Imagine what life would be like if all you knew was the present. Brain has many different memory systems that sometimes do their own things and sometimes interact. Sensory memory systems that exist at the level of our eyes, ears, nose, etc. or at the primary cortical parts; they keep sensory things that we experience alive for a while. Short-term memory (working memory) is like consciousness; where we bring things together and work with them. Long-term memory, where you take info you learn today and keep it in your mind for later periods. Episodic memory episodes from our lives; we share events and experiences in stories. Semantic memory things that we know; e. g. 6x7=42; info that we"ve learned and we have stored in our heads. Implicit memory e. g. clive remembers how to play songs unconsciously. Traces are termed sensory memory and tend to be very short-lived. Sensory memory was most extensively studied by cognitive psychologist george sperling.