Sensation and Perception Flashcards
Absolute Threshold
Minimum amount of physical energy (stimulation) needed for a person to notice a stimulus
Signal Detection Theory
Decision making with uncertainty - suggests that detecting a signal depends on the strength of the signal, background noise and the subjects level of alertness
Also looks at sensory sensitivity (d’) and states that habituation reduces sensitivity to a signal
Subliminal perception
The tendency to percieve information outside of our consciousness
Difference threshold (or JND)
The lowest level of stimulation required to sense a change in stimulation or detect a difference 50% of the time
Trichromatic theory of colour vision
Young-Hemholtz theory that the retina contains 3 types of cones that are sensitive to red, blue and green
Resonance theory of hearing
Hemholtz theory that the different parts of the cochlea respond to different frequencies
Gestalt psychology and three of it’s laws
School of psychology that suggests that we percieve entire patterns or configurations, not just individual parts.
Laws include proximity, closure and similarity
Sensory adaptation
Tendency of sensory systems to respond less to stimuli that continue without change
Subliminal perception
Unconscious perception of a stimulus
What are the 3 physical dimensions of colour?
Hue (colour - determined by wavelength), brightness (amplitude of light wave) and saturation (purity of light)
Two types of photoreceptor
Cones - specialised for colour and high visual acuity
Rods - monochromatic vision, low acuity
Bottom-up processing
Perception begins with raw sensory data that ‘feed’ up to the brain
Top-down processing
Perception driven by prior experience, knowledge and context
Form perception
Organisation of sensations into meaningful shapes and patterns (as in Gestalt psychology)
Depth perception
Distance perception - organisation of perception in 3 dimensions
Motion perception
Perception of movement in objects
Ganglion cells
Nerve cells in the retina that combine information from bipolar cells. Their axons bundle together to form the optic nerve
Accomodation
When the lens adjusts its curvature to alter visual focus (flattens for distant objects, more rounded for nearer objects)
Complexity of sound
Combination of sound waves of different frequencies. Also known as “texture” of a sound (timbre)
Just noticible difference (jnd)
The smallest difference in intensity between stimuli that a person can detect
Percepts
Meaningful perceptual units (such as images of particular objects)
Monocular cues
Visual input from only one eye that contributes to depth perception
Binocular cues
Visual input from both eyes that provides perception of depth
Hair cells
Sound receptors attatched to basilar membrane of cochlea
Basilar membrane
Membrane within cochlear - vibrates in response to sound and stimulates hair cells
Opponent-process theory of colour
Our minds can only register the presence of one color of a pair at a time because the two colors oppose one another. Colour pairs are red-green, blue-yellow, black-white.
Explains after images
What component of sound is measured in Hertz?
Frequency which determines the pitch of sound
What component of sound is measured in decibels?
Amplitude which we percieve as “loudness” of a sound
Three principles that apply to all senses
- there is no one-to-one match between the physical objects and our psychological experience of them
- Senstation and perception are active, not passive
- Sensory and perceptual processes reflect adaptive pressures over the course of evolution
Fovea
Small area of the retina that contains only cones - for central vision and is where visual acuity is the highest
Perceptual constancy
Organisation of changing senstations into percepts that are relatviely stable (size, shape, colour)
Retina
Thin layer of tissue at the back of the eye - absorbs light, processes images and sends visual information to the brain.
