AP Psychology Sept. 28th Objective Opener Understand how your brain takes in information to produce sensation.

Sensation & Perception Chapter 3 Sensation & Perception This multimedia product and its contents are protected under copyright law.  The following are prohibited by law: any public performance or display, including transmission of any image over a network; preparation of any derivative work, including the extraction, in whole or part, of any images; any rental, lease, or lending of the program.

Sensation and Perception A process by which a simulated receptor create a pattern of neural messages that represent the stimulus in the brain Perception A process that makes sensory patterns meaningful

Transduction Transduction Converts a form of physical energy into the form of neural messages

Stimulation Becomes Perception Figure 3.1 Stimulation Becomes Perception For visual stimulation to become meaningful perception, it must undergo several transformations. First, physical stimulation (light waves from the butterfly) is transduced by the eye, where information about the wavelength and intensity of the light is coded into neural signals. Second, the neural messages travel to the sensory cortex of the brain, where they become sensations of color, brightness, form, and movement. Finally, the process of perception interprets these sensations by making connections with memories, expectations, emotions, and motives in other parts of the brain. Similar processes operate on the information taken in by the other senses.

Thresholds Absolute Threshold Difference Threshold Amount of stimulation necessary for a stimulus to be detected Difference Threshold Smallest amount by which a stimulus can be changed and the difference be detected (also called just noticeable difference: JND)

Thresholds Weber’s Law The size of the JND is proportional to the intensity of the stimulus. The JND is always large when the stimulus intensity is high, and small when the stimulus intensity is low.

Signal Detection Theory Sensation depends on the characteristics of the stimulus, the background information, and the detector. Stimulus event Neural activity Comparison with personal standard Action (or no action)

The Anatomy of Visual Sensation

Transduction of Light in the Retina

How the Visual System Creates Color and Brightness Wavelength Intensity (amplitude) Color Brightness

How the Visual System Creates Color Trichromatic Theory Based on three different cone receptors Explains initial stages of color sensation Opponent-Process Theory Based on bipolar cells Colors in complementary pairs Explains afterimages

Afterimages Afterimages Sensations that linger after the stimulus is removed In the following slide, fix your eyes on the dot in the center of the flag.

How the Visual System Creates Color Color Blindness Vision disorder that prevents an individual from discriminating certain colors

How We Hear Sound Waves Cochlea

Auditory Stimulation Becomes Sensation Table 3.3

Decibel Levels of Different Sounds The sound adults can’t hear?

Position and Movement Vestibular Sense Kinesthetic Sense Sense of body orientation with respect to gravity receptors in semicircular canals Kinesthetic Sense Sense of body position and movement of body parts relative to each other receptors in joints, muscles, and tendons

Smell Olfaction Olfactory Bulbs Pheromones Sense of smell Brain sites of olfactory processing Pheromones Chemical signals released by organisms to communicate with other members of the species

Receptors for Smell

Receptors for Taste

The Skin Senses The skin protects against surface injury, holds in bodily fluid, and helps regulate body temperature. Touch Warmth Cold Texture Pain

Pain Arises from intense stimulations Phantom Limb Gate Control Theory Nociceptors (nerve cells) sense painful/unpleasant stimuli. affected by mood and expectation Phantom Limb An amputee feels sensations coming from missing the body part due to the brain generating sensation. Gate Control Theory Explains pain control Involves special interneurons that open or close the pain pathway running up the spinal cord toward the brain

Creating New Senses?