Desenvolvimento da memória: demonstrando como o questionamento repetido leva a falsas memórias
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概述
Source: Laboratories of Judith Danovitch and Nicholaus Noles—University of Louisville
A person is defined as a unique individual based on the people and events they encounter in their lives. Thus, creating, storing, and recalling memories are essential elements of the human experience. However, memory, as adults experience it, takes time to develop. Although young children can learn facts and remember details of their lives from moment-to-moment and day-to-day, they do not create autobiographical memories or detailed memories of events that happen in their lives until age 3 or older.
Even after age 3, children’s memories differ from those of adults in important ways. Children are less effective at evaluating their own memories than adults, which makes it difficult for them to determine, for example, whether or not their memories are accurate. False memories are a problem for both children and adults, as it is quite easy to create a false memory with a poorly-worded question or a story repeated over and over. However, young children are more susceptible to creating false memories than either older children or adults.
This video demonstrates children’s vulnerability to false memories using a method developed by Steven Ceci and his collaborators.1-2
Procedure
Recruit approximately 50 healthy 5- to 6-year-olds with no history of developmental disorders. For the purposes of this demonstration, only one child is tested. Larger sample sizes are recommended when conducting any experiments.
Note that the large sample size is to account for attrition or loss of participants. This procedure uses a longitudinal, multi-session design that requires children to complete a specific number of interviews in a specific amount of time. Any children who miss a session must be excluded from data analyses.
1. Data collection
- Gather the necessary materials.
- Interview the child’s parent to identify events the child has and has not experienced in the last 12 months.
- Design 10 vignettes, including five true events, three check events, and two test events.
- Record true events that consist of actual events the child experienced in the previous year as reported by their parents. Determine the general accuracy of a child’s memories with these events.
- Example: “You went to Disney World and ate a turkey leg.”
- Create check events that consist of events the child has not experienced. These events provide another measure of children’s accuracy, and they also provoke children to say no to some events, so they don’t get into a habit of just answering yes to every question.
- Example: “You saw a baby alligator eat an apple on an airplane.”
- Create test events that consist of believable events the parents report their child has not experienced. These are the events that may or may not generate false memories.
- Example: “You went to the hospital, because your finger got caught in a mousetrap.”
- Print each event on an index card.
- Introduction
- Say to the child: “I am going to read some things that may have happened to you, and I want you to think real hard about each one of them. Try to remember if it really happened. We made this list up by talking to your mother and father to get them to tell us about things that really happened to you when you were younger, but not all of the things I am going to read to you really happened.”
- Test
- Sit near the child while holding the event index cards.
- Have the child select a card at random, and then read it to them.
- After reading, ask: “Did that happen?”
- Continue until all the cards have been read.
- Repeat this procedure 5x over 5 weeks.
- Record the child’s responses, and then transcribe them for future analysis.
2. Analysis
- For each session, code the child’s “yes” responses separately for true events and test events.
- Use an analysis of variance to determine if there are differences between the two types of events presented to the child in sessions one, three, and five.
Both children and adults can experience false memories, which are either memories of events that never happened, or real memories that have been altered by subsequent experiences.
Compared to adults, children are more susceptible to forming false memories. Often, such memories are harmless cases of children recalling events and experiences that never actually occurred—like going to the hospital the day their sibling was born when they actually spent the day with their grandparents.
In addition, when children remember, it can be challenging for them to separate real details and events from those that they imagined or only heard about. As a result, children are less adept than adults at judging the accuracy of their memories.
As the work of psychologist Stephen Ceci has revealed, one of the most worrisome aspects of false memories is that they can be easily created in children, for example by repeatedly asking them a question or telling them a story.
Using the techniques described by Ceci and colleagues, this video demonstrates how to design, collect, and interpret data for an experiment investigating false memories in children, as well as how to apply this method to explore the complex relationship between memory, imagination, and age.
In this experiment, 5- and 6-year-olds are told about different events involving them, and asked to remember whether they experienced these scenarios.
The scenarios consist of three types: true, check, and test events. True events are those that children were actually involved in—like having gone to the fair and winning an enormous stuffed animal—that a researcher identifies by interviewing the children’s parents or guardians beforehand.
In this case, the dependent variable is the average percentage of children that assented, or claimed to have actually experienced, true events. These events are also used to evaluate the general accuracy of children’s memory.
The second type, check events, are fantastical scenarios a researcher creates that children did not experience, for example, having played a board game with a talking dog by a roaring fire.
