INTRO: Sensation and Perception
*not required according to syllabus + notes from YT video only
● 5 senses: vision, hearing, taste, smell, & touch
Basic principles:
● Sensation: the process of receiving stimulus energy from the external env.
● Perception: the process of organizing and interpreting sensory information
● Unified information processing system:
○ Bottom-up processing:
■ Initiated by sensory input
■ Outside world’s influence on perception
○ Top-down processing:
■ Initiated by cognitive processing
■ internal/mental world’s influence on perception (expectations & prior
understanding & knowledge affecting our perception )
Sensation:
● Sensory receptors:
○ Diff receptors for diff senses
○ Help us sense things
○ Specialized cells selectively detect and transmit sensory information that we're
being exposed to to the brain
○ every single cell sends signals through distinct neural pathways in order for us
to detect things
● Synesthesia: one sense induces an experience in another sense; examples:
○ Lexical: experiencing phantom tastes when hearing, reading, think about, or
speaking words
○ Seeing a color when hearing a sound
○ Grapheme: seeing colors when perceiving letters, numbers, or words
● Phantom limb pain: ongoing painful sensations that seem to be coming from the part
of the limb that is no longer there
● Specialized receptors:
○ Photoreceptors/photoreception (vision), detection of light
○ mechanoreceptors/mechanoreception (touch), detection of pressure,
vibration, and movement
, ○ chemoreceptors/chemoreception (smell and taste), detection of chemical
stimuli
Sensory thresholds:
● Absolute threshold: min. amount of energy/smallest level of stimulus an organism can
detect 50% of the time
● Difference thresholds:
○ JND (just noticeable difference)/Weber’s law:
■ ↑ jnd = ↓ sensitivity
■ Jnd increases with stimuli magnitude
*not required according to syllabus + notes from YT video only
● 5 senses: vision, hearing, taste, smell, & touch
Basic principles:
● Sensation: the process of receiving stimulus energy from the external env.
● Perception: the process of organizing and interpreting sensory information
● Unified information processing system:
○ Bottom-up processing:
■ Initiated by sensory input
■ Outside world’s influence on perception
○ Top-down processing:
■ Initiated by cognitive processing
■ internal/mental world’s influence on perception (expectations & prior
understanding & knowledge affecting our perception )
Sensation:
● Sensory receptors:
○ Diff receptors for diff senses
○ Help us sense things
○ Specialized cells selectively detect and transmit sensory information that we're
being exposed to to the brain
○ every single cell sends signals through distinct neural pathways in order for us
to detect things
● Synesthesia: one sense induces an experience in another sense; examples:
○ Lexical: experiencing phantom tastes when hearing, reading, think about, or
speaking words
○ Seeing a color when hearing a sound
○ Grapheme: seeing colors when perceiving letters, numbers, or words
● Phantom limb pain: ongoing painful sensations that seem to be coming from the part
of the limb that is no longer there
● Specialized receptors:
○ Photoreceptors/photoreception (vision), detection of light
○ mechanoreceptors/mechanoreception (touch), detection of pressure,
vibration, and movement
, ○ chemoreceptors/chemoreception (smell and taste), detection of chemical
stimuli
Sensory thresholds:
● Absolute threshold: min. amount of energy/smallest level of stimulus an organism can
detect 50% of the time
● Difference thresholds:
○ JND (just noticeable difference)/Weber’s law:
■ ↑ jnd = ↓ sensitivity
■ Jnd increases with stimuli magnitude
