Week 1 Flashcards
Perception
An experience that results from sensory. Active and Recurring process.
Distal stimulus
Any physical objects in the world that reflect light.
Proximal Stimuli
An interaction of the signal from distal stimuli coming in with the sensory apparatus detecting it.
The Principle of Transformation
The proximal stimulus is not the same as distal stimulus.
The distal stimulus (the nature of the environmental stimulus)
changes is transformed before it is perceived by the observe.
Principle of Representation
The object we perceive is based on interaction of our sensory system with the transformed stimulus.
it no longer interacts with distal stimulus.
Recognition
The ability to categorize what we experience.
Transduction
when energy from the stimulus (e.g., light, air pressure, motion) is converted to electrical energy used by the nervous system
Top-down Processing
Your previous knowledge directs you toward certain conclusions/ actions.
Bottom-Up Processing
Raw sensory data taken from the
world (e.g., sounds)
Sensory Qualia
The first-person mental experiences we have associated with perceiving something that can’t be directly observed by anyone but the person having the experience.
Theoretical/Hypothetical Constructs
It is a broad and abstract concept or idea that exists in theory. Usually involved with unobservable entities.
○ Abstract Ideas such as “intelligence” “the color purple”
Operational definitions
It provides concrete, measurable criteria for measuring or observing a concept. (e.g., pointing to a purple object)
Visual Acuity
The smallest size of letter that a person can identify accurate from a standardized distance (e.g., using an eye chart)
Auditory Threshold
The softest sound that an individual can hear at least 50% of the time under controlled conditions.
Taste Sensitivity
The minimum concentration of a substance (e.g., sugar or salt) dissolved in water that a person can reliably detect as compared to pure water.
Color Blindness
An individual’s ability or inability to distinguish between certain colors
Tactile Sensitivity
The minimum amount of force or the smallest spatial gap required for an individual to detect a touch sensation, usually tested using tools like von Frey hairs or two-point discrimination tasks.
Perceived Loudness
The volume level (in decibels) at which an individual reports a sound to be “very loud” on a standardized scale.
Absolute threshold
smallest amount of stimulus energy required for detection
Difference threshold:
smallest difference between two stimuli that can be detected
Magnitude estimation
relates the intensity of a stimulus to perceived experience
Visual search
Measures accuracy and time it takes to detect a target stimulus. Can help characterize the regularities between physical stimuli and psychological states.
Method of limits
Stimuli are presented at different intensities in ascending or descending order (switching on each trial), and observers indicate whether they detect the signal. When the answer changes, this is called a crossover point. The absolute threshold is the mean value of all crossover points
Method of adjustment
Observers adjust stimulus intensity until they detect the stimulus. Trials can be repeated to get an average stimulus intensity value required for detection.
Not Very accurate + Very Fast
Method of constant stimuli
Present a number of stimuli with different intensities several times in random order. The threshold is defined as the intensity at which the stimulus was detected 50% of the time.
Very Accurate + Very Slow
Adaptive staircase methods
Stimuli are presented in a “dynamic” fashion (determined by the preceding stimuli and responses) to best fit the current test participant. Compared to the other methods, this places most of the stimuli near the threshold that’s being measured, allowing for more efficient estimation of thresholds.
Just-noticeable Difference (JND)
It is the smallest detectable difference between two stimuli
● If stimuli are below this threshold, we say they are at a point of subjective equality (PSE).
● JND increases with the magnitude of the standard stimulus.
Weber’s Law
DL (jnd) / S (value of standard) = K (Weber fraction ‘constant’)
Response Expansion
perceived magnitude increases faster than stimulus intensity
Response Compression
magnitude increases more slowly than stimulus intensity
If two stimuli are physically different, but we can’t tell them apart, we would say they are at a:
A. JND
B. DL
C. PSE
D. Absolute threshold
E. None of these
C. PSE
Magnitude Estimation
A method that is outside DL to qualify the perceived difference between two stimulus of different intensities.
Relates the intensity of a stimulus to perceived experience.
Response expansion
Perceived magnitude increases faster than stimulus
Response compression
Magnitude increases more slowly than stimulus intensity
Steven’s Power Law
P = KS^n
P - perceived magnitude
K - constant
S - stimulus intensity
n > 1, response expansion
n < 1, response compression
Reaction time
The time between presentation of the stimulus and the response
Holistic search (pop-out effect)
Fast because you’re looking for one feature
Feature search
Slower because you have to look for particular features
Iris
Constrict or dilate to regulate light input to the eye
Pupillary light reflex
Constriction in one eye, causes the other pupil to constrict.
Anisocoria
Unequal pupil size condition
Sclera
White and can indicate gaze direction
Cornea
Transparent structure, provides ~80% of the eye’s focal power
Lens
Flexible, thickness can be adjusted to focus light on the retina (accommodation), ~2-% of the eye’s focal power.
Ciliary muscle
Changes thickness of the lens
- if relaxed, flattened lens, bend less light
- if constricted, fatter convex lens, bend more light
Accommodation
Just the process of changing the lens shape in the eye.
When you are focusing on something very near, the ciliary muscles in your eye will ___.
A. Relax
B. Constrict
D. Do nothing
B. They constrict
Shaping the light not a fatter (more convex) configuration. This process is called accommodation
Far point
The point at which ** relaxed ** eye makes an object appear clear
Near point
The closest you can bring an object and keep it in focus.
Myopia
Nearsightedness
- An inability to see objects at a distance (me lol)
- distant images are focused in front of the retina
-Two types: Refractive and Axial
-Treatments are to use corrective lens or to reshape(flatten) the cornea
Refractive Myopia
The cornea or lens converges (focuses) light too much
Axial Myopia
The eye is too long
What does that even mean
Hyperopia
Farsightedness
- an inability to clearly see close objects
- nearby images are focused beyond (back) the retina
- Cause due to cornea/lens shape or eye too short.
- Treatment: corrective lens or surgery
Presbyopia
“Old eye”
Near point increase because ciliary muscles are the ones controlling the near point and they weaken with age.
Vitreous Humor
A gelatinous substance that helps maintain the shape of the eye.
Floaters
Can sometimes be seen in the vitreous as debris casts a shadow on the retina.
(Most people experience it but sudden increase could mean detached retina, retinal tear, or other injury)
If your cornea refracts (bend) light too little, you are most likely to have which vision problems?
Hyperopia (farsightedness)
Objects on the distance are brought to a focal point beyond the fovea, making them harder to see.
Macula
A cone-rich are important for detailed vision. (Allows high resolution)
-has a yellow pigment that absorbs blue and UC light.
Fovea
The center of the macula, with the densest concentration of cones. (No rods)
- has no ganglion cells and capillaries (allows more light thru)
- optimal vision when light directly focus on fovea.
