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Evidence for Inferential Isolation


inferential isolation

example 1

So far we considered physical cognition but inferential isolation is also a feature in social cognition.

inferential isolation

example 2 (background)

There is a behavioural marker of object-indexes called the object-specific preview benefit. Suppose that you are shown an array of two objects, as depicted here. At the start a letter appears briefly on each object. (It is not important that letters are used; in theory, any readily distinguishable features should work.)
The objects now start moving.
At the end of the task, a letter appears on one of the objects. Your task is to say whether this letter is one of the letters that appeared at the start or whether it is a new letter. Consider just those cases in which the answer is yes: the letter at the end is one of those which you saw at the start. Of interest is how long this takes you to respond in two cases: when the letter appears on the same object at the start and end, and, in contrast, when the letter appears on one object at the start and a different object at the end. It turns out that most people can answer the question more quickly in the first case. That is, they are faster when a letter appears on the same object twice than when it appears on two different objects (Kahneman, Treisman, & Gibbs, 1992). This difference in response times is the % $glossary: object-specific preview benefit \emph{object-specific preview benefit}. Its existence shows that, in this task, you are keeping track of which object is which as they move. This is why the existence of an object-specific preview benefit is taken to be evidence that object indexes exist.

Kahneman et al 1992, figure 3

The \emph{object-specific preview benefit} is the reduction in time needed to identify that a letter (or other feature) matches a target presented earlier when the letter and target both appear on the same object rather than on different objects.

Scholl (2007, p. figure 4)

judgement vs object-specific preview effect

How many objects do you see?

OSPB: one

verbal judgement: two

But why suppose that this is a case of inferential isolation? Because there is no trace of any conflict.
Might we instead think of this as information encapsulation of processes underpinning OSPB? Then we could say that shape and texture information is not available to those processes but is available to other processes?
So this is not actually a very clear example of inferential isolation.
[Same could be said of Michotte’s launching phenomena, perhaps. But not of the next example of bouncing vs streaming?]

inferential isolation

example 2

Mitroff, Scholl and Wynn 2005, figures 2–3

information vs inference

inferential isolation

example 3


[Formerly said this figure was `Kozhevnikov & Hegarty (2001, figure 1)` but that is false. Also, they used squares rather than circles.]
Fix shape and density. How would increasing the object’s size affect how quickly it decelerates when launched vertically?
Impetus: larger size entails greater deceleration (so slower ascent).
Newtonian: larger size entails lower deceleration (so faster ascent) if considering air resistance; otherwise size makes no difference.

Kozhevnikov & Hegarty (2001, figures 1, 2)

Kozhevnikov & Hegarty (2001, figures 1, 2)

This example helpfully illustrates two cases of inferential isolation. One is more obvious ...

What is inferentially isolated from what?

fast object-tracking processes from knowledge of physics

limited access
location judgement from fast object-tracking processes

The second illustration of inferential isolation is less obvious. In making the location judgement, subjects are reporting, as accurately as possible, the final location of the object. The fact that they systematically misjudge this location shows that their location judgement is inferentially isolated from the fast processes that enable them to track moving objects.

inferential isolation

example 4

Spelke herself appears to agree with inferential isolation. As well as emphasizing encapsulation, she mentions limited access ...
Spelke even gives an example, the case of number.
Spelke also gives evidence for modularity (implying inferential isolation) for the core place system on pp. 140–141; briefly, the key is that children, adults and nonhumans all fail to use non-geometric information (such as a distinctively coloured or marked wall) after being disoriented and trying to re-orient themselves and find a hidden reward.

‘the core number system is inaccessible to conscious introspection:
When adults are presented with small numerical arrays under conditions that prevent attentive tracking of individual objects,
we show all the neural signatures of the core number system while indicating no awareness of number.’

Spelke (2022, p. 187)