Running head: STATE-DEPENDENT LEARNING AND FALSE MEMORY
State-Dependent Learning and False Memory
St. Bonaventure University
Congruent circustances in state-dependent learning produce better recall;
incongruent situations produce decreased recall (Lowe, 1986 and Schramke and Bauer,
1997). The following study was designed to test
state-dependent learning in congruent and incongruent situations using real and
false memory. Real memory would be the recall of those words actually on the
list and false memory would be recall of any words recalled that are not on the
list. Two 2 (level of training
congruence) x 2 (level of testing congruence) were tested using real and false
memory. It is predicted that real memory
will be greater for congruent than incongruent, and false memory will be
greater for incongruent than congruent situations. The results corrobo
State-Dependent Learning and False Memory
“State-dependent learning is a phenomenon in which the retrieval of information is better if the subject is in the same sensory context and physiological state as during the encoding phase” (Shulz, Sosnik, Ego, Haidarliu, & Ahissar, 2000). Basically, one will be more likely to remember something that they learned if they are in the same physical and mental state as when they learned the information, when they recall the information. Certain conditions are more likely to create the effect of state-dependent learning. These conditions include internal learning tasks and cue-free retrieval, also known as free recall (Lang, Craske, Brown, & Ghaneian, 2001).
A number of studies have been done to examine the effect of different types of drugs on state-dependent learning. Lowe (1986) investigated whether nicotine and alcohol interaction had an effect on state-dependent learning. In this study, 24 undergraduate students ingested 0.66 grams of alcohol per kilogram of bodyweight, and smoked two medium tar cigarettes. They were then asked to learn a route map. Twenty-four hours later, the participants attempted to recall the route map under four different drug states: alcohol and nicotine, alcohol and smoking placebo, nicotine and placebo drink, and no drugs at all (two placebos). Highest recall was seen in the alcohol and nicotine group, while the double placebo group recalled the least. This study showed that both nicotine and alcohol could create a state-dependent learning effect.
A study done by Carter and Cassaday (1998) looked at the effect of antihistamine on state-dependent learning. This study used 100 undergraduate students. The participants were given chlorpheniramine, which is a type of antihistamine, on the first day, while the other half were given a placebo. Fifteen minutes after the chlorpheniramine was administered the subjects were given two minutes to study a list of 20 words. The next day participants returned and were either given the chlorpheniramine or a placebo again, thus four groups were created: antihistamine (AH)-AH, AH-placebo, placebo-placebo, and placebo-AH. The results went along with what was expected. Participants performed better in congruent situations (AH-AH and placebo-placebo), as compared to incongruent situations (AH-placebo and placebo-AH). This study further showed that drugs, specifically antihistamines that are found in allergy medications, could produce state-dependent learning in human subjects.
The effect of caffeine on state-dependent memory has also been examined (Kelemen & Creeley, 2003). Eighty-three undergraduate students were used; individuals who consumed more than 500mg of caffeine a day were excluded from the study. This was a two-day study as well. Participants were randomly assigned to one of four conditions: caffeine-caffeine, caffeine-placebo, placebo-caffeine, or placebo-placebo. Participants were tested at the same time on both days of the experiment and were instructed to abstain from caffeine prior to the study. The participants either received the caffeine drink (4mg/kg of caffeine mixed with 6-oz of Tang), or the placebo drink. Salt was added to all drink in order to make both the caffeine and placebo drinks taste the same. Thirty minutes after receiving the drink, participants studied 40-paired words. They were allowed to study these words twice during day one of the study. On day two, the same procedure as above was followed. To test for recall the participants were shown a word from the original list and had to name the paired word that went with it. The results, as expected, showed that recall was higher when the subjects experienced a congruent situation as opposed to an incongruent situation. The results of this study suggested that there is evidence for state-dependent learning with caffeine.
Other research on state-dependent learning has focused on changing a person’s physical and mental state not with drugs, but with different stimuli, such as exercise. Schramke (1997) conducted a study that examined the effect of both exercise and age on state-dependent learning. There were two different age groups, 18 to 38 years old and 60 to 80 years old. Both groups either rested for five minutes, or exercised for five minutes on an exercise bike. Directly after this, the participants had two minutes to learn a 20-item word list. Twenty minutes after their exposure to the word list, the participants either engaged in five minutes of rest or five minutes of exercise, creating congruent or incongruent situations. It should be noted that there was no difference in learning due to the initial conditions of rest or exercise. The results showed that both age groups had greater recall for the word list when they were in a congruent situation, as compared to an incongruent situation. This study once again shows that congruent situations produce state-dependent learning.
A famous study by Godden and Baddeley (1975) examined environment and state-dependent learning. In this study, experienced scuba divers studied a list of 36 words, either underwater or on land. When they were tested for recall they were once again underwater or on land. When the results were calculated it was shown that the average recall for congruent environments was 35%, while the average recall for incongruent environments was only 24%, producing a significant difference. These studies show that it is not only drugs and alcohol that can produce state-dependent learning, but different situations as well, making an excellent reason to further the research in this area.
