Chapter 5: Sensation and Perception Flashcards
Sensation
The perception of a physical stimulus and the transmission of that information to the brain
Perception
The further processing, organisation, and interpretation of sensory information by the brain
It creates a conscious view of the world and relates stimuli to the meaning of those stimuli
What is bottom up processing?
Based on the physical properties of the stimuli
What is top down processing?
About how existing knowledge and expectations influence the interpretation of sensory experiences
What is sensory coding?
Our sensory system translates the stimuli into patterns of neural impulses
What is transduction
The term for this translation of stimuli
What specialised cells are needed for transduction?
Sensory receptors
What do sensory receptors do?
Receive physical or chemical stimulation and then transmit impulses to the brain
Most of the sensory information passes through the thalamus to a specific area of the cerebral cortex
What are the 2 types of information that the brain receives?
Qualitative
Quantitative
What is the qualitative information about a stimulus?
Refers to the basic properties of the stimulus (the difference between sight and hearing)
What is the quantitative information about a stimulus?
Refers to the degree or strength of the stimulus (the difference between hot and cold)
How are the quantitative properties recognised?
By the rate of firing of a particular neuron
If the firing of a particular neuron is faster it means that the stimulus is more intense
How is sensory information detected?
Needs to reach a certain threshold
What is absolute threshold?
The minimum intensity of the stimulus required before it is experienced
What is the difference threshold?
The smallest difference between two stimuli that can be perceived
What does Weber’s law state?
States that the smallest difference a person can perceive between two stimuli is based on the original stimulus and not on a fixed number
What happens when the stimulus is stronger based on Weber’s law?
The stronger the stimulus, the greater the difference must be to notice it
What does the signal recognition theory state?
States that detecting a stimulus is not an objective process
What are the two components of detecting a stimulus?
Sensitivity to the stimulus in the presence of distraction form other stimuli
The criteria used to form a judgment from ambiguous information
What is sensory adaptation?
The reduction fo sensitivity to a constant level of stimulation
Example of sensory adaptation
No longer noticing the traffic that constantly drives by your bedroom
Synesthesia
The combined experience of, for example, taste with colour
Where does the light enter the eye?
The cornea
What is the pupil (eye)
A narrow opening at the front of the eye
The contraction or dilation of the pupil determines how much light enters the eye
What is the iris?
A circular muscle which determines the colour of the eye and regulates the size of the pupil
When does the pupil dilate?
When the light is weak or when we see something we like
What is accommodation for the eye?
Behind the iris, muscles change the shape of the lens
The lens is flattened to focus on distant objects and thickened to focus on closer objects
What is the retina?
Once the light has passed through the lens, an image forms on the retina, the thin surface at the back of the eye
The retina is the only part of the central nervous system that is visible from the outside
The retina contains sensory receptors that convert light into neural signals
What are the 2 receptors on the retina?
Rods
Cones
Rods
Respond to very low levels of light and are responsible for the night vision
The rods are not good at distinguishing colours and recognising small details
Cones
Are responsible for vision under bright conditions and for seeing colour and detail
Fovea
In the retina, the cones are close together in an area
