Lecture 08 | Origins of Mind (Warwick 2020)

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Origins of Mind : 08

s.butterfill@warwick.ac.uk

the question

How do humans first come to know simple facts about physical objects, colours, minds and the rest?

(Something like) core knowledge exists.

Core knowledge is real. Infants’ have unexpectedly sophisticated abilities concerning physical objects and categorical colour properties (and much more) even from the first year of life.

There is a gap between core knowledge and knowledge knowledge.

There is a gap between core knowledge and knowledge knowledge. It takes months if not years between clear manifestations of core knowledge and knowledge knowledge. Importantly,

Crossing the gap involves social interactions, perhaps involving words.

Crossing the gap involves social interactions, perhaps involving words.

Core knowledge enables one to distinguish things. For example it enables on to distinguish those things which are blue from those which are not; it enables one to distinguish those events which are causal interactions from those which are not; it enables one to distinguish those sets which have two members from others; and it enables one to distinguish different beliefs about the location of an object (say).

(Here I'm using core knowledge in the broad, schematic sense to refer to representations which are knowledge-like but not knowledge.)

How does core knowledge enable one to correctly use words? I think it modifies the overall phenomenal character of your experience, typically by generating phenomenal expectations (which I called them perceptual expectations earlier in this version of the course). Tuning in to the perceptual expectations can take a long time, which is why there may be a long interval between observing core knowledge and observing the correct use of words.

I also conjecture that using the word facilitates concept acquisition. Many people would probably agree. But how does it do this?

My schematic suggestion is that using the word draws attention to all the things which are Xs. The concept is acquired when you are struck by the question, What do all these have in common?

(Clearly this is not an account of how thinking gets started at all; the appeal to reflection should make this obvious.)

We have quite good evidence for this picture in the cases of colour and number, and there is relevant evidence in the case of mindreading too. (Also speech: phonological awareness is linked to literacy and the particulars of the written language learnt, so that alphabetic languages give a different profile --- alphabet is roughly labelling phonemes.)

The question we've been looking at last week is how children come to correctly use words.

This is about the step from discrimination to learning the correct use of a verbal label.

So there's you and you're observing sequence of stimuli and thanks to core knowledge you're able to discriminate them.

(Something like) core knowledge exists.

Core knowledge is real. Infants’ have unexpectedly sophisticated abilities concerning physical objects and categorical colour properties (and much more) even from the first year of life.

There is a gap between core knowledge and knowledge knowledge.

There is a gap between core knowledge and knowledge knowledge. It takes months if not years between clear manifestations of core knowledge and knowledge knowledge. Importantly,

Crossing the gap involves social interactions, perhaps involving words.

Crossing the gap involves social interactions, perhaps involving words.

Gradually build up from understanding minds and actions to words.

Action: When?

When?

When can infants first track goals to which actions are directed?

Consider a much-replicated study by Woodward and colleagues.

Woodward et al 2001, figure 1

goal vs target

I distinguish {goals} from {targets}. The \emph{target} or \emph{targets} of an action (if any) are the things the towards which it is directed. If kicking a football is the goal of an action, the football is its target. To specify a target of an action is to partially specify one of its goals. But more is required to fully specify a goal, of course.

anatomy of a goal

A goal typically involves a type of action---kicking rather than smashing, say---as well as manners of action---discretely, firmly, and precisely, for example---and perhaps more besides. For a process to \emph{track} a target of an action is for how that process unfolds to nonaccidentally depend in some way on whether that thing is indeed a target of the action. The studies we have considered so far focus on infants’ abilities to track the targets of actions.

anatomy of a goal

For a process to \emph{track} a target of an action is for how that process unfolds to nonaccidentally depend in some way on whether that thing is indeed a target of the action. The studies we have considered so far focus on infants’ abilities to track the targets of actions.

