Horror film reactions can range from SHIVERS to screams. SHIVERS, also known as goosebumps, are a physical reaction to fear or excitement. They are caused by the contraction of muscles in the skin, which causes the hairs on the body to stand up. Screams, on the other hand, are an emotional reaction to fear or surprise. They are usually loud and sudden, and can be used to express shock or terror. Both of these reactions are common when watching horror films.