Theories of perception

what did Rene Descartes say and mean?

• Rene Descartes emphasized the role of the mind in perception,

• "I think, therefore I am," which means that the act of thinking is proof of one's existence.

• He argued that sensory perceptions could be deceptive and that knowledge should be rooted in rational thought.

naïve realism

The philosophical and psychological view that the world is exactly as it appears and that perception is a passive copying of external stimuli.

What were the 3 definitions of native realism that were constructed by Neisser

1. Mirroring

2. Temporal synchronisation

3. passivity

Whats mirroring?

Visual experiences are exact copies of external stimuli (though this is challenged by the existence of hallucinations).

What is Temporal synchronisation?

Visual experience begins and ends precisely with the onset and offset of the external stimulus (challenged by visual persistence and memory).

What’s passivity?

Experiences are passive copies of the outside world that can be accurately described through verbal reports.

Stimulus classification

Experiences are passive copies of the outside world that can be accurately described through verbal reports. translating external information into internal experiences

Distal stimulus

The actual object or event in the outside world (e.g., a sound wave).

Proximal stimulus

The registration of that information by the sensory organs (e.g., the vibration in the ear).

Bottom up processing

Bottom-up processing moves from low-level feature detection to high-level perception without the influence of prior knowledge.

What is the pandemonium model?

this model explains visual letter recognition through a hierarchy of "demons":

Process of the pandemonium model

1. information is taken in passively

2. specific demons identify discrete features (straight lines, right angles).

3. Information becomes increasingly complex as it passes through the system until a perception is formed.

What is Fodor’s modularity of mind?

• hypothesized that the mind is composed of specialized input modules for each sense (touch, taste, smell, sight, hearing).

• Information is funnelled from these specialized modules into central processors

What do input modules do?

perform sensory encoding and transduction.

What do central processors do?

thought and interpretation.

Transduction

The process by which sensory encoding converts physical energy from the environment into neural signals.

what did Gestalt argue in the principles of perceptual organisation?

that perception is organized according to innate coding principles that operate bottom-up to facilitate object recognition.

What are the 6 principles of Gestalt’s principles of perceptual organisation?

1. proximity

2. similarity

3. common fate

4. symmetry

5. common region

Proximity principle

Elements close to one another are grouped together (e.g., perceiving rows vs. columns based on spacing).

similarity principle

Elements are grouped based on shared physical characteristics like color or form.

Common fate principle

Elements moving in the same direction are perceived as a single unit.

Symmetry principle

Symmetrical regions are more likely to be perceived as figures.

Common region principle

Elements within the same enclosed boundary are grouped together.

What were the findings of Evidence for Innateness: A study by Quinn, Burke, and Rush involving 3-month-old infants

• supported the idea that grouping is an automatic, innate process.

• Using fixation times, the researchers found that infants treated grouped stimuli as familiar and novel arrangements as distinct,

• suggesting they could perform grouping despite having no prior knowledge of the world.

What was the ‘new look’/top down approach proposed by Bruner?

suggests that perception is an active process where memory, expectation, and value influence how we process information.

Burners and postman’s playing card study procedure?

Participants were shown congruent (normal) and incongruent (e.g., a black heart) playing cards briefly.

Burners and postman’s playing card study findings?

Normal cards were recognized more accurately and faster than incongruous ones, demonstrating that expectations influence recognition.

what has been found in letter masking experiments?

Common letters are reported more accurately than rare letters when presented briefly and masked.

What does frame theory by Minsky propose?

we use "frames" to represent knowledge. When encountering a scene (e.g., a room), we actively generate expectations about its components (ceiling, floor, walls) based on a mental template, comparing reality against these expectations.

What does Bruner’s "Perception Reduces" theory posit of?

that our needs and values alter our construction of the world.

Procedure of the coin study

Participants adjusted a spot of light to match the size of coins.

Findings of the coin study

Participants consistently overestimated the size of coins compared to neutral discs. Overestimation increased with the value of the coin.

What was the socio-economic factor in the coin study?

"Poor" children showed more extreme overestimations than "rich" children, particularly as the value of the coins increased.

What are the 3 principles of interpretation and ambiguity?

1. seeing vs seeing as

2. ambiguous figures and recency

3. minimum vs likelihood

what is an ambiguous figure?

A visual stimulus that can be interpreted in more than one way, such as the Necker cube or the "young woman/old woman" drawing.

Seeing vs seeing as

A critical distinction exists between the raw perceptual operation (seeing) and the interpretive operation (seeing as). While the physical process of "seeing" remains the same, familiar entities trigger different interpretive operations than unfamiliar ones.

seeing

raw perception

seeing as

interpretive operation

What do studies on ambiguous figures show?

(e.g., the Young Woman/Old Woman), researchers tested whether expectancy (based on a sequence) or recency (the last stimulus seen) determined perception. Results showed that current interpretations tended to reflect recency over expectancy.

What’s the minimum principle/simplicity?

The visual system chooses the simplest way to describe or code a scene.

What’s the likelihood principle?

The system perceives whatever object or scene is most likely to fit the sensory pattern under normal circumstances (e.g., assuming light comes from above).

Global precedence

Identifying a "global" letter (a large letter made of smaller letters) is faster than identifying the "local" (smaller) letters.

Global to local interference

Classification of local letters is slowed if they conflict with the global letter.

Local to global interference

This is rarely observed; the local information generally does not influence the processing of global information.

Theoretical synthesis

The current understanding of perception can be summarized into two competing/complementary frameworks

What are the 2 models of perception?

1. Modality of mind (Fodor)

2. Interactive hypothesis generation and testing

Modularity of Mind (Fodor) summary

A strictly bottom-up, passive model where sensory information is transduced and then interpreted by central processors.

What is the Interactive Hypothesis Generation and Testing?

an active cyclical process

1. Initial bottom-up processing and preprocessing take in global information.

2. A Hypothesis Generator

3. The system then performs further preprocessing, seeking local information to confirm or fail the hypothesis.

4. Successful hypotheses lead to output behaviour and consciousness ("Qualia flagging the present"), while failures provide feedback to the knowledge base.

A hypothesis generator

uses conceptual and perceptual knowledge to create a top-down prediction.