Given the liberal way I have defined tracking a goal, a process which tracks a target is thereby a process which tracks a goal. (The converse will often hold too, although there could be exceptions.) It is conceivable that some types of processes \emph{merely} track targets: that is, processes of this type only ever track goals in virtue of tracking targets. The studies we have considered so far are consistent with the hypothesis that infants are merely tracking targets in this sense.

Are infants under 10 months of age merely tracking targets?

To answer this question, we would ideally have pairs of scenarios in which the target of an action is kept constant while the type of action varies. To the extent that subjects respond appropriately to the difference in type of action, we can be confident that they can distinguish actions not just by their targets but also by their types.

This is illustrated here, where you are habituated to a grasping event and the test events are (a) grasping but with novel kinematics (from a different angle), or (b) a novel goal event (pushing).

Unfortunately, as far as I know this has not yet been done. But there are some studies which, although not intended to get at exactly the issue of whether infants track goals and not just targets of actions, do indirectly shed light on this issue.

These studies demonstrate competence in goal-tracking from nine months of age, and give us no reason to doubt that, in simple enough cases, infants might show competence in goal tracking much earlier.

\citet{Behne:2005dw} created just such pairs of contrasting scenarios. In one of their contrasts, an experimenter holds a ball out for an infant to grasp and then either ‘accidentally’ drops it or teasingly pulls it back. So in each case there is a goal-directed action involving the ball, but in one case the goal of the action is to pass the ball to the infant whereas in the other case the goal is to tease the infant. \citet[Study 2]{Behne:2005dw} found that nine-month-olds (but not six-month-olds) consistently and appropriately discriminated between these scenarios by, for example, banging more when the ball was ‘accidentally’ dropped than when it was teasingly retracted. This and other research (e.g. \citealp{ambrosini:2013_looking}) suggests that, at least from nine months of age, infants can indeed distinguish both the type and target of a goal-directed action.

% \citet{ambrosini:2013_looking} is important: shows that type of grasp and not just target is tracked, implying that anticipatory looking is not merely perceptual animacy.

Evidence from infants in the first nine months

	age (mnths)	target varies	type varies	manner varies
Woodward et al, 2001	6 & 9	✓	x	x
Behne et al, 2005	9	x	✓	x
Ambrosini et al, 2013	6 & 9	✓	✓	x

Infants can track goals from nine months of age (or earlier).

The Teleological Stance

How?

Infants can identify goals from around six months of age.

To more fully specify goal-tracking we need a theory that specifies both the models and the processes involved in goal-tracking.

1. models (How are goals and actions related from the point of view of a 9-month-old?)

2. processes (What links the model to the infant?)

first specify the problem to be solved: goal ascription

Let me first specify the problem to be solved.

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

Planning

1. This outcome, G, is the goal (specification)

2. Means M is a best available* way of bringing G about

3. ∴ adopt means M

Note that this is not exactly an answer to our question, How can infants track goals from nine months of age (or earlier)? It provides what Marr would call a computational description.

That is, it provides a function from facts about events and states of affairs that could be known without knowing which goals any particular actions are directed to, nor any facts about particular mental states to one or more outcomes which are the goals of an action.

Providing this function explains how pure goal-tracking is possible in principle.

But what we want to know, of course, is how infants (and adults) actually compute this function. If this is (roughly) the function which computationally describes pure goal tracking, what are the representations and processes involved in pure goal tracking?

To more fully specify goal-tracking we need a theory that specifies both the models and the processes involved in goal-tracking.

1. models (How are goals and actions related from the point of view of a 9-month-old?)

2. processes (What links the model to the infant?)

The Simple View

The Simple View is a view about the PROCESSES involved ...

\begin{quote} Infants' (and adults') goal tracking depends on beliefs concerning relations which hold quite generally between means and goals; and they identify particular goals by making inferences from these beliefs plus their observations. \end{quote}

Infants and adults engaged in goal-tracking reason about to which outcome a means is the best available in fundamentally the same way that you or I do when trying to work it out explicitly.

