6.6 SUMMARY

• Encoding is the process of transforming into a lasting memory the information our senses take in.
• Memory is influenced by the type of encoding we perform regardless of whether we consciously intend to remember an event or a fact.
• Semantic encoding, visual imagery encoding, and organizational encoding all increase memory, but they use different parts of the brain to accomplish that task.
• Encoding information with respect to its survival value is a particularly effective method for increasing subsequent recall, perhaps because our memory systems have evolved in a way that allows us to remember especially well information that is relevant to our survival.

• Sensory memory holds information for a second or two. Short-term or working memory retains information for about 15 to 20 seconds. Long-term memory stores information anywhere from minutes to years or decades.
• The hippocampus and nearby structures play an important role in long-term memory storage. The hippocampus is also important for memory consolidation, the process that makes memories increasingly resistant to disruption over time.
• Memory storage depends on changes in synapses, and long-term potentiation (LTP) increases synaptic connections.

• Whether we remember a past experience depends on whether retrieval cues are available to trigger recall. Retrieval cues are effective when they are given in the same context as when we encoded an experience. Moods and inner states can serve as retrieval cues.
• Retrieving information from memory can improve subsequent memory of the retrieved information, as exemplified by the beneficial effect of testing on later recall, but it can also impair subsequent remembering of related information that is not retrieved.
• Neuroimaging studies suggest that trying to remember activates the left frontal lobe, whereas successful recovery of stored information activates the hippocampus and regions in the brain related to the sensory aspects of an experience.

• Long-term memory consists of explicit memory, the act of consciously or intentionally retrieving past experiences, and implicit memory, the unconscious influence of past experiences on later behavior and performance.
• Implicit memory in turn includes procedural memory, the acquisition of skills as a result of practice, and priming, a change in the ability to recognize or identify an object or a word as the result of past exposure to it.
• People who have amnesia are able to retain implicit memory, including procedural memory and priming, but they lack explicit memory.
• Episodic memory is the collection of personal experiences from a particular time and place; it allows us both to recollect the past and imagine the future. Semantic memory is a networked, general, impersonal knowledge of facts, associations, and concepts.

• Memory’s mistakes can be classified into seven sins, which are the price we pay for the benefits that allow memory to work as well as it does most of the time.
• Some of these “sins” reflect an inability to store or retrieve information we want. Transience is reflected by a rapid decline in memory followed by more gradual forgetting. Absentmindedness results from failures of attention, shallow encoding, and the influence of automatic behaviors. Blocking occurs when stored information is temporarily inaccessible, as when information is on the tip of the tongue. In contrast, persistence is the intrusive recollection of events we wish to forget.
• Other “sins” reflect errors in memory content. Memory misattribution happens when we experience a sense of familiarity but don’t recall—or we mistakenly recall—the specifics of when and where an experience occurred. Suggestibility gives rise to implanted memories of small details or entire episodes. Bias reflects the influence of current knowledge, beliefs, and feelings on memory or past experiences.