Perception Flashcards
What is sensation?
The detection of physical energy by the sense organs, which then send information to the brain.
What is perception?
The process through which people take raw sensations from the environment and interpret them, using knowledge, experience, and understanding of the world, so that sensations become meaningful experiences.
Describe perceptual illusions
Important because inform us how our perceptual system works (usually similar for most people but can be influenced by experience and learning)
Occur in daily life
Important to know when our perceptions are likely to be distorted
Describe bottom-up processing
Perception is direct - relies solely on incoming sensations
Brain processes only the sensory information it actually receives and directly converts this into perceptions
Higher-level cognitive analysis not needed
Describe top-down processing
Construct representation from fragments of sensory info
Perception not passive - we actively interpret to understand (perceive more than sensory info would allow alone)
Perception guided by higher-order cognitive processing (schemas, past experiences, interpretation)
What are implications of top-down processing?
Perception is complex
Perception is subjective
Sensation and perception very different
What is signal detection theory?
The most basic task for any sensory system is detecting the presence/alteration of energy changes (detecting stimuli required for perception)
Bottom-up theory - if sensed, perception occurs, if not sensed, no perception
Absolute threshold - minimum amount of energy needed to detect stimulus 50% of time
Just Noticeable Difference (JND) - smallest change in the intensity of a stimulus that we can detect
What is signal detection
Observer is involved in cognitive act of making a decision as to whether a stimulus is present or absent
The most basic of sensory acts - determining whether a signal is there - has a cognitive component (top-down)
Motivation and expectancies affect perceptual judgements as much as stimulus reception itself
How do we organise our environment?
Figure-ground discrimination
Perceptual grouping
Depth perception
Perceptual constancy
What is figure-ground discrimination?
To make sense of the environment, we need to know what to focus on
How do we separate figure and ground
Figure has more detail so it stands out in comparison to a formless ground. Figure is more likely to be meaningful
