We all have had trouble, at one time or another, recalling the details of an event, a word, or a person's name. Those "tip-of-the-tongue" experiences can be frustrating, making us wonder why we can't access the information that seems so within reach.
Cues from the environment, called retrieval cues, aid in this process by helping link an outside object or hint to the information we are looking for. Returning to the particular place where the information was first learned can also be helpful in retrieval. This concept, known as the encoding specificity principle, states that information processed and encoded in a certain physical space is more retrievable in that space. This suggests that in memory retrieval, context matters.
Mood is also an important factor in memory retrieval in that it acts as a retrieval cue. A positive mood reminds us of a positive experience we've had, and a negative mood reminds us of a negative experience. The more we activate associations, the easier it will be to retrieve the information in the future.
Various parts of the brain are responsible for storing our memories. When these areas are activated patterns of neural activity are formed, and this has the potential of changing the physical structure of the brain.