Memory Psychology - The Role of Cognition and Emotion
Memory Psychology - Research
The study of memory in psychology encompasses both cognition and emotion with the influence of emotions being at the core. The development of modern and objective psychological study methods has renewed interest in human emotions, once dismissed by Darwin as ‘childlike responses’ and an area which was rejected by the Behaviourists for its non-observable nature.
It is widely accepted that emotion does indeed influence the cognitive processes of memory and much research has been undertaken to investigate this further. Exactly how emotion exerts influence over our memories operation and ability is of particular interest.
Mood and Memory
Memory could be considered as a fragmented stage by stage process where encoding is the first stage of the process and retrieval is the last
Mood Congruent Memory (MCM) is a concept suggested by Gordon Bower, a key research figure in the 1970’s.
MCM is said to occur when the stimulus being encoded by an individual matches the mood state of the individual performing the encoding. For example, a person reading a tragic love story in a depressed mood state.
A second concept is Mood Dependent Memory (MDM). In MDM it is thought that memory for a specific stimulus is much better if there is a match between the mood state at the time of experiencing the stimulus and the mood state when trying to recall the stimulus. For example, if trying to remember what was said in a heated argument, when an individual is angry again they will remember the details much better.
It is important to highlight the difference between MCM and MDM:
- Mood Congruent Memory (MCM) – can only occur if there is a match between the emotional stimulus being remembered and the mood state of the individual at the time of remembering. There is match between the mood state at encoding and the stimulus being encoded.
- Mood Dependent Memory (MDM) – solely focused on the effect of mood on recall. Is not concerned with the material actually being recalled. There is a match between mood state at encoding and mood state at retrieval.
Psychology of Memory
MCM is a well-known and accepted phenomenon within the study of memory. MDM on the other hand, is possibly a more intriguing phenomenon as it appears less robust and is harder to produce and measure.
Bower (1981) conducted a number of experiments in order to try to recreate MDM in a laboratory setting. He used the emotions of happiness and sadness, due to their clear distinctiveness, and hypnotic suggestion as a method of mood induction with his participants.
In early studies, participants were requested to read a word list in their mood induced states. They were then tested on their recall of this word list after 10 minutes, while either in the same mood as they were the first time or the opposite mood.
The results showed that MDM was not present. It was concluded this was due to only one word list being presented. Bower claimed that just one word list was so distinctive that participants were able to retrieve it from memory despite being in an altered mood state.
Furthermore, he claimed that a common stimulus that can easily be confused with another or where the details could lost over time, such as a simple word list, is a requirement for MDM to occur.
Mood at Learning
Mood at Retrieval
MDM Predicted Recall
In further experiments, Bower used two word lists to test this theory under the same conditions and did indeed produce MDM effects.
This replicated the results with student volunteers in Teasdale and Fogarty (1979) and earlier clinical based studies with depressed patients (see Lloyd and Lishman, 1975 and Weingartner and Murphy, 1973).
Their agreement of the presence of MDM confirms its existence and the studies of Bower enhance this evidence by suggesting that memory for distinctive stimuli may not be heavily influenced by emotion. This is why the effect can only be seen under certain conditions.
Depression and Emotions
The study of patients suffering from depression has been prominent in much of the research conducted into emotion and memory.
Clinical reports and laboratory evidence suggest that individuals suffering from depression are less efficient learners (Beck,1988).
It has been found that clinically depressed patients report feeling in a constant low mood and that all patients show a MCM effect. Specifically, they show a bias for negative material (Rutherford, 2005).
Furthermore, the MCM effect appears to be more powerful when the negative nature of the material is stronger than their mood and when patients are consciously aware of a connection between the material and their mood.
Perhaps the strongest evidence for how powerful emotion can be comes from suggestions that MCM may contribute to keeping someone in a depressed mood and showing signs of depression.