As these events couldn’t have happened, they ensure that children don’t get into the habit of automatically answering “Yes” to every question, and also evaluate memory accuracy.
The final type of events—test events—are the trickiest, and consist of plausible scenarios that children did not experience, such as going to see a doctor after stepping on broken glass.
The percentage of children who claimed to have experienced test events serves as the dependent variable.
Over a 5-week period, children are repeatedly asked about the same set of scenarios, which includes true, check, and test events.
Based on the previous work by Ceci and colleagues, it is expected that the percentage of children assenting to test events will increase over questioning sessions, indicating that in some children these scenarios form false memories.
To prepare for the experiment, confer with every child’s parents to identify events that they have and haven’t experienced over the last year.
Using this information, design a collection of 10 individualized vignettes on index cards for each child. Ensure that each set includes five true, three check, and two test events.
To begin the study, greet the child and introduce them to the task they will be performing. Emphasize that some of the events they will be told about didn’t actually happen.
Sit nearby while holding index cards on which events are printed.
Have the child select a card at random, and read to them what’s written on it. Afterwards, ask the child whether the event happened.
Continue until all the cards have been read, and transcribe the child’s responses. Repeat this procedure five times over a period of five weeks.
For each of these five sessions, code the child’s “yes” responses separately for true events and test events.
To analyze the data, calculate the average percentage of children who claimed to have experienced both true and test events across sessions 1, 3, and 5.
Perform an analysis of variance to determine if there are differences between the two types of events presented to children in these three sessions.
Notice the rate at which children claim to have experienced realistic test events increased over time, indicating that many of them come to believe these events actually happened—forming false memories.
Now that you know how repeated questioning can be used to investigate false memories in children, let’s look at how psychologists are studying the plasticity of memory in other contexts.
One application of this work evaluates whether repeated questioning by authority figures—such as law enforcement officials—during interviews can result in children forming false memories.
As this can have serious legal ramifications, many psychologists are looking to identify and develop questioning strategies that encourage children to accurately report what they know about an event without influencing their memory of it.
Similarly, psychologists are trying to understand how children can mistake something they’ve heard, imagined, or thought about for something that they’ve actually experienced.
This may be due to the fact that each time a memory—like a specific birthday party—is recalled, there are opportunities for details to be added to or subtracted from it—like who was there and what food was served. Thus, remembering is more like construction than recollection.
As a result, unlike photographs, over time memories can become increasingly imperfect representations of a life event.
Finally, some researchers use techniques—like functional MRI—that can identify metabolically active tissues to compare areas of the brain involved in the formation and retrieval of false and true memories.
Although individuals experience both true and false memories in much the same way, it is possible that these imaging techniques can identify structures in the brain—like the hippocampus—that may help differentiate between these types of memories.
You’ve just watched JoVE’s video on the development of false memories in children. By now, you should understand how repeated questioning can lead to false memories in children, and know how to collect and interpret data revealing children’s tendencies to form false memories. You should also have an idea of what makes children particularly susceptible to false memories.
Thanks for watching!
Results
Children presented with real events and unrealistic events from their lives are typically very accurate at identifying situations they have and have not experienced. However, when presented with realistic events they have not experienced, many preschoolers believe they experienced those events, even after only hearing about them once, and the rate at which they say they have experienced them increases over time (Figure 1). In addition to the data from children’s responses, children may also spontaneously add their own details to the false memories presented to them in earlier testing sessions.
Figure 1: Average percentage of children who say they experienced an event that happened to them (true memory) or did not happen to them (false memory) after one, three, or five sessions.
Applications and Summary
Memories are not perfect representations of life events. They degrade over time, and details can be added or subtracted. Remembering is more like construction than recollection. So, it is very easy for a person to mistake something they have heard before, or something they have thought about before, for something that they’ve actually experienced. This is especially true for children, who are particularly likely to form false memories when asked to think about or imagine situations or events. More generally, these findings indicate that people should take special care when questioning children about serious legal and personal matters. Children are typically questioned repeatedly and with very specific questions when they are interviewed, and parents, teachers, social workers, and law enforcement officials commonly employ these practices. Thus, there is a delicate balance between creating false memories and effectively provoking children to report what they know about important events.
References
- Ceci, S.J., & Bruck, M. Jeopardy in the courtroom: A scientific analysis of children’s testimony. Washington, DC: American Psychological Association (1995).
- Ceci, S.J., Crotteau Huffman, M.L., Smith, E., & Loftus, E.F. Repeatedly thinking about a non-event: Source misattributions among preschoolers. Consciousness and Cognition. 3, 388-407 (1994).
