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A Problem

As just mentioned, the Simple View is the view that the principles of object perception are things that we know, and we generate expectations from these principles by a process of inference..

scientific intuitive arguments against the simple view

Why must we reject the simple view?
You might have intuitive arguments against it. It is perhaps hard to accept that four-month-old infants are in the business of formulating and revising hypotheses. (Come to think of it, it’s quite hard to accept that adults typically acquire representations of unperceived objects by formulating and revising hypotheses.) Also we might think of inference as something that a detective does. It is not obvious that the same process is occurring in infants. But these considerations are narrowly intuitive. Science sometimes indicates that intuitions are wrong, even intuitions about very fundamental things like space and time. And, most importantly, if infants aren’t making inferences on the basis of knowlegde, what are they doing that enables them to pass violation-of-expectation tasks?
I think we shouldn't try to challenge the simple view on the basis of intution.
And we don't need to because there are also scientific reasons for rejecting the simple view.
One set of reasons concerns the apparent discrepancy between looking times and manual search ...
*(The basic idea is to say there's a discrepancy regarding BOTH (a) permanence and (b) causal interactions)

conflicting evidence: permanence

Baillargeon et al 1987, figure 1

Recall this experiment which used habituation to demonstrate infants' abilities to represent objects as persiting while unperceived (in this case, because occluded). Infants can do this sort of task from 2.5 months or earlier \citep{Aguiar:1999jq}.
But what happens if instead of measuring how infants look, we measure how they reach?
\citet{Shinskey:2001fk} did just this. Here you can see their appratus. They had a screen that infants could pull forwards to get to an object that was sometimes hidden behind it. They made two comparisons. First, were infants more likely to pull the screen forwards when an object was placed behind it? Second, were how did infants' performance compare when the barrier was not opaque but transparent?

Shinskey and Munakata 2001, figure 1

Here are their results with 7-month old infants.

Shinskey and Munakata 2001, figure 2

Now we have the beginnings of a problem. The problem is that, if the Simple View is right, infants should succeed in tracking persisting objects regardless of whether we measure their eye movements or their reaching actions. But there is a gap of around five months between looking and reaching.

Responses to the occlusion of a desirable object

  • look (from 2.5 months)

    (Aguiar & Baillargeon 1999)

  • reach (7--9 months)

    (Shinskey & Munakata 2001)

The attraction of the simple view is that it explains the looking. The problem for the simple view is that it makes exactly the wrong prediction about the reaching.
Can we explain the discrepancy in terms of the additional difficulty of reaching? A lot of experiments have attempts to pin the discrepancy on this, or on other extraneous factors like task demands. But none of these attempts have succeeded. After all, we know infants are capable of acting because they move the transparent screen.
As Jeanne Shinskey, one of the researchers most dedicated to this issue says,

‘action demands are not the only cause of failures on occlusion tasks’

\citep[p.\ 291]{shinskey:2012_disappearing}

Shinskey (2012, p. 291)

If there were just one discrepancy, concerning performance, we might be able to hold on to the Simple View. But there are systematic discrepancies along these lines.
Related discrepancies concerning infants' understanding of physical objects occur in the case of their abilities to track causal interactions, too.

conflicting evidence: causal interactions

Recall this experiment about causal interactions, which used a habituation paradigm. Now imagine a version which involved getting infants to reach for the object rather than simply looking. What would the results be? There is an experiment much like this which has been replicated several times, and which shows a discrepancy between looking and searching. Basically infants will look but not search.

Spelke et al 1992, figure 2

Here are the looking time results.
You can even do looking time and reaching experiments with the same subjects and apparatus \citep{Hood:2003yg}.
2.5-year-olds look longer when experimenter removes the ball from behind the wrong door, but don't reach to the correct door


here are the search results (shocking).

Hood et al 2003, figure 4

*todo: describe
**todo: Mention that \citep{mash:2006_what} show infants can also predict the location of the object (not just identify a violation, but look forward to where the object is)
Amazingly, 2 year old children still do badly when only the doors are opaque, so that the ball can be seen rolling between the doors, as in this diagram \citep{Butler:2002bv}.
Similar discrepancies between looking and reaching are also found in some nonhuman primates,
both apes and monkeys (chimpanzees, cotton-top tamarins and marmosets).
(Some of this is based on the gravity tube task and concerns gravity bias.)

‘A similar permanent dissociation in understanding object support relations might exist in chimpanzees. They identify impossible support relations in looking tasks, but fail to do so in active problem solving.’


(Gomez 2005)

Likewise for cotton-top tamarins (Santos et al 2006) and marmosets (Cacchione et al 2012).

Note that this research is evidence of dissociations between looking and search in adult primates, not infants.
This is important because it indicates that the failures to search are a feature of the core knowledge system rather than a deficit in human infants.
‘to date, adult primates’ failures on search tasks appear to exactly mirror the cases in which human toddlers perform poorly.’

‘to date, adult primates’ failures on search tasks appear to exactly mirror the cases in which human toddlers perform poorly.’

\citep[p.\ 17]{santos:2009_object}

(Santos & Hood 2009, p. 17)

What about the dogs?

This isn't straightforward.
As I mentioned earlier, \citep{kundey:2010_domesticated} show that domestic dogs are good at solidity on a search measure.
And for many of the other animals I mentioned, object permanence is measured in search tasks, not with looking times.
But let's focus on the fact that you get the looking/search in any adult animals at all.
This is evidence that the dissociation is a consequence of something fundamental about cognition rather than just a side-effect of some capacity limit.
So far we can draw two conclusions about infants' and adults abilities to track interactions.
My first conclusion from this section is that infants from around 4 months of age or younger and nonhuman animals are able to track simple causal interactions.

conclusion so far: three things

I started by identifying three requirements for knowledge of physical objects: abilities to segment objects, to represent them as persisting, and to track their causal interactions.
My second conclusion is that a single set of principles likely underlies these abilities.
The ability to segment objects is bound up with the ability to represent them as persisting and with the ability to track their interactions.

principles of object perception




causal interaction

My third conclusion is that we have a problem.
The problem is that we have to reject the simple view.
Recall that the simple says that the principles of object perception are things that we know.
We must reject this view because it makes systematically incorrect predictions about actions like searching for objects.

the simple view

But why is this a problem?
Because, as we'll see, it is hard to identify an alternative.