Transcript Lecture 2 Individuating, Selecting, Referring

Selecting, Referring & Predicating:
Basic ingredients of the mind-world
connection
The functions of focal attention

A central notion in the present analysis is the notion of
“picking out” or selecting. The usual mechanism that is
appealed to in explaining perceptual selection is attention
(sometimes called focal attention or selective attention).

Why must we select anyway?
This is a rarely asked question to which there are several answers:
 We need to select because we can’t process all the information
available. This is the resource-limitation reason.
 We need to select because certain patterns cannot be computed
without first marking certain special elements of a scene
 We need to select because of the way relevant information in
the world is packaged (Strawson’s Collecting Principles). It is
a response to the Binding Problem
 We need to select because selection is a consequence of the
first line of causal contact between mind and world: it
precedes all conceptualizing and encoding
What does visual attention select?

If attention is selection, what does visual attention
select?
One obvious answer is places. We can select places by
moving our eyes so our gaze lands on different places.
Must we always move our eyes to change what we
attend to?
 Studies of Covert Attention-Movement: Posner
(1980).
How does attention switch from one place to another?
When a place is selected, is selection automatic
(exogenous) or voluntary (endogenous)?
Exogenous movements of attention
Example of an experiment using a cue-validity paradigm for showing that the
locus of attention moves without eye movements and for estimating its speed.
Posner, M. I. (1980). Orienting of Attention. Quarterly Journal of Experimental Psychology, 32, 3-25.
Endogenous movements of attention
Exogenous & endogenous control of attention

Attention shifted in exogenous and endogenous ways
differs in a number of ways:
 Only exogenous attention shift leads to Inhibition of Return
 Automatic attention shifts are faster and the attention effects are
stronger.
 Voluntary attention shifts can be interrupted by exogenous cues,
so it is considered secondary to automatic control
 With voluntary attention control the person only knows which
direction to move attention, so it may occupy intermediate
locations
Exogenous & endogenous control of attention

Attention shifted by exogenous and endogenous ways
differs in other ways as well:
 With automatic shift, the apparent attention increase at
intermediate locations can be explained by decreasing attention at
the source and increasing attention at the target (Sperling &
Weichselgarter, 1995).
 It is doubtful that there is attentional selection of empty regions –
empty space does not have the causal power to attract exogenous
attention and voluntary control is special (also some doubt that
voluntary movements are continuous – Pylyshyn & Cohen, 1999)

If attentional selection is to play the role of initial
nonconceptual contact between mental representations
and the world, it must be exogenously driven attention –
the world must impose itself on the perceptual system.
Evidence that attention is object-based

Although the earliest evidence showed that
attention moves through space (covert
movement) there is now evidence that
attention attaches to “objects” as a whole
 The main source of evidence initially was
based on same object superiority
Single object superiority even
when the shapes are controlled
Pay attention to the blue object. Which vertex is higher, the left or the right?
Pay attention to the red object.
Which vertex is higher, the left or the right?
Attention spreads over perceived objects
A
C
A
C
Spreads to
B and not C
Spreads to
C and not B
B
A
D
C
B
A
D
C
Spreads to
B and not C
Spreads to
C and not B
B
D
B
D
Using a priming method (Egly, Driver & Rafal, 1994) showed that the effect of a prime spreads t
other parts of the same visual object compared to equally distant parts of different objects.
Inhibition of return

Inhibition-of-return is the phenomenon whereby
an object that has been attended is less likely to
attract attention again in a period of 300 ms to
900 ms after it is first attended. The attended
item is said to be inhibited.

This is thought to help in visual search since it
prevents previously visited objects from being
revisited

IOR is Object-Based (the only counter-evidence
involves easily-marked locations – like between
two objects)
But IOR appears to be object-based (so it
travels with the object that was attended)
Visual neglect syndrome is object-based
When a right neglect patient is shown a dumbbell that rotates,
the patient continues to neglect the object that had been on the
right, even though It is now on the left (Behrmann & Tipper, 1999).
Simultanagnosic (Balint Syndrome) patients
only attend to one object at a time
Same length?
Trapezoid?
Simultanagnosic patients cannot judge the relative length of two
lines, but they can tell that a figure made by connecting the ends
of the lines is not a rectangle but a trapezoid (Holmes & Horax, 1919).
Balint patients can only attend to one object at a
time even if they are overlapping
Luria, 1959
What does attention select preconceptually?

