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Original Study - State Dependent Forgetting

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Original Study - State Dependent Forgetting

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Alcohol and recall: state-dependent effects in man. - PubMed - NCBI

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1. Your favourite place!
2. Where you should all be Wednesday P4!
3. Your second favourite place - on the savannah!
4. Music to my ears!
5. Near a scary place where all the teachers sleep at night.
6. A place where creativity flows - Mr Biddle's favourite place!
7. This one is where the younger years hang out - and stuff themselves with the mighty chicken burger!

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http://psychyogi.org/fisher-et-al-1989/

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Fisher et al., (1986) - 'Field test of the cognitive interview: enhancing the recollection of the actual vicitims and witnesses of crime', Journal of Applied Psychology 74 (5), 722-7.

This study is also referred to as:

Fisher et al., (1989)

Fisher and Geiselman (1989)

Geiselman et al., (1989)

Background

This is the third study we look at from the ' Interviewing Witnesses' section of ' Making a case'. As part of your OCR A2 Psychology Exam. It is further categorised into ' The Cognitive Interview. '

Fisher et al., (1989) focuses on police interviews of witnesses.

What is an interview?

An interview is simply trying to elicit information from a person or witness, while keeping the information valid. This is easier said than done. You may remember two studies from AS: Loftus et al., (1974) and Samuel and Bryant (1984), which demonstrate this. Firstly, Loftus showed the impact that leading questions could have upon participant recall and she concluded that an actual change in memory had occurred. Memory is easily malleable, changing how a question is asked can change the memory itself. Secondly, Samuel and Bryant showed the impact of repeating the same question. Repeating the same question to children will cause them to completely change their answer, even if their answers were perfectly correct.

One of the most important aspects of police work is the ability it obtain accurate and detailed information from eyewitnesses of crime. One experienced judge has stated that incorrect eye witness identifications have led to more miscarriages of justice than all other factors combined (Sobel, 1972).
Fisher et al, (1986) is an important study to understand.
This study focuses not at the normal interviews that the police conduct, but something called the enhanced cognitive interview.

"This research evaluated an innovative interview procedure, the cognitive interview, that was designed to aid eyewitnesses recall of the details of crimes."

- (Fisher et al., 1989)
The enhanced cognitive interview has two underlining assumptions:

It is possible to access memories from different retrieval points.

Retrieval from memory will be more effective if at the time of retrieval the context of the original event can be reinstated.

There are four main retrieval mnemonics to the cognitive interview:

1. Interview Similarity - An attempt to reinstate the context of memory, interviews must take account of the external factors. How were the participants feeling emotionally? What was the weather like? "Mentally reinstating the context that surrounded a to-be-remem bered event has been shown to be a powerful memory aid in numerous laboratory experiments." - (Fisher and Geiselman, 1989)

2. Focused Retrieval - This is also called free recall. Interviewees are encouraged to recall as much as possible without interruptions from the person conducting the interview.

3. Extensive Retrieval - The interviewer makes as many attempts as possible at retrieval from many entry points, for example: what happened when you entered the building? What happened when you left the building? Irrelevant parts are requested by the interviewer in order to maximise the amount recalled, as the more irrelevant details that the interviewee recalls the more likely they are to remember something significant through association, for example, you might have noticed the something peculiar about the carpet and that led you to recall the criminals shoes.

4. Witness - Compatible Questioning - Each witness will be different, have different values and perceptions and thus the interviewer should consider that.

Aim

To study and test the cognitive interview in the field.

Design

Field experiment with actual interviews of real witnesses by serving Police detectives.

Participants

16 detectives from the Robbery Division of Dade County Florida. All were experienced with a minimum of five years with the division.

Procedure

In the first phase of the experiment, detectives were asked to record a selection of their next interviews using the standard interview techniques they normally used. This took four months and 88 interviews were recorded, mostly relating to bag snatches or robbery. The detectives were then divided into two groups with one being trained on Cognitive Interview techniques.

