1. Sensation and Perception
Chapter 4
Sensation and Perception

2. Sensation Occurs anytime a stimulus activates one of your receptors
The sense organ detect physical changes in energy such as light, heat, sound and physical pressure. The skin recognizes change in temperature and pressure, the eye notice changes in light, etc.

3. Perception
Is the organization of sensory information into meaningful experiences
Psychophysics is the study of the relationship between sensory experiences and the physical stimuli that cause them
Look at page 85 in your book

4. Absolute threshold
Is the least amount of stimulus required to produce a sensation. For example, it is thought by scientists that the absolute threshold for human vision would be seeing a candle flame 30 miles away on a clear night
For hearing it would be hearing a ticking from 20 feet away.
For smell it is smell one drop of perfume in a 3 room house
For touch it is feeling a bee’s wing falling a distance of 1cm onto your cheek

5. Difference Threshold
Is the smallest amount of change in a physical stimulus that can be detected between two stimuli
Examples temperature change in room or brightness of room
Weber’s law says the larger the stimulus, the larger a change required for a person to notice that any change has occurred

6. Senses Experts
People who can detect even the smallest of changes of sensation are called experts and may have jobs such as food tasters( Ben and Jerry’s) wine tasters ( Crown Valley), or perfume experts.
In addition to our five senses we also have two more senses
Vestibular and Kinesthetic

7. Vestibular system
The body’s sense of balance is regulated by your vestibular system, which is inside the inner ear. Without it you wouldn’t be able to walk, stand up or even sit up

8. Kinesthesis Is the sense of movement and body position
Your sense of kinesthesis consists of receptors in your joints, tendons, and muscles.
Without this sense all of your movements would be jerky and uncoordinated
Actions such as playing the piano, or sports would be impossible

9. Vision Light enters through the pupil and reaches the lens
The lens is a flexible structure that focuses light on the retina
The retina consists of millions of rods and cones, which are responsible for changing light into energy in neuronal impulses that travel to the optic nerve. Optic nerve carries the message to the brain

10. Vision The message reaches the brain and it goes to the occipital lobe
Your cones work best in the day, and your rods work best at night. Only cones are sensitive to color.