Irrespective of who endorses it, the Simple View is a good starting point for at least three reasons. First, it involves postulating no novel psychological states, processes or systems. (It does not entail the existence of a goal-tracking module, for example.) Second, as just illustrated, it is a generalisation from cases in which its claim is known to apply. Third, there are no published, suitably detailed accounts of any alternative. So what if anything is wrong with the Simple View?

How?

Infants can identify goals from around six months of age.

The Teleological Stance is a proposed solution.

To more fully specify goal-tracking we need a theory that specifies both the models and the processes involved in goal-tracking. The Simple View gives us this; but as usual we will see in the next section that it generates incorrect predictions ...

1. models (How are goals and actions related from the point of view of a 9-month-old?)

2. processes (What links the model to the infant?)

A Limit on Goal Tracking in the First Nine Months

limit:

Limits on performance are important because they provide clues about the nature of the underlying processes.

Flanagan and Johansson, 2003 figure 1 (part)

To explain this I have to step back and show you something interesting about adults when they perform, and when they observe actions.

Performing actions (e.g. stacking blocks): you don't look at your hand but at the block it will pick up, or, when holding a block, at the location where it will place a block. That is, in acting the eyes move just ahead of the action.

Kanakogi and Itakura, 2011 figure 1

‘Positive relative times of the arrival of gaze at the goal area indicate that gaze precedes the agent’s arrival (predictive); negative values indicate gaze arrival after agent arrival (non-predictive). Each age group is n = 12. Error bars are s.e.m.’

GH : grasping hand; BH : back of hand; MC : mechanical claw

Kanakogi and Itakura, 2011 figure 5 (part)

Kanakogi & Itakuar, 2011 show that abilities to grasp objects are correlated with abilities to track the goal of a grasping action (as measured by proactive gaze).

x-axis is alpha, grasping angle. ‘An α angle value from 90 to 180° indicates that the infant is engaged in a one-handed grasping action.’

‘The angle α is an index of the development of the onehanded grasping action and was calculated by measuring the angle of a straight line de ned by the infant’s two hands (the apex of the junction of the thumb and index nger) when crossed by an imaginary line projecting frontally from the infant (Fig. 2b). If infants grasped for the objects with their le hand, we reversed the red rightangled triangle from one side to the other side and calculated the angle α in the same way. e angle α value of 90° corresponded to a perfect alignment of the hands in a twohanded reach. erefore, the angle α value deviates from 90° towards 180°, and bigger angle α value indicates more mature onehanded grasping. If the angle α was over 90°, the infant was considered to be engaged in a onehanded grasping action.’

Ambrosini et al, 2013 figure 1 (part)

Further support for a link between action performance and goal tracking comes from a developmental study by Ambrosini et al which studied whether proactive gaze in infants is influenced by pre-shaping of the hand, and, in particular, whether it is influenced by precision grips.

Ambrosini et al, 2013 figure 1 (part)

Ambrosini et al, 2013 figure 1 (part)

By using no shaping (a fist), Ambrosini et al could treat sensitivity to whole-hand grasp and precision grip separately.

Ambrosini et al, 2013 figure 3

‘infants’ ability to perform specific grasping actions with fewer fingers directly predicted the degree with which they took advantage of the availability of corresponding pre-shape motor information in shifting their gaze towards the goal of others’ actions’ \citep[p.~6]{ambrosini:2013_looking}.

Kanakogi and Itakura, 2011 figure 1C (part)

Further, changing from a bodily action to the operation of a mechanical claw (say) undermines the goal tracking effect.

So Kanakogi & Itakuar, 2011 make two points: (i) goal-tracking depends on action capabilities; and (ii) only works for events involving biomechanically similar affectors

Kanakogi and Itakura, 2011 figure 5

If infants can only track goals of actions they can perform, what happens if you intervene on their abilities to act?

Needham et al, 2002 / https://news.vanderbilt.edu/files/sticky-mittens.jpg

Needham et al, 2002 showed that putting ‘sticky mittens’ on 3-month-old infants (for 10-14 play sessions of 10 minutes each) resulted in their spending more time visually and manually exporing novel objects.

