03/25/22 SENSATION AND PERCEPTION MCGONIGLE INTRO TO PSYCHOLOGY
Dec 26, 2015
04/19/23
Example of Determining Factor:
• Sentry : at wartime
• Sentry: at peacetime
• Who will be more likely to sense danger?
04/19/23
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?
04/19/23
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.
04/19/23
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?
04/19/23
Signal Detection Theory
• Method of distinguishing sensory stimuli that takes into account not only their strengths, but :
• Setting• Physical state• Mood• Attitudes
04/19/23
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”
04/19/23
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.
04/19/23
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.
04/19/23
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..
04/19/23
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.
04/19/23
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.
04/19/23
Visual Acuity
• Sharpness of vision is called visual acuity.
• Snellen Vision Chart : 20/20
• Nearsighted, Farsighted. (Myopia, Hyperopia)
04/19/23
Color Circle
• Each color has a complementary partner
• Discussion of Traffic Lights
• Why are school buses yellow??
04/19/23
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.
04/19/23
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.
04/19/23
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)
04/19/23
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)
04/19/23
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.
04/19/23
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?
04/19/23
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.
04/19/23
Taste
• 5 Taste Buds
• Sweetness, Sourness, Saltiness, Bitterness, Umami
• Without a sense of smell, our sense of taste can be compromised..
04/19/23
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 !!!
04/19/23
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.
04/19/23
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”
04/19/23
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)
04/19/23
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
04/19/23
Perception ( Cont’d)
• Proximity ( 6 lines)
• Similarity ( x’s + o’s)
• Continuity ( wavy lines)
• Common fate ( people running together)
04/19/23
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.
04/19/23
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)