Chapter 3: Perception Flashcards
Perception
Conscious experience resulting from stimulation of the senses
Basic Concepts of Perception
- Perceptions can change based on added information
- Involves a process similar to reasoning or problem solving
- Perceptions occur in conjunction with actions
It is possible that true human perceptual processes are […]
It is possible that true human perceptual processes are unique to humans
- Attempts to create artificial forms of perception (Machines) have been met with limited success and each time have had problems that could no be solved
Why can’t machines perceive like humans
- Inverse Projection Problem _ Objects can be hidden or blurred - People can often identify objects that are obscured and therefor incomplete, or in some cases objects that are blurry - Viewpoint Invariance - Scenes contain high-level information - Scenes are more complex
Inverse Projection Problem
Refers to task of determining the object responsible for a particular image on retina
Viewpoint Invariance
Objects look different from different viewpoints
Human perceptual system uses two types of information
- Environmental energy stimulated receptor (bottom up)
2. Knowledge and expectations observer brings to situation (top down)
Bottom-Up Processing
Processing that starts with info received by receptors
Top-Down Processing
Processing that involves a person’s knowledge or expectations
Direct Perception Theories
Perception comes from stimuli in the environment
- bottom up
Constructive Perception Theories
People actively construct perceptions using information based on expectations
[…] infleunces our perception of language based on our individual experience with the language
Top-down processing infleunces our perception of language based on our individual experience with the language
Speech Segmentation
Processing of perceiving individual words within continuous flow of speech signal
- ability to tell when one word ends and another begins
Transitional Probabilities
Likelihood that one speech sound will follow another within a word
- knowing which sound will likely follow another in a word
Statistical Learning
Processes of learning about transitional probabilities and about other characteristics of language
Hearing Words in a Sentence
- Top-down theory
- Some perceptions are the result of unconscious assumtption we make about the environment
- We infer much of what we know about the world
- Likelihood principle
Likelihood Principle
Way we perceive based on what is most likely to occur based on past experiences
- We perceive object that is most likely to have caused pattern to stimuli we have received
Helmholtz’s Unconscious Inference
some of our perceptions are result of unconscious assumptions that we make about environment
“Old” View- Structuralism
Perception involves adding up new sensations
“New” view- Gestalt Principles
Mind groups patterns according to intrinsic laws of perceptual organization
Perceptual Organization
Small elements of scene/ displat become perceptually grouped to form larger units
Gestalt Psychologists
Proposed principles governing perception, such as laws of organization, and perceptual approach to probelm solving involving restructuring
Appararent Movement
Illusion of movement perception that occurs when stimuli in different locations are flashed one ofter another with proper timing
Principle of Good Continuation
Points that, when connected, result in straight or smoothly curving lines are seen as belonging together
Law of Pragnanz
Every stimulus pattern is seen in such a way that resulting structure is as simple as possible
Principle of Similarity
Similar things appear to be grouped together
Gestalt Principles of Perceptual Organization
- Perception is determined by specific organizing principles, not just dark and light stimuli activating retina
- Role fo experience is minor compared to these intrinsic, “built in” principles
- Experience can infleunce perception but is not the key driver
Regularities of the Environment:
Common physical properties of the environment
- Oblique effect - Light-from-above assumption - Semantic
Oblique Effect
Vertical and horizontal orientations cna be perceived more easily than other (slanted) orientations
- due to natural selection
Light-from-above Assumption
- We assume light vomes from above because this is common in our environment
- We perceive shadows as specific information about depth and distance
Semantic
- Characteristics associated with functions carried out in different types of scenes
- Meaning of given scene is related to what happens within that scene
- Semantic regularities are the characteristics associated with functions carried out in different types of scenes
- Scene schema
Scene Schema
Person’s knowledge about what is likely to be contained in particular scene
Bayesian Inference
One’s estimate of the probability of a given outcome is influenced by two factors:
- The prior probability - The likelihood of a given outcome
Prior Probability
Person’s initial belief about probability of outcome
Likelihood of a Given Outcome
Extent to which available evidence is consistent with outcome
Comparing Conceptions of Object Perception
Top-down processing
- Unconscious inference - Environmental regularities - Bayesian inference
Bottom-up processing
- Gestalt principles
Neurons, Knowledge, and the Environment
- Some neurons respond best to things that occur regularly in the environment
- Neurons become tuned to respond best to what we commonly experience
- Horizontals and verticals
- Experience- dependent plasticity
- Learning can shape response properties of neurons through process of experience-dependent plasticity
Movement Facilitates Perception
- As observers, our movement adds complexity to perception compared to if we remain static, but moving around a stimulus offers us more views to create accurate perceptions
- Coordination continuously occurs between perceiving stimuli and taking actions towards these stimuli
Object Discrimination
- Ventral (what pathway)
- remember object based on its shape and shoose it when presented with another object after delay
Landmark Discrimination
- Dorsal (where pathway)
- Remember an object’s location and to choose that location after delay
Brain Ablation
Procedure in which specific area is removed from animal’s brain
- Done to determine function of this area by assessing effect of animal’s behavior
Perception Pathway
- What pathway
- From visual cortex to temporal lobe
Action Pathway
- Where pathway
- From visual cortex to parietal lobe
Mirror Neuron System
Network of neurons in brain that have mirror neuron properties
Mirror Neurons
- Neurons in premotor cortex
- These neurons respond while a subject watches an action being performed in the same way as if the subject was performing the action
- fMRI research has found evidence of a neuron system in the brain
- Higher rate of mirroring if the subject’s intention to perform the action was greater