Sommerville, Woodward and Needham, 2005

Play wearing mittens then observe action.

vs

Observe action then play wearing mittens.

In this study, I think infants wore the mittens for just 200 seconds (so the play sessions were much shorter than in Needhman et al, 2002).

The observation was based on this study, which we saw earlier

Woodward et al 2001, figure 1

Sommerville, Woodward and Needham, 2005 figure 3

Sommerville, Woodward and Needham, 2005 figure 3

The results show that infants who played wearing the mittens first were more attentive to the goal.

From at least three months of age, some of infants’ abilities to identify the goals of actions they observe are linked to their abilities to perform actions \citep{woodward:2009_infants}.

But one potential objection to this study concerns observation vs performance. The infants who played wearing sticky mittens first had spent longer observing actions by the time it came to the violation of expectations trial. Could it be observation of action (including one’s own) rather than performance that matters?

In adults, tying the hands impairs proactive gaze \citep{ambrosini:2012_tie}; in infants, boosting grasping with ‘sticky mittens’ facilitates proactive gaze (\citealp{sommerville:2005_action}; see also \citealp{sommerville:2008_experience}, \citealp{ambrosini:2013_looking}).

Sommerville et al 2008, figure 1

To address this issue, \citet{sommerville:2008_experience} did a study in which one group had observation while the other group had performance. The participants were 10-month-old infants this time.

The materials were a bit different: so that training vs observation could be as similar as possible with respect to the causal structure exposed, there was a hook to get an object.

Sommerville et al 2008, figure 2

The results show that infants with the training paid attention to the distal goal (choice of toy) whereas those without paid attention to the choice of cane.

... or IMPAIR INDIRECTLY ...

Bruderer et al, 2015 figures 1, 4

Experiment 1 : shows that 6-month-old infants can distinguish a phonetic contrast they have never heard before (one that occurs in Hindi but not their linguistic environments.) (The contrast used was the Hindi dental /d/̪ versus retroflex /ɖ/ distinction.)

These graphs show a difference in mean looking time between cases in which phonemes are alternated and cases in which they are not. (Iff infants distinguish, they should find the alternating phonemes more interesting.)

Experiment 2: but not when they have a tongue-controlling dummy in their mouths

Experiment 3: but yes when they have a dummy which leaves the tongue free.

limit:

I don’t think we have found strong evidence for this limit. What we can conclude, more weakly, is that there is some limiting relation linking goal-tracking and abilities to act.

infants in their first nine months of life
can only track the goals of an action
if they can perform a similar enough action
around the time the action occurs.

Why?

In infants (and adults),
goal-tracking is limited by their abilities to act.

Why is this true? Why is goal-tracking in infants (and adult) limited by their abilities to act? On the Simple View, goal tracking is a matter of thinking and reasoning about the best means to perform an action. On this View, there’s no obvious reason why your goal-tracking should be limited by your abilities to act in this way.

Although I can’t jump over a house, I can perfectly well think about different ways to do so and distinguish better and worse approaches, at least to some extent.

The Motor Theory of Goal Tracking

Fogassi et al 2005, figure 5

The Double Life of Motor Representation

What follows rests on three background assumptions about the control of action. First, I follow \citet{jeannerod_motor_2006} and others in rejecting the view that all motor representations specify only bodily configurations, joint displacements and end states. Instead some motor representations specify outcomes to which actions are directed, such as the grasping of a particular handle or the transporting of a given object.

Second, some motor processes involve computing means from ends and generating sensory expectations concerning the effects of actions \citep[e.g.][]{Wolpert:2003mg}.

Third, multiple means--ends computations can occur simultaneously, or at least rapidly enough for action preparation to involve selection on the basis of multiple means-ends computations \citep[e.g.][]{wolpert_internal_1998}.

We know this in large thanks to the discovery of mirror neurons and their consequences.

