Joan put her hand out and in it was placed a pile of sand. Then tiny amounts of sand were added to her hand and when asked to tell when she noticed any change in the overall weight she demonstrated what as soon as she detected any change in the weight?

A. Difference threshold
B. Perception
C. Meditation
D. Sensory adaptation

I think it's D, but not sure

I agree.

For further reading:

http://www.google.com/search?sourceid=navclient&ie=UTF-8&rlz=1T4VRHB_enUS648US649&q=sensory+adaptation

I disagree. A "change" would indicate a difference threshold.

To determine the correct answer, let's break down the options and discuss the concepts involved.

A. Difference threshold: The difference threshold is the minimum amount of change in a stimulus that can be detected by a person. It refers to the point at which a person notices a change in the sensory input. While this concept is related to the question, it is not the specific term for what Joan demonstrated.

B. Perception: Perception refers to the process of organizing and interpreting sensory information to give meaning to the environment. While the change in weight could be considered part of perception, it does not specifically represent what Joan demonstrated.

C. Meditation: Meditation is a practice of training the mind to induce a state of consciousness that promotes relaxation, focus, and self-awareness. This concept is unrelated to the situation described in the question.

D. Sensory adaptation: Sensory adaptation is the process by which our sensory receptors become less responsive to a constant or unchanging stimulus. This adaptation allows our attention to shift to more important or changing stimuli. In this case, as tiny amounts of sand were gradually added to Joan's hand, she would likely demonstrate sensory adaptation if she didn't notice any change in weight immediately.

Given the explanation, it seems that the correct answer is D. Sensory adaptation. Joan demonstrated sensory adaptation when she didn't immediately detect any change in the overall weight of the sand being added to her hand.