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Memory Model

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Three processes and three types of memories are included.

  • Encoding is the process of getting information into our brains.
  • Storage is the process of retaining the information.
  • Retrieval is the process of getting the information back from our brain.
  • Sensory memory is an immediate and brief encoding of sensory information.
  • Working memory comprises the short-term memory from consciousness and the long-term from our brain.
  • Long-term memory is a relatively permanent type of memory, including knowledge, skills, and experiences.

Based on which, we have the following flowchart.

\begin{equation} \text{External events} \overset{\mbox{Sensory input}}{\longrightarrow} \text{Sensory memory} \overset{\mbox{Encoding with attention}}{\longrightarrow} \text{Working memory} \overset{\mbox{Retrieving/encoding}}{\longleftrightarrow} \text{Long-term memory} \end{equation}

Note that the external events can also be directly and automatically encoded to long-term memory. The working memory has a similar role to the computer memory. Attention and rehearsal can help to achieve efficient encoding towards long-term memory.

Memory Encoding

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There are two ways to encode the memory into our brains: an effortless one called implicit memory, and an effortful one called explicit memory, constituting the dual-track memory! Again we meet another elegant duality of ours (the last one is the conscious-unconscious duality), where a track is for daily routine and another one for expensive consciousness.

Implicit memories mainly include automatic skills such as swimming and bicycling, and associations such as the fears aroused by an approaching dog and the past experience of being bitten.

Explicit memories include sensory memory, working memory, and also long-term memory (the long-term memory contains both the implicit and explicit components).

  • Sensory memories are like the raw input to our brains. By the selective attention and inattention, they are filtered. The preserved ones are then present to working memory for further processing.
  • Working memories are like a pool where both the preserved sensory memories and retrieved long-term memories are mixed. Older adults have less working memory capacity.
  • The long-term memories are like the saved data in the hard disk of a computer.

How to memorize more efficiently?

There are several strategies.

  • Chunking, which is to rearrange and group the information as multiple meaningful blocks.
  • Mnemonics, which is to embed vivid imagery or meanings into the information.
  • Distributed practice, which is to rehearsal frequently rather than massively, supposing that the total practicing time is equal. A better strategy to acquire long-term memory.
  • Deep processing, which is to focus your attention on the information to memorize, instead of mechanically repeating the raw information.
  • Customization, which is to adjust the information according to your preferences. We have much better recall for information we can meaningfully relate to ourselves. This effect is called the self-reference effect.

Memory Storage

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The explicit memory system and the implicit memory system are involved in our memory, as we mentioned before.

The explicit memory system is found to be relevant to the frontal lobes and hippocampus. The former is the space for working memory processing, and the latter is the save button of the explicit memory system. When you request data from your brain, many regions will send the relevant data to the frontal lobes. The left and right frontal lobes prefer abstract and vivid memory processing, respectively.

The hippocampus is a cache of the registered information. The latter will then be sent for storage elsewhere, this process is called memory consolidation, which is greatly supported by sleep. Interestingly, during sleep, the hippocampus and brain cortex manifest simultaneous activity rhythms, as if they were having a conversation!

The implicit memory system is found to be relevant to the cerebellum and basal ganglia. Without the cerebellum, people cannot develop certain conditioned reflexes, like blinking when hearing a tone with a puff of air. Without the basal ganglia, people cannot retain procedural memories for skills such as riding a bike.

Emotion is a strong influence on our memory formation. We can therefore long remember exciting or shocking events, some of which are terrible.

Researches also manifest that the increased activity of memory-related processes can form and strengthen neural interconnections. Therefore, it is recommended to use your brain more often!

Memory Retrieval

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Memory retrieval is the task after the encoding and storage. The retrieval cues serve this purpose. It is similar to the pointer in computer programming, where a pointer can point to other objects with their own pointers. The association of pointers matters!

There are several factors that can affect our memory.

  • Priming is the activation worked unconsciously. It is the invisible memoryless memory. Priming can influence our behaviors. It is the key for Pickup of Artist.
  • Context-dependent memory is the type of memory that is mostly triggered in a certain environment.
  • State-dependent memory, similar to the above, but for the state such as mood. Memories of being drunk are more likely recalled during that state. A happy mood can trigger happy memories, which in turn strengthens the happy mood, the ditto for a bad mood.
  • Serial position effect, an interesting phenomenon that people tend to remember the first and last objects from a sequential list. Precisely, the last object and first object are better memorized by immediately and later recalls, respectively.

Forgetting and Errors

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There are mainly two scenarios regarding forgetting. The first one is caused by the disability of the brain. A person like is may lose the ability to construct new or recall past memories, respectively. Another scenario is for most of us with normal brains. And it has several implications, in a sequence of the memory subprocess.

