Could Motor Representations Ground Collective Goals?

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Could Motor Representations Ground Collective Goals?

other references: Clarke et al. (2019)

shared intention shared intention shared intention shared intention shared intention shared intention shared intention shared intention shared intention

‘I take a collective action to involve a collective [shared] intention.’

(Gilbert, 2006, p. 5)

‘The sine qua non of collaborative action is a joint goal [shared intention] and a joint commitment’

(Tomasello, 2008, p. 181)

‘the key property of joint action lies in its internal component [...] in the participants’ having a “collective” or “shared” intention.’

(Alonso, 2009, pp. 444--5)

‘Shared intentionality is the foundation upon which joint action is built.’

(Carpenter, 2009, p. 381)

very small scale action

Few discussions of joint action have considered the existence of Very Small Scale Shared Agency ...

Very Small Scale
Joint Action

(preliminary)

A _very small scale action_ is one that is typically distantly related as a descendent by the means-end relation to the actions which are sometimes described as ‘small scale’ actions, such as playing a sonata, cooking a meal or painting a house (Bratman, 2014, p. e.g.][p. 8).

There are very small scale joint actions like playing a chord together in the course of playing a duet, clinking glasses in the course of toasting our success, or plassing a plate between us in the course of doing the washing up together.

Small Scale
Shared Agency

Very Small Scale
Shared Agency

Playing a piano duet

Playing a chord together

Toasting our success together

Clinking glasses

Washing up together

Passing a plate between us

Philosophers have rarely considered such very small scale joint actions. But at least some such cases seem to involve exercising shared agency no less than larger scale activities like painting a house together.

But very small scale joint actions create a challenge to views like Gilbert’s.

Those views hinge on the roles of intention and practical reasoning.

But in at least some cases, very small scale joint actions are not a consequence of practical reasoning concerning those particular actions, nor need they involve intentions which specify outcomes to which the very small scale joint actions are directed. There is simply no need for practical reasoning, or intention, in many such cases. This is particularly obvious if you think about very small scale joint actions which occur in the context of larger scale activities, such as our playing a chord in the course of playing a piano duet.

Of course, there is no principled bar to having intentions concerning the goals of such very small scale actions (as far as I know), and such intentions may sometimes exist. But in very small scale cases of acting together, intentions and practical reasoning are often superfluous and sometimes absent.

Despite this, these very small scale interactions appear to involve exercises of shared agency no less than small scale activities such as playing a piano duet.

For very small scale cases, in virtue of what might they have collective goals?

collective goal goal outcome

A collective goal (df):

an outcome to which two or more agents’ actions are directed

where

this is not, or not only,

a matter of each action being directed to that outcome.

In virtue of what could two or more agents’ actions have a collective goal?

Let me illustrate the question ...

Recall how Ayesha takes a glass and holds it up while Beatrice pours prosecco; and unfortunately the prosecco misses the glass, soaking Zachs’s trousers. Ayesha might say, truthfully, ‘The collective goal of our actions was not to soak Zach's trousers in sparkling wine but only to fill this glass.’ What could make Ayesha’s statement true?

As this illustrates, some actions involving multiple agents are purposive in the sense that

among all their actual and possible consequences,

there are outcomes to which they are directed

and the actions are collectively directed to this outcome

so it is not just a matter of each individual action being directed to this outcome.

In such cases we can say that the actions have a collective goal.

As what Ayesha and Beatrice are doing---filling a glass together---is a paradigm case of joint action, it might seem natural to answer the question by invoking a notion of shared (or `collective') intention. Suppose Ayesha and Beatrice have a shared intention that they fill the glass. Then, on many accounts of shared intention,

the shared intention involves each of them intending that they, Ayesha and Beatrice, fill the glass; or each of them being in some other state which picks out this outcome.

The shared intention also provides for the coordination of their actions (so that, for example, Beatrice doesn't start pouring until Ayesha is holding the glass under the bottle). And coordination of this type would normally facilitate occurrences of the type of outcome intended. In this way, invoking a notion of shared intention provides one answer to our question about what it is for some actions to be collectively directed to an outcome.

