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Action: The Basics

Our first question is, When do human infants first track goal-directed actions and not just movements? In examining nonlinguistic communication, we've assumed that infants from around 11 months of age can produce and comprehend informative pointing. This commits us to saying that they have understood action.

When do human infants first track goal-directed actions
rather than mere movements only?

Background assumption

‘intention attribution and action understanding are two separable processes’

Uithol and Paulus, 2014 p. 617

Background assumption: ‘intention attribution and action understanding are two separable processes’ \citep[p.~617]{uithol:2014_what}.
\#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.
There was also a control group who were habituated to a display like this one but with the central barrier moved to the right, so that the action of the ball is 'non-rational'.

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 acction, 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

Consider a related study by Woodward and colleagues.
(It's good that there is converging evidence from different labs, using quite different stimuli.)

Woodward et al 2001, figure 1

'Six-month-olds and 9-month-olds showed a stronger novelty response (i.e., looked longer) on new-goal trials than on new-path trials (Woodward 1998). That is, like toddlers, young infants selectively attended to and remembered the features of the event that were relevant to the actor’s goal.'
\citep[p.\ 153]{woodward:2001_making}

from three months of age

Using a manipulation we’ll discuss later (‘sticky mittens’), \citet{sommerville:2005_action} used this paradigm to show that even three-month-olds can form expectations based on the goal of an action (for another study with three-month-olds, see also \citealp{luo:2011_threemonthold}).

Daum et al, 2012 figure 1

\citet{daum:2012_actions} adapted Woodward et al’s paradigm so that they could simultaneously measure looking time and anticipatory looking.
You can see that there’s a round occluder in the middle of the display. The agent, a red fish, moves behind this on it’s way to visit one of two objects.
In Experiment 1, First a small fish moves towards one object six times (familiarization). Then the locations of objects were swaped and infants’ responses were measured during six test trials. In these trials, the agent (red fish) moved on the same path towards a new goal three times; and it did the converse three times.
Just as you'd expect given Woodward et al 2001, 9-month old infants looked longer when the fish (agent) moved towards a new goal (same path) than when it moved towards the same goal on a new path.
BUT where were the infants looking in anticpation of the agent’s reappearance? It turns out that, on the whole, they were looking as if the agent were moving on the same path to a new goal. So there’s a dissocaition between anticipatory looking and violation-of-expectations measures for 9 month olds.
‘The results of the analysis of the infants’ eye movements contrast the looking time results and showed at the age of 12 months (and less reliably at the age of 9 months) infants predicted the reappearance of the agent based on the location of the goal during an observed action and that it was not until the age of 3, that this dissociation disappeared and that children predicted the reappearance of the agent after occlusion based on goal identity’ \citep[p.~9]{daum:2012_actions}/
‘Early in life, action expectations measured online seem to be organized around goal locations whereas action expectations measured post-hoc around goal identities. With increasing age, children then generally organize their action expectations primarily around goal identities’ \citep[p.~10]{daum:2012_actions}

Daum et al, 2012 figure 2 (part)

In a follow up experiment, \citet{daum:2012_actions} considered anticipatory looking with these stimuli for a range of agents including adulthoot.
As you can see, adults’ anticipatory looking is generally to the same-goal but different-path location, which is also what 3-year-olds do.
Why is there a dissocaition between anticipatory looking and violation-of-expectations measures for 9 month olds?
One possibility noted by \citet{daum:2012_actions} is that anticipatory looking requires rapid computation of the goal and its consequences for movement. It may be that infants simply cannot compute the goal in the few hundren milliseconds available for anticipatory looking.
This doesn’t sound very interesting, but note that 9-month-old infants seem to be making anticipatory looks. This suggests that they may be guided by contingency information in making their anticipatory looks. This is potentially important as a clue that action anticipation is driven by a mixture of goal ascription and statistical information.
Also these findings need cautious interpretation. Cf \citep[p.~7]{ambrosini:2013_looking}: ‘some visual anticipation studies show that 12-month-olds and even 10-month-olds, but not 6-month-olds, can predictively gaze to the goal position when observing displacement actions [9,12], while some others demonstrate that even 6-month-olds show anticipatory fixations to the goal of observed actions [34,35].’ See also` \citet{cannon:2012_infants}.

Green et al, 2016 figure 1 (part)

Chopsticks vs spoons, Sweeden vs China, 8-month-olds.
Would they look at the bowl when the chopsticks or spoon was held? (No!)
Would they look at the mouth when the chopstick or spoon was loaded with a cracker? Let’s have a look ...

Green et al, 2016 figure 1 (part)

Green et al, 2016 figure 1 (part)

Green et al, 2016 figure 2

\citep[p.~743]{green:2016_culture}: ‘Consistent with prior findings, the current study also demon- strates that infants need to have the ability to per- form similar actions themselves. In other words, culture appears to work together with the obser- vers’ own motor plans in order to facilitate goal prediction. Infants predict the goal of actions that are similar to their own motoric capability (like put- ting things in their mouth), but only for actions per- formed with a tool frequently occurring in the cultural context in which they live. The influence of one’s own motor capability is expressed primarily as a lack of prediction during the picking up food part of the action and the presence of prediction during self-oriented actions (i.e., bringing objects to the mouth and eating).’
Figure caption: ‘Mean gaze latency (negative numbers = prediction) to arrive at the goal when observing eating actions directed toward the mouth using a spoon (squares) and chopsticks (circles) in China and Sweden. Error bars represent standard errors.’