Chapter 4 Flashcards
what is sensations
the process of receiving energy from stimuli in our internal or external environment and transforming this energy into action potentials
what 3 things do all sensory systems have in common
- specialized receptor cells
- transduction
- multiple subsystems
what is transduction
- when receptor cells register a stimulus, transduction occurs which is the conversion of energy into an action potential that relays information about the stimulus through the nervous system to the brain
what is perception
- the process of organizing and interpreting sensory information so that it makes sense
i.e. receptor cells in our eyes record, a silver object in the sky, but they don’t recognize it as a plane (our perception does that)
what is the difference between sensation and perception
sensation is the raw materials of experience (light, sound, touch)
perception is how our brain processes and makes sense of that information
- you can think of it as the brains way of interpreting the sensory input to give it meaning
what is bottom-up processing
sensory receptors register information about the external environment and send it up to the brain for interpretation
- so you are taking in information and trying to make sense of it
what is top-down processing
it starts with cognitive processing in the brain
- we begin with some sense of what’s happening (we use what we already know) and interpret incoming details instead of just reacting to new information
example of bottom-up and top-down processing
experiencing a song:
- the first time you listen to a snog, you listen carefully to analyze rhythm, lyrics, etc.
- this is bottom-up processing, as you initially receive sensory signals (external audio) and then you can perceive/interpret it as music
- after hearing the song multiple times, you have expectations of what lyrics and melody will come next, and sometimes you find yourself thinking about the song and start playing it in your head: HUMMING
what are sensory receptors
specialized cells that detect stimulus information and transmit it to sensory (afferent) nerves in the brain
- sensory nerves bring information from the world into the brain
- sensory receptors are the opening through which the brain and nervous system experience the world
what are the 3 categories of energy sense organs + receptors can detect
1) photoreception: detection of light (sight)
2) mechanoreception: detection of pressure, vibration, and movement (touch, hearing, equilibrium)
3) chemoreception: detection of chemical stimuli (smell and taste)
examples of sense confusion
- synaesthesia
- mirror-touch synaesthesia
- phantom limb pain
where do most of sensory signals go to?
- THALAMUS
- the brains relay station
- they are then routed to the sensory areas of the cerebral cortex
which areas in the cerebral cortex are responsible for each sense
Occipital Lobe= visual information
Temporal Lobe=hearing
Parietal Lobe=pain and touch
what does psychophysics examine
interactions between sensory signals and perception to answer questions
i.e. “how much of a stimulus is necessary for you to see, hear, taste, smell, or feel smth?”
and “what was the lowest amount of stimulation that will still be detected?”
what is the absolute threshold
- minimum amount of stimulus energy that a person can detect
- so if energy falls below this threshold, we CANNOT detect its presence but if its falls above the absolute threshold we CAN detect the stimulus
how did scientists detect what the absolute threshold
- the point at which the individual detect the stimulus 50% of the time
what is the difference threshold?
- the difference between 2 stimuli before the difference is detected
- “just noticeable difference” (also 50% of the time)
what is weber’s law
the principle that 2 stimuli must differ by a constant proportion to be perceived as different
e.g.: mentioned candle example
what is subliminal perception
- the detection of information below the level of conscious awareness
i.e. participants in a study were exposed to either words to do with thirst or normal words, the ones who got the words w/ thirst, drank more
couldnt actually see the flashed word
what is the signal detection theory
focuses on the decision making about stimuli under conditions of uncertainty
- the detection of sensory stimuli depends on many factors beside the physical intensity of the stimulus and the sensory abilities of the observer
- it provides a way to detect and account for subjects’ biases
what is an example of the signal detection theory
- if you are expecting an important phone call, you’re overly responsive and can shift your tendency towards more “YES” responses
- if the stimulus is present (phone ringing) you can respond either “YES” (answering call) or “NO” (failing to notice the call)
- if the stimulus is absent (phone isn’t ringing), you can respond either “YES” (answering call but nobody is calling) or “NO” (correctly identify that nobody is calling)
what are the two main components of decision making in the signal detection theory
1) information acquisition
2) criterion
what is information acquisition
- the gathering of relevant indicators, e.g. noticing the signal whether the phone is ringing or not
what does criterion refer to in the signal detection theory
- the standards used to make a decision
e.g. if its an important call, you may set low criterion and interpret any sound as the phone ringing
- if its not an important call, you’ll set high criterion and only respond if you’re sure the phone is ringing
