Using either fear of snakes or the construct underlying your second pool of 10 items, list directly observable behaviors that could be used to validate a scale measuring that construct and explain how...

Using either fear of snakes or the construct underlying your second pool of 10 items, list directly observable behaviors that could be used to validate a scale measuring that construct and explain how you could use behavioral data for validation. Describe the difference in appearance for the item characteristic curves (ICCs) of two binary items differing in their discrimination parameters.