Training was over four, 60 minute sessions. Seven detectives completed the programme and were used in the results which follow. Over the next seven months more interviews were recorded by the two groups. The post training interviews were analysed by a team at the University of California who were blind to the conditions.

Results

The seven trained detectives elicited 47% more information after training and 63% more information than the untrained detectives. In terms of accuracy, laboratory based research had shown no difference between the cognitive interview and the standard interview with approximately 85% of all statements being correct in all conditions. In this field study, accuracy had to be established by corroboration with another source. In 24 cases with corroborating evidence (16 by pre-trained detectives), 94% of statements were corroborated.

The time taken to interview witnesses using the cognitive interview was longer, but not significantly longer; on average in this study it was one minutes longer.

Conclusions

Strong support was obtained for the effectiveness of the cognitive interview in the field. More information was obtained from witnesses to real events with no loss of accuracy and a minimal increase in time taked to interview them. The results in the field replicated those of the laboratory and perhaps give it more weight although the sample is small and may have been particularly well motiviated to run the trial.

The cognitive interview have since been applied to other clinical settings with therapists using it to develop medical histories.

This study is also referred to as:

Fisher et al., (1989)

Fisher and Geiselman (1989)

Geiselman et al., (1989)

Fisher et al., Evaluation

- Demand characteristics, as Police detectives were paid $50 for participating, they may have feel the need to act in a way which the experimenter would want.

+ Ecological Validity, as the experiment used real police detectives, we can say that the experiment is high in ecological validity.

+ Ethics, as the participants were informed about the interview beforehand, we can say that the study was ethical, however we can argue the opposite as the participants were paid for their participation, which is against the BPS's code of ethics.

- Ethnocentrism, the study was only focused on detectives from Dade county Florida.

+ Experimenter bias, as the results of both experiments were analysed by laboratory assistants who were blind to the conditions, we can say that the study is lacking in experimenter bias, which is a strength.

+ Construct Validity, the results of the study showed support for the effectiveness of the cognitive interview.

Audio Podcast

References

Fisher et al., (1986) - 'Field test of the cognitive interview: enhancing the recollection of the actual vicitims and witnesses of crime', Journal of Applied Psychology 74 (5), 722-7.

Further Reading
OCR A2 Psychology Student Unit Guide: Unit G543: Forensic Psychology (Student Unit Guides)

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Fisher et al., (1989) - The Cognitive Interview

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This study is also referred to as: Fisher et al., (1989) Fisher and Geiselman (1989) Geiselman et al., (1989) Background This is the third study we look at from the ' Interviewing Witnesses' section of ' Making a case'. As part of your OCR A2 Psychology Exam.

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Cognitive Interview

By Saul McLeod, updated 2019

Findings concerning the unreliability of eye-witness accounts have led researchers to attempt to devise methods for improving retrieval. One of these methods is the cognitive interview (Fisher & Geiselman, 1992).

The Cognitive Interview is a questioning technique used by the police to enhance retrieval of information about a crime scene from the eyewitnesses and victims memory.

Because our memories are made up of a network of associations rather than discrete and unconnected events, there are a number of ways that these memories can be accessed. The cognitive interview exploits this by using multiple retrieval strategies.

The cognitive interview involves a number of techniques/mnemonics:

Mental Reinstatement of Environmental and Personal Contexts

The interviewer tries to mentally reinstate the environmental and personal context of the crime for the witnesses, perhaps by asking them about their general activities and feelings on the day. This could include sights, sounds, feelings and emotions, the weather etc.

 In the interview, witnesses are often asked to use all of their 5 senses in their recollection of the event. This can help in recreating the event clearly in their mind and may trigger the recall of context dependent memories.

Reporting the Event from Different Perspectives

Witnesses are asked to report the incident from different perspective, describing what they think other witnesses (or even the criminals themselves) might have seen.

Describing the Event in Several Orders

Recounting the incident in a different narrative order. Geiselman and Fisher proposed that due to the recency effect, people tend to recall more recent events more clearly than others. Witnesses should be encouraged to work backwards from the end to the beginning.

In-depth Reporting

Witnesses are asked to report every detail, even if they think that detail is trivial. In this way, apparently unimportant detail might act as a trigger for key information about the event.

