Sensation & Perception

Jessica Auger
Mind Map by Jessica Auger, updated more than 1 year ago
Jessica Auger
Created by Jessica Auger over 4 years ago


Chapter 4 Psychology 104 Concept Map Sensation & Perception

Resource summary

Sensation & Perception
1 Psychophysics
1.1 Just Noticeable Difference (JND)
1.1.1 Weber's Law Size of a JND is a constant proportion of the size of initial stimilus 1/3 for weight & pain 1/60 for vision 1/10 for hearing Different fractions apply to different types
1.1.2 Fechner's Law The amount of sensory experience is proportional to # of JND's Stimilus is above absolute threshold Same amount of increase in stimilus Brings smaller increases in perceived increase light sound
1.2 Threshold
1.2.1 The diving point between energy levels That do & do not have a detectable effect
1.2.2 Absolute Threshold Input is the minimum amount of stimulation that an organism can detect Stimulus Intensity Increase Subjects probability of responding increases Detected 50% of the time Define the boundaries of an organism's sensory capabilities
1.3 The study of how physical stimuli are translated into psychological experience
1.4 Sensory Adaption
1.4.1 Gradual decline in sensitivity due to prolonged stimulation
1.4.2 Pervasive aspect of everyday life
1.4.3 Built-in Process Sensory Input Keeps people tuned in to changes Rather than constants
1.4.4 Ignore the obvious
1.4.5 Focuses on changes
2 Vision
2.1 Eye
2.1.1 Lens Behind the Iris Transparent eye structure Focuses light rays That fall on the Retina Made up of soft tissue Capable of adjustments Accomodation Occurs when curvature of the lens adjusts to visual focus Lens of eye gets fatter To give Clearer Image
2.1.2 Pupil opening in center of Iris regulate amount of light passing into rear chamber of eye Constricts lets LESS light in sharpens the image Dilates lets light in Image is LESS sharp Saccades Constant Motion eyes constantly scan environment making brief fixations Essential to good vision
2.1.3 Retina Neural tissue lining the inside of the back surface of eye absorbs light, processes images, sends info to brain Optic Disk Hole in the retina where optic nerve fibres exit the eye Cones Visual receptors Key role in daylight vision Key role in color vision Do not respond well to dim light Provide better visual acuity sharpness precise detail Fovea Tiny spot in Center of Retina Contains only cones Visual acuity is BEST at this spot Rods Visual Receptors Key Role Night Vision Peripheral Vision Light Adaption Light Less Sensitive To Light in High illumination Dark More Sensitive To light in LOW illumination
2.2 Brain
2.2.1 Info. Processing Receptive Field of a visual cell Retinal Area When stimulated affects the firing of cell Optic Nerve Collection of axons Connect the eye with the brain Center-Surround Arrangement Center being excitatory Surround inhibitory or vice versa Allows us to see edges clearly
2.2.2 Optic Nerve Divided Optic Chasm Optic Nerve crosses here half of each eye left side of each eye goes to left brain Goes to other side of brain
2.2.3 VISUAL CORTEX Simple Cells Respond to Certain witdth angle position in receptive field Complex Cells any position Certain Width Angle SOME ONLY RESPOND TO A LINE MOVING IN A CERTAIN DIRECTION CELLS IN THE CORTEX ARE HIGHLY SPECIALIZED Known as FEATURE DECTECTORS Neurons that respond only to specific features of more complex stimuli
2.2.4 VISUAL AGNOSIA inability to recognize objects
2.2.5 PROSOPAGNOSIA inability to recognize familiar faces
2.3 Color Vision
2.3.1 Trichromatic Theory Hermann von Helmholtz (1852) Human eye has 3 types of receptors Differing sensitivities to diff. Light Wavelengths Red Blue Green tv works this way Color Blindness Occurs more frequently in MALES Dichromats They only see with 2 channels Lack red, green or blue channel rare to not have blue working SUPPORTS TRICHROMATIC THEORY Hard to distinguish green from red yellow from blue
2.3.2 Opponent Process Theory Complementary Colours pairs of colours produce gray tone when mixed Afterimage Image persists after stimulus is removed Trichromatic Theory CAN'T account for afterimage effect Ewald Hering (1878) Color Perception depends on receptors Opposite Responses to 3 pairs of colours blue/yellow red/green black/white also colors of afterimages
2.3.4 RETINA HAS 3 TYPES OF CONES red blue green
2.4 Processing
2.4.1 Top-Down like reversible figures when we perceive a word before we know all the letters
2.4.2 Bottom-Up Used in feature Analysis starts at parts and builds towards the whole
3 Hearing
3.1 Properties of Sound
3.1.1 Wavelength/Frequency - PITCH Measured in HERTZ (HZ) Humans only hear 20-20,000 Hz usually 2000-4000
3.1.2 Wave Amplitude quality of loudness Measured in Decibels (dB) Painful after 120 dB
3.1.3 Wave purity/mixture Timbre Complexity of sound wave Purest sound has only one frequency of vibration
3.1.4 Auditory Perception they INFLUENCE Place Theory Hermann von Helmholtz (1863) proposed place theory of pitch Spiral Cochlea Basilar Membrane Hair Cells Auditory Receptors Frequency Theory Entire Basilar Membrane Vibrates at different frequencies Auditory nerve fibres fire at different rates Letting brain know pitch of sound
3.1.5 George von Bekesy (1947) sound travels in waves Peak in a certain place depending on frequency Builds on PLACE THEORY
3.2 How it processes
3.2.1 Basilar Membrane runs length of cochlea Hair Cells Stimulated by waves of fluid
4 The Other Senses
4.1 Taste
4.1.1 Gustatory Receptors Taste Buds line the trenches around tiny bumps called papillae
4.1.2 FOUR MAIN TASTES Sweet Babies like sweet Sour Bitter Salty
4.1.3 Most taste Preferences are learned
4.1.4 SUPER tasters 4 times as many taste buds women DISLIKE Sweets Veggies alcohol smoking high fat foods
4.1.5 If a person lacks smell taste will be affected
4.2 Smell
4.2.1 Receptors Olfactory Cilia Hairlike structures In upper portion of nasal passages Axons that Synapse with cells In olfactory bulb base of brain
4.2.2 10,000 different odors
4.2.3 Pheremones Chemical Messages Linked to sexual attraction send from one member of species to another
4.3 Touch
4.3.1 Sensing Pressure Nerve Fibres Carry messages from outside world To spinal cord To brain stem go to opposite side of brain Signals pass through THALAMUS To Somatosensory cortex Parietal Lobe
4.4 Pain
4.4.1 Pathways Fast Uses myelinated neurons Registers pain in a second Slow Unmyelinated Neurons Less localized, longer aches Burning pain comes later
4.4.2 Gate Control Theory Incoming Pain passes through process in spinal cord can be closed by skin receptor signals Can be closed by brain receptor signals
5 Sensation
5.1 The stimulation of sense organs
6 Perception
6.1 The selection, organization, & interpretation
6.1.1 of Sensory Input
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