Weber's law of just noticeable difference

In summary: Thanks for the question! Honestly, I don't know. I wish I could be of more help, but I've never read anything dealing with perceived size.Thanks for the question!
  • #1
SoggyBottoms
59
0

Homework Statement


This question is about the line length experiment, which can be seen here: http://people.usd.edu/~schieber/coglab/WebersLaw.html

Basically you are shown two lines and you have to pick the one that is longer. This is repeated X number of times and the results allow you to calculate the smallest detectable difference in line length, the threshold.

1) If the lines are now made twice as long and the viewing distance stays the same, what will happen to the threshold?

2) If the viewing distance is doubled, but the lines stay the same length, what will happen to the threshold?

The Attempt at a Solution



1) I expect that the threshold is a fixed percentage of line length, so if the line length doubles, so would the threshold.

2) I expect it would double again, but I'm not sure how to back that up.
 
Last edited by a moderator:
Physics news on Phys.org
  • #2
SoggyBottoms said:

Homework Statement


This question is about the line length experiment, which can be seen here: http://people.usd.edu/~schieber/coglab/WebersLaw.html

Basically you are shown two lines and you have to pick the one that is longer. This is repeated X number of times and the results allow you to calculate the smallest detectable difference in line length, the threshold.

1) If the lines are now made twice as long and the viewing distance stays the same, what will happen to the threshold?

2) If the viewing distance is doubled, but the lines stay the same length, what will happen to the threshold?

The Attempt at a Solution



1) I expect that the threshold is a fixed percentage of line length, so if the line length doubles, so would the threshold.

2) I expect it would double again, but I'm not sure how to back that up.

This is the first time I've ever heard of this experiment, but when you speak of "viewing distance" do you mean the the distance between you and the object? Think about what that would do to your perceived length. How does the appearance of an object change if you double the distance between you and the object?
 
Last edited by a moderator:
  • #3
Ignea_unda said:
This is the first time I've ever heard of this experiment, but when you speak of "viewing distance" do you mean the the distance between you and the object?

Correct.

Ignea_unda said:
How does the appearance of an object change if you double the distance between you and the object?

I suppose the perceived length either drops off linearly or quadratically?
 
  • #4
SoggyBottoms said:
I suppose the perceived length either drops off linearly or quadratically?

Alright. Then if the threshold is a fixed percentage of length (or more accurately, perceived length), what would the threshold do?
 
  • #5
If linearly, then it would double. If quadratically, then it would quadruple. Just going by my gut feeling I would say perceived length drops off quadratically with distance. Is that correct?
 
  • #6
SoggyBottoms said:
If linearly, then it would double. If quadratically, then it would quadruple. Just going by my gut feeling I would say perceived length drops off quadratically with distance. Is that correct?

Honestly, I don't know. I wish I could be of more help, but I've never read anything dealing with perceived size.
 

FAQ: Weber's law of just noticeable difference

What is Weber's law of just noticeable difference?

Weber's law of just noticeable difference is a principle in psychology that states that the smallest detectable difference between two stimuli is a constant proportion of the original stimulus. In other words, the perceived difference between two stimuli is not dependent on the absolute difference, but rather on the ratio between the differences.

Who developed Weber's law of just noticeable difference?

Weber's law was developed by German physician and physicist Ernst Heinrich Weber in the mid-19th century. However, it was later popularized by German psychologist Gustav Theodor Fechner in the late 1800s.

How does Weber's law apply to real-life situations?

Weber's law has been observed in various real-life situations, such as differences in weight, brightness, loudness, and taste. For example, you may not be able to tell the difference between two weights if one is 100 grams and the other is 105 grams, but you can easily notice the difference if one is 1kg and the other is 1.05kg.

Is Weber's law applicable to all senses?

Weber's law is commonly applied to vision, hearing, and touch, but it may not apply to all senses. Some studies have shown that it may not hold true for smell and taste, as these senses rely more on absolute differences rather than ratios.

How is Weber's law related to the concept of sensory adaptation?

Weber's law is closely related to the concept of sensory adaptation, which is the tendency of our senses to become less sensitive to constant or repetitive stimuli. According to Weber's law, as the magnitude of a stimulus increases, the change needed to detect a difference also increases, which can lead to sensory adaptation.

Similar threads

Faraday's law with Calc 3 integration help
Replies
1
Views
1K
Finding final speed of object on incline
Replies
5
Views
4K
B Estimate the difficulty of a mountain route
Replies
10
Views
1K
Induced EMF and current for a bar sliding on a circular rail
Replies
22
Views
2K
Using Ampere's Law for these two different integration paths
Replies
1
Views
1K
Hubble's law and the age of the universe
Replies
2
Views
3K
How Do You Propose a Reaction Mechanism for a Multi-Step Reaction?
Replies
10
Views
5K
Two launches ferrying between two landing stations along a river
Replies
23
Views
865
How Do Viscous Interactions Differ in Vertical and Horizontal Geometries?
Replies
31
Views
3K
NS Derailment, East Palestine, Ohio - 3 Feb, 2023 - Engineering Aspect
Replies
9
Views
2K

Hot Threads

Recent Insights

Back
Top