It is believed that the change of narrative order and change of perceptive techniques aid recall because they reduce witness' use of prior knowledge, expectations or schema.

A psychology laboratory experiment conducted by Geiselman, Fisher, MacKinnon, and Holland (1985) compared the cognitive interview with a standard police interview and hypnosis.

Geiselman et al. (1985)

Aim: Geiselman (1985) set out to investigate the effectiveness of the cognitive interview.

Method: Participants viewed a film of a violent crime and, after 48 hours, were interviewed by a policeman using one of three methods: the cognitive interview; a standard interview used by the Los Angeles Police; or an interview using hypnosis. The number of facts accurately recalled and the number of errors made were recorded.

Results: The average number of correctly recalled facts for the cognitive interview was 41.2, for hypnosis it was 38.0 and for the standard interview it was 29.4. There was no significant difference in the number of errors in each condition.

Conclusion: The cognitive interview leads to better memory for events, with witnesses able to recall more relevant information compared with a traditional interview method.

Cognitive Interview Video

Karen Matthews (Shannon's mum) was arrested for abducting her own daughter. Although we know that Karen wasn't the witness watch this clip to see the techniques used to elicit information from Karen.

Download this article as a PDF

APA Style References

Geiselman, R. E., Fisher, R. P., MacKinnon, D. P., & Holland, H. L. (1985). Eyewitness memory enhancement in the police interview: Cognitive retrieval mnemonics versus hypnosis. Journal of Applied Psychology, 70[2], 401-412.

Fisher, R. P., & Geiselman, R. E. (1992). Memory enhancing techniques for investigative interviewing: The cognitive interview. Springfield, IL: Charles C. Thomas.

Download this article as a PDF

How to reference this article:

McLeod, S. A. (2019, Jan 11). Cognitive interview. Simply psychology: https://www.simplypsychology.org/cognitive-interview.html

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By Saul McLeod, updated 2019 Findings concerning the unreliability of eye-witness accounts have led researchers to attempt to devise methods for improving retrieval. One of these methods is the cognitive interview (Fisher & Geiselman, 1992). The Cognitive Interview is a questioning technique used by the police to enhance retrieval of information about a crime scene from the eyewitnesses and victims memory.

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https://www.simplypsychology.org/eyewitness-testimony.html

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By Dr. Saul McLeod, updated 2018

Eyewitness testimony is a legal term. It refers to an account given by people of an event they have witnessed.

For example they may be required to give a description at a trial of a robbery or a road accident someone has seen. This includes identification of perpetrators, details of the crime scene etc.

Eyewitness testimony is an important area of research in cognitive psychology and human memory.

Juries tend to pay close attention to eyewitness testimony and generally find it a reliable source of information. However, research into this area has found that eyewitness testimony can be affected by many psychological factors:

Anxiety / Stress

Anxiety or stress is almost always associated with real life crimes of violence. Deffenbacher (1983) reviewed 21 studies and found that the stress-performance relationship followed an inverted-U function proposed by the Yerkes Dodson Curve (1908).

This means that for tasks of moderate complexity (such as EWT), performances increases with stress up to an optimal point where it starts to decline.

Clifford and Scott (1978) found that people who saw a film of a violent attack remembered fewer of the 40 items of information about the event than a control group who saw a less stressful version. As witnessing a real crime is probably more stressful than taking part in an experiment, memory accuracy may well be even more affected in real life.

However, a study by Yuille and Cutshall (1986) contradicts the importance of stress in influencing eyewitness memory.

They showed that witnesses of a real life incident (a gun shooting outside a gun shop in Canada) had remarkable accurate memories of a stressful event involving weapons. A thief stole guns and money, but was shot six times and died.

The police interviewed witnesses, and thirteen of them were re-interviewed five months later. Recall was found to be accurate, even after a long time, and two misleading questions inserted by the research team had no effect on recall accuracy. One weakness of this study was that the witnesses who experienced the highest levels of stress where actually closer to the event, and this may have helped with the accuracy of their memory recall.

