QUOTE : We can now give you a biological reason why cramming doesn’t work,” says Dr. Tully. The best way to prepare for a final exam is to mentally review the material periodically during the day, until the material becomes part of your long-term memory. This may also explain why emotionally charged memories are so vivid and can last for decades. The CREB repressor gene is like a filter, cleaning out useless information. But if a memory is associated with a strong emotion, it can either remove the CREB repressor gene or increase levels of the CREB activator gene.