This idea was developed by Teasdale in 1988 who likened the pattern to a revolving circle; depressed patients see the world in negative terms and therefore focus on their negative memories. This in turn increases their current depressed mood state and repeats the cycle. Teasdale suggested that if this cycle can be disturbed, it may help to lift mood and ease the patient’s depression.
This is an exciting notion which has evoked an influx of research into the possibilities of such intervention. Moreover, it gives an indication of the extent that emotion can influence a cognitive process such as memory.
Semantic Network Theory – Interaction of Emotions
In an attempt to explain the effects of MCM and MDM in emotion and memory research, Bower developed the Semantic Network Theory. This theory suggests that emotions are represented as nodes which interconnect with each other and produce outputs such as behaviour.
Activation of nodes can come from internal and external stimuli and transcends across the network via links between units. Bower claims some connections are inhibitory which means activation of one may suppress any activation in another.
According to Bower, Semantic Network Theory can provide explanation for how emotion and memory effects such as MDM are organised and function.
In the case of his laboratory studies, Semantic Network Theory would mean that when a word list is learned by a participant, connections are created between the appropriate emotion node and the memory representations of the word list items.
Due to activation in the network cascading through the various interconnections, a participant will be aided in recall of the word list due to such activation from the appropriate emotion node.
This could also explain why, if participants are in a different mood at the time of recall, they find recall more difficult. No association link would be present at the time of recall to activate an emotion node and aid memory. Furthermore, inhibition of the memory representation from a different emotion node may take place complicating the process further.
Memory Cognition Explained
Looking more in-depth at the processes of memory provides valuable insights into the usefulness of Bower’s Semantic Network Theory.
Many studies have suggested memory is greatly benefited from the organisation of stimulus at the encoding stage, for example, categorizing stimulus due to their shared properties (see Deese 1959 and Tulving 1962).
It is a reasonable assumption that such a shared property could be an emotion or group of emotions which are associated with such stimulus.
Imagine seeing a snake in the grass when out for an afternoon stroll and noticing your child fall off a swing in the garden.
These are two entirely different events however, they may invoke the same emotions of fear and anxiety.
Encoding Specificity Hypothesis within Emotion and Memory
Theories emerging from studies of memory highlight interesting points when considering emotion and memory. The Encoding Specificity Hypothesis was introduced by Tulving and Osler (1968) with relation to a study of the role of cues in memory and recall.
In their studies, participants were presented with target words in capital letters and in amongst those words were either none, one or two weakly associated words written in lowercase. Participants were advised the words in lower case may help them to remember the words in capital letters.
The results were that one weak associate helped participant’s recall of the target word as long as the weak associate was presented at the time of learning.
Such results suggest the encoding stage of memory is very important and cues or stimuli presented at that stage could have great influence during the later retrieval stage.
These findings echo the suggestions of Bower through his Semantic Network Theory. If applying this theory to emotion and memory, it could be said that an emotion experienced at the encoding stage of experiencing stimuli, could be the associate link required to aid memory of such stimuli at the retrieval stage.
This is an example of MCM and highlights in memory terms the importance of associate links made at encoding. If such an associate link was an emotion, it is entirely plausible to consider when that same emotion is felt again the stimuli leading to encoding is better remembered.
Influence of Emotion on Cognition and Memory
Such evidence from the study of memory provides more depth to the debate of the influence in which emotion has over cognitive processes.
It is clear that in the case of memory, emotion is a very powerful tool. Mood Congruent Memory (MCM) and Mood Dependent Memory (MDM) are both effects which potentially show the power in which emotion has over memory and the size of its role within memory.
MDM has proved to be more complex in that in order for it to occur, stimuli requires to have some distinctive qualities. However, its presence has been found in numerous laboratory and clinical studies suggesting that as research continues, its existence may become as accepted as MCM.
Bower’s Semantic Network Theory mirrors the finds of Tulving and Osler's memory cue studies and when taken together, they provide a solid and stable foundation for the powerful role of emotion and its influence over the cognitive processes of memory.
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