- ACQUISITION, STORAGE, RETRIEVAL
- Any act of remembering begins with acquisition, the process of gathering information and placing it into memory. The next aspect of memory is storage, the holding of information in some enduring form in the mind for later use. The final phase is retrieval, the point at which we draw information from storage and use it in some fashion.
- ACQUISITION
- Memory
acquisition includes cases of intentional learning and also incidental learning. In either case, the person must pay attention to the to-be-remembered material in order to achieve memory encoding.
- According to the stage theory of memory, information is held in working memory while one is thinking about it, but lodged in long-term memory for storage for longer intervals. This theory is supported by studies of free recall. In these studies,
primacy effects reflect that early items in a presentation receive more rehearsal, and are more likely to be transferred to long-term storage. Recency effects reflect the fact that just-heard items can be retrieved directly from working memory.
- Chunking is the process through which items are recoded into a smaller number of larger units. The active nature of memory is also evident in the fact that mere maintenance rehearsal does little to promote
long-term storage. Long-term retention is instead promoted by elaborative rehearsal.
- According to the depth-of-processing hypothesis, successful remembering depends on the depth at which the incoming information is processed, where shallow processing refers to encoding that emphasizes the superficial characteristics of a stimulus, and deep processing refers to encoding that emphasizes the meaning of the material. Consistent with this perspective, we remember
best material that we have understood, thanks to the memory connections that link one memory to the next. At the time of recall, these connections serve as retrieval paths.
- Mnemonics help a person form memory connections, and these connections can provide dramatic improvement in memory. Many mnemonics utilize imagery, but imagery is helpful only if the visualized items are imagined in some interaction—linking the items to each other, as one would expect if imagery is a
means of promoting memory connections.
- STORAGE
- There is debate about how the memory trace is actually represented in the brain. However, evidence suggests that different elements of a single memory (what things looked like, how one felt) may be stored in different brain sites.
- The establishment of a long-term memory depends on a memory consolidation process, during which new connections are formed among neurons. The need for
consolidation is reflected in cases in which this process has been disrupted, resulting in retrograde amnesia.
- RETRIEVAL
- The retrieval of memories is often promoted by our having an appropriate retrieval cue. Whether a cue is useful depends on whether the cue re-creates the context in which the original learning occurred. This context reinstatement allows the person to use the connections they formed earlier as retrieval paths.
- What is stored in memory reflects how the person thought about or reacted to the object or event being remembered. This encoding specificity is reflected in the fact that remembering is more likely if one thinks about the target information during retrieval in the same fashion that one did during encoding.
- WHEN MEMORY FAILS
- Many cases of forgetting can be understood as the result of inadequate encoding. This is reflected in the fact that
fMRI data, collected during encoding, show different patterns for later-remembered material and later-forgotten material.
- Forgetting generally increases the longer the retention interval, but the causes of forgetting are still a matter of debate. One theory holds that traces gradually decay. Another view argues that the cause of forgetting is interference produced by other memories. In some cases, this is because the other memories promote retrieval failure—an
inability to find information that is nonetheless still in storage. Retrieval failure is evident when some new cue allows us to recall previously forgotten materials, and it is also demonstrated by the tip-of-the-tongue effect.
- Interference can also result from the mixing together of memories. These intrusion errors are evident in the misinformation effect, in which specific episodes are blurred together. In other cases, intrusion errors are the result of generic
memory intruding into someone's memory of a particular event. This reflect a broader pattern of evidence indicating that events are usually understood (and remembered) with reference to knowledge structures called scripts or schemas.
- Another source of memory errors is source confusion. This mistake is promoted by the fact that familiarity and recollection are distinct in several ways, including the principles that govern them and also the brain
areas that support them during learning and during retrieval.
- Psychologists have searched unsuccessfully for means of distinguishing correct memories from mistaken ones. The confidence expressed by the person remembering turns out to be of little value for this discrimination. Hypnosis also does nothing to improve memory and can actually increase the risk of memory error.
- VARIETIES OF MEMORY
- Researchers find it useful to
distinguish several types of memory. Episodic memories concern specific episodes; generic memories concern broader knowledge, not tied to a particular episode. Explicit memories are consciously recalled; implicit memories are revealed when there is an effect of some past experience without the person being aware that she is remembering at all—or even that there was a relevant past experience.
- Certain injuries to the brain produce anterograde amnesia,
in which the patient's ability to fix material in long-term memory is reduced. However, someone with amnesia may still have intact implicit memories or procedural knowledge.
- Being emotional at the time of an event seems to promote memory for that event, with several mechanisms contributing to this effect. In the extreme, an emotional event may produce a flashbulb memory, which is recalled vividly years after the event. However, flashbulb memories probably do not involve
some separate and specialized mechanism, because flashbulb memories can sometimes include errors (just like any other memory), and other memories are also sometimes very long-lived.
- Traumatic events are usually remembered extremely well, but the data pattern is mixed: Some traumatic events seem not to be remembered, and several mechanisms contribute to this forgetting.
- There has been considerable controversy over the status of repressed memories. Evidence suggests,
though, that enormous caution is required in assessing these memories.
We get information into our brains through a process called encoding, which is the input of information into the memory system. Once we receive sensory information from the environment, our brains label or code it. We organize the information with other similar information and connect new concepts to existing concepts.
Memory consolidation is the process where our brains convert short-term memories into long-term ones.
Knowledge acquisition is the process of absorbing and storing new information in memory, the success of which is often gauged by how well the information can later be remembered (retrieved from memory).
Encoding is the process of converting information into a useable form or 'code' so that it can enter and be stored in memory. Information is received, converted from its raw sensory state to a form that the brain can use or process, and stored in memory.
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