question

stimulus ; sensation

answer

Psychophysics: scientific study of the relation between a _______and a __________

question

Quantitative

answer

_________ study of how a species describes a defined stimulus

question

1. *Detects* is it there? can you see it? 2. *Discriminates* discontinuity/changes 3. *Scales* put a number on it 4. *Identifies* what is it?

answer

4 ways to describe a defined stimulus

question

physical stimuli ; psychological reaction

answer

Examines the relationship between _______ ________and the _________ __________to them

question

Sweetness *Psychological Reaction* Amount of Sugar *Physical Stimulus*

answer

Example of a relationship between physical stimuli and psychological reaction

question

EH Weber GT Fechner

answer

Who introduced techniques for measuring mental events? The transition of psychology from a philosophical speculation to a scientific discipline.

question

Wilhelm Wundt (1832-1920)

answer

Father of Experimental Psychology

question

This marked the beginning of psychophysics

answer

When Wundth moved to Leipzig, The First Experimental Psychology Lab was Established in 1879

question

The Principles of Physiological Psychology

answer

What famous work did Wundth have?

question

Threshold ;)

answer

Minimal amount of energy required for the accomplishment of a perceptual task

question

Absolute Threshold or Stimulus Threshold

answer

The smallest amount of the stimulus energy necessary to produce a sensation

question

Detect a change from zero to some finite value

answer

What does the absolute threshold involve?

question

Visual Stimulus - Detect the first light in the dark Auditory Stimulus- Gradually increase the volume from zero Taste: sweetness

answer

Examples of Absolute Threshold

question

TO SOMETHING! *Absolute Threshold*

answer

From nothing......

question

weakest detectable sensations in terms of the stimulus energy necessary to produce them

answer

Using measurement techniques of physics and well trained human observers to specify the ...................................................................................

question

Need to find the threshold (the change)

answer

When you decrease intensity, you see less light. When you increase intensity, you see more light.

question

Difference Threshold

answer

Smallest amount of change in a stimulus required to produce a just noticeable difference in a sensation

question

comparing from 2 things

answer

Difference Threshold

question

*discriminating*

answer

Difference Threshold involves detecting a change from one finite value to another

question

the intensity of this stimulus must be increased or decreased by some critical amount before a person is able to report any change in sensation

answer

When a stimulus above threshold is applied to a sense organ,

question

to something else *Difference Threshold*

answer

From something...........

question

Visual Auditory Taste Perfect Weight: one pound more fat, one pound less too skinny

answer

Examples of Difference Threshold

question

1. Variations 2. Relationship to Sensitivity

answer

Two Properties of Threshold

question

1. Random Fluctuations in the stimulus 2. Fluctuation in the neurons carrying visual signals 3. Level of Alertness 4. Psychological Bias

answer

Threshold Value can vary due to:

question

Normal Curve

answer

Over time, threshold values are randomly distributing making what curve?

question

that means that only a low intensity of that stimulus is required you to say "I (see) detect it"

answer

When you have a low threshold for a stimulus,

question

Higher the Sensitivity

answer

Lower the Threshold

question

*Low Threshold* for perceiving a dim light *Sensitivity* is high

answer

You have been in a dimly lighted room for 20 minutes

question

*High Threshold* for perceiving a dim light *Sensitivity* is Low

answer

When you have been out in bright sunlight and first enter a dark room

question

method to obtain a threshold chance to adjust stimulus

answer

Subjective

question

adjusts the intensity (size, contrast) of the stimulus with a dial or some other device

answer

Observer rather than experimenter

question

Keratometer

answer

An example of method of adjustment

question

Rotate knobs so that markers superimpose. In this case, you are making a singleness judgement, using the method of adjustment

answer

Keratometer

question

applantation (flattening of the cornea by pressure)

answer

Pressure is measured by ___________ of the eye

question

Clinician (the observer)

answer

__________ who adjusts the force until the mires line up

question

width

answer

The ______ of the mires represents less than the normal variation of pressure

question

Visual Judgement

answer

The instrument is designed to make the _______ ___________ as easy as possible, so your judgement noise doesn't contribute much to measurement noise

