Use LEFT and RIGHT arrow keys to navigate between flashcards;
Use UP and DOWN arrow keys to flip the card;
H to show hint;
A reads text to speech;
14 Cards in this Set
- Front
- Back
|
Describe how the structure of our visual system affects the way we interpret the world around us |
Through wavelengths and amplitudes of light waves we are able to understand the physical characteristics of light and therefore understand vision and have an adequate stimulus in order to see and perceive the world around us
|
|
|
Identify which physical characteristics of light corresponds to which psychological characteristics |
Wavelength = colour Amplitude = brightness/intensity |
|
|
Describe the visual system from eye to cortex |
Light enters the eye via cornea, anterior chamber (aqueous humour), pupil and lens Posterior chamber (vitrious humour) to the retina at back of eye Retina transduces light to action potentials via photoreceptors to the bipolar neurons to send signals to ganglion cells Axons of cells form optic nerve - sensory info to LGN to form optic radiations to visual cortex in occipital lobe |
|
|
Differentiate between rods and cones (function, location, convergence) |
Rods - dim light, see in greys, several rods converge on a single ganglion cell Cones - bright light, colour vision, focused on fovea, one cone converged to one ganglion cell |
|
|
Recount the 3 sources of behavioural evidence for two classes of photoreceptors |
1. Dark Adaptation - move from bright to dark conditions, eyes adjust gradually to become more sensitive 2. Colour Sensitivity - in dim conditions we lose colour information and instead see shades of grey 3. Purkinje Shift - yellows/reds more brilliant in day, blues/greens in the evening; cones are more sensitive to yellows/reds - twilight rods become active and cones lose sensitivity |
|
|
Understand how the three types of cone photopigments give rise to colour vision |
Colour perception is the result of levels of activity across different channels Need different types of photopigments to respond to different wavelengths in different ways 3 different cone photopigments activate to different levels based on wavelength of light |
|
|
Explain why eye movements are important for visual perception |
Fine spatial detail only available in small area at centre of retina Eyes have to move rapidly so that every point can be seen in detail |
|
|
Describe how we perceive objects |
We perceive the world in three dimensions, vision information passes through the retina, which processes in two dimensions
|
|
|
Describe the cues contributing to visual depth perception |
Motion Parallax - perceive objects that are closer to us to be moving faster than objects further away Partial Occlusion - blocking one object, the first is closer than the second Relative Height - lower the base of an object, the closer it is Familiar Size - general standard size, therefore smaller = further away and vice versa Retinal Disparity - different distances = different portions of retina, disparity between images providing depth perception |
|
|
Contrast the functions of the dorsal and ventral streams of cortical processing |
Ventral Stream - flow of info from primary visual cortex through the lower temporal lobe, perception of object's shape, colour, and orientation Dorsal Stream - flow of info from primary visual cortex through the parietal lobe, perception of object's location and actions related to |
|
|
Describe visual perceptual disorders that result from damage to different brain regions |
Visual Agnosia - inability to recognize the identity of an object visually due to damage in the visual processing areas of brain Prosopagnosia - face recognition is impaired Akinotopsia - inability to see motion (motion blindness) Neglect - inability to attend to one side |
|
|
Describe lateral inhibition and its role in help the brain 'find edges' of objects |
Lateral Inhibition - if one receptor in the retina gets excited, it inhibits its neighbour Vision works to extract the edges of each object, permitting perception of object's form or shape Colour and texture info is "filled in" on extracted shapes |
|
|
Describe the concept of the receptive field and how receptive fields contribute to object perception (neural convergence) |
Receptive Field - presentation of visual stimuli produces a change in firing rate of particular neuron Neural Convergence - signals from different neurons come together and meet at a single neuron, which can add up the signals, or compare them |
|
|
Describe how perception of a visual object differs from the raw retinal image |
Photoreceptors are the bottom-most latyer, the pass through several cell layers (ganglion, amacrine, bioplar, and horizontal) before landing on rods and cones Image is inverted mirror image, as well as being 2D |
