Encoding is the first process in forming a memory, according to HowStuffWorks. It is a biological phenomenon that starts with perception and is rooted in the senses.
When creating a memory, different sensations travel to the hippocampus, the part of the brain that integrates perceptions into a specific experience, HowStuffWorks explains. Once a memory is formed, it is stored in in short-term memory, then in long-term memory. Researchers believe the hippocampus and the frontal cortex analyze different sensory inputs and determine whether these sensations are worth remembering. Those that are deemed important sensations become part of a person's long-term memory. Different parts of the brain store various pieces of information, although it is not yet known how the brain later identifies and retrieves these bits of information to form a cohesive memory. Experience, education and training are important factors that affect the creation of memories and how the brain organizes and reorganizes itself in response to various experiences.
HowStuffWorks states that a person must pay attention to encode a memory properly. Scientists believe that focusing on information is likely the most important factor affecting the number of memories a person can access. However, people cannot concentrate on everything that happens around them. Most of what people encounter daily is filtered out, with only a few stimuli traveling into the conscious awareness.