The Yuille and Cutshall study illustrates two important points:

1. There are cases of real-life recall where memory for an anxious / stressful event is accurate, even some months later.

2. Misleading questions need not have the same effect as has been found in laboratory studies (e.g. Loftus & Palmer).

Reconstructive Memory

Bartlett 's theory of reconstructive memory is crucial to an understanding of the reliability of eyewitness testimony as he suggested that recall is subject to personal interpretation dependent on our learnt or cultural norms and values, and the way we make sense of our world.

Many people believe that memory works something like a videotape. Storing information is like recording and remembering is like playing back what was recorded. With information being retrieved in much the same form as it was encoded.

However, memory does not work in this way. It is a feature of human memory that we do not store information exactly as it is presented to us. Rather, people extract from information the gist, or underlying meaning.

In other words, people store information in the way that makes the most sense to them. We make sense of information by trying to fit it into schemas, which are a way of organizing information.

Schemas are mental 'units' of knowledge that correspond to frequently encountered people, objects or situations. They allow us to make sense of what we encounter in order that we can predict what is going to happen and what we should do in any given situation. These schemas may, in part, be determined by social values and therefore prejudice.

Schemas are therefore capable of distorting unfamiliar or unconsciously 'unacceptable' information in order to 'fit in' with our existing knowledge or schemas. This can, therefore, result in unreliable eyewitness testimony.

Bartlett tested this theory using a variety of stories to illustrate that memory is an active process and subject to individual interpretation or construction.

In his famous study 'War of the Ghosts', Bartlett (1932) showed that memory is not just a factual recording of what has occurred, but that we make "effort after meaning". By this, Bartlett meant that we try to fit what we remember with what we really know and understand about the world. As a result, we quite often change our memories so they become more sensible to us.

His participants heard a story and had to tell the story to another person and so on, like a game of "Chinese Whispers".

The story was a North American folk tale called "The War of the Ghosts". When asked to recount the detail of the story, each person seemed to recall it in their own individual way.

With repeating telling, the passages became shorter, puzzling ideas were rationalized or omitted altogether and details changed to become more familiar or conventional.

For example, the information about the ghosts was omitted as it was difficult to explain, whilst participants frequently recalled the idea of "not going because he hadn't told his parents where he was going" because that situation was more familiar to them. For this research Bartlett concluded that memory is not exact and is distorted by existing schema, or what we already know about the world.

It seems, therefore, that each of us 'reconstructs' our memories to conform to our personal beliefs about the world.

This clearly indicates that our memories are anything but reliable, 'photographic' records of events. They are individual recollections which have been shaped & constructed according to our stereotypes, beliefs, expectations etc.

The implications of this can be seen even more clearly in a study by Allport & Postman (1947).

When asked to recall details of the picture opposite, participants tended to report that it was the black man who was holding the razor.

Clearly this is not correct and shows that memory is an active process and can be changed to 'fit in' with what we expect to happen based on your knowledge and understanding of society (e.g. our schemas).

Weapon Focus

This refers to an eyewitness's concentration on a weapon to the exclusion of other details of a crime. In a crime where a weapon is involved, it is not unusual for a witness to be able to describe the weapon in much more detail than the person holding it.

Loftus et al. (1987) showed participants a series of slides of a customer in a restaurant. In one version the customer was holding a gun, in the other the same customer held a checkbook. Participants who saw the gun version tended to focus on the gun. As a result they were less likely to identify the customer in an identity parade those who had seen the checkbook version

However, a study by Yuille and Cutshall (1986) contradicts the importance of weapon focus in influencing eyewitness memory.

APA Style References

Allport, G. W., & Postman, L. J. (1947). The psychology of rumor. NewYork: Holt, Rinehart & Winston.

Bartlett, F.C. (1932). Remembering: A Study in Experimental and Social Psychology. Cambridge: Cambridge University Press.

Clifford, B.R. and Scott, J. (1978). Individual and situational factors in eyewitness memory. Journal of Applied Psychology, 63, 352-359.

Deffenbacher, K. A. (1983). The influence of arousal on reliability of testimony. In S. M. A. Lloyd-Bostock & B. R. Clifford (Eds.). Evaluating witness evidence. Chichester: Wiley. (pp. 235-251).

Loftus, E.F., Loftus, G.R., & Messo, J. (1987). Some facts about weapon focus. Law and Human behavior, 11, 55-62.

Yerkes R.M., Dodson JD (1908). The relation of strength of stimulus to rapidity of habit-formation. Journal of Comparative Neurology and Psychology, 18: 459-482.

Yuille, J.C., & Cutshall, J.L. (1986). A case study of eyewitness memory of a crime. Journal of Applied Psychology, 71, 291-301.

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By Dr. Saul McLeod, updated 2018 Eyewitness testimony is a legal term. It refers to an account given by people of an event they have witnessed. For example they may be required to give a description at a trial of a robbery or a road accident someone has seen.

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https://www.tutor2u.net/psychology/reference/misleading-information-post-event-discussion

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One source of misleading information comes from leading questions. However, misleading information in the real world can come from other sources, for example other witnesses (co-witnesses), when they discuss the details of a crime of accident, following an incident. This is known as post-event discussion.

Gabbert et al. (2003) investigated the effect of post-event discussion on the accuracy of eyewitness testimony. Her sample consisted of 60 students from the University of Aberdeen and 60 older adults recruited from a local community.

Participants watched a video of a girl stealing money from a wallet. The participants were either tested individually (control group) or in pairs (co-witness group). The participants in the co-witness group were told that they had watched the same video, however they had in fact seen different perspectives of the same crime and only one person had actually witnessed the girl stealing. Participants in the co-witness group discussed the crime together. All of the participants then completed a questionnaire, testing their memory of the event.

Gabbert et al. found that 71% of the witnesses in the co-witness group recalled information they had not actually seen and 60% said that the girl was guilty, despite the fact they had not seen her commit a crime. These results highlight the issue of post-even discussion and the powerful effect this can have on the accuracy of eyewitness testimony.
Evaluation:
The results of Gabbert et al. also have questionable ecological validity. The participants in the co-witness condition witnessed different perspectives of the same crime, as would typically be the case in real life crimes. However, like Loftus and Palmer, these witnesses knew they were taking part in an experiment and were more likely to have paid close attention to the details of the video clip. Therefore, these results do not reflect everyday examples of crime, where witnesses may be exposed to less information.

Gabbert et al. tested two different populations, university students and older adults and found little difference between these two conditions. Therefore her results provide good population validity and allow us to conclude that post-even discussion affects younger and older adults in a similar way.

Although Gabbert's results provide an insight into the effect of post-event discussion on the accuracy of eyewitness testimony, we are unable to conclude why the distortion occurs. The distortion could be the result of poor memory, where people assimilate new information into their own accounts of the event and are unable to distinguish between what they have seen and what they have heard. On the other hand, it could be that the distortion occurs due to conformity and the social pressure from the co-witness. Further research is required answer this question.

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​Misleading Information - Post-event Discussion | tutor2u Psychology

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One source of misleading information comes from leading questions. However, misleading information in the real world can come from other sources, for example other witnesses (co-witnesses), when they discuss the details of a crime of accident, following an incident. This is known as post-event discussion.

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https://digest.bps.org.uk/2017/09/29/mock-jury-study-will-behavioral-genetic-evidence-get-defendants-off-the-hook/https://digest.bps.org.uk/2017/09/29/mock-jury-study-will-behavioral-genetic-evidence-get-defendants-off-the-hook/

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Have a look at this YouTube channel for videos on all the topics in psychology

https://youtu.be/IWo_txzvscA

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https://www.tutor2u.net/psychology/reference/explanations-for-forgetting-revision-quiz

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https://www.simplypsychology.org/forgetting.html

https://www.tutor2u.net/psychology/reference/retrieval-failure-due-to-absence-of-cues

Godden and Baddeley - http://lca-psychology.weebly.com/godden--baddeleys-study-of-context-dependent-forgetting.html

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You will have been allocated a type of LTM, I would like you to write a cue card worth of information on this topic, including but not limited to the following information:

- What is the main purpose of the store? - give a brief description of the store and what type of information it holds
- Give 2 examples of the type of memory held in this store
- Is it explicit or implicit?
- What part of the brain is it associated with?

Challenge: find out what other functions this area of the brain does and give a reason for why this type of LTM might be stored there.

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https://www.livescience.com/43595-procedural-memory.html

https://explorable.com/procedural-memory

http://www.human-memory.net/types_declarative.html

If you are stuck use P73 of the textbook

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http://www.human-memory.net/types_episodic.html

https://www.simplypsychology.org/long-term-memory.html

https://www.livescience.com/42920-semantic-memory.html

If you are stuck use P72/3 of the textbook

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http://www.psychology24.org/what-is-episodic-memory/

https://www.simplypsychology.org/long-term-memory.html

If you are stuck use P69 of the textbook.

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Peterson and Peterson (1959) read nonsense trigrams to participants and asked them to count down from a three digit number in threes for varying lengths of time and then repeat the trigram.

They found that the duration of STM was approximately 20 – 30 seconds.

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Baddeley (1996) – participants were presented with one of 4 word lists, either acoustically similar or dissimilar words or semantically similar or dissimilar words and were asked to repeat it 4 times, immediately after the participant had to rearrange the words in the correct order.

They found only 10% remember the acoustically similar words, the other lists were similar.

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Patient H.M. was unable to form new memories (episodic) but was still able to perform procedural tasks, highlighting a clear distinction between different types of LTM.

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Finke et al. (2012) studied PM who was a cellist who suffered from amnesia as a result of a virus. Like Patient H.M. his explicit memory (episodic and semantic) memory were affected, but his procedural memory, reading and performing music, remained intact.

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Vicari et al. (2007) reported on the case study of CL, an 8 year-old who suffered brain damage as a result of a tumor being removed. She had deficiencies in her episodic memory but not semantic.

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https://www.simplypsychology.org/working%20memory.html

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https://www.tutor2u.net/psychology/reference/reliability

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https://www.tutor2u.net/psychology/reference/validity

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Print this off and put it in your folder

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Find an interesting fact about memory, write it on the tag and decorate.

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https://www.youtube.com/watch?v=CA-QGdqBUA0

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https://www.youtube.com/watch?v=fGY7-cxJby0

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AS Level Psychology - The Multi-Store Model Revision

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AS Level Psychology - The Multi-Store Model Revision This video outlines the Multi-Store Model in detail and will help you revise and take notes for your AS Level psychology course.

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http://www.psypost.org/2017/01/study-practice-makes-perfect-overlearning-locks-47230

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Want to learn something and then quickly make that mastery stick? A new Brown University study in which people learned visual perception tasks suggests that you should keep practicing for a little while even after you think you can't get any better. Such "overlearning" locked in performance gains, according to the Nature Neuroscience paper that describes the effect and its underlying neurophysiology.

Everybody from actors learning lines, to musicians learning new songs, to teachers trying to impart key facts to students has observed that learning has to "sink in" in the brain. Prior studies and also the new one, for example, show that when people learn a new task and then learn a similar one soon afterward, the second instance of learning often interferes with and undermines the mastery achieved on the first one.

The new study shows that overlearning prevents against such interference, cementing learning so well and quickly, in fact, that the opposite kind of interference happens instead. For a time, overlearning the first task prevents effective learning of the second task - as if learning becomes locked down for the sake of preserving master of the first task. The underlying mechanism, the researchers discovered, appears to be a temporary shift in the balance of two neurotransmitters that control neural flexibility, or "plasticity," in the part of the brain where the learning occurred.

"These results suggest that just a short period of overlearning drastically changes a post-training plastic and unstable [learning state]to a hyperstabilized state that is resilient against, and even disrupts, new learning," wrote the team led by corresponding author Takeo Watanabe, the Fred M. Seed Professor of Cognitive Linguistic and Psychological Sciences at Brown.
Different ways to learn
The findings arose from several experiments in which Watanabe, lead author Kazuhisa Shibata and their co-authors asked a total of 183 volunteers to engage in the task of learning to detect which one of the two successively presented images had a patterned orientation and which depicted just unstructured noise. After eight rounds, or "blocks," of training, which lasted about 20 minutes total, the initial 60 volunteers seemed to master the task.

With that established, the researchers then formed two new groups of volunteers. After a pre-test before any training, a first group practiced the task for eight blocks, waited 30 minutes, and then trained for eight blocks on a new similar task. The next day they were tested on both tasks to assess what they learned. The other group did the same thing, except that they overlearned the first task for 16 blocks of training.

On the next day's tests, the first group performed quite poorly on the first task compared to the pre-test but showed substantial progress on the second task. Meanwhile the overlearning group showed strong performance on the first task, but no significant improvement on the second. Regular learning subjects were vulnerable to interference by the second task (as expected) but overlearners were not.

In the second experiment, again with new volunteers, the researchers lengthened the break between task training from 30 minutes to 3.5 hours. This time on the next day's tests, each group - those who overlearned and those who didn't - showed similar performance patterns in that they both demonstrated significant improvement on both tasks. Given enough time between learning tasks, people successfully learned both and neither kind of interference was evident.

What was going on? The researchers sought answers in a third experiment by using the technology of magnetic resonance spectroscopy to track the balance of two neurotransmitters in volunteers as they learned. Focusing on the "early visual" region in each subject's brain, the researchers tracked the ratio of glutamate, which promotes plasticity, and GABA, which inhibits it. One group of volunteers trained on a task for eight blocks while the other group trained on it for 16. Meanwhile they all underwent MRS scans before training, 30 minutes after, and 3.5 hours after, and took the usual pre-training and post-training performance tests.

The overlearners and the regular learners revealed a perfectly opposite pattern in how the ratio of their neurotransmitter levels changed. They all started from the same baseline, but for regular learners, the ratio of glutamate to GABA increased markedly 30 minutes after training, before declining almost back to the baseline by 3.5 hours. Meanwhile, the overlearners showed sharp decline in the ratio of glutamate to GABA 30 minutes after training before it rose nearly back to baseline by 3.5 hours.

In other words, at the stage when regular learners were at the peak of plasticity (leaving their first training vulnerable to interference from a second training), overlearners were hunkered down with inhibition (protecting the first training, but closing the door on the second). After 3.5 hours everyone was pretty much back to normal.

In a final experiment, the researchers showed that the amount of decline in the glutamate to GABA ratio in each volunteer was proportional to the degree to which their first training interfered with their second training, suggesting that the link between the neurotransmitter ratio and the effects of overlearning were no coincidence.
Timing is everything
Though the study focused on a visual learning task, Watanabe said he is confident the effect will likely translate to other kinds of learning, such as motor tasks, where phenomena such as interference work similarly.

If further studies confirm that overlearning's effects indeed carry over to learning in general, then such findings would suggest some advice optimizing the timing of training:

To cement training quickly, overlearning should help, but beware it might interfere with similar learning it that follow immediately.

Without overlearning, don't try to learn something similar in rapid succession because there is a risk that the second bout of learning will undermine the first.

If you have enough time, you can learn two tasks without interference by leaving a few hours between the two trainings.

"If you want to learn something very important, maybe overlearning is a good way," Watanabe said. "If you do overlearning, you may be able to increase the chance that what you learn will not be gone."

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Study: Practice makes perfect, and 'overlearning' locks it in

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Want to learn something and then quickly make that mastery stick? A new Brown University study in which people learned visual perception tasks suggests that you should keep practicing for a little while even after you think you can't get any better.

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https://thepsychologist.bps.org.uk/volume-28/april-2015/looking-back-how-it-all-began

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https://goo.gl/forms/H8swbfJTVK9Db0xm1

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http://www.psypost.org/2016/08/study-on-earwitnesses-finds-children-better-at-recalling-a-sound-when-it-evokes-emotion-44630