  • Encoding failure, due to insufficient attention and rehearsal.
  • Storage decay, caused by the gradual fading of the memory library.
  • Retrieval failure, caused by several possible reasons such as:
    • Interference, the influence from old/new memories.
    • Motivated forgetting, a self-protective mechanism to self-censored the unwanted information, usually painful or unacceptable.

As for memory construction errors, it is found that memory is not precise. Our memory can be corrupted by our imagination and expectation, and misleading information. Our memory can also be influenced by the source amnesia, under which people refer to a false source of an event we have experienced. Unintentional plagiarization is usually caused by the source amnesia.

The interesting deja vu might be explained by the source amnesia as well. Normally, we experience a feeling of familiarity before we consciously recall the details. Once the system is out of sync, we may experience a familiar feeling without recalling the details. Since our brain attempts to explain this phenomenon, we get an eerie feeling about we have already foreseen this moment in our past.

Improving Memory

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Several suggestions are provided for improving memory.

  • Rehearse repeatedly.
  • Make the information meaningful.
  • Be in a similar context or state.
  • Wisely apply chunking and mnemonic.
  • Minimize the interference. By focusing the mind and choosing a good time, e.g., before sleep.
  • Sleep more to help memory consolidation.

The Components of Thinking

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Thinking is relevant to concepts, prototypes and categories. The first step of the thinking is forming concepts, so that similar objects, events, ideas, or people are abstractly represented. A concept is usually determined by a prototype, which is the most expressive example of a category. Concepts can speed and guide our thinking, and the effect is not always welcomed.

Problem Solving

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There are generally two problem-solving strategies: the trial and error, and the algorithm. Specifically, the latter has step-by-step procedures, and can guarantee a solution after laborious and exasperating efforts.

In addition to these two strategies, we have another powerful weapon, the insight, which usually comes with the feeling of light bulb flashing, followed by a workable solution. Interestingly, when the answer pops into mind, we usually have a sense of satisfaction.

Good vs Bad

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Confirmation Bias

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Sometimes our inventive cognitive tendencies may lead us astray. For example, we tend to accept evidence that supports our idea other than those that deny it. This tendency is called confirmation bias. In short, people tend to evade facts, become inconsistent, or systematically defend themselves against the threat of new information relevant to the issue.

Mental Set

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Sometimes our cognitive tendencies tend to be fixed, once we represented a problem, or obtained a solution. The mental set (recall the perceptual set we have met before) is a prime example of this. We tend to approach a problem with what has worked for us before.

The Availability Heuristic

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Heuristic enables instant judgment. Though effective, it screws up sometimes. Because we tend to estimate the likelihood of events according to the mental availability – how easily they come to mind – not the objective facts. Anything that makes information pop into our mind can make it commonplace.

We reason emotionally and neglect probabilities. We overfeel and underthink. We fear wrong things, like flying, because we visualize air disasters. We overlook true threatens, like global climate change, because the temperature variation nearby is not obvious. This slackness of climate will be gone only if we experienced some extreme weather like hurricanes.


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Our judgments often go awry simply because we are confident to be correct. The less people know, the more immoderate they are.

Belief Perseverance

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We tend to cling to our beliefs even if we are facing negative evidence. The more we come to appreciate the correctness and greatness of our beliefs, the more tightly we cling to them. Far more evidence are required to change a justified belief than it did to create it.

The Effects of Framing

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Amazingly, the way we present an issue that can affect our decisions and judgments. For example, saying “$90\%$ survive” is less terrible than saying “$10\%$ die”, and saying “kill 10 of every 10 million people” is much worse than saying “$0.0001\%$ killing rate”. Those who understand the power of framing can use it to nudge our decision!!

The Power of Intuition

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One thing is extremely interesting and useful for me. Sometimes, it is actually wise to put the current problem aside, and attend to other things, during which our intuition may incubate the problem!

Give me some time not to think about this! Because our unconscious mental machinery can work in the background!

For a higher level, deliberative thinkers are aware of the intuitive options, but know when to override it.

Thinking Creatively

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There are 5 important components.

  • Expertise. We have to be knowledgeable, just like the soils to plants.
  • Imaginative thinking skills, the ability to see things from a new perspective, recognize patterns, and make associations.
  • A venturesome personality, never cease to seek new experiences, be willing to risk, and perseveres in overcoming obstacles.
  • Intrinsic motivation, being interest-driven, other than by external pressures.
  • A creative environment, a crucial one to spark, support, and refine creative ideas.