Figuring out your personal JND percentage?
How is JND measured?
Dear Tutor,
I don’t understand this psychology assignment, could you explain to me how to solve it. Give me an example from your own observation of how you can solve this task.
How do I understand this table , what is it supposed to tell me?
Overview
Purpose: The purpose of this activity is to investigate the concept of “just noticeable differences” (JNDs) and gain insight into how Weber or anyone else might determine a JND.
someone to assist you.
Find 60 small identical items (something similar in weight – pennies, beads, coins, dry beans) AND two identical bags.
Ask your helper to place twenty identical items in each bag. There should be no obvious way for YOU to tell these bags apart.
Hold one bag in each hand and notice the weight.
Put down both bags, placing them between you and your helper.
TURN AROUND! You shouldn’t be able to see or feel anything as items are added to a bag.
Instruct your helper to place one additional item in one of the bags (When you repeat this step, your helper should be careful to secretly add the item to the SAME BAG each time).
Turn back around and hold the bags again.
Use the following table if you need help figuring out your personal JND percentage.
| Number of original items | Number of additional items needed to detect a difference on 3 out of 4 tries | JND Percentage |
| 20 | 1 | 5% |
| 20 | 2 | 10% |
| 20 | 3 | 15% |
| 20 | 4 | 20% |
| 20 | 5 | 25% |
| 20 | 6 | 30% |
| 20 | 7 | 35% |
| 20 | 8 | 40% |
| 20 | 9 | 45% |
| 20 | 10 | 50% |
| 20 | 11 | 55% |
| 20 | 12 | 60% |
| 20 | 13 | 65% |
| 20 | 14 | 70% |
| 20 | 15 | 75% |
| 20 | 16 | 80% |
| 20 | 17 | 85% |
| 20 | 18 | 90% |
| 20 | 19 | 95% |
| 20 | 20 | 100% |
| 20 | 21 | 105% |
