6B vision Flashcards
Reception
Eye receives incoming light and focuses it onto the retina where an image of the visual stimulus is captured.
Transduction
Light arrives as electromagnetic energy when it reaches the photoreceptors (rods and cones) which convert light into signals that are processed by ganglion cells.
Transmission
Ganglion cells generate neural impulse which is sent along the optic nerve via the thalamus to the brain.
Thalamus
Sends the message to the Primary Visual Cortex.
Thalamus
Sends the message to the Primary Visual Cortex.
Thalamus
Sends the message to the Primary Visual Cortex.
Selection
Feature detectors filter out visual signals according to importance.
Thalamus
Sends the message to the Primary Visual Cortex.
Organisation
Selected visual signals are reorganised to reflect reality.
Interpretation
Primary Visual Cortex and temporal lobe make sense of visual stimuli.
1.
Cornea - glassy outer window which protects the eye + focuses light waves onto retina.
2.
Aqueous humour - the watery substance of the eye which helps it to maintain it’s shape.
3.
Pupil - opening of the iris which controls the amount of light entering the eye.
Constricted pupil
Bright light/restrict amount of light.
Dilated pupil
Dim light/allow more light in.
4.
Lens - adjusts its shape to focus light onto the retina depending on the distance of the object being viewed.
Lens buldge
Focus nearby
Lens flatten
Focus on distance
5.
Vitreous humour - substance that helps to maintain eye’s shape.
6.
Retina - contains photoreceptors and receives images as upside-down and back-to-front.
7.
Optic nerve - carries visual information the the primary visual cortex.
8.
Blind spot - no photoreceptors so light can not be detected there.
9.
Ciliary muscles - controls the lens changing shape.
10.
Iris - ring of muscles that expand or contract to change the size of the pupil.
Path of light throughout the eye
Cornea, aqueous humour, pupil, lens, vitreous humour, retina.
GESTALT PRINCIPLES
- Proximity
- Similarity
- Figure-ground
- Closure
- Camouflage
Proximity
Grouping items together because of their physical closeness.
Similarity
Grouping parts of an image together because of similarities (shape, colour, size).
Figure-ground
Dividing what we see into foreground and backround.
Closure
Mentally completing images that are ‘incomplete’ (filling in the gaps).
Camouflage
When the figure and the ground aren’t easily separated.
Visual constancies
Size, shape, and brightness constancy.
Size constancy
Understanding that an object doesn’t change size when looking at it from another angle when move closer/further away.
Shape constancy
How an object is perceived as keeping the same shape even when viewed at different angles.
Brightness constancy
Perceive the brightness of an object as the same even when light conditions change.
Depth cues
Binocular depth cues (retinal disparity, convergence), monocular depth cues (accommodation, pictorial cues).
Binocular depth cues
Involves the use of both eyes together
Retinal disparity
The slight difference in location of images due to our eyes being 6-7cm apart.
Convergence
Changes in tension in the eye muscles that occur when both eyes turn inward to focus on a close-by object.
Monocular depth cues
Involves the work of only one eye individually.
Accommodation
The lens changes shape depending on how far away an object is (to accommodate the distance).
Pictorial cues
Creates depth and distance in 2D to make something look 3D. (linear perspective, interposition, texture, gradient, relative size height in the visual field).
Linear perspective
The illusion of the coming together of parallel lines as they go back in the distance.
Interposition
When one object partially covers another object making one look closer and the other look further away.
Texture gradient
The gradual reduction of detail on a surface as it goes into the distance, compared to one that is close with fine detail.
Relative size
Perceiving the object that focuses the larger image onto the retina as being closer and the smaller image as being further away.
Height in the visual field
Refers to the location of the objects (further away=closer to horizon and vice-vera)
Perceptual set
- Context
- Motivation
- Emotional state
- Past experience
- Culture
Context
Refers to the setting/environment you are in.
Motivation
Our motivations might make us more likely to understand stimuli in a certain way. (eg hungry > see food)
Emotional state
The mood we are in might make use perceived in different ways (eg. happy > perceive others’ facial expressions as happy).
Past experience
Our past experiences with stimuli might lead us to perceive and assign meaning to stimuli in certain ways.
Cultural backround
Our cultural background/experience can lead us to perceive differently to people in other cultures.
Ratman experiment
- Presented participants with a figure that could either be perceived as a rat or as a man.
- Participants’ prior experience was manipulated before they saw the figure by showing them a series of drawings of either animals or people.
- This meant that their past experience was manipulated.
- The results showed that if participants were shown a human face, they were much more likely to see a human face in the end figure.
