Sensation, Perception, and Consciousness Flashcards
What is sensation?
The detection of physical energy by our sensory organs, which is then relayed to the brain
What organs are associated with which senses?
- Light waves (eyes)
- Sound waves (ears)
- Pressure (skin)
- Chemicals (tongue)
- Air born chemicals (nose)
What is perception?
The process of attending to, organizing, and interpreting the raw sensory input from the sensory organs, how psychology starts to play in
How do we make sense of the world?
- Bottom-up processing: taking sensory information and then assembling and integrating it (what are you seeing?)
- Top-down processing: using models, ideas, and expectations/schemas, to interpret sensory information (is that something you have seen before?)
How do the sensory organs communicate to the brain?
- Reception: the stimulation of sensory receptor cells by energy (sound, light, heat, etc.)
- Transduction: transforming this cell stimulation into neural impulses
- Transmission: delivering this neural information to the brain to be processed
What is absolute threshold?
The minimum level of stimulus intensity needed to detect a stimulus half the time
What is subliminal?
Below our threshold for being able to consciously detect a stimulus, but still registered by the sensory organ
What is difference threshold?
Refers to the minimum difference for a person to be able to detect the difference half the time
What is Weber’s law?
For two stimuli to be perceived as different they must differ by a constant minimum percentage (proportion) and not a constant amount ♣ Light = 8% ♣ Weight = 2% ♣ Tone = 3% ♣ Pitch = 0.3%
What is the signal detection theory?
Aims to explain whether or not we detect a stimulus, particularly with background noise
- Suggests that detection depends on psychological factors such as alertness, expectations, motivation, as well as sensory experience (not just receptors)
- Thus, detection is impacted by both sensation (bottom up) and perception (top-down)
What is Gestalt psychology?
Tries to understand the laws of our ability to acquire and maintain meaningful perceptions in an apparently chaotic world
What is the law of Pragnanz?
We perceive stimuli in our environment in their simplest form
- Proximity: objects physically close to each other tend to be perceived as unified wholes
- Similarity: objects similar to each other tend to be perceived as unified wholes
- Continuity: we still perceive objects as wholes even if others block part of them
- Closure: parts are combined to create wholes
- Symmetry: we perceive objects that are symmetrically arranged as wholes
- Figure-ground: figure is the centre of our attention, we ignore the background
What are energy waves to our eye?
Wavelength: becomes colour, or hue
Amplitude: becomes intensity, or brightness
How does vision work?
- Light entering eye triggers photochemical reaction in rods and cones at back of retina
- Chemical reaction in turn activates bipolar cells
- Bipolar cells then activate ganglion cells, the axons of which converge to form the optic nerve
- Some ganglion cells are dedicated (visual patterns, certain edges, lines, movement)
- Supercells integrate these feature signals to recognize more complex forms (faces, Jennifer Aniston cells)
- This nerve transmits information to visual cortex (thalamus) in the brain
What is the Young-Helmholtz Trichromatic Theory?
Assumes 3 types of colour receptors/cones (red, green, blue), anything else is a combination of these 3
- Bees also have trichromatic vision, except see colours more to the purple end of things
- Dogs have dichromatic vision (blue and green/yellow)
What is the Ishihara test?
Genetic disorder that prevents people to perceive certain colours like red and green (colour-blind)
Observations which support the trichromatic theory
What is the opponent-process theory? What is one example?
Neural process based on sets of complementary colours
- White/black, yellow/blue, red/green
- Pairs inhibit each other
- Eg. normally if white is coming in the eyes, red and green will fire at the same time
- But if red has just been stimulated, it is tired, and only green fires
- So, the brain thinks it’s seeing a green dot, when in fact the eye is presented with white
Which colour theories are supported?
- Both colour theories are supported
- Young-Helmholtz Trichromatic Theory works at the receptor level (cone)
- Opponent process theory works in ganglion cells in the eye as well as the visual cortex
- Another example of how sensation (eg. types of cones) and perception (eg. visual cortex) have to interact to create our experience of a whole
What are the cues that give our brain information about depth?
Monocular cues, and binocular cues
What are monocular cues?
Cues that only require one eye, which we use to perceive depth