URGENT What makes shampoo basic/alkaline?

Ok, I know that shampoos nowadays are acidic and that the conditioner is basic, but I need to find out what ingredient in shampoo increases the pH? It's for my science ignment (due tomorrow!) and I need to explain why some shampoos have a higher pH than others. Thanks in advance! Any answer is appreciated that will help me to answer the question. Best answer gets 10 points! I promise!!!