For a recipe requiring 10 grams of salt, how much more salt should be added to create a noticeable increase in saltiness, given Weber's constant for saltiness is 1/5?

To determine how much more salt should be added to create a noticeable increase in saltiness, we can apply Weber's Law. This psychological principle states that the smallest detectable difference in a stimulus (in this case, saltiness) is proportional to the magnitude of the original stimulus.

In this scenario, the original amount of salt is 10 grams, and according to Weber's constant for saltiness, which is 1/5, the just noticeable difference (JND) can be calculated. This means that to perceive a difference in saltiness, the increase must be 1/5 of the original amount:

1. Calculate the JND:

• JND = original amount of salt × Weber's constant

• JND = 10 grams × (1/5) = 2 grams

This calculation indicates that to create a noticeable change in saltiness, you need to add 2 grams of salt. Thus, the total amount of salt would then be 12 grams. This aligns with the reasoning behind the correct answer, which emphasizes the necessity of increasing the amount of salt by the calculated JND to perceive a difference.