The Interface Problem: Motor Representation vs Intention

Click here and press the right key for the next slide.

(This may not work on mobile or ipad. You can try using chrome or firefox, but even that may fail. Sorry.)

also ...

Press the left key to go backwards (or swipe right)

Press n to toggle whether notes are shown (or add '?notes' to the url before the #)

Press m or double tap to slide thumbnails (menu)

Press ? at any time to show the keyboard shortcuts

The Interface Problem: Motor Representation vs Intention

✓ intention and motor representation match

[glossary:] Two collections of outcomes, A and B, *match* in a particular context just if, in that context, either the occurrence of the A-outcomes would normally constitute or cause, at least partially, the occurrence of the B-outcomes or vice versa.

is it possible?

What do you think? How could this happen? Can you imagine how this might come about?

anarchic hand syndrom from dr strangelove (Della Sala, Marchetti, & Spinnler, 1991)

[for the future—do not say this yet!] One limit of AHS: it does not show that the intention gives rise to a non-matching motor representation (instead it appears that other factors overcome the intention’s influence).

By contrast Norman’s croutons (coming later) do show an intention causing a motor representation but the wrong one.

anarchic hand syndrom

‘The right hand frequently carried out complex activities that were not willed by G.C.

(Della Sala et al., 1991, p. 1114)

Go really slowly here. Drive it home by saying it again. (Do not comment, just repeat)

Bing AI / Marchetti & Sala (1997, p. 344)

More background on AHS: (Mylopoulos & Pacherie, 2016, p. 7): ‘Typically the result of lesion to SMA or anterior corpus callosum, AHS is a condition in which patients perform complex, goal-oriented movements with their cross-lesional limb that they feel unable to directly inhibit or control. The limb is often disproportionately reactive to environmental stimuli, carrying out habitual behaviors that are inappropriate to the context, e.g., grabbing food from a dinner companion’s plate (Della Sala 2005, 606). It is clear from many of the behaviors observed in these cases that the anarchic limb fails to hook up with the agent’s intentions.’

Btw, although (Mylopoulos & Pacherie, 2016, p. 7) are correct that the example is given in Della Sala 2005 (=https://www.bps.org.uk/psychologist/anarchic-hand), it involves ice-cream and is better explained in Marchetti & Sala (1997, p. 344) (the canonical source).

See Marchetti & Sala (1997, p. 344) On Mrs GP: ‘the patient told us that on one occasion, at dinner with friends and relatives, much to her embarassment and others’ dismay, her left hand grabbed the ice-cream that one of the guests was eating, unable to stop herself, at the same time complaining that this was not what she wanted to do.’

✓ intention and motor representation match

✗ intention and motor representation fail to match

is it possible?

Tucker & Ellis (1998, p. figure 1)

Task is to judge whether right-way-up or up-side-down. Responses are left–right keypress.

Tucker & Ellis (1998, p. figure 2)

✓ intention and motor representation match

✗ intention and motor representation fail to match

One limit of AHS: it does not show that the intention gives rise to a non-matching motor representation (instead it appears that other factors overcome the intention’s influence).

By contrast Norman’s croutons (coming later) do show an intention causing a motor representation but the wrong one.

Everyday counterpart is action slips.

action slips

ex Norman’s student’s croutons

Norman (1981); Mylopoulos (2022)

‘I was at the end of a salad bar line, sprinkling raisins on my heaping salad, and reached into my left pocket to get a five-dollar bill. The raisins knocked a couple of croutons from the salad to the tray. I reached and picked them up, intending to pop them into my mouth. My hands came up with their respective loads simultaneously, and I rested the hand with the croutons on the tray and put the bill in my mouth, actually tasting it before I stopped myself.’ (Norman, 1981, p. 10) [this was a student]

bing.com ai / Norman (1981, p. 10)

[source:] https://www.bing.com/images/create/anime-create-a-four-panel-comic-depicing-this-stor/1-656222512eb74c629cf230e655e63ee3?id=dZMlKTDnkpWAFeSDic5R%2bw%3d%3d&view=detailv2&idpp=genimg&FORM=GCRIDP&mode=overlay

Norman’s (Student’s) Croutons

✓ intention and motor representation match

✗ intention and motor representation fail to match

Action slips overcom the limit of AHS: they do not show that the intention gives rise to a non-matching motor representation (in the sense that the intention clearly plays some role—the actions are not entirely contrary to the intention).

‘both mundane cases of action slips and pathological conditions, such as apraxia or anarchic hand syndrome (AHS), illustrate the existence of an interface problem.’

