Sensation and Perception Flashcards
Sensation
The process of receiving environmental stimuli and translating those to nerve impulses that are sent to the brain
- The process is called Sensory Transduction
Perception
The process of interpreting and understanding sensory information
- Context matters
Bottom-up Processing
Stimuli shape the perception of what we see
- Spontaneous
Top-down Processing
Use of background knowledge to make sense of stimuli
- What do we see and compare it to previous experiences
What are the senses for?
- To get information
Focal attention
Directing focus/attention onto something, like visual attention, and disregarding other stimuli. Its responsible for transferring that information short-term memory.
Psychophysics
Relations between stimuli and sensory capabilities
- How sensitive are our senses?
- How do our enses convert signals into sensations and how does experiences play a part?
What are the two kinds of perceptual sensitivity?
- Absolute Threshold
Lowest intensity at which a stimulus can be detected by 50% of the times - Difference Threshold (JND)
Smallest difference between stimuli that can be detected
Hear or feel a difference - Lifting weights
Decision criterion
A standard of how certain one have to be to say they detected something
- Individual differences
Signal Detection Theory
- What are the factors that influence sensory judgements
- Research based on decision during uncertainty
- How do we come up with a decision with “two options”
Good mail or spam? - 4 outcomes to it
Hit
Miss
Correct Rejections
False alarms
Signal detection task
- Used in researches
- Is the stimulus present or not - decision
- De composes a mental process into sensory and decision sub-processes
- Assumes all stimuli are detected in the presence of noise
Hit rate
Hits - reports when the stimulus was present
Proportion false alarms
False alarms - stimulus present when it wasnt
What can influnce people for hit rates?
Individual differences
- Standard criterion
- Says it often vs more conservative
- Fatigue, doing it during an extended period of time
Situational differences
- Cost and/or reward for hit rates - diagnosing a patient
- Expectations
Sensitivity index d
Reperesents the participants ability to detect the stimulus
Likelihood Beta
Represents the participants response criterium
- The participants tendency to report the presence of the stimulus
- Can be affected by cost - reward influences
Subliminal stimulus
Weak or brief stimulus, it gets perceived but not consciously
Webers Law
The JND is proportional to the magnitude of the stimulus with which the comparison is being made
- Detecting differences
-The smaller the Weber fraction, the greater sensitivity to differences
degree of change/ stimulus intensity
Fechners Law *
Addd seubjective experience to Webers law
- Noticing the difference
Sensory Adaption
A process of adjusting sensitivity of our sensory systems
- From survival
- Part of our daily life
- Wearing a watch, not noticing it constantly
- The sensory systems
Adapting to a cold/warm room
