question: How do we forget something easily even if we try to remember it as hard as we can, but the same thing comes to our mind when we are not even thinking about it?
comment: Psychologist here. It's the tip of the tongue phenomenon. There are different theories about this. Let me ELI5 on this simple example: & #x200B; Your memory is like a house and you are looking for a thing, e.g. your teddy bear. Now you (wrongly) remember or simply (wrongly) guess that your teddy is in the living room where you might left him yesterday. So you go the the living room and looking for it, but you can't find it. But you are sure he is close to you - this is the feeling of the tip of the tongue phenomenon. It feels "kinda close". Now you stop thinking about it - it means, you stop searching in the living room for your teddy and go outside, play with your friends, doing other stuff. After that you want to find your teddy again. You go into the house and this time you remember you left him in the bathroom yesterday. You come into the bathroom and here he is: your teddy bear sits on the toilet lid. & #x200B; In sum: To access this memory you use a "wrong strategy" or other wrong "cues" (that are kinda linked to a memory). These things block or inhibit the access to this memory. After doing other stuffs or just after a while not thinking about it, you kinda "forget" this old strategy (or cue) and can find it correctly.
passages: Betsy Sparrow (Columbia), Jenny Liu (Wisconsin) and Daniel M. Wegner (Harvard) described the Google effect in July 2011 after having conducted four experiments. They found that the participants thought about search engines when searching for information. Perhaps, the most important finding from their studies suggests that individuals have a tendency to forget information that they believe will be readily available to them in the future. In other words, why remember certain information if it is easily assemble through the use of an on-hand electronic device? Fortunately, their studies also claimed that people's ability to learn information offline remains the same.
   Konnikova helps the reader conceptualize acts of memory formation, retention and retrieval by borrowing Holmes's problem solving metaphor: the brain attic. If the brain is an attic, with finite space, then each bit of information placed there needs to be chosen carefully, organized and stored in a way that is both useful and accessible. "When we are forced to do multiple things at once," Konnikova says, "not only do we perform worse on all of them but our memory decreases and our general well-being suffers a palpable hit."
   Section::::Factors that affect recall.
  
  Section::::Factors that affect recall.:Attention.
  
  The effect of attention on memory recall has surprising results. It seems that the only time attention largely affects memory is during the encoding phase. During this phase, performing a parallel task can severely impair retrieval success. It is believed that this phase requires much attention to properly encode the information at hand, and thus a distractor task does not allow proper input and reduces the amount of information learned.
   It is possible for one with a well-trained memory to compose clearly in an organized fashion on several different subjects. Once one has the all-important starting-place of the ordering scheme and the contents firmly in their places within it, it is quite possible to move back and forth from one distinct composition to another without losing one's place or becoming confused.
  
  Again discussing Hugh of St. Victor's works on memory, Carruthers clearly notes the critical importance of order in memory:
   Emotional items also appear more likely to be processed when attention is limited, suggesting a facilitated or prioritized processing of emotional information. This effect was demonstrated using the attentional blink paradigm in which 2 target items are presented in close temporal proximity within a stream of rapidly presented stimuli.
   Section::::Sources.
  
  To the extent that greater positivity for subsequently remembered items spans several ERP components (P300, N400, and an LPC), coupled with differing topographical distributions depending on task, it is likely that the neural generators of the Dm effect are widespread in the brain. Pinning down the location in the brain that gives rise to any ERP component is very difficult if not impossible because of the inverse problem.
   Section::::Commercial performance.
   Anderson and Spellman's model of retrieval-induced forgetting suggests that when items compete during retrieval, an inhibitory process will serve to suppress those competitors. For instance, retrieval of one meaning for a word (e.g. the verb meaning of the word "sock") will tend to inhibit the dominant meaning of that word (e.g. the noun meaning of "sock"). In 1995, Anderson and Spellman conducted a three-phase study using their retrieval-induced forgetting model to demonstrate unlearning as inhibition.
   BULLET::::- If people are asked to explain their impressions and experience, they are less likely to remember what they felt. The act of describing an experience with words overrides part of the ability in the brain to remember the feelings as Jonathan W. Schooler showed.
  
  Section::::Research and examples.
   Crowley and Hawhee state about memory and kairos, "... kairos and memory were partnered in several ways. First, both require a kind of 'attunement' in that the rhetor who is gathering items for reserve in the memory must be thinking simultaneously about what's available now that might be useful later. Secondly, memory requires an attunement during the moment of speaking or composing, a recognition of the right time for recalling an illustrative example, an argument, and so on" (317).
  
  Section::::Memory Systems.
   Section::::In popular culture.
  
  Memory phenomena are rich sources of storylines and novel situations in popular media. Two phenomena that appear regularly are total recall abilities and amnesia.
  