Mylopoulos and Pacherie (2016, p. 7)

Jeannerod 2006, p. 12: ‘the term apraxia was coined by Liepmann to account for higher order motor disorders observed in patients who, in spite of having no problem in executing simple actions (e.g. grasping an object), fail in actions involving more complex, and perhaps more conceptual, representations.’

Can people with ideomotor apraxia form intentions?

Marchetti & Sala (1997, p. 341): ‘Apraxia is generally defined by default as a disorder in the purposeful execution of movements which cannot be explained by elementary motor or sensory deficits or cognitive impairment (De Renzi, 1989).’

Apraxia maybe best thought of as continuous with action slips.

Compare Mayer, Reed, Schwartz, Montgomery, & Palmer (1990, p. 263): ‘our observations suggest that there is a continuum of executive impairment, such that at the most severe end, patients experience difficulties with planning and organizing in even the most routine (ADL) tasks and are incapable of engaging in higher-level, nonroutine activities. With recovery, or less severe impairment, the patient may carry out ADL tasks normally but break down where more extensive planning and organization is required (e.g., managing family budgets).’

Their examples include eating breakfast cerial with a fork, putting on trousers before underwear and putting pepper into milk or custard on to bread, and putting toothpaste onto razor (Mayer et al., 1990, p. table 11–1, 262).

So time to say what it is ...

The interface problem: explain how intentions and motor representations, with their distinct representational formats, are related in such a way that, in at least some cases, the outcomes they specify non-accidentally match.

‘both mundane cases of action slips and pathological conditions, such as apraxia or anarchic hand syndrome (AHS), illustrate the existence of an interface problem’ (Mylopoulos & Pacherie, 2016, p. 7).

Two collections of outcomes, A and B, \emph{match} in a particular context just if, in that context, either the occurrence of the A-outcomes would normally constitute or cause, at least partially, the occurrence of the B-outcomes or vice versa. To illustrate, one way of matching is for the B-outcomes to be the A-outcomes. Another way of matching is for the B-outcomes to stand to the A-outcomes as elements of a more detailed plan stand to those of a less detailed one.

image is from dall-e

Imagine that you are strapped to a spinning wheel facing near certain death as it plunges you into freezing water. To your right you can see a lever and to your left there is a button. In deciding that pulling the lever offers you a better chance of survival than pushing the button, you form an intention to pull the lever, hoping that this will stop the wheel. If things go well, and if intentions are not mere epiphenomena, this intention will result in your reaching for, grasping and pulling the lever. These actions---reaching, grasping and pulling---may be directed to specific outcomes in virtue of motor representations which guide their execution. It shouldn't be an accident that, in your situation, you both intend to pull a lever and you end up with motor representations of reaching for, grasping and pulling that very lever, so that the outcomes specified by your intention match those specified by motor representations. If this match between outcomes variously specified by intentions and by motor representations is not to be accidental, what could explain it?

As we have just seen, motor representations specify goals.

Intentions specify goals.

And of course, so do intentions.

Some actions involve both intention and motor representation.

Further, many actions involve both intention and motor representation. When, for example, you form an intention to turn the lights out, the goal of flipping the light switch may be represented motorically in you.

The nonaccidental success of our actions therefore depends on the outcomes specified by our intentions and motor representations matching.

We know that they do not always match, but ...

On the other hand, if there are never non-accidental matches then good luck getting off that spinning wheel even if you are right about the lever

Now we have to ask, How are nonaccidental matches possible? If you asked a similar question about desire and intention, the answer would be straightforward: desire and intention are integrated in practical reasoning, so it is no surprise that what you intend sometimes nonaccidentally conforms to what you intend. But we cannot give the same sort of answer in the case of motor representations and intentions because ...

Intention and motor representation are not inferentially integrated.

Beliefs, desires and intentions are related to the premises and conclusions in practical reasoning. Motor representations are not. Similarly, intentions do not feature in motor processes.

Failure of inferential integration follows from the claim that they differ in format and are not translated. But I suspect that more people will agree that there is a lack of inferential integration than that they differ in representational format. (must illustrate format with maps).

So this is the Interface Problem: how do the outcomes specified by intentions and motor representations ever nonaccidentally match?

Check you understand (lots on solutions)

interface problem #1:
motor representations vs intentions ✓

interface problem #2:
preference vs aversion

Keyboard Shortcuts?f

The Interface Problem: Motor Representation vs Intention

Keyboard Shortcuts`?f`