‘(A) Congruence between the visual and the motor response of a mirror neuron. Unit 169 has a stronger discharge during grasping to eat than during grasping to place, both when the action is executed and when it is observed. Conventions as in Fig. 1. (B) Population-averaged responses during motor and visual tasks (12).’

Suppose you are reaching for, grasping, transporting and then placing a pen. Performing even relatively simple action sequences like this involves satisfying many constraints that cannot normally be satisfied by explicit practical reasoning, especially if performance is to be rapid and fluent. Rather, such performances require motor representations. These representations are paradigmatically involved in preparing, executing and monitoring actions.% \footnote{% See \citet{wolpert:1995internal, miall:1996_forward, jeannerod:1998nbo, zhang:2007_planning}. Note that motor representations sometimes occur in an agent who has prepared an action and is required (as it turns out) not to perform it: although she has prevented herself from acting, motor representations specifying the action persist, perhaps because they are necessary for monitoring whether prevention has succeeded \citep{bonini:2014_ventral}. } But they also live a double life. Motor representations concerning a particular type of action are involved not only in performing an action of that type but also sometimes in observing one. That is, if you were to observe Ayesha reach for, grasp, transport and then place a pen, motor representations would occur in you much like those that would also occur in you if it were you---not Ayesha---who was doing this.

Converging evidence for this assertion comes from a variety of methods and measures; but I won’t mention any of that here.

Motor Theory of Goal Tracking (including Speech Perception)

mTgt is an alternative to the Simple View. The idea is that pure goal-tracking involves motor processes rather than thinking and reasoning about goals.

But how could motor processes enable goal tracking?

Sinigalia & Butterfill 2015, figure 1

Goal-tracking is acting in reverse. -- in action observation, possible outcomes of observed actions are represented -- these representations trigger planning as if performing actions directed to the outcomes -- such planning generates predictions -- a triggering representation is weakened if its predictions fail The result is that the only only outcomes to which the observed action is a means are represented strongly.

There is evidence that a motor representation of an outcome can cause a determination of which movements are likely to be performed to achieve that outcome \citep[see, for instance,][]{kilner:2004_motor, urgesi:2010_simulating}. Further, the processes involved in determining how observed actions are likely to unfold given their outcomes are closely related, or identical, to processes involved in performing actions. This is known in part thanks to studies of how observing actions can facilitate performing actions congruent with those observed, and can interfere with performing incongruent actions \citep{ brass:2000_compatibility, craighero:2002_hand, kilner:2003_interference, costantini:2012_does}. Planning-like processes in action observation have also been demonstrated by measuring observers' predictive gaze. If you were to observe just the early phases of a grasping movement, your eyes might jump to its likely target, ignoring nearby objects \citep{ambrosini:2011_grasping}. These proactive eye movements resemble those you would typically make if you were acting yourself \citep{Flanagan:2003lm}. Importantly, the occurrence of such proactive eye movements in action observation depends on your representing the outcome of an action motorically; even temporary interference in the observer's motor abilities will interfere with the eye movements \citep{Costantini:2012fk}. These proactive eye movements also depend on planning-like processes; requiring the observer to perform actions incongruent with those she is observing can eliminate proactive eye movements \citep{Costantini:2012uq}. This, then, is further evidence for planning-like motor processes in action observation.

So observers represent outcomes motorically and these representations trigger planning-like processes which generate expectations about how the observed actions will unfold and their sensory consequences. Now the mere occurrence of these processes is not sufficient to explain why, in action observation, an outcome represented motorically is likely to be an outcome to which the observed action is directed.

To take a tiny step further, we conjecture that, in action observation, \textbf{motor representations of outcomes are weakened to the extent that the expectations they generate are unmet} \citep[compare][]{Fogassi:2005nf}. A motor representation of an outcome to which an observed action is not directed is likely to generate incorrect expectations about how this action will unfold, and failures of these expectations to be met will weaken the representation. This is what ensures that there is a correspondence between outcomes represented motorically in observing actions and the goals of those actions.

