Which option correctly describes absolute threshold?
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C. A and B.
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Which option correctly describes absolute threshold?
C. A and B.
What are examples of actions in response to environmental stimuli?
Moving the head or eyes through the environment.
What type of energy is associated with visual sensation?
Light energy.
What is an environmental stimulus?
All of the things in our environment that we can potentially sense.
Which order is true in terms of accuracy of determining absolute threshold?
A. M of constant stimuli > M of adjustment > M of limits.
What is perception?
Conscious sensory experience.
Is it common for the absolute threshold to have a sharp transition?
No, it is rare in reality.
What is the difference threshold?
The minimum difference between two stimuli that can be detected.
What is the exponent (n) for brightness in the power law?
n < 1.
What intensity level received a 100% 'Y' response?
What is the length of the longer straight line that can be differentiated from a 35 cm line?
35.35 cm.
What is the time taken for the Method of Limits?
Middle.
What occurs after the attended stimulus?
Stimulus on the receptors.
What is the exponent (n) for electric shock in the power law?
n > 1.
What was the response percentage for intensity 150?
0% detected.
How many participants answered 'Y' at intensity 190?
What is absolute threshold?
The minimum level of stimulus intensity needed for detection.
What is the method of constant stimuli?
A method used to determine absolute thresholds by presenting stimuli at varying intensities in a random order.
How does the transition between not detecting a stimulus and detecting it usually occur?
It is usually gradual rather than abrupt.
What is the method of adjustment?
A method where the participant adjusts the stimulus intensity until it reaches their threshold of detection.
Which method has the lowest accuracy?
Method of Adjustment.
What is the first step in the perceptual process?
Environmental stimulus.
What is Weber's law formula?
JND = KS, where K is the Weber fraction and S is the environmental stimulus value.
What is the value of K when S is 10 cm?
0.01.
What is the final outcome of the perceptual process?
Perceptual response.
Why is perception considered a continuously changing process?
Because of the observer's movements and shifts in attention.
Why does Weber’s law become invalid if the stimulus is close to the threshold?
Because the Weber fraction is no longer a constant.
What does Stevens' Power Law correlate?
Perception with the environmental stimulus.
What is the Method of Constant Stimuli used for?
To detect light at different lighting intensities.
What is involved in the processing stage of the perceptual process?
Knowledge and interpretation of stimuli.
What is the power index used in Stevens' Power Law in this example?
0.75.
What is the absolute threshold?
The smallest amount of stimulus energy necessary for an observer to detect the stimulus.
How are the intermediate intensity stimuli presented in the Method of Constant Stimuli?
They are detected on some presentations and not on others.
What happens when we focus our attention on an attended stimulus?
We find it particularly interesting.
What is the relationship between light intensity and percent stimuli detected in the Method of Constant Stimuli?
As light intensity increases, the percent of stimuli detected also increases until reaching the threshold.
What is the advantage of the Method of Adjustment?
It gives the observer an active role, maximizing the probability that they will stay awake during the experiment.
What is taken as the absolute threshold in the Method of Adjustment?
The intensity level at which the stimulus can just barely be detected.
How is the constant K calculated in Weber's Law?
K = JND/S.
What is aural sensation?
A type of sensation related to the perception of sound.
If the lighting intensity is 100 units and the Weber fraction is 0.05, what is the JND?
5 units.
How is the constant K calculated in this example?
K = 10/(150)⁰⁷⁵ = 0.2333.
What is the formula for Stevens' Power Law?
P = K (S - S₀)ⁿ or Log P = n log (S - S₀) + log K.
What is the definition of absolute threshold?
The smallest amount of stimulus energy necessary for an observer to detect the stimulus.
What happens to electrical signals in perception?
They are transformed by the brain into the experience of seeing an object.
What is the Method of Adjustment?
A technique where the observer slowly changes the intensity of the stimulus until it can just barely be detected, determining the absolute threshold.
What does the observer do in the Method of Adjustment?
The observer adjusts the intensity of the stimulus.
What is the Just Noticeable Difference (JND) when comparing a line of 10.1 cm to a reference line of 10 cm?
0.1 cm.
What is visual sensation?
A type of sensation related to the perception of light and images.
What is thermal sensation?
A type of sensation related to the perception of temperature.
What is the Method of Constant Stimuli?
A method where five to nine stimuli are presented to an observer, ranging from clearly detectable to undetectable.
What characterizes the least intense stimulus in the Method of Constant Stimuli?
It is clearly below the threshold so that the observer can never detect it.