Are there also ways of answering the question which involve psychological structures other than shared intention? In this paper we shall draw on recent discoveries about how multiple agents coordinate their actions to argue that the collective directedness of some actions to an outcome can be explained in terms of a particular interagential structure of motor representations. Our actions having collective goals is not always only a matter of what we intend: sometimes it constitutively involves motor representation.

a clue: when agents perform joint actions, motor representation concerning a partner’s action can occur.

a clue:

motor representations concerning
another’s actions occur in joint action

An important clue as to how we might be in the ‘we mode’ is provided by some experimental data concerning motor representation in joint action ...

would normally recap but you can just go right back

[if need it, have nifty recap somewhere joint-action-bochum?]

Kourtis, Sebanz, & Knoblich (2013)

The CNV is a signal of motor preparation for action which is time-locked to action onset. In this research, Kourtis et al show

that the CNV occurs when joint action partners act, suggesting that when acting together we represent others' actions motorically as well as our own, and also that the stronger CNV peak is correlated with better coordination (Kourtis et al., 2013);

and in earlier research they show, roughly, that a stronger CNV occurs in relation to actions of others one is engaged in joint action than in relation to actions of others one is merely observing (Kourtis, Sebanz, & Knoblich, 2010).

Kourtis et al. (2013)

Kourtis et al. (2013, p. figure 5)

‘the (motor) CNV of a “receiver” peaked approximately at the time of the partner’s response. This suggests that in the receiving 610 condition participants were not only preparing their own actions but also sampling the average speed their partner took to initiate the giving action. This, in turn, allowed them to predict the time their partner would take to initiate the giving action on a given trial.’ (Kourtis et al., 2013, p. 9)

‘there was a significant correlation between the receiver’s motor CNV amplitude and the improvement in coordination. The behavioral analysis clearly showed that the speed-up in receiving led to the improvement in coordination as receiving was getting faster at a greater rate than giving. This finding can be well explained by the assumption that motor simulation allowed the receiver 655 to predict the timing of the giver’s action and to improve coordination by decreasing the asynchrony in action onset between initiating the giving and receiv- ing action.’ (Kourtis et al., 2013, p. 9)

Kourtis, Knoblich, Woźniak, & Sebanz (2014, p. figure 1c)

I think we're a long way from having a large body of converging evidence for this conjecture, but there is some that points in this direction. One of the most relevant experiments is this one by Kourtis et al. (2014).

They contrasted a simple joint action involving two agents clinking glasses.

The CNV is a signal of motor preparation for action which is time-locked to action onset. In previous research, Kourtis et al show (i) that the CNV occurs when joint action partners act, suggesting that when acting together we represent others' actions motorically as well as our own (Kourtis et al., 2013); and (ii) (roughly) a stronger CNV occurs in relation to actions of others one is engaged in joint action than in relation to actions of others one is merely observing (Kourtis et al., 2010).

Kourtis et al hypothesised that in actions like clinking glasses, A single outcome represented is motorically, which triggers planning-like processes concerning all the agents' actions. This leads to the prediction that the CNV in joint action will resemble that occurring in bimanual action more than that occuring in unimanual action.

Kourtis et al. (2014, p. figure 4a)

... and this is exactly what they found.

Ramenzoni et al, 2014 figure 1

Importantly there is converging evidence for the involvement of motor representation concerning a partner’s action in joint action from studies which use behavioural measures ... Joint performance is better when observing joint actors; individual performance when observing individual actors.

Ramenzoni et al, 2014 figure 1

So once again we are forced to ask,

What are those motor representations doing here?

Conjecture:

Collective goals are represented motorically.

Let me explain what this amounts to. > #. There is one outcome which each agent represents motorically, and > #. in each agent this representation triggers planning-like processes > #. concerning all the agents’ actions, with the result that > #. coordination of their actions is facilitated.