question

Experimenter

answer

Measurement is controlled by the _____________ NOT the subject

question

Not the other way around

answer

Me testing you:

question

trial

answer

A stimulus presentation

question

Descending Trial

answer

Experimenter begin with a stimulus that is clearly noticeable and then you present increasingly weaker stimuli until the observer reports "No, I can't detect it"

question

Ascending Trial

answer

Experimenter begin with a stimulus that is clearly too weak and then you present increasingly stronger stimuli until the observer reports "Yes, I detect it"

question

needs to use both ascending and descending series because observers typically have different thresholds, depending on which series is used

answer

methods of limits

question

Ascending ; Descending

answer

Psychophysics use both ____________ and _______________ series to correct for the human tendency to perceive different thresholds, depending on which stimuli have been presented previously

question

1. Habituation / Perseveration 2. Anticipation / Expectation

answer

Two Types of Constant Errors

question

observers operate on the principle that "the stimulus is likely to be the same as last time, and tend to give the same answer"

answer

Errors of Habituation

question

The subject thinks the stimulus is likely to be different on the next trial and changes his/her answer "Jumping the Gun"

answer

Error of Anticipation/Expectation

question

From no to yes

answer

Ascending series, they claim that they can detect the stimulus when in fact THEY CAN'T.

question

From yes to no

answer

Descending series, they claim that they can no longer detect the stimulus when in fact THEY STILL CAN!

question

Measuring Near Point Convergence in binocular vision testing

answer

Method of Limits in Clinic

question

A target is moved toward the patient (or increasingly strong prisms are added) to stimulate convergence until the patient says "double".

answer

Near Point Convergence

question

"break"

answer

When a patient says "double" it is called a __________

question

"recovery"

answer

Prism is then reduced until the patient says "single" , this is called _________

question

1. the effect being measured is transient /fast 2. when it Is important to avoid the presentation of stimuli in an ordered sequnce

answer

Method of Constant Stimuli is used when

question

random order

answer

Stimuli are presented in a _____ _______

question

5-9

answer

Random order is presented usually between ___ to ___ stimuli

question

clearly below threshold

answer

Weakest stimulus

question

clearly above threshold

answer

Strongest stimulus

question

Positive Exponential curve

answer

Intensity Vs. Percent of "Yes" Response

question

1. There are a constant set of stimuli before the testing begins 2. Stimuli presented a constant number of times 3. Procedure is designed to maintain the observer's expectations at the same level from presentation to presentation

answer

The name constant stimuli is appropriate because:

question

PRECISE! This method is preferred when one wishes to obtain a careful measurement of a threshold

answer

Advantage of Constant Stimuli

question

TIME CONSUMING! 'ain't nobody got time for that' (jk)

answer

Disadvantage of Constant Stimuli

question

1. Presentation of the stimulus 2. Practice 3. Fatigue 4. Guessing

answer

Errors - All Methods

question

If stimulus is presented in a strict ascending or descending order, the subject can count the number and forget about the task of perceiving the even. The presentation of the stimulus is RANDOMIZED!

answer

Error: Presentation of Stimulus

question

Trials in which either a stimulus that should not be detected, or one that should always be detected is presented

answer

Catch Trials

question

informed

answer

The subject or observer usually is not _______ that catch trials are being included

question

Correct for guessing

answer

Catch Trials can be used for what?

question

(Observed fraction of "Yes" Responses - Guessing Rate) / (1- Guessing Rate) X 100

answer

True % of "YES" responses

question

last stimulus

answer

Only the _____ ________ in each series contribute to the threshold estimate

question

Inefficient!

answer

Rest of the stimuli: tell us little about the threshold but takes a lot of time to test --> _________

question

1. Staircase Method 2. Interleaved staircase

answer

Method of Limits (2 Procedures)

question

The examiner reverses the direction of the stimulus values based on a set of responses

answer

1. Staircase Method

question

The experimenter adjusts the stimulus levels downward until observer says "Not Seen" then increases intensity until observer says " Seen" and repeats this sequence for several cycles

answer

Staircase Method

question

Diagram in Notes!

