that joint commitments involve deontic normativity, it is tempting to
consider them as a case of moral thought. This, however, may not prove a fruitful
approach, because the deontic relationships produced by a joint commitment
appear to be different from moral obligations. In our opinion, a major difference
between moral obligations and the obligations of joint commitments is that,
contrary to the former, the latter are intentionally created by people. To clarify the
difference, suppose that Bob, motivated by his moral conviction that one should
care after the ill, agrees with an elderly neighbour of his that he will soon visit her
at the hospital. While one may dispute whether visiting his neighbour was really a
moral obligation of Bob’s, there is no doubt that after promising Bob is obliged to
do so. Even if Bob changes his idea about the moral obligation of caring after the
ill, he will still be obliged, because he freely committed his will by making an
agreement.
In any case, it is clear that the ability to enter into joint commitments
presupposes the ability to understand obligations, rights, entitlements, and the like.
We believe that such ideas cannot be reduced to non-deontic psychological states,
like beliefs and intentions. Being obliged to do X is more than just expecting that if
one does not do X something bad will happen. Suppose for example that Bob,
together with a group of clients of the local branch of his bank, is caught in a
robbery and is ordered by a masked guy to sit on the floor and stay still. Bob
knows that something bad will happen if he tries to escape, and in some sense of
the word we can actually say that he is obliged to sit on the floor and stay still.
However, this obligation cannot be considered as a deontic relationship between
Bob and the masked criminal.
The problem of finding suitable primitives to which all deontic ideas can be
reduced has long be considered in such fields as the philosophy of law and deontic
logic. In [23], John Searle defends the idea that all deontic relationships can be
defined in terms of one primitive, like for example obligation. This means that any
being capable of entertaining thoughts of the kind “I am obliged to ...” would be
able to represent all deontic relationships. A different approach, developed for the
first time by Anderson in the field of deontic logic [32], is to reduce deontic
notions like obligation and right to a lower-level concept, like violation. To
understand this idea, suppose again that Ann and Bob agreed that Bob will visit
Ann at her summer cottage next Sunday. Bob, in particular, is now obliged to Ann
to go to Ann’s cottage next Sunday. This idea may take the following form: “If I
do not go to Ann’s cottage next Sunday, then I make a violation to Ann.” What
seems to be sufficient to have joint commitments is therefore a concept of directed
violation, that is, of a violation relative to some individual.
A different approach is taken by Margaret Gilbert, who proposes to understand
the obligations of joint commitments in terms of “owing” (see [15], Chapter 11).

The general idea is that once a joint commitment has been created, every party
owes certain actions to the other parties; symmetrically, all parties “own,” even if
they do not yet possess, the actions that are owed to them. It may indeed be the
case that the concept of owing can be reduced to the more primitive notion of
violation we have previously introduced. But it may also be the other way round:
the concept of owing may be a psychological primitive, on which more complex
aspects of social cognition are based. In any case, we think that only empirical
research may settle this issue.
Whether joint commitments are based on a primitive notion of directed
violation, or an a primitive notion of owing, it would be extremely interesting to
discover at what age human beings are capable of building the relevant
representations. Since the publication of Kohlberg’s pioneering paper on moral
stages [33], much research has been carried out on the development of moral
reasoning, but situations of joint commitment have not been a primary concern.
Monika Keller and colleagues [34] reported on some experiments in which
children were asked to reason on situations in which an agreement between a child
and his mother was either fulfilled or violated, and found that even children of
about three years of age were able to correctly detect situations of agreement
violation. This kind of experiments, though, rather than testing whether children
are able to engage in joint commitments in first person, test the children’s ability to
reason on third-person situations of joint commitments. Moreover, due to the
cognitive complexity of the experimental task, such experiments can be run only
on children of at least three years of age. However, recent literature on the early
development of sociality (like [18, 22, 35]) suggest that certain fundamental social
abilities show up considerably earlier.
Recently Maria Gräfenhain and colleagues [36] reported on an experiment
aimed to identify the presence of joint commitments in social play contexts. The
preliminary results show that the deontic implications of joint commitment begin
to emerge at two years, and are clearly established by three years of age. Of
course, further research is needed before we have a clear picture of the ontogeny of
joint commitment.
13.4.4 The life cycle of plural subjects
As everything on earth, plural subjects have a beginning, a period of life, and an
end – that is, a life cycle. Describing all possible life cycles of plural subjects is
beyond the scope of this article. In what follows we shall just sketch a few
important points.
As we have already remarked in Section 2, the joint commitment that constitutes
a plural subject may be created through an explicit agreement or may come to exist
as an implicit consequence of the parties’ interaction. For example, at a dancing
party two persons may just start dancing together without prior agreement: the
joint activity they engage in will imply a joint commitment to dance together at
least for a while.
Margaret Gilbert suggests that the necessary and sufficient condition for a group
of people to form a plural subject is that it is out in the open (i.e., common
knowledge) that all members of the group are ready to engage in some common
enterprise. Often, the readiness to engage in the common enterprise will mature
through a more or less lengthy phase of negotiation.

