Units 14+15

Sensation Process by which body gathers information about environment Connects us to the world Sensation generally occurs in the sense organs – vision (detects light waves) – audition (sense of hearing) – olifaction (sense of smell) – gustation (sense of taste) – cutaneous (sense of touch)

Perception Process by which the brain organizes and interprets sensory information (“sensation PLUS perception”) Perception occurs in the brain 3 basic principles adaptive active no one-on-one correspondence between physical and psychological reality

Perception Top-down processing “ Conceptually-driven processing” Take information already existing in the mind to interpret environment Bottom-up processing “ Data-driven processing” Take stimuli from the environment and make attempts to determine its meaning

Sensation Sensory receptors – Eyes, ears, nose, etc. detect physical energy (light/sound/smell) Transduction – Translates physical energy into neural signals Absolute threshold – Each system’s minimal amount of energy required to activate it Difference threshold – Each system’s minimal amount of energy required to detect change from one level of stimulus to another – Just-noticeable difference (Weber’s Law)

In this experiment, say the color of the word (not what the word says) Example: For the word RED you should say “Red”. For the word RED you should say “Yellow“ As soon as the words appear on your screen, read the list as fast as you can Stroop Effect

Stroop Effect In this experiment, look at a picture of an animal and say the name of the animal. Do NOT read the word placed on the picture. For example: You should say "Cow" because the animal in the picture is a cow. You should sat “Cat” because the animal in the picture is a cat.

Vision Allows for the detection of movement, light, depth perception Transduction – impulses from optic nerve carry visual information from retina to optic chiasm; neural messages then travel to thalamus and into the visual cortex

Vision Motion perception Rods in retina sensitive to motion activate neurons in the visual cortex 2 systems for processing movement Eye stationary as object moves Eye moves to maintain object at same place on the retina

Vision Photoreceptors Cones - Highest concentration in the fovea - Require light to be activated - Less numerous (7+ million) - Color vision/trichromatic theory (“photopic vision”) - High visual acuity - Low sensitivity Rods Highest concentration in the retina More numerous (120+ million) Night vision (“scoptic vision”) Low visual acuity High sensitivity (esp. motion detection)

Vision Color blindness Inability to distinguish colors “ Disease” is linked to the X chromosome, thus males more likely than females to be color blind Most common condition is red-green color blindness (difficulty distinguishing red and green)

Hearing Transduction Outer ear collects physical stimuli (sound waves) Middle ear converts waves of air pressure into movements Inner ear carries movements via waves of fluid (in ear drum) that generate neural signals Signals sent to thalamus then to temporal lobe

Hearing Volume – “loudness” determined by the height of sound wave (amplitude) Pitch – refers to the frequency of the sound wave (low B flat/high C tone)

Touch Protects body from injury, helps identify objects, maintain body temperature 4 basic skin sensors (heat, cold, pain, pressure) Touch sensations differ throughout the body Transduction Sensory neurons in skin send impulses to spinal cord or communicate with interneurons (that in turn stimulate motor neurons)

Taste Refers to four basic tastes (sweet, sour, salty, bitter) and protects us from injecting toxic substances Transduction Occurs in the taste buds Physical stimulus (soluble chemicals) activate taste receptor neurons which carry information to thalamus and primary cortex to help identify taste

Smell Detect danger (e.g., smoke, spoiled food) and/or recognize familiar odors Transduction Physical stimulus (air molecules) enter nasal cavity through nose Receptors in olfactory epithelium pass information through the olfactory bulb to the primary cortex, which then connects with thalamus and amygdala

Units 14+15

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Units 14+15