This is not my conjecture but something which I take several researchers to be moving towards. The conjecture has recently been very neatly formulated by Lucia Sacheli and colleagues:

‘motor interactions might be based on the ability to integrate one’s own and a partner’s action within a unitary, dual-person (dyadic) motor plan that incorporates the goal of the JA that both partners share’ (Sacheli, Arcangeli, & Paulesu, 2018)

see also (Sacheli, Musco, Zazzera, & Paulesu, 2021)

1. If true, how would this conjecture answer our questions about in virtue of what two or more agents’ actions could have a collective goal?

2. How can we know whether this conjecture is true?

Let me start by stepping back and consider an individual action.

An agent moves a mug from one place to another, passing in from her left hand to her right hand half way [*demonstrate].

It’s a familiar idea that motor representations of outcomes resemble intentions in that they can trigger processes which are like planning in some respects.

These processes are like planning in that they involve starting with representations of relatively distal outcomes and gradually filling in details, resulting in a structure of motor representations that can be hierarchically arranged by the means-end relation (Bekkering, Wohlschlager, & Gattis, 2000; Grafton & Hamilton, 2007).

Processes triggered by motor representations of outcomes are also planning-like in that they involve selecting means for actions to be performed now in ways that anticipate future actions (Jeannerod, 2006; Zhang & Rosenbaum, 2007; Rosenbaum, Chapman, Weigelt, Weiss, & Wel, 2012).

Now in this action of moving a mug, there is a need, even for the single agent, to coordinate the exchange between her two hands.

(If her action is fluid, she may proactively adjust her left hand in advance of the mug’s being lifted by her right hand (compare \citealp{diedrichsen:2003_anticipatory,hugon:1982_anticipatory, lum:1992_feedforward}).)

How could such tight coordination be achieved?

Part of the answer involves the fact that motor representations and processes concerning the actions involving each hand are not entirely independent of each other.

Rather there is a plan-like structure of motor representation for the whole action and motor representations concerning actions involving each hand are components of this larger plan-like structure.

It is in part because they are components of a larger plan-like structure that the movements of one hand constrain and are constrained by the movements of the other hand.

But how is any of this relevant to the case of joint action?

Earlier we considered what is involved in performing an ordinary, individual action, where an agent moves a mug from one place to another passing it between her hands half-way.

Compare this individual action with the same action performed by two agents as a joint action.

One agent takes the mug and passes it to the other, who then places it.

The joint action is like the individual action in several respects.

First, the goal to which the joint action is directed is the same, namely to move the mug from here to there.

Second, there is a similar coordination problem---the agents’ two hands have to meet.

And, third, the evidence we have mentioned suggests that in joint action, motor representations and processes occur in each agent much like those that would occur if this agent were performing the whole action alone. Why would this be helpful?

Suppose the agents' planning-like motor processes are similar enough that, in this context, they will reliably produce approximately the same plan-like structures of motor representations. Then having a single planning-like motor process for the whole joint action in each agent means that > #. in each agent there is a plan-like structure of motor representations concerning each of the others’ actions, > #. each agent's plan-like structure concerning another's actions is approximately the same as any other agent's plan-like structure concerning those actions, > #. each agent's plan-like structure concerning her own actions is constrained by her plan-like structures concerning the other’s actions. So each agent’s plan-like structure of motor representations concerning her own actions is indirectly constrained by the other agents' plan-like structures concerning their own actions by virtue of being directly constrained by her plan-like structures concerning their actions. In this way it is possible to use ordinary planning-like motor processes to achieve coordination in joint action. What enables the two or more agents' plan-like structures of motor representations to mesh is not that they represent each other's plans but that they processes motorically each other's actions and their own as parts of a single action.

So how does the joint action differ from the corresponding individual action? There are at least two differences. First, we now have two plan-like structures of motor representations because in each agent there is a planning-like motor process concerning the whole action. These two structures of motor representations have to be identical or similar enough that the differences don’t matter for the coordination of the agents’ actions---let us abbreviate this by saying that they have to _match_. The need for matching planning-like structures is not specific to joint action; it is also required where one agent observing another is able to predict her actions thanks to planning-like motor processes concerning the other’s actions (we mentioned evidence that this occurs above).

