Sensation and Perception Flashcards
Sensation
The process of detecting external events by the sense organs
Transduction
Process in which physical or chemical stimulation is converted into a neural impulse that is relayed to the brain
Perception
Involves attending to, organizing, and interpreting stimuli that we sense
Absolute threshold
The minimum amount of energy or quantity of a stimulus required for it to be reliably detected at least 50% of the time it is presented
Difference Threshold
Smallest difference between two stimuli that a subject can detect
- “just noticeable difference” expressed as a Weber fraction
Weber’s Law
K = DL/S
K = Difference threshold/Standard
Signal Detection Theory
How we make decisions under conditions of uncertainty
- Thresholds can vary depending on the individual or context in which the decision is being made
Signal Detection Theory (Correct Responses)
- Hit: detecting the stimulus when it is present
- Correct Rejection: not detecting the stimulus when it is absent
Signal Detection Theory (Incorrect Responses)
- Miss: failing to detect the stimulus when it is present
- False Alarm: detecting the stimulus when it is absent
Subliminal Messaging
- Subliminal stimuli: presented to a person below their conscious threshold
- We detect subliminal stimuli without conscious awareness
- Activation in certain brain regions
- Effects are limited
- Will not make you do anything you would not normally do
Perceptual Organization
The process by which elements are organized to form perceptible objects
- Grouping and segregation
- Gestalt psychologists proposed several principles by which we achieve perceptual organization
Figure-ground principle
(Gestalt Principles of Perception)
Objects and figures in our environment tend to stand out against a background
Gestalt Principles
- Good Continuation
- Proximity
- Similarity
- Closure
Good Continuation
(Gestalt Principles)
Objects that are partially covered by other objects are seen as continuing behind those objects
Top-Down Processing
Occurs when prior knowledge and expectations guide what is perceived
Bottom-Up Processing
Is constructing a whole stimulus or concept from bits of raw sensory information
Selective Attention
Involves focusing on one particular event or task
Divided attention
Involves paying attention to several stimuli/tasks at once
- Self-proclaimed multi-taskers perform worse on cognitive tests
- Distracted driving
Inattentional blindness
A failure to notice clearly visible events or objects because attention is directed elsewhere
Amplitude
Height of the waves
Wavelength
Distance between waves
Sclera (Eye)
White outer layer of eye
Cornea (Eye)
Clear layer that covers the front of the eye
Pupil (Eye)
Regulates amount of light let into eye