EXAM 2: CHAPTER 4 Flashcards
Synesthesia
Two Greek words syn meaning together, and aesthesis meaning perception = joined perception. People with this condition experience stimulus that is perceived by one sense in most people in two or more sensory modalities
Why is it hard to measure those who experienced synesthesia
Because they assume their experiences are normal, but prevalence estimates 1 in 23 people
Grapheme-color synesthesia
Most common form of synesthesia. Person with this type sees color in response to specific letter or number
Sensation
Act of using our own sensory systems to detect environmental stimuli
Perception
The conscious recognition and identification of a sensory stimulus
Transduction
Process that involves converting stimulus energy into neural impulses to be interpreted by brain
5 senses and their physical stimuli:
- Olfactory (smell); odorants (airborne chemicals)
- Somatosensory (touch, heat, pain); pressure or damage to skin
- Gustatory (taste); chemicals (typically in food)
- Auditory (hearing) ; sound waves
- Visual (sight) ; light (photons)
Sensory receptor cells
Specialized cells that convert a specific form of environmental stimuli into neural impulses
Sensory transduction
Process of converting a specific form of environmental stimuli into neural impulses
Can sensory receptors be activated by weak stimuli?
Yes, but it must reach a certain level of intensity called threshold
Threshold
The point at which the magnitude or intensity of a stimulus initiates a neural impulse
Absolute threshold
Minimal stimulus necessary for detection by an individual
Difference threshold vs noticeable differences
The minimal difference between 2 stimuli necessary for detection of a difference between the two
Signal detection theory
Theory that the response to a signal in every situation depends on an individual’s ability to differentiate between signal and noise
Sensory adaptation
The process whereby repeated stimulation of a sensory cell leads to a reduced response (Eg. When some stimulus in our surroundings stays the same for a period of time, like pressure of clothing on skin, the sensory cells will respond to it less and less)
Olfactory adaptation
Occurs when a change in sensitivity to a particular odour reaches a point where the odour cannot be distinguished after a prolonged exposure
How does perception occur?
Through bottom-up processing
Bottom-up processing
Perception that proceeds by transducing environmental stimuli into neural impulses that move into successively more complex brain regions (Eg. When looking at your friends face, our eyes convert light energy into neural impulses)
Top-down processing
Perception processes led by cognitive processes such as memory or expectations (Eg. When looking at your friends face, our brain stores information about that face and helps you perceive)
Perceptual set
Top-down processing is more than our memories. The knowledge about how things typically appear/expectations will play a role. It is about the readiness to interpret a certain stimulus a certain way (Eg. Fuzzy photo of a UFO will look different depending on whether you believe in UFOs)
Ambiguous stimuli
Stimuli that could be interpreted in different ways (Eg. Photo of old women with big nose vs young)
Sensory systems
Part of nervous system consisting of sensory receptors that receive stimulus information and conduct information to parts of brain responsible for processing sensory information
Aritstotle claims
First to claim that there are five senses: Smell, taste, touch, sound and sight
Proprioceptive feedback
Our five senses + kinesthetic sense (body movement, posture, position). It is the unconscious awareness of the self and spatial orientation arising from stimulation within body
Kinesthetic
Monitors the position of the various parts of body. You know where your limbs are because you thought about putting them there
Vestibular
Responds to gravity, keeps you informed of your body’s location in space
Which sense is the major sense
Vision
The auditory system is designed for what
To convert sound waves, vibrations of the air into neural impulses
2 major qualities of sound waves to produce perception of different sounds
Frequency & amplitude
Frequency
Frequency of sound wave refers to the number of cycles the wave completes in a certain amount of time. It is measured in units called hertz (Hz). It is responsible for producing the pitch of a sound
Which range (in Hz) do we hear best
2,000-5,000 Hz
Amplitude
Amplitude of a sound wave refers to the strength of a given cycle. It is responsible for our detection of loudness and is measured in units called decibels (dB)
Steps of converting sound waves to neural impulses (10):
- Sound waves enter outer ear at its deepest part, reflect the ear drum (tympanic membrane)
- Vibrations of ear drum set in motion a series of three tiny bones (ossicles) called maleus, incus, and stapes.
- Stapes, the last bone in chain hits the oval window (membrane separating ossicles and inner ear)
- Deflection of oval window causes wave to form in the fluid-filled structure in inner ear (cochlea)
- When fluid moves in cochlea, it deflects the basilar membrane (structure in cochlea where hair cells are located)
- Movement of basilar membrane bends hair cells that transduce the fluid sound wave into electrical activity
- Hair cells communicate with nerves in cochlea and send impulses to brain
- After sound waves are transduced, it travels as signals from nerves in the cochlea to brainstem, the thalamus, then auditory cortex (temporal lobe)
- Auditory information from one ear sent to auditory cortex areas on both sides of brain
- Auditory information moves to the auditory association areas in corte
Tympanic membrane
Ear drum
Ossicles
Tiny bones in the ear called the maleus, incus, and stapes
Oval window
Membrane separating the ossicles and the inner ear, deflection of which causes a wave to form in cochlea
Cochlea
Fluid-filled structure in inner ear with hair cells