Unit 4: Sensation and Perception Flashcards
In the field of Sensation and Perception, what does “Sensation” mean?
Sensation is the process of gathering sensory information from our environment. (Seeing, hearing, touching, smelling…)
In the field of Sensation and Perception, what does “Perception” mean?
Perception is how we interpret the sensory information we gather from our environment. (recognizing objects or events, judging distance, stereotyping,…)
What is the difference between “bottom-up” and “top-down” processing?
Bottom-up processing *starts* with sensory information and makes sense of the information without preconceived ideas.Top-down processing *starts* with preconceived ideas that shape how we view our sensory information
What is Selective Attention?
Selective Attention is where our conscious awareness is focused. We can only focus on a very relatively small amount of information at a time.
Even in a crowd of people talking, we can successfully shift our attention to a single group of people talking, and listen in on their conversation. What is this effect called?
Cocktail Party Effect
We can become consciously “blind” to the information that we are not consciously focused on. What is this called?
Selective Inattention
What is Change Blindness?
Change blindness is when a person becomes unaware of changes made to the stimuli around them.
What is Psychophysics?
Psychophysics is a branch of psychology that studies how our mind (“Psycho”) interprets the physical (“physics”) environment around us.
What is an Absolute Threshold?
The absolute threshold is the smallest amount of a stimulus that is still detectable 50% of the time.
What is Signal Detection Theory
Signal Detection Theory states that the absolute threshold depends on our psychological state, and the situation around us. (i.e. it may increase or decrease depending on context)
What does “Subliminal” mean?
Any stimulus that is presented below the absolute threshold is said to be “subliminal”
What is a stimulus called that is above the absolute threshold?
Supraliminal
What does it mean if a person is “primed” by subliminal stimuli?
Priming is the unconscious activation of certain associations. (i.e. a person presented with a subliminal picture of Coke may be more likely to select Coke for their next drink)
What is a Difference Threshold?
Difference threshold is the absolute threshold for change between two stimuli.
What is Weber’s Law?
Weber’s Law says that the absolute threshold of any stimuli varies by a percentage of what it is being compared with, not by a fixed amount.
What is Sensory Adaptation, and come up with one example.
Our brains are presented with an overwhelming amount of information - so to deal with it all, we only perceive a very small amount of it, the rest is “adapted” out. (i.e. you did not feel your shoes on your feet before you read this sentence)
The process of converting light energy into neural impulses is called what?
Visual Transduction
The distance from one wave peak to another is called:
Wavelength
(the distance from one wave peak to another over time would be called frequency)
Our perception of color determined by the wavelength of light is called:
Hue
What characteristic of light makes up its intensity?
The height, or amplitude, or each wave determines the light’s intensity (low amplitude waves make dim light, whereas high amplitude waves make bright light)
What is the pupil?
The pupil is the section of the front of the eye that allows light to enter. It is surrounded by the iris.
Where is the Iris and what does it do?
The iris is a muscle that is the colored part of the front of the eye. It grows and constricts to allow more or less light into the eye through the pupil
Where is the fovea and what is its purpose
The fovea is the section of the retina in the back of the eye that is in the direct center of our vision. It is especially good at distinguishing detail, and has a very high concentration of cones.
Where is the retina and what does it do?
The retina is the layer of tissue that lines the entire back of the eye. It is made up of light receptor cells (rods, cones, bipolar cells and ganglion cells), and allows light energy to be changed into action potentials that are sent to our brain to allow visual perception.
What is the optic nerve?
The optic nerve is a bundle of axons from the neurons in the retina leading to the visual cortex in the brain.
Why do we have a blind spot?
There is no retina in the area of the back of the eye where the optic nerve leaves the eye.
Where is the lens and what does it do?
The lens is behind the pupil, and can move in and out to focus light rays onto the retina
What is the process by which light rays are being bent by the lens to provide focus?
Accomodation
What are the three characteristics of cones?
Cones are a type of visual receptor located in the retina which are:
- Most active in bright light
- Most prevalent in the center of vision (near the fovea)
- Used in color vision
What are three characteristics of rods?
Rods are a type of visual receptor in the retina of the eye which:
- Work best in dim light
- Only perceive black and white
- Most prevalent in peripheral vision
What are the four types of cells that make up the retina?
- Rods
- Cones
- Bipolar Cells
- Ganglion Cells
Rods and cones receive the light energy and send signals to the bipolar cells, which send signals to the ganglion cells - the axons of which make up the optic nerve, and send that signal to the occipital lobe of the brain.
Our brain interprets many different aspects of vision at once; depth, speed, form, color - which is this process of multiple perceptions called?
Parallel Processing
How does the Trichromatic (Young-Helmholtz) Theory of Color Vision explain color vision?
The trichromatic theory of color vision says that we have three types of cones, each of which specify in either short, medium, or long wavelengths of light. When we see a particular color, the cones that handle that particular wavelength fire according to how close to their wavelength the color is. The *percentage* of the cones firing tells our brain which color we see.
According to the Trichromatic Theory of Color Vision, what are the three types of cones?
- Short wavelength cones
- Medium wavelength cones
- Long wavelength cones
How does the Opponent Process Theory of Color Vision help to explain afterimages?
The opponent process theory of color vision says that we have three types of cones that each operate in terms of color opposites. One of these is a red / green cone. When we look at the color green for a very long time, our cone gets tired, and when we look away, instead of stopping firing, it overshoots, and we perceive green for a short time, until the cone finally stops firing.
What is the part of the ear circled in this picture?
Pinna
What are the parts of the ear circled in this picture
Hammer - Anvil - Stirrup
These three parts transfer sound energy from the eardrum to the oval window of the cochlea
What is the part of the ear circled in this picture
Eustachian Tube
What is the part of the ear circled in this picture
Auditory Nerve
What is the part of the ear circled in this picture
Eardrum
What is the part of the ear circled in this picture
Cochlea
In the picture below, we can only perceive either a saxophone player or a face, not both. What does this illustrate?
Figure-Ground Perception
In FGP, you focus on one object (the figure) and everything else becomes the background (ground)
In the images below, we perceive them as a circle or rectangle, instead of just a set of lines. What Gestalt principle is used?
Closure
Our brain “closes” off incomplete figures, and we see the completed shape, even though it does not exist
In the image below, we perceive the left set of dots as a square, and the right set as three columns. What gestalt principle is used?
Proximity
In the image below, we perceive a plus sign. What Gestalt principle is used?
Similarity
In the figure below - we see lines AD and CB, instead of any other combinations. What Gestalt principle is used?
Continuity
If one object partially blocks our view of another, we perceive the blocked object as farther away. Which monocular cue is this?
Interposition
Parallel lines, such as railroad tracks, appear to converge with distance. The more they converge, the more far away they seem.
Linear Perspective
