Modular vs non-modular processing in vision

Why does fast visual identification challenge top-down feedback?

Because objects, faces, and words can be identified extremely quick;y

What did Thorpe, Fize & Marlot (1996) study?

Speed of animal detection in visual images

What was the task in Thorpe et al. (1996)?

Decide whether a briefly presented image contained an animal

How long were images shown in Thorpe et al’s study?

20ms

What did participants do on '“go” trials?

Release a button if an animal was present

What did participants do on “no-go” trials?

Keep their finger on the button if no animal was present

Why is Thorpe et al.’s study important?

it suggests visual classification can occur too quickly for feedback

What does ERP stand for?

Event-related potential

What is an ERP?

A time-locked electrical brain response to a specific event

How are ERPs measure?

Using EEG electrodes on the scalp

What have ERP studies found about object and face identification?

Evidence of identification around 100-150ms

What does it mean when ERP waveforms diverge?

The brain is processing two stimulus categories differently

In animal-detection ERP studies, when do waveforms diverge?

Around 150ms

What does ERP divergence around 150ms suggest?

The brain distinguished animals from non-animals very early

How many synapses separate the retina from object/ face-selective temporal cortex cells?

At least 10 synapses

Why does the number of syanpses matter?

Each synapse takes time to transmit information

What did Thorpe et al. argue from the timing evidence?

There is no time for feedback in rapid animal/ non-animal classification

What type of processing does rapid visual classification support?

Feedforward processing

What is feedforward processing?

Information flows from lower sensory areas to higher visual areas without feedback

What do classic visual illusions show about knowledge and perception?

Knowing the truth does not remove the illusion

Why are illusions relevant to modularity?

They suggest perception is party immune to top-down knowledge

What does persistence of illusions support?

The idea that vision is at least partly modular/ information-encapsulated

What is cognitive penetrability?

The idea that beliefs, desires, emotions, actions, or language directly affect perception

What did Firestone & Scholl (2016) argue?

Cognition does not genuinely affect perception

What do Firestone & Scholl claim many top-down findings can be explained by?

Low-level visual features, response bias, or attentional shifts

What distinction did Firestone & Scholl make?

Top-down effects within vision vs cognition penetrating vision

What do they question specifically?

Whether beliefs/ desires/ emotions/ language directly influence what we see

What is the Word Superiority Effect?

Letters are identified better in words than alone

What is another part of the Word Superiority Effect?

Words can be identified better than individual letters

Which model explains the Word Superiority Effect?

McClelland & Rumelhart’s Interactive Activation model

Why is the Word Superiority Effect considered a top-down effect?

Word-level information helps letter-level identification

Why might it not violate Fodorian modularity?

It may occur within the orthographic / visual word system

What are examples of motivation-based effects on perception?

Desired objects look closer, muffins look larger when hungry, moral words are easier to perceive

What are examples of action-based effects on perception?

Heavy backpacks make slopes look steeper; good shots make targets look larger

What are examples of emotion-based effects on perception?

Fear makes hills look steeper; negative thoughts make the world look darder

What are examples of language/ category effects on perception?

Race categories affect face perception; colour terms affect perceived colour

Why are many claimed top-down effects considered weak evidece?

They are subtle and may not alter subjective visual experience

What alternative explanation may account for many claimed effects?

Attention changes what visual input is processed

What does the Ames Room illusion show?

Vision makes assumptions about 3D structure

Why do identical twins look different in an Ames Room?

The distorted room creates misleading depth cues

What is the inverse problem in vision?

A 2D retinal image could come from many possible 3D objects

Why must the visual system solve the inverse problem?

It has to infer the 3D world from 2D retinal input

Does background knowledge directly solve the inverse problem?

No, visual computations do

What does the Ames Room support?

Complex visual processing can occur without cognitive pentration

Which one is more compelling example of background knowledge possible affecting perception?

Race appearing to influence perceived face lightness

Why is this effect tricky to interpret?

It may arise within visual processing rather than from conceptual knowledge

What makes the race/ lightness effect less clearly cognitive?

The effect persists even when race is hard to identify

What broader problem does this example illustrate?

It is hard to distinguish cognitive penetration from within-vision processing

What apparent example suggests conceptual knowledge affects perception?

The meaning of arrows appearing to alter perceived colour/ brightness

What was the initial interpretation of the allow illusion?

Arrow meaning dramatically affects perception

What did further anaylsis show?

The illusion has nothing to do with allow meaning

What actually causes the arrow/ disk illusion?

The edges of the disk

What can make the disk illusion disappear?

Manipulating/ removing the relevant disk edges

What does the arrow/ disk illusion teach?

Apparent cognitive effects may have low-level visual explanations