Psychology Module 5

5.1: Sensation vs Perception

Sensation:

  • Sensory receptors = specialized receptors -> specific types of stimuli

  • Sensory Information -> Sensory Receptor -> Sensation (Ex: Light)

  • Sensory Stimulus Energy -> Action Potential = Transduction

  • Five Senses (Vision, Audition, Olfaction, Gustation, Somatosensation) + Balance (Vestibular), Body Position/Movement (Proprioception and Kinesthesia), Pain (Nonciception), and Temperature (Thermoception)

  • Absolute Threshold = Minimum amount of stimuli for stimuli to be detected 50% of the time

  • Human senses are AMAZING -> Candle flame 30 miles, Clock tick 20 feet away

  • Subliminal Messages -> Messages that are presented below threshold (Conscious Awareness)

  • Absolute Threshold = Stimuli strong enough to excite sensory receptors that sends nerve impulses to brain

  • Below = Subliminal Message -> Receive it, Not consciously aware of it

  • Difference Threshold (JND): How much difference in stimuli is required to detect difference between Absolute Threshold/Subliminal Message

  • Weber’s Law -> Difference Threshold = constant fraction of the original stimulus (Phone in movie theater vs basketball court during day)

Perception:

  • Perception = Way sensory information is organized, interpreted, and consciously experienced = Interpret sensory information

  • Bottom-Up Processing = Stimulus in Environment Driving a Process -> Sense basic features of stimuli ->Integrate them [RAW INFORMATION GOES FROM BOTTOM-UP]

  • Top-Down Processing = Knowledge/Expectancy Driving a Process -> Previous experience/expectation are first used to process stimuli [CONCEPTS & EXPERIENCES GOES FROM TOP-DOWN]

  • EX: Bottom-Up -> Waiter drops a plate -> Sound from Environment -> Attentional Capture

  • EX: Top-Down Processing (Slow, Deliberate, Effortful, Under Control) -> Lost Keys -> Yellow Spiderman -> Look for specific yellow it in known spots, not ceiling fan

  • Sensation is physical, Perception is Psychological

  • Not all Sensations result in Perception -> Sensory Adaption

  • Sensory Adaptation -> Getting used to a stimuli over a prolonged period of time -> No perception

  • EX: People talking really loudly while reading, after a while ignored

  • Attention -> Divides what is sensed and what is perceived

  • EX: Cocktail Party Effect -> Loud Party, Talking with friends -> Tune out background noise to listen to friend

  • Inattentional Blindness: Failure to notice something completely noticeably because actively attending to something else -> No attention

  • EX: Gorilla and Basketball, Black & White vs Red

  • Motivation affects perception -> Important phone call, Instantly filter to hear any noise from phone

  • Signal Detection Theory: Ability to detect stimulus in distracting environment

  • EX: Mother Sleeping -> Baby Murmur

  • Perceptions affected by beliefs, values, prejudices, expectations, and life experiences -> Culture

  • Culture & Perception -> Western Cultures -> Illusions

  • EX: Muller-Lyer -> Western Perceived Different Lines in Space -> Same Lines/Length

  • Western Perceptions -> Perceptual Context of Buildings with Straight Lines -> Carpented World (Segall)

  • Non-Western Perceptions -> Zulu of South Africa -> Round Hubs in Circles -> Less susceptible

  • Other senses vary cross-culturally

  • Personality affects perception: Child (Thrill-Seeker) -> Intense Sour Flavors