answer

Look at Staircase Method

question

1. Start with intensity well above the expected threshold region and decrease until the observer declares it as invisible 2. Reverse the direction of stimulus change and increase intensity until the response changes again 3. Go on until 6-7 Reversals 4. Threshold estimate: average of stimulus intensities at the reversals

answer

Staircase Method: Steps

question

Efficient

answer

Stimuli is concentration around the threshold

question

interleaved staircase

answer

Serial ordering of stimuli: observer may become aware of the scheme; this may influence responses

question

Detection Threshold Task

answer

When you go from nothing to something

question

Detection Threshold Task

answer

Both detection and discrimination task depend on a response to change

question

Discrimination Threshold Task

answer

When you go from something to something else. You have two stimuli.

question

Point on the curve where the comparison stimulus is called "lighter" half of the time and "heavier" half of the time

answer

Point of Subjective Equality

question

Point at which "heavier" and "lighter" can be distinguished from the point of equality.

answer

Interval of Uncertainty

question

An average of the stimulus difference needed to produce either a heavier or a lighter discrimination

answer

Difference Threshold

question

Difference Threshold

answer

The size of the difference between the standard stimulus and the comparison stimulus that can be discriminated half the time

question

Just Noticeable Difference

answer

Difference Threshold is also known as

question

Decrease Sensitivity

answer

Increase Threshold

question

Smaller Threshold

answer

Steeper Slope

question

Higher Sensitivity

answer

Smaller Threshold

question

1. Method of Adjustment 2. Method of Limits 3. Method of constant stimuli

answer

What are the three classical methods?

question

M = k x I

answer

Weber's Law

question

Difference Threshold

answer

M

question

Intensity of the standard stimulus

answer

I

question

constant, Weber fraction

answer

k

question

Decrease sensitivity

answer

Increase Weber Fraction

question

Flat part of the curve actually covers nearly 99% of the total range of intensities

answer

Range of Weber's Law

question

test stimulus on each other, adjacently

answer

Increment Threshold Test

question

two seperate stimuli, one is constant, the other is variable

answer

Difference Threshold Test

question

As the stimulus luminance increases, the minimum discriminable threshold increases in proportion to the square root of the intensity level

answer

DeVries-Rose Law

question

DL/ Square root L = K

answer

DeVries Rose Law Equation

question

Threshold luminance difference

answer

DL

question

Reference luminance

answer

L

question

constant

answer

K

question

1. Stimulus size 2. Duration 3. Wavelength 4. Retinal Location

answer

What is Weber's fraction affected by?

question

Visual system is concerned with the difference between the optotype and its background rather than the luminance of the optotype in isolation

answer

Lightness Constancy

question

Appearance of objects does not change as the lighting conditions vary

answer

Lightness Constancy

question

1. Stimulus Size 2. Intensity 3. Retinal Locus

answer

Three main dimensions that are varied in visual perimetry

question

stimulus of constant size and intensity is moved across the patient's view, until the patient can notice it, thus defining a point on an isopter

answer

Kinetic perimetry

question

used for static permetry

answer

Humphrey Field Analyzer

question

Increment thresholds are measured at many specific points in the visual field

answer

Static Perimetry

question

1. Identity 2. Order 3. Interval 4. Origin

answer

What are the "Properties"

question

1. Nominal 2. Ordinal 3. Equal Interval 4. Ratio

answer

What are the "Scales"

question

non-quanitative, merely symbols distinguishing one thing from another

answer

Nominal Scale

question

think of "order" set of measurements in which the amount of a property of objects or events can be ranked

answer

Ordinal Scale

question

how much difference there is between two objects or individuals b/w numbers

answer

Interval Scale

question

Has true origin (0 and constant unit) Properties of order, distance, and natural origin

answer

Ratio Scale

question

1. Indirect Scale 2. Direct Scaling

answer

Two Psychological Scales

question

measurements are derived from data on how well observers can tell one stimulus from another

answer

Indirect Scale

question

A method involving the observer's direct judgements of the sensation magnitudes

answer

Direct Scaling

question

Fechner

answer

Who created three classical methods of measurement

question

Elements of Pscyhophysics

answer

What was Fechner's publishment?

Psychophysics – Flashcards

Unlock all answers in this set

Haven't found what you were looking for?

Search for samples, answers to your questions and flashcards