Sensation
a physiological process involving sensory receptors detecting and responding to the presence of stimuli
Perception
the mental process of organising and interpreting sensory stimuli sent from the senses so it achieves a meaningful form
Feature detector cells
– neurons specialised to respond to specific perceptual features of a stimulus pattern
Perceptual features
basic elements of a stimulus pattern (lines, shapes, colour)
Visual perception principles
Rules our brain automatically applies to visual stimuli to help organise and interpret them in a consistent and meaningful way
Reception:
- stimulus is detected at sensory receptor sites in a sense organ
- if not intense enough to activate a response, no further processing occurs
Transduction:
- receptors convert received energy into electrochemical energy required for neural impulses
- information about the various features of the energy received is coded into a neural impulse
Transmission:
- begins when electrochemically charged neural impulses leave their receptor site
- travel along specific nerve fibres (neural pathways) that connect to a particular location in the brain
Basic neural pathway
– left portion of each eye’s retina connects to occipital lobe in the left side of brain, right to right side, with the crossover point called the chiasma. This results in each eye supplying visual information to both right and left occipital lobes (back of the brain)
Selection:
Selection:
- feature detector cells filter visual stimuli
- specialised to respond to specific perceptual features (eg line, shape, edges, spots, colours)
- select perceptual features for further processing, ignore less important ones
- not enough time to fully process all stimuli
- further higher level selection occurs in occipital lobes
Organisation
- selected stimuli arrive individually, with no meaning
- the brain must organise stimuli into meaningful pattern to know what they represent
- involves the application of visual perception principles to help organise and interpret the stimuli in consistent and meaningful way
Interpretation
- assigning meaning to sensory stimuli so we understand what it represents about the external world
- information often incomplete or inconsistent
- we have to make an initial guess (perceptual hypothesis) as to what stimuli represent
- first impression of stimulus sometimes wrong
- influenced by which features were selected for further processing
- psychological factors such as past experience, expectations, and motivation
- psych. factors are unique to individual, so perceptions are all different n