  Section::::In popular culture.:Total recall.
   Ironic process theory
  
  Ironic process theory, ironic rebound, or the white bear problem refers to the psychological process whereby deliberate attempts to suppress certain thoughts make them more likely to surface. An example is how when someone is actively trying not to think of a white bear they may actually be more likely to imagine one.
  
  "Try to pose for yourself this task: not to think of a polar bear, and you will see that the cursed thing will come to mind every minute."
   Thought suppression has been shown to be a cause of inhibition in several ways. Two commonly-used methods to study this relationship are the list method and the item method. In this list method, participants study two lists of words, one after the other. After studying the first list, some participants are told to forget everything that they have just learned, while others are not given this instruction. After studying both lists, participants are asked to recall the words on both lists. These experiments typically find that participants who were told to forget the first list do not remember as many words from that list, suggesting that they have been suppressed due to the instruction to forget. In the item method, participants study individual words rather than lists. After each word is shown, participants are told to either remember or forget the word. As in experiments using the list method, the words followed by the instruction to forget are more poorly remembered. Some researchers believe that these two methods result in different types of forgetting. According to these researchers, the list method results in inhibition of the forgotten words, but the item method results in some words being remembered better than the others, without a specific relation to forgetting.
   Similar to the verbal paradigm is fuzzy-trace theory, which dictates that one encodes two separate things about a memory: the actual information itself and the semantic information surrounding it (or the gist). If we are given a series of semantic information surrounding a false event, such as time and location, then we are more likely to falsely remember an event as occurring. Tied to that is Source Monitoring Theory, which, among other things, dictates that emotionally salient events tend to increase the power of the memory that forms from said event. Emotion also weakens our ability to remember the source from the event. Source monitoring is centralized to the anterior cingulate cortex.
   Section::::Attention.
   Section::::Causes.:Physiological factors.:Emotion.
   The knew-it-all-along effect is a variant of the hindsight bias. It is the tendency for people to misremember and think that they knew more in the past than they actually did. In such situations it is difficult for us to remember what it was like when we did not have an understanding of something. For example, one might have a hard time teaching a concept to another individual because they can not remember what it is like to not understand the material.
  
  Section::::Related phenomena.:Hindsight bias.
   Section::::Empirical research.:"Think/no-think" paradigm and intentional inhibition.
   What Socrates and Quintilian feared is still debated in modern-day society. Thanks to the Internet and common search engines like Google, often referred to as humankind's collective memory, remembering seems to be less important than it once was. With the right search cues and the click of a button, any person can find almost any piece of information. The Google effect, also called digital amnesia, refers to the tendency to forget information that can be found readily online by using Internet search engines such as Google.
   Section::::Phenomena.:The Face Advantage.
   When groups collaborate to recall information, they experience collaborative inhibition, a decrease in performance compared to the pooled memory recall of an equal number of individuals. Weldon and Bellinger (1997) and Basden, Basden, Bryner, and Thomas (1997) provided evidence that retrieval interference underlies collaborative inhibition, as hearing other members' thoughts and discussion about the topic at hand interferes with one's own organization of thoughts and impairs memory.
   Another study done using cued recall found that learning occurs during test trials. Mark Carrier and Pashler (1992) found that the group with a study-only phase makes 10% more errors than the group with a test-study phase. In the study-only phase, participants were given Ai-Bi, where Ai was an English word and Bi was a Siberian Eskimo Yupik word. In the test study phase, participants first attempted to recall Bi given Ai as a cue then they were shown Ai-Bi pair together. This result suggests that after participants learn something, testing their memory with mental operations helps later recall. The act of recalling instead of restudying creates new and longer lasting connection between Ai and Bi. This phenomenon is commonly referred to as the testing effect.
   Section::::Hypothesized mechanism.
  
  Sedikides and Green (2004) offered a mechanism by which they believe mnemic neglect occurs. Self-referent information is processed in two stages. The first stage checks the information for compatibility with self-concept. Self-threatening information is confined to this stage because it is found to be incompatible with self-concept. During the second stage, self-flattering information is compared to similar episodic memories. The theory is that deeper processing occurs at the second stage, so information processed at this stage is recalled more easily.
   The typical finding is that participants often miss the second target item, as if there were a "blink" of attention following the first target's presentation, reducing the likelihood that the second target stimulus is attended. However, when the second target stimulus elicits emotional arousal (a "taboo" word), participants are less likely to miss the target's presentation, which suggests that under conditions of limited attention, arousing items are more likely to be processed than neutral items.
   Mind-wandering tends to occur during driving, reading and other activities where vigilance may be low. In these situations, people do not remember what happened in the surrounding environment because they are preoccupied with their thoughts. This is known as the decoupling hypothesis. Studies using event-related potentials (ERPs) have quantified the extent that mind-wandering reduces the cortical processing of the external environment. When thoughts are unrelated to the task at hand, the brain processes both task-relevant and unrelated sensory information in a less detailed manner.
  