‘proactive gaze’ and ‘explicit judgement’ are variables whose values represent whether there is a proactive gaze or explicit judgement, and what is it to or about. Likewise, ‘motor process’ is a variable whose values represent ...

The lines depict how the variables are causally related. I’ve used thick and thin lines informally, to indicate weaker and stronger influences.

The dual-process theory of goal-tracking makes perfect sense of development. It says that what we observe in six- and nine-month-olds is motor-based goal-tracking. Presumably the more flexible, reasoning-based goal-tracking processes emerge some time later in development.

Motor Conjecture

In 9-month-olds,

all pure goal-tracking is explained by the Motor Theory;

How?

Infants can track goals from nine months of age (or earlier).

Why?

In infants (and adults),
goal-tracking is limited by their abilities to act.

The ‘Teleological Stance’
~ The goals of an action are those outcomes which the means is a best available way of bringing about.

Csibra & Gergely

Tracking

1. This means, m, has been adopted (observation)

2. G is an outcome such that: m is a best available* way of bringing G about

3. ∴ G is a goal of the observed action

Important that mTgt is not an alternative to the Teleological Stance but to it plus the claim about reasoning.

Simple View and mTgt do not differ on the relation between means and goals that is to be computed in pure goal-tracking. The Simple View and mTgt differ only on what processes is responsible for identifying which outcome or outcomes the observed means is a best available way of achieving.

‘simulation is clearly a natural and effective way to find the most efficient action towards a goal state.’

Csibra & Gergely, 2007 p. 72

	The Simple View	Motor Conjecture
What is the function to be computed?	[Teleological Stance]	[Teleological Stance]
How is this function computed?	By reasoning from beliefs.	By using motor processes ‘in reverse’.
Why is goal-tracking limited by action ability?	???	Because both rely on motor processes.

A Puzzle About Goal Tracking

Kanakogi and Itakura, 2011 figure 1C (part)

Earlier I mentioned this experiment, which shows that infants fail to track goals involving things which would appear to them to be biomechanically non-agent-like events. But ...

\#source 'research/teleological stance -- csibra and gergely.doc'

\#source 'lectures/mindreading and joint action - philosophical tools (ceu budapest 2012-autumn fall)/lecture05 actions intentions goals'

\#source 'lectures/mindreading and joint action - philosophical tools (ceu budapest 2012-autumn fall)/lecture06 goal ascription teleological motor'

When do human infants first track goal-directed actions and not just movements?

Here's a classic experiment from way back in 1995.

The subjects were 12 month old infants.

They were habituated to this sequence of events.

Gergely et al 1995, figure 1

For the test condition, infants were divided into two groups. One saw a new action, ...

... the other saw an old action.

Now if infants were considering the movements only and ignoring information about the goal, the 'new action' (movement in a straight line) should be more interesting because it is most different.

But if infants are taking goal-related information into action, the 'old action' might be unexpected and so might generate greater dishabituation.

Gergely et al 1995, figure 3

Gergely et al 1995, figure 5

‘by the end of the first year infants are indeed capable of taking the intentional stance (Dennett, 1987) in interpreting the goal- directed behavior of rational agents.’

\citep[p.\ 184]{Gergely:1995sq}

‘12-month-old babies could identify the agent’s goal and analyze its actions causally in relation to it’

\citep[p.\ 190]{Gergely:1995sq}

You might say, it's bizarre to have used balls in this study, that can't show us anything about infants' understanding of action.

But adult humans naturally interpret the movements of even very simple shapes in terms of goals.

So using even very simple stimuli doesn't undermine the interpretation of these results.

Heider and Simmel, figure 1

Consider a further experiment by \citet{Csibra:2003jv}, also with 12-month-olds. This is just like the first ball-jumping experiment except that here infants see the action but not the circumstances in which it occurs. Do they expect there to be an object in the way behind that barrier?