A second difference between the joint action and the individual action is this. In joint action there are planning-like motor processes in each agent concerning some actions which she will not eventually perform. There must therefore be something that prevents part but not all of the planning-like motor process leading all the way to action. Exactly how this selective prevention works is an open question. We expect bodily and environmental constraints are often relevant. There may also be differences in how others’ actions are processed motorically (Novembre, Ticini, Schütz-Bosbach, & Keller, 2012, p. compare][). fn { (Novembre et al., 2012, p. \ 2901): 'in the context of a joint action—the motor control system is particularly sensitive to the identity of the agent (self or other) of a represented action and that (social) contextual information is one means for achieving this distinction'} And inhibition could be involved too (Sebanz, Knoblich, Prinz, & Wascher, 2006, p. compare][).

My proposal, then, is this. In both practical reasoning and motorically, sometimes agents are able to achieve coordination for joint action not by representing each others’ plans but by treating each other's actions and their own as if they were parts of a single action. This is the fundamental idea behind co-representation, as I see it.

Conjecture :
collective goals are represented motorically

> #. There is one outcome which each agent represents motorically, and > #. in each agent this representation triggers planning-like processes > #. concerning all the agents’ actions, with the result that > #. coordination of their actions is facilitated.

Let me explain what this amounts to.

I.e. sometimes, when two or more actions involving multiple agents are, or need to be, coordinated:

Each represents a single outcome motorically, and
in each agent this representation triggers planning-like processes
concerning all the agents’ actions, with the result that
coordination of their actions is facilitated.

Each represents a single outcome motorically, and
in each agent this representation triggers planning-like processes
concerning all the agents’ actions, with the result that
coordination of their actions is facilitated.

What do we need? (i) Evidence that a single outcome to which all the actions are directed is represented motorically.

(ii) Evidence that this triggers planning-like processes,

(iii) where these concern all the agents' actions,

and (iv) the existence of such representations facilitates coordination of the agents' actions.

What are those motor representations doing here?

Conjecture:

Collective goals are represented motorically.

1. If true, how would this conjecture answer our questions about in virtue of what two or more agents’ actions could have a collective goal?

In virtue of each agent representing the collective goal motorically!

But a collective goal is just an outcome. How could you and I each representing an outcome motorically make it a collective goal of our actions?

2. How can we know whether this conjecture is true?

Conjecture:

Collective goals are represented motorically.

Prediction 1 (della Gatta et al., 2017):

Framing two agents’ simultaneous unimanual actions as joint can induce effects similar to bimanual coupling.

Prediction 2 (Sacheli et al., 2018):

Framing two agents’ sequential actions as a joint action modulates the effects of ‘incongruent’ actions.

Sacheli et al, 2018 figure 2 (part)

Sacheli et al, 2018 figure 5

[Skip -- just in case anyone asks]

Sacheli et al, 2018 figure 3

Conjecture:

Collective goals are represented motorically.

Prediction 1 (della Gatta et al, 2017):

Framing two agents’ simultaneous unimanual actions as joint can induce effects similar to bimanual coupling.

Prediction 2 (Sacheli et al):

Framing two agents’ sequential actions as a joint action modulates the effects of ‘incongruent’ actions.

What are those motor representations doing here?

Conjecture:

Collective goals are represented motorically.

1. If true, how would this conjecture answer our questions about in virtue of what two or more agents’ actions could have a collective goal?

In virtue of each agent representing the collective goal motorically!

But a collective goal is just an outcome. How could you and I each representing an outcome motorically make it a collective goal of our actions?

2. How can we know whether this conjecture is true?

collective goal goal outcome

A collective goal (df):

an outcome to which two or more agents’ actions are directed

where

this is not, or not only,

a matter of each action being directed to that outcome.

In virtue of what could two or more agents’ actions have a collective goal?

An interagential structure of motor representation.

In virtue of what could two or more agents’ actions have a collective goal?

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Could Motor Representations Ground Collective Goals?

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