Although there is now considerable evidence that attention
attaches itself to objects, conventional wisdom insists that
to detect properties is to detect properties-at-locations

To reconcile this intuitive view with the object-based
attention evidence, one might say that what is attended is
spatiotemporal regions or “worms” – and many people do
believe that*

But the problem with this argument – and the problem with
most ways of trying to reconcile the location view with
empirical data – is that a spatiotemporal “worm” is simply
the region that is traced out by a moving object! Without
the independent notion of object there would be no worm!
* This may even be a terminological variant of the object view since objects and
worms are mathematical duals – you can always translate one into the other.
The Binding Problem


Our perceptual system can distinguish scenes that differ by
conjunctions of properties, so early vision must not fuse together or
lose the co-occurrence or conjunctiveness of properties it detects.
In reporting properties early vision must bind them together.
How it binds them together is a central question in vision. The
most common answer is that it binds them according to co-location.
The role of attention to location in Treisman’s Feature Integration Theory
Conjunction detected
Color maps
Shape maps
Orientation maps
R
Y
G
Master location map
Attention “beam”
The more elaborate version of Treisman’s Feature Integration Theory
Austen Clark (& P. Strawson) and
feature placing languages
What kind of representations are provided by (preconceptual) sensations?
Strawson’s answer: Just those permitted by feature-placing “languages”
“The hypothesis ...is that sensation is feature-placing: a pre-linguistic system
of mental representation. Mechanisms of spatio-temporal discrimination …
serve to pick out or identify the subject-matter of sensory representation.
That subject-matter turns out invariably to be some place-time in or around
the body of the sentient organism. …the various reasons cited for thinking
that sensation is intentional can also be explained on this hypothesis. The
‘aboutness’ of sensation reduces to its spatial character. (Clark, 2000, p 165)”
“…there is a sensory level of identification of place-times that is more
primitive than the identification of three-dimensional material objects. Below
our conceptual scheme – underneath the streets, so to speak – we find
evidence of this more primitive system. The sensory identification of placetimes is independent of the identification of objects; one can place features
even though one lacks the latter conceptual scheme.”
Why Objects are a better target than Locations

It would have to be regions rather than locations
anyway. Points are irrelevant to the binding problem
 The only regions that are relevant are occupied regions – i.e.,
“objects”.
 The boundaries of regions must coincide with the boundaries
of things, otherwise it does not help with the binding problem
 Properties (e.g. features) are properties of things, not of space.

If it is to be the primitive nonconceptual contact (the
“first responder”) what is selected must capture
attention and therefore must have causal powers. So it
can’t be empty regions of space.
 There is experimental evidence that attention attaches to
things rather than places, especially for exogenously
captured attention (cf Sperling)
Solving the binding problem requires not just picking out
places or regions. It requires that the regions coincide with
things (objects) in the word that have the relevant properties
Some philosophical issues
that arise from FINST theory

Distinguishing causes and codes

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Conceptual and nonconceptual contents
Representing and carrying information

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What causes Object Files to be created vs what is entered
into them
The case of clusters, figure-ground, and correspondence
Can information-carrying properties (e.g., location
on the proximal pattern) create clusters without
representing locations of features that are
clustered?
The relevance of this research
to understanding sentience
Austen Clark and Feature Placing
 Feature placing and the binding problem
 Feature-placing and the causal link
 Feature-placing and nonconceptual
access
FINSTs and nonconceptual
representation (a reprise)

What does the early vision system deliver to the
mind in a nonconceptual manner?
 What classes and properties can be recognized
without the apparatus of concepts?
 Causality? Cardinality (of small sets)?
 3D object shapes? Shape-from motion? Shape
from shading? Shape from contours?

What can be selected in a nonconceptual
manner, and how does this help with the
problem of connecting vision with the world?