by REM phase. This study found that sleep improved memory retention of emotional text only during late sleep phase, which was primarily REM. Similarly, Hu & Stylos-Allen, et al. performed a study with emotional versus neutral pictures and concluded that REM sleep facilitates consolidation of emotional declarative memories. The view that sleep plays an active role in declarative memory consolidation is not shared by all researchers. For instance Ellenbogen, et al. argue that sleep actively protects declarative memory from associative interference. Furthermore, Wixted believes that the sole role of sleep in declarative memory consolidation is nothing more but creating ideal conditions for memory consolidation. For example, when awake, people are bombarded with mental activity which interferes with effective consolidation. However, during sleep, when interference is minimal, memories can be consolidated without associative interference. More research is needed to make a definite statement whether sleep creates favourable conditions for consolidation or it actively enhances declarative memory consolidation. Encoding and retrieval The encoding of explicit memory depends on conceptually driven, top-down processing, in which a subject reorganizes the data to store it. The subject makes associations with previously related stimuli or experiences. This was termed deep encoding by Fergus Craik and Robert Lockhart. This way a memory persists longer and will be remembered well. The later recall of information is thus greatly influenced by the way in which the information was originally processed. The depth-of-processing effect is the improvement in subsequent recall of an object about which a person has given thought to its meaning or shape. Simply put: To create explicit memories, you have to do something with your experiences: think about them, talk about them, write them down, study them, etc. The more you do, the better you will remember. Testing of information while learning has also shown to improve encoding in explicit memory. If a student reads a text book and then tests themselves afterward, their semantic memory of what was read is improved. This study – test method improves encoding of information. This Phenomenon is referred to as the Testing Effect. Retrieval: Because a person has played an active role in processing explicit information, the internal cues that were used in processing it can also be used to initiate spontaneous recall. When someone talks about an experience, the words they use will help when they try to remember this experience at a later date. The conditions in which