Sensation and Perception Flashcards
What is sensation?
How our sensory receptors and nervous system receive and represent stimulus energies from our environment
What is perception?
How we organise and interpret sensory information. Enables us to recognise meaningful objects and events
How do we construct or perceptions and sensations?
Using bottom up processing whilst relying on experiences and expectations to interpret stimuli through top down processing
What is bottom-up processing?
Starts at sensory receptors and works up to brain’s integration of sensory information
What is top-down processing?
Constructs perceptions from sensory input by drawing on experiences and expectations
What are the core concepts of sensation?
- Transduction
- Thresholds
- Signal Detection
- Subliminal Stimulation
- Sensory Adaptation
What is transduction?
Converting characteristics of a stimulus into nerve impulses
What is the study of psychophysics?
Studies relationships between physical characteristics of stimuli and sensory capabilities
What is the absolute threshold?
Minimum stimulus energy needed to detect a particular stimulus
What is signal detection theory?
A theory predicting how and when we detect the presence of a faint stimulus (signal) amid background stimulus (noise)
Describe subliminal stimulation
- Stimulus is so weak or brief that although it is received by senses, it cannot be perceived consciously (below absolute threshold)
- Can be affected by this stimuli without being aware of it (subliminal stimuli responses to later question)
- Subtle effects on attitudes and judgements
What is difference threshold?
Minimum difference between two stimuli that people perceive 50% of the time
What is Weber’s Law?
Principle that to be perceived as different, two stimuli must differ by a constant minimum percentage
What is sensory adaptation?
- Diminished sensitivity as a consequences of constant stimulation
- Frees up senses from mundane and detect changes important for survival
- Eyes constantly moving to ensure retinal image changes, sense receptors do not become fatigued by focusing on same image
What is perceptual set?
Mental predisposition to perceive one thing and not another
What is wavelength?
Distance from the peak of one light or sound wave to peak of next
What is hue?
Dimension of colour that is determined by the wavelength of light
Describe intensify with vision
Amount of energy in a light wave or sound wave, influences what we perceive as brightness or loudness
What are parts of the eye?
- Retina
- Cornea
- Iris
- Pupil
- Lens
- Blind Spot
- Optic Nerve
What is the retina?
Light sensitive inner surface of the eye, containing the receptor rods and cones, plus layers of neuron’s that begin the processing of visual information
What is the cornea?
Bends light to help provide focus as light enters
What is the iris?
Responds to cognitive and emotional states. Muscle that dilates/constricts in response to light intensity
What is the pupil?
Small, adjustable opening where light passes through into eye
What is the lens?
Focuses light rays onto retina, that pass through to create clear images of objects positioned at various distances
What is the blind spot?
Where optic nerve and blood vessels leave eyeball, creating a “blind spot” because no receptor cells are located there
What is the optic nerve?
Nerve that carries around neural impulses from eye to visual centres in brain
What is accommodation?
Process which eye’s lens changes shape to focus near or far object
What are rods?
Retinal receptors detects black, white, gray are sensitive to movement; necessary for peripheral and twilight vision, when cones don’t respond
What are cones?
Retinal receptors that are concentrated near the centre of the retina and that function in daylight or in well-lit conditions. Cones detect fine detail and give rise to colour sensation
Describe use adaptations of audition
- Keen differentiation frequently around human voice
- Very sensitive to faint sounds and changes in sound that might alert us to danger
- Process aspects in different areas of brain
- Sound localisation: nervous system uses time to intensify differences of sounds arriving at 2 ears to locate sounds
Describe senses of olfaction
- Smell via receptors that project through nasal cavity int mucous membrane
- Receptors have binding site for thousands of potential odour molecules
- Send input to olfactory bulb, force brain structure able nose coding for odours
Describe sense of touch
- Pressure, pain and temperature
- Allows us to escape external danger
- Alerts us to disorders within our body
- Source of pleasure
- Essential to our development
- Pain strongly tied to perception
Describe sense of kinaesthesia
Provides us with feedback about our muscles and joint positions and movements
- Nerve endings in muscles, tendons, joints
- Receptors provide basis for coordinated movements
Describe vestibular sense
- Sense of body orientation or equilibrium
- Receptors in vestibular apparatus in inner ear
What is Gestalt Principles?
- Argue that whole is more than sum of its parts
- Emphasised our tendency to integrate pieces of information into meaningful wholes
What are figure-ground relations?
Organisation of stimuli into a foreground figure and a background
What is grouping?
Perceptual tendency to organise into coherent groups
What is depth perception?
Ability to see objects in 3D although the images that strike the retina are 3D, allows us to judge distance
Describe perceptual schemas
- Mental representations containing the distinctive features of a person, object, event or other perceptual phenomenon
- Allows us to identify and classify sensory input
