Study Guide (3): Unit 1 - PSYC 311 (Cognitive Psychology): Perception

* - not in the study guide

What is Sensation?

An irreducible unit of experience produced by stimulation of a sensory receptor, producing basic awareness of a stimulus

• Or, the physical process of detecting environmental stimuli through sensory organs

What is Perception?

The organization, identification, and interpretation of sensory information in order to represent and understand the presented information or environment

• Or, the psychological process of organizing and interpreting those signals in the brain

Where is light that enters the eyes through the left visual field ultimately end up processed in the brain (on what side, and in what lobe)?

Light entering the eyes through the left visual field is ultimately processed on the right side (hemisphere) of the brain in the occipital lobe.

What is Bottom-Up Processing?

• Processing which is driven entirely by an
  external stimulus itself, insulated from
  pre-existing knowledge

• Sensation is typically bottom-up

  • Or, your brain builds a perception based strictly on the raw data coming in through your senses, without any help from your past experiences, expectations, or background knowledge

Example:

Lines and Contrast: Your eyes naturally detect sharp borders and bright vs. dark areas instantly, without you having to "decide" to see them.

What is Top-Down Processing?

• Processing which draws from pre-existing knowledge or brain states, modifying new information that enters the system with pre-existing knowledge

• Deliberate behavior is typically top-down

  • Or, your brain uses pre-existing knowledge, memories, context, and expectations to interpret the raw sensory data coming in

Example:

A bistable image is a visual illusion that can be seen in two completely different ways—like the famous drawing that can look like either a vase or two facing faces. The raw sensory data (the black and white lines) never changes. However, your perception shifts back and forth because your top-down focus dictates which mental concept you expect to see, completely changing your conscious reality.

What is the Template Matching Theory of Vision, and what are its Cons?

The Template Matching Theory of Vision:

• The idea that perception occurs by comparing visual sensations to a store of templates in memory

  • Or, whenever you look at something (a visual sensation), your brain tries to recognize it by comparing it to an internal library of exact, pre-saved images (templates) stored in your memory.

The Cons:

• Your brain would have to store an impossibly large set of ‘templates’

• There would be an exponential, unmanageable surge in processing demands that happens when the brain tries to store and compare a unique mental template for every possible variation of an object (Mental-Computational explosion)

• You can easily recognize an object if it is tilted, flipped, or upside down, but template matching fails here because the angled object no longer perfectly lines up with your standard, straight-on template (Non-canonical orientations)

• When an object is partially blocked or hidden from view (ex. a car parked behind a tree), its shape changes, meaning it will no longer match your full memory template even though you still know what it is (Occlusion)

What is the Affordance Theory of Vision? What is the Affordance you perceive when looking at a mug?

The Affordance Theory of Vision:

• The Idea that perception is supported by automatically extracting rich information from the environment

  • Or, organisms perceive their environment directly in terms of the action possibilities it offers, rather than as a neutral collection of shapes and colors

What is the Affordance you perceive when looking at a mug?:

• When looking at a mug, the primary Affordance you perceive is that the handle allows you to hold it, and the hollowed-out shape allows you to pour liquid into it and drink from it without spilling.

What is a Geon?

Geons:

• Perception is supported through the dynamic

  combination of a set of core shapes into a 3-D

  model that is then matched against a template

  (or prototype)

  • Or, geons are simple, three-dimensional geometric shapes—such as cylinders, cones, blocks, and wedges—that serve as the basic building blocks of object recognition in psychology.

What is Shape Constancy?

Shape Constancy:

• We perceive stimuli to have constant properties in the world even though sensory information may change

  • Close/Far: As sensory information changes with distance we typically perceive objects at a constant size

  • Occlusion: Partial occlusion does not influence our perception

  • Non-Cannonical Orientations: Changing to strange angles rarely seen does not break shape perception

What is the Face Inversion Effect?

The Face Inversion Effect:

• Is a phenomenon in which identifying upside-down faces compared to upright faces is much more difficult and slower than doing the same for non-facial objects.

What types of stimuli are processed in special ways by the Visual System?

• Contrast

• Line

• Shape

• Movement

What are the Anatomical and Functional Regions of the brain that process a special visual category?

Anatomical Regions:

• V1 (Primary Visual Cortex): Processes contrast/edges

• V2 (Secondary Visual Cortex): Processes lines/boundaries

• V4: Processes shapes and colors

• MT: Processes movement and speed

Functional Regions:

• Parahippocampal Place Area (PPA): Processes scenes

• Lateral Occipital Cortex (LOC): Processes objects

• Visual Word Form Area (VWFA): Processes letters and words

How are Functional Regions located in the Brain?

Frontal Lobe

• Motor Cortex: Controls physical body movement

• Prefrontal Cortex: High executive processing, such as problem-solving, decision-making, goal orientation, thinking, and abstract thought

• Broca’s Area: Speech production

Parietal Lobe

• Somatosensory Cortex: Enables tactile sensations; also responsible in the feeling of physical pain

Temporal Lobe

• Wernickes Area: Speech comprehension

  • also the Fusiform Face Area (FFA): Processes faces (on Ventral Surface)

Occipital Lobe

• The Primary Visual Cortex: Processes contrast/edges

What are the 6 Gestalt Properties of Vision?

They are rules that explain how the human brain automatically organizes individual visual pieces into a meaningful whole.

• the "whole is different than the sum of its parts"

There are 6 of them:

• Closure

• Figure Ground

• Similarity

• Proximity

• Good Continuation

• Common Fate

Gestalt Properties of Vision: Closure

We perceive incomplete forms as complete, synthesizing the missing units so as to perceive the image or sound as a whole

• Example shown: Kanizsa Triangle

Gestalt Properties of Vision: Figure Ground

Perception requires segmentation of the focus from the background

• Or, your brain cannot make sense of what you see until it decides what is the main object (the figure) and what is just the backdrop (the ground)

Gestalt Properties of Vision: Similarity

People tend to organize objects with similar qualities into a perceptual group and interpret them as a whole

Gestalt Properties of Vision: Proximity

We typically group objects close to each other into a perceptual group and interpret them as a single entity

Gestalt Properties of Vision: Good Continuation

We tend to perceive objects in alignment as forming smooth, unbroken contours

Gestalt Properties of Vision: Common Fate

We typically group together stimuli that share similar patterns of movement

What is Perceptual Learning? Give one example.

Perceptual Learning are the changes in perception that occur as a function of practice or experience with the stimuli

• Or, training your brain to see and perceive things more accurately through practice.

• The more experience you get with a specific sight or sound, the better you become at processing it.

Example:

Identifying Musical Pitches: Music students practice listening to notes over and over until they can instantly tell the difference between two closely related musical pitches or tones