Csibra et al 2003, figure 6

Here then is the puzzle about development that I mentioned this talk was about:

Puzzle

In infants under 10 months,
it appears that
some,
but not all,
goal-tracking is limited by their abilities to act.

Let me recap how we got here and why this is puzzling.

I started by asking, How 9-month-olds track can goals? The Simple View offers one answer: the principles comprising the Teleological Stance are things they know or believe, and they are able to track goals by making inferences from these principles.

I suggested that the Simple View should be rejected because it cannot explain why infants’ abilities to track goals are limited by their abilities to perform actions.

At least, mTga provides a better alternative to the Simple View. According to mTga, Infants’ pure goal-tracking depends on the double life of motor processes.

mTga correctly predicts that infants’ pure goal-tracking should be limited by infants’ abilities to act ...

Daum et al, 2012 figure 1

Daum et al created a modified version of Woodward’s paradigm which allowed them to measure both anticipatory looking and dishabituation.

where researchers have measured two different responses to a single scenario, anticipatory looking and either dishabituation or pupil dilation. Generally, they appear to find evidence for goal tracking in dishabituation or pupil dilation but not in anticipatory looking. (This is true of Daum et al, 2012; and Gredeback and Melinder, 2010.)

Why the discrepancy? This is another question we can’t answer with the Motor Theory of Goal Tracking.

Daum et al, 2012 figure 2

[skip -- just here in case need for discussion; shows that anticipatory looking to cartoon fish takes years to develop]

Here then is another puzzle about development:

Puzzles

In infants under 10 months,
it appears that
some,
but not all,
goal-tracking is limited by their abilities to act ...

... and that goal-tracking sometimes manifests in dishabitution or pupil dilation but not proactive gaze.

The \textbf{second puzzle} is how to explain, in a principled way, why there should be discrepancies between these measures. We cannot do this by invoking mTgt because on mTgt, proactive gaze is a case in which goal-tracking is paradigmatically manifest.

Perceptual Animacy

\emph{perceptual animacy}, the detection by broadly perceptual processes of animate objects and their targets.

Gao et al, 2009 figure 2

Evidence for the existence of perceptual animacy comes from a variety of studies where adults are given a simple visual task such as identifying which circle is the ‘wolf’ and which the ‘sheep’, or, in another experiment, moving the sheep around in order to avoid being caught by the wolf.

It is also possible to examine how having a sheep and a wolf affects how attention is allocated by measuring how well participants can detect probes placed on different shapes.

The literature on perceptual animacy mostly confounds it with goal tracking. But there are two key differences.

First, perceptual animacy is a broadly perceptual phenomenon.

Second, the perceptual detection of animacy is clearly distinct from goal tracking for it involves detecting relations between objects in motion rather than outcomes to which actions are directed. Relatedly, it does not involve sensitivity to the type of action. And the perceptual detection of animacy appears to depend on simple cues and heuristics and is unlikely to be correctly described by the Teleological Stance. So perceptual animacy does not involve tracking goals to which an action is directed: it is a matter of tracking objects to which animate movements are directed.

Gao et al, 2009 figure 3b

\emph{{perceptual animacy}}, the detection by broadly perceptual processes of animate objects and their targets. To illustrate, consider a groundbreaking experiment by \citet[experiment 1]{gao:2009_psychophysics}. Adults were shown a display which contained some moving circles. In some cases the circles moved independently of each other, but in other cases there was a ‘wolf’ which chased a ‘sheep’ with varying degrees of subtlety. The adults’ task was simply to detect the presence of a wolf. \citeauthor{gao:2009_psychophysics} established that adults can do this providing the chasing is not too subtle. In further experiments, they also showed that adults’ abilities to perceptually detect chasing depend on several cues including whether the chaser ‘faces’ its target (‘directionality’) and how directly the chaser approaches its target (‘subtlety’). The detection of animacy appears to be a broadly perceptual phenomena since it depends on areas of the brain associated with vision and influences how perceptual attention is allocated \citep{scholl:2013_perceiving} irrespective of your beliefs and intentions \citep{buren:2016_automaticity}.

