SENSATION AND PERCEPTION MCGONIGLE INTRO TO PSYCHOLOGY
Example of Determining Factor: • Sentry : at wartime • Sentry: at peacetime • Who will be more likely to sense danger?
Sensory Adaptation • Imagine yourself at a bonfire, marshmallow roast, what happens to the faces in the background after a while? • What animals see better in the night time as opposed to day? Why do you think this is true?
Absolute Threshold • Weakest amount of a stimulus that can be sensed. • Dogs – can hear certain whistles that we can not hear. • Biological & Psychological factors determine different thresholds.
Difference Threshold • The minimum amount of difference that can be detected between two stimuli is known as the difference threshold. • Dark blue/ Navy blue – could you tell the difference? Stang baseball hats- maroon?
Signal Detection Theory • Method of distinguishing sensory stimuli that takes into account not only their strengths, but : • Setting • Physical state • Mood • Attitudes
Sensory Adaptation • We become more sensitive to weak stimuli such as the faces around the fire. • We become less aware of the heat of the fire or the sound of the wood burning or the smell of the marshmallows. • “Attleboro apartment near commuter rail”
Threshold Receptors • Vision: Rods and cones in the retina. • Hearing : Hair cells of the inner ear. • Smell : Receptor cells in the nose. • Taste: Taste buds on the tongue. • Touch: Nerve endings on the skin.
Light • Think of a rainbow/ prism • What colors are most brilliant to you? • Main colors of spectrum: (Roy G Biv) • Red, Orange, Yellow, Green, Blue, Indigo, Violet. • Not visible* - Infrared and ultraviolet.
Eye • Amount of light that enters the eye is determined by the size in the opening in the colored part of the eye. (pupil) • Pupil dilation : discussion • Lens : adjusts to the distance of objects by changing its thickness. • FST – why do people squint? Eye glasses/ contac lens..
Human Eye (cont’d) • Retina: sensitive surface in the eye that acts like film in a camera. Made up of neurons not film. • Photoreceptors: once the light hits the photoreceptors, a nerve carries the visual input to the brain. • Blind spot: Where optic nerve leaves the eye 4-3.
Eye ( last slide) • Rods and Cones: Rods are sensitive only to the brightness of light. • Rods : allow us to see in black and white • Cones: allow us to see in color.
Visual Acuity • Sharpness of vision is called visual acuity. • Snellen Vision Chart : 20/20 • Nearsighted, Farsighted. (Myopia, Hyperopia)
Snellen Chart • T E • P V L
Snellen Chart H C O E H P D N L Z A
Snellen Chart D V H T L U E V O C U C P C Y L H N
Snellen Last • P C Y L h D v • Don’t squint!!!!!!
Color Circle • Each color has a complementary partner • Discussion of Traffic Lights • Why are school buses yellow??
Afterimage/ Color Blindness • Afterimage : Of a color is its complementary color. ( USA Flag) • Color blind: unable to distinguish color due to an absence of or malfunction in the cones. • Total Color blindness : is very rare.. • Socks – Black socks / Navy blue – hard for men.
Hearing • Pitch: How high or low a sound is depends on its frequency or # of cycles per second. • AI – term used often.. • More cycles per second, the higher the pitch. • Women’s voices: higher pitch than men, shorter vocal cords.
Loudness • Loudness: determined by the height, or amplitude , of sound waves. • Higher the amplitude: the louder the sound. • Loudness is measured in decibels. ( 0 = watch ticking 20” away in a quiet room)
Ear • Shaped to capture sound waves, the outer ear is what we see. • Eardrum: thin membrane that vibrates when sound hits it. • Transmits sound to the three bones in the ear. ( hammer, anvil, and stirrup)
Cochlea • Latin for Snail ( Its shape) in the inner ear. • Contains fluids & neurons that move in response to vibrations of the fluids. • Movement - Generates neural impulses that are transmitted to the brain. • Auditory nerve – transmits this message.
Deafness • Conductive Deafness: Occurs because of damage to the middle ear. • Sensorineural deafness: Caused by damage to the inner ear. Neurons in cochlea are destroyed or damage to auditory nerve. • What occupations would experience sensorineural deafness?
Other Senses: Smell & Taste • Dogs : incredible sense of smell.. • Helen Keller ( 90) • Onion/ Apple w/out smell??? • Odors: are detected by neurons in each nostril. • Receptors: send info to the brain via the olfactory nerve.
Taste • 5 Taste Buds • Sweetness, Sourness, Saltiness, Bitterness, Umami • Without a sense of smell, our sense of taste can be compromised..
Skin Senses • Some are more sensitive than others: • P.91 • Fingertips • Lips • Cheeks
Less sensitive to touch • Shoulders • Thighs • Calves
Temperature • 98.6 • Neurons – beneath the skin • Hot day- receptors for warmth fire • Cold day- receptors for cold fire • Adjustment – cold water after a while • NE Patriot fan vs. Miami Dolphin fan !!!
Pain • Not all areas are equally sensitive to pain. • Pain – point of contact 1st. • Pain - sent to the spinal cord 2nd. • Pain – now enters the thalamus in the brain. • Pain – ends in the cerebral cortex.
Gate Theory • Gate = Limit • Only a certain amount of info can be processed at one time. • Rubbing the area can transmit sensations to the brain that compete w/ pain. • Western Movies – “ Bite the bullet”
Body Senses • Vestibular sense: Tells you whether you are physically upright w/out using your eyes. ( gymnasts) - role of ears! • Kinesthesis : sense that informs people about the position and motion of their bodies. (kinesiology)
Perception • Closure : Figure 4-10- Tendency to perceive a complete or whole figure even when there are gaps in what your senses tell you. • Figure-Ground Perception: Vase vs. 2 faces. Is the perception of figures against a background
Perception ( Cont’d) • Proximity ( 6 lines) • Similarity ( x’s + o’s) • Continuity ( wavy lines) • Common fate ( people running together)
Stroboscopic Motion • Page 95- give illusion of motion (cat) • Illusion of motion – produced by showing the rapid progression of images or objects that are not moving at all. • Little picture books- flipped to look like motion pictures.
Visual Illusions • Muller- Lyer illusions- which line is longer? • Ponzo illusion – lines appear to be coming together. • Rule of size constancy. ( looking at people from a plane)
Quiz Thursday Taste Buds Roy G Biv Rods & Cones Lens & Retina Absolute Threshold Difference Threshold Types of Deafness Bones in the Ear Decibel levels