Chapter 5 - sensation and perception Flashcards
(119 cards)
sensation
is the process through which the senses detect visual, auditory, and other sensory stimuli and transmit them to the brain
perception
is the process by which sensory info is actively organized and interpreted by the brain
thresholds
how much stimulation has to be out there before we can detect that it is there
sensory transduction
converting info in environment into neural applications
absolute threshold
- Difference between not being able to perceive a stimulus and being able to just barely perceive it
- The minimum amount of sensory stimulation that can be detected 50% of the time
difference threshold
the minimal difference between two stimuli necessary for detection of a difference between the two.
JND example
Radiology example
○ Have to be able to determine between shading in order to detect the “tumour”
-Notice it’s darker or lighter in certain areas
inequality threshold
variation across senses
Sensory Adaptation- “not seeing”
○ Become less sensitive to unchanging sensory stimulus overtime
○ Automatic process
○ Allows us to shift attention
two types of processing
bottom up and top down
bottom up
○ Individual components of stimulus detected by sensory receptors
Bits of info transmitted to areas of the brain to be combined and assembled into a unified whole.
Top down
○ Past experiences and knowledge influence our perceptions
○ We find meaningful links between the individual elements taken in by our sensory receptors
○ Use existing knowledge, concepts, ideas, expectations
Perceptual Set:
where individuals’ expectations affect their perceptions
Anatomy of Smell
○ Olfactory epithelium
○ Olfactory receptor neurons
○ Olfactory bulb
Taste: Sensation
Chemical receptors/sensation-independent, “Taste”
○ Chemical receptors = taste buds- consist of several receptor cells
○ Ab 9,000 taste buds grouped in different regions
○ Located on edges & top of tongue
○ Thalamus
○ Prenatal-childhood more
Neuro gustatory
study of taste and smell etc
Taste Flavour Gustation Influenced by
○ Appearance/ palatability
○ Texture
○ Previous experience
parts of the eye
○ Cornea ○ Lens ○ Retina ○ Rods ○ Cones ○ Fovea ○ Optic Nerve
optic nerve
○ Perceive small part of electromagnetic (EM) spectrum
○ Light waves measured in nanometers (billionths of meter)
Three dimensions of colour vision
Hue is the specific colour perceived, wavelengths
○ Brightness refers to the intensity of the light energy that is perceived, ampitutde of a wave
○ Saturation refers to the purity of the colour
Trichromatic theory (young-helmholtz)
the manner in which the visual system gives rise to the phenomenological experience of color.
Opponent- Process theory (Herring, 1870)
○ Three cone types ○ Each responds to two different wavelengths-opposing pairs ○ Red or green ○ Blue or yellow ○ Black or white
Dual Process Theory
○ Combines trichromatic & opponent-process theories
current view of colour
○ 3 types of cones sensitive to short (blue) medium (green) and long (red) wavelengths
○ These cones stimulate opponent- process reactions
○ Opponent processes occur in ganglion cells, neurons in relay stations & visual cortex