Gao et al, 2009 figures 3b, 4a

[This comparison is a bit confused because pure-goal tracking is the kind of thing that can be (and is) achieved by way of different mechanisms (e.g. reasoning; motor processes), whereas perceptual animacy is a mechanism.]

	pure goal-tracking	perceptual animacy
What is tracked?	actions & goals	animate objects & targets
Computational description?	Teleological Stance	spatio-temporal heuristics (e.g. subtlety, directionality)
Processes & representations?	motoric	perceptual

The perceptual detection of animacy resembles goal tracking, for it involves detecting a relation between a chaser and its target. However the perceptual detection of animacy is clearly distinct from goal tracking.% \footnote{% Contrast \citet{schlottmann:2010_goal,Scholl:2000eq} who all claim that perceptual animacy is a matter of, or involves, tracking goals. } For one thing, it involves detecting relations between objects in motion rather than outcomes to which actions are directed. Relatedly, it does not involve sensitivity to the type of action. Finally, the perceptual detection of animacy appears to depend on simple cues and heuristics and is unlikely to be correctly described by the Teleological Stance. For these reasons, we should distinguish the perceptual detection of animacy from tracking goals to which actions are directed.

To illustrate, we have to recognise that, in adults, there are multiple processes involved in tracking actions, which are differently affected by changes in context, and which probably have different affects on different kinds of responses to observed and anticipated actions.

Here is a rough guess about how things look IN ADULTS.

Motor Conjecture Revised

In 9-month-olds,

all pure goal-tracking is explained by the Motor Theory;

appearances that goal-tracking is not limited by their abilities to act are due to perceptual animacy.

what’s already in infants ...

How does the conjecture help with the puzzles about development?

Puzzles

In infants under 10 months,
it appears that
some,
but not all,
goal-tracking is limited by their abilities to act ...

... and that goal-tracking sometimes manifests in dishabitution or pupil dilation but not proactive gaze.

The second puzzle was a dissociation between dishabituation and pupil dilation on the one hand and proactive gaze on the other. The conjecture I have formulated suggests a solution: perhaps perceptual animacy is sometimes responsible for pupil dilation and dishabituation; but never responsible for proactive gaze.

objection

Gao et al, 2009 figure 3b; Csibra et al 2003, figure 6

further complication: associative learning for sequencing

conclusions

First conclusion: there is a developmental puzzle about goal tracking

Puzzles

In infants under 10 months,
it appears that
some,
but not all,
goal-tracking is limited by their abilities to act ...

... and that goal-tracking sometimes manifests in dishabitution or pupil dilation but not proactive gaze.

The \textbf{second puzzle} is how to explain, in a principled way, why there should be discrepancies between these measures. We cannot do this by invoking mTgt because on mTgt, proactive gaze is a case in which goal-tracking is paradigmatically manifest.

I defended this conjecture (partially)

Motor Conjecture Revised

In 9-month-olds,

all pure goal-tracking is explained by the Motor Theory;

appearances that goal-tracking is not limited by their abilities to act are due to perceptual animacy.

This conjecture is quite bold, but I think it’s one worth betting on partly because, as I suggested, it generates readily testable predictions.

This conjecture also has another virtue. Goal-tracking is so fundamental to social cognition and joint action that it is likely to depend on a rich mix of many kinds of processes, including associative learning. We need ways to identify these processes, to distinguish their limits and to understand their synergies. Distinguishing motor processes which support goal-tracking by realising the Teleological Stance from perceptual animacy is a step towards meeting this need.

What do infants understanding of goal-directed actions?

They can track goals from around 3 months of age,

but this does not imply knowledge of action

because infants’ abilities, like adults’, involve motor processes (and perhaps associative learning too).

Key thing is that we don’t have to postulate knowledge of goals; earliest goal-tracking abilities can be invoked to explain the developmental emergence of knowledge (of goals, and of other things).

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