A plural subject exists as long as the underlying joint commitment is in force.
During this period the parties of the plural subject are bound by a network of
deontic relationships, produced by the joint commitment in a context-dependent
way. Such deontic relationships may be classified into two classes: basic and
derivative. The basic deontic relationships are the directed obligations, rights,
entitlements, and so on that are directly related to carrying out the common
enterprise. For example, if Ann and Bob agreed that Bob will visit Ann at her
summer cottage next Sunday, then Ann is obliged to Bob to be at her summer
cottage next Sunday, Bob has the correlative right to Ann that Ann be at her
summer cottage next Sunday, Bob is entitled to go to Ann’s summer cottage next
Sunday, and so on. The derivative deontic relationships concern the management
of the joint commitment in the face of violations by the parties of the plural
subject. For example, in case Ann is not at her cottage next Sunday, Bob has the
derivative entitlement to rebut; or, if after their agreement Ann discovers it will be
impossible for her to be at her summer cottage next Sunday, she has the derivative
obligation to tell Bob and to provide a suitable justification.
A plural subject may come to an end in many different ways. In some cases, the
underlying joint commitment will have a well-defined deadline: consider for
example the joint commitment of moving a table together, which terminates when
the action is completed. In other cases the deadline will be only vaguely defined,
and consequently the termination of the joint commitment will require some form
of explicit or implicit negotiation. As an example, consider the joint commitment
of going for a walk together: given that “a walk” is a vague concept, sooner or
later the parties will start negotiating the end of the common enterprise, for
example by saying “I start feeling tired now” or “I’m afraid I have to go back now,
I have to dress up for dinner.” A plural subject may also come to an end due to a
violation by one of the parties. In the case of two parties, a violation by one of
them is sufficient to wipe out the joint commitment, thus freeing the other party of
all obligations. With more than two parties the situation is more complex, and we
shall not try to deal with it here.
13.5 Conclusions
In this article we have argued that joint activities involve a particular form of
deontic normativity, that following Margaret Gilbert we call joint commitment.
Joint commitments arise when a number of subjects make it overt that they are
ready to engage in a common enterprise, and generate deontic relationships
(directed obligations, rights, and entitlements) among these subjects. By creating
such deontic relationships, joint commitments play an essential role in stabilising
interaction, which is particularly relevant to anticipatory planning.
More work needs to be done before we can form a satisfactory picture of the
deontic normativity of joint commitments as part of the general phenomenon of
human intersubjectivity. Below we mention some issues that seem to us to be
important.
At the theoretical level, we think that the relationship between joint
commitments and moral obligations is in need of clarification. Intuitively, the
deontic normativity of joint commitments appears to be distinct from moral

normativity. However, what this difference exactly amounts to, and what are the
relationships between commitment and morality is still unclear.
At the empirical level, there seems to be at least four areas in which it would be
interesting to carry out experimental work. First, research on the ontogenesis of
joint commitment, which as we have seen has already started, may contribute to
our understanding of the development of sociality; moreover, considering results
in the light of the available literature on moral development may help to
understand the relationships between the normativity of commitments and moral
normativity. Second, the analysis of adult interactions may clarify important
aspects of the life-cycle of plural subjects and the relationships between joint
commitments and what we have called the degree of coupling of collective
activities. Third, the analysis of narratives may shed light on the affective side and
on the first-person perspectives of joint commitment. Finally, it would be
interesting to find out how certain types of cognitive and/or relational disorders,
due to brain injuries or neurological disorders, influence the human capacity to
engage in joint commitments.
13.6 Acknowledgments
We are grateful to Margaret Gilbert for kindly engaging with us in a stimulating
electronic discussion on joint commitment.
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