成績單
Both children and adults can experience false memories, which are either memories of events that never happened, or real memories that have been altered by subsequent experiences.
Compared to adults, children are more susceptible to forming false memories. Often, such memories are harmless cases of children recalling events and experiences that never actually occurred—like going to the hospital the day their sibling was born when they actually spent the day with their grandparents.
In addition, when children remember, it can be challenging for them to separate real details and events from those that they imagined or only heard about. As a result, children are less adept than adults at judging the accuracy of their memories.
As the work of psychologist Stephen Ceci has revealed, one of the most worrisome aspects of false memories is that they can be easily created in children, for example by repeatedly asking them a question or telling them a story.
Using the techniques described by Ceci and colleagues, this video demonstrates how to design, collect, and interpret data for an experiment investigating false memories in children, as well as how to apply this method to explore the complex relationship between memory, imagination, and age.
In this experiment, 5- and 6-year-olds are told about different events involving them, and asked to remember whether they experienced these scenarios.
The scenarios consist of three types: true, check, and test events. True events are those that children were actually involved in—like having gone to the fair and winning an enormous stuffed animal—that a researcher identifies by interviewing the children’s parents or guardians beforehand.
In this case, the dependent variable is the average percentage of children that assented, or claimed to have actually experienced, true events. These events are also used to evaluate the general accuracy of children’s memory.
The second type, check events, are fantastical scenarios a researcher creates that children did not experience, for example, having played a board game with a talking dog by a roaring fire.
As these events couldn’t have happened, they ensure that children don’t get into the habit of automatically answering “Yes” to every question, and also evaluate memory accuracy.
The final type of events—test events—are the trickiest, and consist of plausible scenarios that children did not experience, such as going to see a doctor after stepping on broken glass.
The percentage of children who claimed to have experienced test events serves as the dependent variable.
Over a 5-week period, children are repeatedly asked about the same set of scenarios, which includes true, check, and test events.
Based on the previous work by Ceci and colleagues, it is expected that the percentage of children assenting to test events will increase over questioning sessions, indicating that in some children these scenarios form false memories.
To prepare for the experiment, confer with every child’s parents to identify events that they have and haven’t experienced over the last year.
Using this information, design a collection of 10 individualized vignettes on index cards for each child. Ensure that each set includes five true, three check, and two test events.
To begin the study, greet the child and introduce them to the task they will be performing. Emphasize that some of the events they will be told about didn’t actually happen.
Sit nearby while holding index cards on which events are printed.
Have the child select a card at random, and read to them what’s written on it. Afterwards, ask the child whether the event happened.
Continue until all the cards have been read, and transcribe the child’s responses. Repeat this procedure five times over a period of five weeks.
For each of these five sessions, code the child’s “yes” responses separately for true events and test events.
To analyze the data, calculate the average percentage of children who claimed to have experienced both true and test events across sessions 1, 3, and 5.
Perform an analysis of variance to determine if there are differences between the two types of events presented to children in these three sessions.
Notice the rate at which children claim to have experienced realistic test events increased over time, indicating that many of them come to believe these events actually happened—forming false memories.
Now that you know how repeated questioning can be used to investigate false memories in children, let’s look at how psychologists are studying the plasticity of memory in other contexts.
One application of this work evaluates whether repeated questioning by authority figures—such as law enforcement officials—during interviews can result in children forming false memories.
As this can have serious legal ramifications, many psychologists are looking to identify and develop questioning strategies that encourage children to accurately report what they know about an event without influencing their memory of it.
Similarly, psychologists are trying to understand how children can mistake something they’ve heard, imagined, or thought about for something that they’ve actually experienced.
This may be due to the fact that each time a memory—like a specific birthday party—is recalled, there are opportunities for details to be added to or subtracted from it—like who was there and what food was served. Thus, remembering is more like construction than recollection.
As a result, unlike photographs, over time memories can become increasingly imperfect representations of a life event.
Finally, some researchers use techniques—like functional MRI—that can identify metabolically active tissues to compare areas of the brain involved in the formation and retrieval of false and true memories.
Although individuals experience both true and false memories in much the same way, it is possible that these imaging techniques can identify structures in the brain—like the hippocampus—that may help differentiate between these types of memories.
You’ve just watched JoVE’s video on the development of false memories in children. By now, you should understand how repeated questioning can lead to false memories in children, and know how to collect and interpret data revealing children’s tendencies to form false memories. You should also have an idea of what makes children particularly susceptible to false memories.
Thanks for watching!