1. Psychophysics: the study of relationships between the physical characteristics of stimuli, such as their intensity, and out psychological experience on them; what stimuli can we detect? 2. Absolute Thresholds: the minimum stimulation needed to detect a particular stimulus 50% of the time ( light, sound, pressure, taste, odor); expose eats to varying sound level- each pitch, test defines where half the time you correctly detected the sound and half the time you do not 3. Signal Detection:
* Signal Detection Theory: a theory predicting how and when we detect the presence of a faint stimulus amid background stimulation. Assumes that there is no single absolute threshold and that detection depends partly on a person’s experience, expectations, motivation, and level of fatigue; ration of false alarms to hits; absolute thresholds vary- exhausted parents hear small noise, but miss large; war causes responsiveness to increase, may cause false alarms * People respond differently to same stimulus, same person’s reactions vary as circumstances changes- vigilance diminished after 30 minutes of judging when a fait signal appears- depends on task, time of day, and exercise 4. Subliminal Stimulation:
* Subliminal: below one’s absolute threshold for conscious awareness * We can sense stimuli below absolute threshold; detect half the time, slightly below still detect some of the time; people plead ignorance when asked to make some perceptual judgmental usually beat chance * We can be affected weak and unnoticed stimuli: experiment: flash emotionally positive or negative scenes- viewers only see flash- more positive ratings to people whose photos were associated with positive scenes- people look nicer if photo is followed by a unperceived kittens rather than a werewolf * Image is quickly flashed, replaced by a masking stimulus that interrupts the brains processing before conscious perception- 1/7 name hammer after presented for 47 milliseconds- see hammer in same position 15 minutes later and after 20 presentations of other images- name 1/3- second presentation of hammer reminded the brain of the first; hidden bread- detect related words, butter, before anything else * Advertisers cannot manipulate us with “hidden persuasion”- subtle, fleeting effect on thinking- thirsty people with the subliminal work thrist might for a brief interval, make a beverage ad more persuasive- placebo * Canadian Broadcasting Corporation: subliminal message 352 times, no one guessed the message; ½ reported hungry or thirsty during show, but message was telephone now; subliminal procedures offer little or nothing of value to the marketing practitioner 5. Difference Thresholds: the minimum difference between 2 stimuli required for detection 50% of the time; just noticeable; increases with magnitude of the stimulus ex.- 10 grams to 100 gram weight will detect, 10 grams to 1-kg will not * Weber’s Law: the principle that, to be perceived as different, 2 stimuli must differ by a constant minimum percentage ( rather than a constant amount); lights must differ in intensity by 8%; approximate; bike vs. Mercedes both increased by 10% B. Sensory Adaptation
1. Sensory Adaptation: diminished sensitivity as a consequence of constant stimulation; stink * Eyes constantly...