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

Using a priming method (Egly, Driver & Rafal, 1994) showed that the effect of a prime spreads to other parts of the same visual object compared to equally distant parts of different objects.

Spreads toB and not C

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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

Simultanagnosic patients cannot judge the relative length of twolines, but they can tell that a figure made by connecting the endsof the lines is not a rectangle but a trapezoid (Holmes & Horax, 1919).

Same length? Trapezoid?

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

Color maps Shape maps Orientation maps

Master location map Attention “beam”

Conjunction detected

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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 place-times 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 What causes Object Files to be created vs what is entered

into themConceptual and nonconceptual contentsRepresenting and carrying information

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?