Memory is a factor that should be examined when looking at state-dependent learning as well as false memory. Memory is the retention of an experience. It is a cognitive process and is necessary for our functioning and development (Ceci, Fitneva, & Gilstrap, 2003). Memory is created in three stages. This first stage of memory development is encoding. This stage impacts how a person will store information that they encounter, and also how detailed the memory will be. The second stage is storage. During this stage, encoded information will become short-term memory, and may eventually become long-term memory. The third and final stage of memory is retrieval. This stage deals with how stored memory is recalled and retrieved. It should also be noted that during learning, a person will process the information that is required to be learned and will also associate this information with different internal and external cues (Miles & Hardman, 1998).
There have been many studies done in the area of false memory. Earlier research by Pesta, Murphy, and Sanders (2001) used the Deese-Roediger-McDermott (DRM) paradigm to study false memory. In this task participants are asked to learn word lists (e.g., cape, tape, ripe; part, perk, dark) related to one critical non-presented word (e.g., rape; park) (Pesta et al., 2001). They were then tested for recognition and recall of the words. Results showed that there were high levels of false recognition as well as false recall of the target word which illustrated how false memory can be created (Takahashi, 2002).
Another study by Garcia-Bajos and Elvira (2003) resulted in high confidence scores for false memories. A high confidence score means that the participants believed that what they remembered was something that they actually had seen. This suggested that the false memories represented real recollections for the participants, meaning that participants believed their false memories were actual, “true” memories. Their research also demonstrated that false memories were still present after a delay of a week and would even develop with explicit warnings against these errors (Garcia-Bajos & Elvira, 2003).
Seamon, Luo, Kopecky, Price, Rothschild, Fung, and Schwartz (2002) demonstrated that false memory is much more persistent in recall memory as compared to recognition memory (Seamon et al., 2002). In other words, people are more likely to produce false memories when they are asked to freely recall information instead of being given choices (i.e. a recognition task).
Another study (Kellerman, 2002) investigated whether negative and highly arousing words, negative and less arousing words, or neutral words were more memorable. As expected, it was found that highly arousing words are remembered better than less arousing and neutral words. This author suggests that more attention-based resources were given to the highly arousing words (Kellerman, 2002).
Pesta et al. (2001) studied emotional words and the false memory effect using verbal stimuli. Their study produced significant false memory for emotional words. However, false memory was not as great on a recognition test as compared to free recall. In the end, participants had greater false memory for non-emotional words when compared to emotional words (Pesta et al., 2001).
Previous research by a number of experimenters, including Lowe (1986) and Schramke (1997) shows that congruent situations of state-dependent learning produce better memory recall, and that incongruent situations produce a decreased memory recall, it can be assumed that these same situations will have an effect on false memory. The present study would like to extend the research of state-dependent learning beyond the conditions in which drugs or alcohol are used as a factor. It would also focus on the effect of state-dependent learning, created by congruent and incongruent situations, into the field of false memory, to see if there will be an overlap.
Based on previous research by Lowe (1986) and others that shows memory is negatively affected by incongruent state-dependent learning, a main effect for state-dependent learning is expected. It is hypothesized that better memory results will be seen in congruent situations when compared to incongruent situations. Due to the fact that memory is improved in congruent situations, it is also hypothesized that false memory should be greater for incongruent situations, as compared to congruent situations. Interactions are expected such that both false memory and memory will be affected by the congruent and incongruent situations. It is expected that memory will be greater for congruent than incongruent, and false memory will be greater for incongruent than congruent situations.
For the proposed study, 40 undergraduates students will be selected. All participants will be 18 years of age or older. The participants will be selected from the psychology department participant pool. Participants will be informed that they may be eligible for extra credit in certain psychology classes in exchange for their participation.
In order to determine the dependent variables of memory and false memory participants will be exposed to a list of 15 neutral words (the word list can be found in Appendix A). Similar lists of words have been used in a number of studies, including Schramke (1997) as well as Carter and Cassaday (1998) for state-dependent learning research. Seamon et al. (2002) and Pesta et al. (2001) also used similar lists for false memory research. It has also been shown by Eich (1980) that free recall tests (produced using lists) are maximally sensitive to state-dependent learning. The word list will be composed of neutral words to maximally influence the dependent variable of false memory. Research by Kellerman (2002) showed that arousing words produce less false memory and are remembered better, and Pesta et al. (2001) demonstrated that false memory is better for neutral words, as compared to emotional words. Music will be used for the state-dependent learning condition and will be played off of a CD over a portable CD player.
