![\"e_sugimori_img1\"](\"http:\/\/www.waseda.jp\/inst\/wias\/assets\/uploads\/2016\/06\/e_sugimori_img1.jpg\")
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My research focuses on how memory errors happen. For example, have you ever had an experience where you were going somewhere, and you wondered \u201cDid I lock the door?\u201d I became interested in this mechanism and started this research because I often experience such memory errors myself. Since I have thought of utilizing the theories obtained in basic research in our daily lives, I am now putting additional effort into applied research.<\/p>\n
Determining the source of a specific memory is called \u201csource monitoring.\u201d There are different types of source monitoring; monitoring whether or not you have seen something is called \u201cinput monitoring,\u201d and monitoring whether or not you have done something is called \u201coutput monitoring.\u201d<\/p>\n
In my basic research, I have clarified that memory errors are provoked when a person fails to properly get the sense of actually having seen or done something, or when this sense is obtained in the wrong way. For example, the previously mentioned \u201cDid I lock the door?\u201d output error becomes more likely when you lock the door while talking on a mobile phone. This is because this lessens the sense of having locked the door.<\/p>\n
Studying memory errors leads to understanding the mechanism of mental disorders. It is said that schizophrenia is a disorder of the sense of self-agency (the feeling of having doing something for yourself). For example, auditory hallucinations, which are one of the most common symptoms, are considered to be caused by falsely recognizing internal thoughts or murmurs as things said by others. Another common symptom is delusion. The cause of this symptom is also the inability to recognize your thoughts as your own, even though they come from your own mind.<\/p>\n
Therefore, in the applied research, I have focused on memory errors seen in persons with a delusional tendencies or auditory hallucinatory tendencies. Experimental subjects were healthy people (university students) who were not seeing a doctor for mental illness.<\/p>\n
First, I conducted an experiment regarding input errors related to delusional tendencies and visual memory. Specifically, I measured whether each subject had positive or negative delusional tendencies using question cards, and I analyzed the influence of this on input errors.<\/p>\n
For example, I would show a card saying, \u201cYou are a cooperative person,\u201d and then ask, \u201cDid you see a card that says \u2018You are a busybody.\u2019?\u201d In this case, the correct answer is \u201cNo,\u201d but people with strong negative delusional tendencies might answer \u201cYes.\u201d As a result of this experiment, people with positive delusional tendencies were likely to answer as if they had seen a positive adjective even though they have been shown a negative one, and vice versa. This means that transformation of memory occurs according to an individual\u2019s delusional tendencies (Figure 1).<\/p>\n
Next, in contrast to the previous experiment, I would show a card that says, \u201cYou are a cooperative person,\u201d and then ask an either\/or question: \u201cWhich one did you see, \u2018cooperative\u2019 or \u2018busybody\u2019?\u201d I would ask this immediately after and then again two weeks later. The results showed that for the question asked immediately after, there were almost no errors, regardless of the delusional tendencies of the individuals. However, for the same question asked two weeks later, errors were observed in accordance with their delusional tendencies. Therefore, we can suppose that transformation of memory has occurred over time.<\/p>\n
![\"Figure](\"http:\/\/www.waseda.jp\/inst\/wias\/assets\/uploads\/2013\/07\/e_sugimori_fig.1.jpg\")
Figure 1: Experiment investigating the relationship between positive\/negative tendencies and the transformation of memory (Courtesy of Assistant Professor Sugimori). The left side is the learning stage. The \u201cP\u201d refers to positive words, and the \u201cN\u201d to negative words. The right side is the testing stage. \u201cBusybody\u201d at the top was listed as \u201ccooperative\u201d in the corresponding learning stage. Therefore, the correct answer is \u201cNo.\u201d However, people with negative delusional tendencies might answer \u201cYes.\u201d<\/p><\/div>\n
Regarding input errors, I have also studied the relationship between auditory hallucinatory tendencies and auditory memory. In particular, I have conducted associated term tests and found that people with auditory hallucinatory tendencies are likely to recognize words associated by themselves as if they were words heard from somebody else.<\/p>\n
Regarding output errors, I have studied the relationship between auditory hallucinatory tendencies and behavioral memory. In this experiment, I presented the subjects with a concrete noun, such as \u201capple\u201d and \u201craccoon dog,\u201d along with an action word, either \u201cspeak,\u201d \u201cmouth\u201d or \u201cimagine.\u201d For example, if I present \u201cspeak\u201d and \u201capple,\u201d then the subject should speak the word \u201capple\u201d aloud, and for \u201cmouth and \u201craccoon dog,\u201d the subject should mouth \u201craccoon dog\u201d silently. As for speaking, I created an additional pattern where the subject hears their voice change in a strange way. When the subjects were asked whether they had spoken each word, the rate of incorrect answers (in other words, answering the question \u201cI did not speak that word\u201d) increased when their voices were changed. I have also found that there is a negative correlation between auditory hallucinatory tendencies and the accuracy rate of judgments on whether or not they had spoken. In short, when people hear a voice different from their own, it lessens their sense of having spoken for themselves. Perhaps people with auditory hallucinatory tendencies may recognize that the voice they are hearing is not identical to the voice in their thoughts.<\/p>\n
Recently I performed a study using fMRI, an imaging procedure using a device called MRI to visualize which parts of the brain are activated in response to external stimuli or when performing exercises. First, I had a subject in the MRI device hear or imagine a word. Then, I had them answer whether they had heard or imagined the word. As a result, brain activity was observed in the following three areas.<\/p>\n
First is the area called the left middle frontal gyrus, which is considered to be activated when we imagine or plan a behavior. In the experiment, when this area was activated, there was a tendency for the subjects to be able to definitively answer that they had imagined those words that they had been told to imagine during the learning stage. In short, if this area is activated when imagining something, the sense of having imagined persists after that.<\/p>\n
![\"Figure](\"http:\/\/www.waseda.jp\/inst\/wias\/assets\/uploads\/2013\/07\/e_sugimori_fig.2.jpg\")
Figure 1: The left middle frontal gyrus is the part in the red circle. In the graph on the right, the right-hand side indicates cases where the subjects imagined the words at the learning stage, and the left-hand side indicates cases where they heard the words. The bars show what they answered: \u201cheard\u201d in black, \u201cimagined\u201d in white, and \u201cneither\u201d in gray. The vertical axis indicates the average change ratio of blood flow in the brain.<\/p><\/div>\n
Next is the area called the left inferior frontal gyrus. This area is considered to be activated when we speak. In the experiment, when this area was activated during the learning stage, there was a tendency for the subjects to be likely to answer that they had heard the words in the test, both for words they had imagined and words they had heard. In short, this area is activated when a subject can clearly and successfully imagine a voice, and as a result, they may falsely recognize a voice as something they heard even though it was actually imagined. This means that the more successfully a subject can imagine, the more difficult it is for them to judge whether something was heard or imagined.<\/p>\n
Lastly, the superior temporal gyrus is considered to be activated when we hear, but not when we imagine. However, the experiment results indicated that the greater the subject\u2019s auditory hallucinatory tendencies, the more this area is activated, even when imagining words. In short, for people with auditory hallucinatory tendencies, the area in the brain activated upon hearing something is activated even if they have not heard anything.<\/p>\n
As it takes a long time to take images in the study using fMRI, this experiment allows only one subject per day. This experiment also requires subjects to stay still in the MRI device for a long period of time. These are the aspects of this research that I find difficult. However, it is much harder for me to write papers than to do experiments because no matter how interesting a phenomenon is, it is difficult to look up whether it\u2019s true that such studies have never been conducted.<\/p>\n
However, continuing this kind of research will offer opportunities to show society that there are individual differences in human memory errors. I hope that this will help us to understand ourselves and others, and moreover, provide us with clues on how to prevent errors. Also, the precise mechanism of schizophrenia remains unknown, and so drugs with side effects are sometimes used for treatment. One of my future goals is to understand the mechanism of schizophrenia through my research in order to help develop more efficient treatment methods.<\/p>\n
Interview and Composition: Seiko Aoyama\/Chisato Hata\/Ryo Oneda
\nIn cooperation with: Waseda University Graduate School of Political Science J-School<\/p>\n","protected":false},"excerpt":{"rendered":"
Eriko Sugimori, Assistant Professor (July, 2013) How Do Memory Errors Happen? My research focuses on how memor […]<\/p>\n","protected":false},"author":1,"featured_media":1966,"comment_status":"closed","ping_status":"closed","sticky":false,"template":"","format":"standard","meta":{"_acf_changed":false,"footnotes":""},"categories":[95],"tags":[73,107],"class_list":["post-1965","post","type-post","status-publish","format-standard","has-post-thumbnail","hentry","category-news-en","tag-research-en","tag-spotlight-en"],"acf":[],"_links":{"self":[{"href":"https:\/\/www.waseda.jp\/inst\/wias\/wp-json\/wp\/v2\/posts\/1965","targetHints":{"allow":["GET"]}}],"collection":[{"href":"https:\/\/www.waseda.jp\/inst\/wias\/wp-json\/wp\/v2\/posts"}],"about":[{"href":"https:\/\/www.waseda.jp\/inst\/wias\/wp-json\/wp\/v2\/types\/post"}],"author":[{"embeddable":true,"href":"https:\/\/www.waseda.jp\/inst\/wias\/wp-json\/wp\/v2\/users\/1"}],"replies":[{"embeddable":true,"href":"https:\/\/www.waseda.jp\/inst\/wias\/wp-json\/wp\/v2\/comments?post=1965"}],"version-history":[{"count":2,"href":"https:\/\/www.waseda.jp\/inst\/wias\/wp-json\/wp\/v2\/posts\/1965\/revisions"}],"predecessor-version":[{"id":4536,"href":"https:\/\/www.waseda.jp\/inst\/wias\/wp-json\/wp\/v2\/posts\/1965\/revisions\/4536"}],"wp:featuredmedia":[{"embeddable":true,"href":"https:\/\/www.waseda.jp\/inst\/wias\/wp-json\/wp\/v2\/media\/1966"}],"wp:attachment":[{"href":"https:\/\/www.waseda.jp\/inst\/wias\/wp-json\/wp\/v2\/media?parent=1965"}],"wp:term":[{"taxonomy":"category","embeddable":true,"href":"https:\/\/www.waseda.jp\/inst\/wias\/wp-json\/wp\/v2\/categories?post=1965"},{"taxonomy":"post_tag","embeddable":true,"href":"https:\/\/www.waseda.jp\/inst\/wias\/wp-json\/wp\/v2\/tags?post=1965"}],"curies":[{"name":"wp","href":"https:\/\/api.w.org\/{rel}","templated":true}]}}