The overall goal of this experimental task is to study gist based false memories in the laboratory. This method can help answer key questions in cognitive neuroscience, such as how memories are not only created but transformed. More specifically how we forget the details, but remember the gist.
The main advantage of this technique is its simplicity, since it's quite straight forward to prepare and conduct this task. Begin by selecting word lists with the highest probability of false recall and recognition. Next, digitally record all the words in each list by using professional equipment, an unfamiliar voice and a soundproof room.
Record the word list in descending strength of association at a rate of one word every two seconds. To help participants separate each list, include a delay of 12 seconds of silence followed by a one second tone and two seconds of silence at the end of each list. Then, start the next list.
Next, on the computer, drag and drop the audio file into audio editing software. Use the mouse to select the portion of audio to which silence will be applied. Then, select Edit, Remove Audio, and Silence Audio.
Use Copy/Paste to apply the one second tone at the start of each list. And then, press stop to save the recording. Select file, export, and choose the file format and destination of the audio file.
For the free recall task, have a blank piece of paper and pen ready. Then, select words to include in the recognition task from positions one, eight and 10 from each list that was included in the encoding task. Include all critical lure words from each list that were included in the encoding task.
Additionally, include the same number of additional non presented words from other non studied DRM word lists from the same positions, one, eight, and 10 and their corresponding critical lures. Then, use experiment creation software to create self paced presentation of the words and to collect data. Use black font with a white background and reasonable font size.
Finally, for the standard old new recognition test, assign separate keys to different responses, such that the Z key means old and the M key means new. Add this legend in with the presentation of each word on the screen. Begin the encoding task by having the subject sit in front of the device containing the recording of the word list and provide instructions about the task to the subject.
For this cognitive task, you will be listening to lists of words. At the final word of each list, there will be a 12 second break followed by a one second tone, two seconds of silence and then the start of the next list. Pay close attention to the words because you will be tested on them at the next session.
Then, have the subject put on headphones. Press play to begin the test, and turn off the computer monitor to limit any distractions. After the encoding task has ended, provide the subject with instruction for the next testing session.
You will come back tomorrow at the same time, okay? Okay.Thank you. 24 hours later, begin by asking the subject to sit at a table with a piece of paper in front of him or her and provide instructions on how to complete the free recall test.
This part of the task involves a simple memory test. Please write down all the words you can remember from the list you heard in the last session. You have 10 minutes to recall all the words you can.
When there are two minutes left, I will let you know. Then start the timer and inform them of the two minute warning mark. Let the subject complete the test.
After time is up, stop the subject. Begin by opening the recognition test within the experiment creation software. Then, have the subject sit in front of the testing computer.
Provide the subject with verbal instructions on how to complete the test. You will see a word on the screen. Press Z if you hear or saw this word on a previous list and press M if you think the word is new.
Answer as quickly and as accurately as you can. Then, start the recognition test, and wait for the subject to finish. Finally, debrief the subject and thank them for their participation in the study.
Results indicated that the overall proportion of words recalled and recognized was higher for false critical words than for the true presented words. Importantly, recognition of false critical words was also significantly higher than recognition for unrelated foil words. Similar results in the second experiment were obtained, such that subjects who returned 24 or 48 hours later to complete the free recall and recognition test also proportionally recalled and recognized more false critical words than true presented words.
Once mastered, this technique can be done in five to 30 minutes depending on the number of word lists used as well as other relevant factors. While attempting this procedure, it's important to remember that there are many variations of the DRM test. Please the review the manuscript for examples of such variations.
After it's development, this technique paved the way for researchers in the field of psychology and cognitive neuroscience to explore the reconstructive nature of human memory. After watching this video, you should have a good understanding of how to appropriately perform the DRM task in your lab to study gist based false memories.
