Read the paragraph. Laughter is a message we send to other people. Most people rarely laugh when they are alone. Laughter helps us interact with others. "The first laughter appears at about 3.5 to 4 months of age, long before we’re able to speak” (Provine). Babies, who cannot speak, use laughter to relate to their mothers, and their mothers, who can speak, use laughter rather than words to relate back. Which header would be best for this paragraph?