The participants in this study will all be asked to read and sign a consent form prior to their involvement in this study. The independent variable in the present study will be state-dependent learning, with two levels, congruent and incongruent situations. Congruent and incongruent situations will be produced using music. Therefore, music-music and no music-no music will be congruent variables, while music-no music and no music-music will be incongruent variables. The four different situations will be between subjects, meaning that each participant will experience one of the four situations. There will be two dependent variables in this study. The first dependent variable will be memory, which will be defined as the number of words a participant correctly recalls from the word list. The second dependent variable will be false memory, which will be defined as the number of words a participant recalls that were not on the original list.
Participants will be randomly assigned to one of four different groups. Each group will consist of 10 participants, so each group will have an equal number of observations. The four possible groups will be music-music, no music-no music, music-no music, and no music-no music. The music played will be the same song in every situation, to control for a confounding variable of song differences.
Participants will be given the word list to study in their assigned situation. They will then have a minute and a half (90 seconds) to study the word list. After the time has elapsed, the participants will have a ten-minute waiting period, in which they will be instructed not to discuss the word list. Participants will then be brought back to the room in either a congruent or incongruent situation; depending on what group they are allocated to. They will then have a three minute time period to recall as many of the words from the list as they can. They will record their answers on a separate sheet of paper so it may be collected at the end of the experiment. No cues, or recognition charts will be given, the participants will be recalling the information freely from their memory. After the experiment has been completed the participants will be debriefed and informed of the purpose of the study. If participants have any additional questions the experimenter will answer them.
The mean scores for memory in the congruent situations of music-music and no music-no music were 11(standard deviation of 4.909) and 12.2 (standard deviation of 5.02) out of a possible 15. The mean scores for the incongruent situations of music-no music and no-music-music were 4.8 (standard deviation of 5.16) and 5.5 (standard deviation of 7.25) out of a possible 15. The mean scores for false memory in the congruent situations of music-music and no music-no music were 3.3 (standard deviation of 4.82) and 3.1 (standard deviation of 4.31). The mean scores for false memory in the incongruent situations of music-no music and no music-music were 7.3 (standard deviation of 5.38) and 7.7 (standard deviation of 4.27).
Two ANOVA tests were performed after the data had been collected. The first ANOVA was done for the dependent variable of memory. The test showed no main effect for congruent or incongruent situations, with F (1, 36) 0.700, p ns and F (1, 36) 0.530, p ns respectively. An interaction between congruent and incongruent situations was found for memory with F (1, 36) 44.521, p < 0.000.
The second ANOVA was done for the dependent variable of false memory. The test showed no main effect for congruent or incongruent situations, with F (1, 36) 0.035, p ns and F (1, 36) 0.314, p ns respectively. An interaction between congruent and incongruent situations was found for memory with F (1, 36) 64.500, p < 0.000.
The results of the current study agree with prior findings by Lowe (1986) and Schramke and Bauer (1997). It was shown that memory was indeed better in congruent situations when compared to incongruent situations. Also, the hypothesis stated prior to running the experiments were shown to be statistically significant. This suggests that both the situation in which an individual studies or learns information, as well as the situation in which they recall this information has an effect on both memory and false memory. When the individual studies and recalls the information in the same situation, or a congruent situation, their memory will be better as opposed to if they had studied and recalled the information in different, or incongruent situations.
The exact opposite is true for false memory. False memory is more likely to be greater when the study and recall situations are different, or incongruent, as compared to when the study and recall situations are the same, or congruent. This goes along with the fact that something that hampers a person’s memory is likely to increase the event of a false memory. The graphs showing these interactions can be seen in Appendix B.
The implications of this study can be related to a number of different areas. The idea that an individual should be in the same situation when they recall information as when they learned it is applicable for many things. This emphasis the fact that students should study test material in an environment that they anticipate to be similar to that of the test taking area, which should help to increase their recall.
This study also suggests that a person will falsely recall information when they study material in an incongruent situation as to the situation that they recall the information in. This aspect of the study could be linked to eyewitness testimony in courts. Many court cases use eyewitness testimony as a key aspect to the prosecution or defense. If a person is recalling an event that took place in a specific environment it may be possible that they will be more likely to correctly recall that information if placed in a similar environment when they are questioned. It also would help to decrease the likelihood of a false memory. Putting somebody in a situation similar to that of the environment in which they witnessed the crime may not be the easiest concept, but it could play a factor in the accuracy of their recall.
Future studies could branch off into a number of different areas. One good area to stem into could be specifically looking at false memory in eyewitness testimonies as well as courtroom situations. This would be a good area for future research since it is something that occurs everyday and would be a major benefit to the judicial system. Also, knowing how likely a person is to properly recall specific information will help to see just how accurate a persons testimony may be.
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Mean scores for memory in incongruent and congruent situations
Mean scores for false memory in incongruent and congruent situations
Figure 1. Mean score for memory in both congruent and incongruent situations
Figure 2. Mean score for false memory in both congruent and incongruent situations
Neutral word list: