1. Sensation

2. Sensation
Information coming into our brain from our sensory receivers

3. Scientific Names for the Six Senses
Seeing: Visual
Hearing: Auditory
Tasting: Gustatory
Smelling: Olfactory
Sense of Touch: Tactile
Balance: Vestibular

4. Psychophysics Light - brightness Sound - volume Pressure - weight
Psychophysics: study of the relationship between physical characteristics of stimuli and our psychological experience of them
Light - brightness
Sound - volume
Pressure - weight
Taste - sweetness

5. Thresholds Absolute Threshold
Minimum stimulation (weakest level) needed to detect a particular stimulus 50% of the time
Vision: Flame of a candle seen 30 miles away on a dark and clear night
Hearing: Ticking of a watch from 20 feet away
Taste: 1 teaspoon of sugar in 2 gallons of water
Smelling: 1 drop of perfume diffused in a 3 bedroom apartment
Touch: A bee’s wing falling on your cheek from a distance of 1 centimeter

6. Subliminal Stimulation/Messages
Messages presented below absolute thresholds – not consciously perceived
Some have argued that humans still “pick up” these messages that influence our “unconscious.” Do these messages have suggestive powers?
Skeptics argue “Subliminal Messages” are heavily influenced by top down processes.
Example: Feeling “hungry” during subliminal advertisements.

7. Difference Threshold
Minimum difference between any two stimuli that a person can detect 50% of the time
Weber’s Law: The greater or stronger the stimulus, the greater the change required to notice that a change has occurred. The two stimuli must differ by a constant minimum percentage (rather than a constant amount), to be perceived as different.
Just Noticeable Difference (JND): Difference thresholds low enough to detect minute changes in important stimuli.

8. Sensation: Thresholds
Signal Detection Theory: predicts how and when we detect the presence of a faint stimulus (signal) amid background stimulation (noise)
Assumes that there is no single absolute threshold because the idea of a threshold ignores the decision- making ability of the test subject.

9. Sensory Adaptation
Diminished sensitivity as a consequence of constant stimulation.
Preview Question 3: What function does sensory adaptation serve?
Put a band aid on your arm and after awhile
you don’t sense it.