What does it mean if n < 1 in Stevens' Power Law?
It indicates response compression.
What is an attended stimulus?
A stimulus that captures our attention due to its interesting nature.
What does the method of limits involve?
A method for determining absolute thresholds by gradually increasing or decreasing the intensity of a stimulus until it is detected or no longer detected.
What is thermal sensation related to?
Temperature of air.
What do the dashed lines in the experiment results indicate?
The crossover point for each sequence of stimuli.
What are the two orders in which stimuli can be presented in the Method of Limits?
Ascending and descending order.
What is sensation?
The power of perceiving through the senses; a physical experience from the stimulation of sense organs.
What happens to the constant K in Weber's law when the stimulus is close to S₀?
K is no longer a constant.
Which statement is true about sensation?
A. Sensation is the result of perceiving through the senses.
What does S represent in the context of Weber's Law?
S represents the stimulus intensity, which is 100 units in this example.
What does it mean if n > 1 in Stevens' Power Law?
It indicates response expansion.
What is the threshold in the Method of Constant Stimuli?
The intensity that results in detection on half the trials, which is 180.
If the index of Stevens’ power law for an electric shock is 2, how much times a person could perceive the shock when the current increases from 50 A to 150 A?
C. 9.
What does Weber's Law help identify?
The minimum detectable difference between two stimuli.
Which method is the quickest?
Method of Adjustment.
What is the process of converting stimuli into neural signals called?
Transduction.
What is the formula to calculate the just noticeable difference (JND) using Weber's Law?
JND = K * S, where K is the Weber fraction and S is the stimulus intensity.
What formula is used to calculate perceived brightness in this example?
P = K (S - S₀)ⁿ.
What is the perceived brightness when the surface luminance increases to 450 cd/m²?
22.80 units.
What type of energy is associated with aural sensation?
Sound energy.
What is the accuracy level of the Method of Constant Stimuli?
Highest.
Which method takes the longest time?
Method of Constant Stimuli.
What does JND stand for?
Just Noticeable Difference.
At what intensity level did 50% of participants respond 'Y'?
What intensity level had a 0% 'Y' response?
Give an example of perception.
Wearing clothes when you feel cold.
What is the threshold stimulus if the measured stimulus rises from 11 to 21 units to give a double response?
What is the Method of Limits in sensory perception?
A technique where stimuli are presented in either ascending or descending order to determine thresholds.
How many tests were conducted in the example experiment?
8 tests.
What does the exponent of the power law indicate?
Whether doubling the stimulus intensity causes more or less than a doubling of the response or perceived magnitude.
What is the exponent (n) for apparent line length in the power law?
n = 1.
What is the JND when S is 35 cm?
0.35 cm.
What is perception?
The process by which an organism detects and interprets information from the external world using sensory receptors.
What is the role of the most intense stimulus in the Method of Constant Stimuli?
It is clearly above the threshold so that the observer detects it without fail.
How are stimuli presented in the Method of Constant Stimuli?
Each stimulus is presented a number of times in random order.
In the context of the Method of Constant Stimuli, what does a threshold intensity of 180 indicate?
It indicates the point at which 50% of stimuli are detected.
What follows the environmental stimulus in the perceptual process?
Attended stimulus.
Under what condition is Weber's law valid?
When the stimulus is well above the threshold (denoted by S₀).
What is the perceived brightness when the luminance is 150 cd/m²?
10 units.
Which statement is true about perception?
C. Perception is the art and science of perceiving.
What was the response pattern for intensity levels from 150 to 200?
Increasing 'Y' responses from 0% to 100%.
In Stevens' Power Law, what does P represent?
The perceived magnitude.
In the example provided, what does K represent?
K represents the Weber fraction, which is 0.05.
What happens at the absolute threshold regarding stimulus intensity?
The stimulus intensity has a sharp transition at around the absolute threshold.
What does K represent in Stevens' Power Law?
A constant.
What does perception imply?
It implies something thought of, deduced, or figured out.
What does Stevens' Power Law describe?
The relationship between perception and stimulus.
What does n indicate in Stevens' Power Law?
The exponent indicating the slope of the lines in the log-log plot.
What is the significance of S in the formula?
It represents the stimulus.
What does S₀ represent in Stevens' Power Law?
The threshold stimulus.
What does it mean if n = 1 in Stevens' Power Law?
It indicates a linear response.
What is the focus of sensation and perception?
Understanding the perceptual process of an environmental stimulus.
What is the focus of the course SEHH2262?
Architectural Technology in the Built Environment.
