Which affect-cognitive relationships are related to memory? - Chapter 7

Are affective events better remembered than neutral events?

There is evidence that people withhold their affective responses to certain stimuli, even when they cannot consciously remember having seen that stimulus before. This is also called implicit memory; the impact that a previous confrontation with an (explicitly forgotten) stimulus has on current behavior and assessment.

What is the result of studies of autobiographical memories?

The affective properties of a situation can provide an improved memory of everyday events. A good example of this are flashbulb memories, very vivid memories of highly emotional events, such as the attack on the WTC in 2001. A high correlation is found between the vividness of the memory and how emotional the event was. This is independent of whether the emotions were positive or negative. However, the vividness of the memory is no guarantee that it is actually accurate, which is often not the case. After a few years, people tell the event in great detail and are therefore sure that what they say is correct. However, the retelling has often changed a lot after a few years and is no longer in line with the actual event.

Research into autobiographical memory is problematic because you cannot know whether people who retrieve more affective events from the memory do this because it is easier to retrieve those events or because they have experienced more such events. That is why memory testing is often conducted in the laboratory.

What is the result of laboratory-based studies?

The remember / know paradigm measures two independent processes that underlie remembrance. The first is remember and is about recalling an event with different contextual details. The second is know and is a sense that an item is familiar without any precise memory of the contextual details. In this study, participants must determine whether they have remember or know an (affectively positive, negative or neutral) item. Highly affective items were better remembered (both positive and negative). For negative items, the 'remember' rating was more often given. This confirms the vividness of autobiographical memories of negative events (even though the accuracy is not necessarily better).

An fMRI study confirms the finding that accuracy between positive and negative stimuli does not differ, but that negative stimuli are more often referred to as 'remember'. This is probably due to a greater activity in the amygdala of negative items. For neutral items, a higher 'remember' score was linked to a greater activity in the parahippocampal cortex.

Memory for the gist of things

There are indications that affect mainly improves the accuracy of our memories for the central, or the gist of a scene. For example, eyewitnesses of a crime can often describe the weapon in detail, but the better the weapon is described, the less the details about the perpetrator are remembered.

These findings are consistent with a previous hypothesis that a narrowing of the emotional arousal of attention (narrowing of attention has) the effect, so that especially the central part of a scene is processed in detail. Thus affect improves the accuracy of memory for the central aspects of an event, but reduces the memory for the peripheral aspects.

We might remember emotional events better because we think about them more often, so we actually 'rehearse' these events. In addition, negative stimuli attract attention much more strongly, resulting in improved coding in the memory. These arguments indicate that memory would be improved by indirect effects of affect on initial encoding and rehearsal.

Does affect influence memory by means of arousal or valence?

We know that arousal and valence have a distinct effect on neural processes when attention is given to stimuli. However, there has not been much research that distinguishes the two when it comes to affect and memory.

What are the effects of arousal on memory for affective material?

The amygdala is said to be important for improving memory for arousing stimuli. Psychological arousal leads to activation of beta-adrenergic receptors in the amygdala. This in turn causes hippocampal activity, which provides for improved consolidation (storage) of memories of events that triggered an arousal response.

It was found that damage to the amygdala mainly limits memory of central aspects of a scene, but not of the more peripheral aspects. In addition, a study found that activity in the amygdala during the coding of an aversive emotional event is strongly correlated with the recall of the event at a later time. This correlation was not present at the neutral events, but there is a correlation between the activity in the hippocampal area and the recall of neutral stimuli. This indicates that the amygdala is involved in an improved memory for emotional stimuli, and the hippocampal region is associated with the recall of neutral stimuli.

Finally, Kensinger and Corkin also found that activation of the amygdala and the hippocampus correlated while encoding affective words that were later recalled. This suggests that an amygdala-hippocampal network could underlie the improved explicit memory for emotionally arousing stimuli.

What are the effects of valence on memory for affective material?

A study into the influence of valence on memory found that participants remembered more negative words, independent of excitement. However, the improved memory for high and low arousal words seemed to be associated with different neural networks. For the negative high excitement words there was mainly activity in the amygdala and hippocampus, for the negative low arousal words especially in the PFC and hippocampus. In the final behavioral output, there was no difference in recalling the negative words, whether they were high or low on arousal.

There are also studies that find no difference between memory for positive and negative events, and even studies that find that positive events are better remembered. The latter is called the positivity bias . However, the question is whether this is actually a bias, because in general people actually experience more positive situations than negative ones.

Affective memory for pleasant and unpleasant events seems to fade at different speeds; this is faster for negative than for positive events. This effect (fading affect bias) gives us a sense of positivity; we see our life as more positive.

So, is there any effect for valence? It seems that under laboratory conditions there is no difference between memory for positive and negative events. However, events that are relevant to us show a bias in which positive events linger better. It does depend on whether the task is about the self or an unknown person. Negative information about the self is processed in a fairly superficial way, while information that is flattering to the self is processed much more accurately. We remember much more negative information about others than about ourselves.

Does affect influence memory at encoding, consolidation or retrieval?

There are three times when affect can influence memory. The first moment is with encoding, whereby emotionally salient events are processed in more detail and therefore better remembered. The second moment is consolidation, so when the memories are recorded in the long-term memory. The third moment is when we are attempting to retrieve specific memories. These stages do not just follow one another, but overlap to a large extent. In addition, they use different neural circuits.

The fact that consolidation takes some time (minutes to hours or more) means that memory for affective arousing events is likely to improve compared to neutral events as time goes on. This means that when memories are retrieved just after the event, there should be little difference in memory for affective and neutral events. After a while this difference should be greater.

It turns out that affect does indeed have an effect on memory during both encoding and consolidation, and perhaps also during the retrieval of memories.

What are the effects of encoding?

The effect of attentional bias, as discussed in the previous chapter, is that increased attention to arousing stimuli provides a better mental image. This therefore provides a boost in memory for affective stimuli. Support for this theory comes from research in which the amygdala activity during the coding phase is correlated with how well the emotional events are remembered. However, improved memory was not found immediately after encoding, but only a few weeks later. Thus, it is possible that the amygdala activity during coding has an effect on the subsequent consolidation process in a way that needs some time to develop.

What are the effects of consolidation?

Many of the findings in this area come from animal studies. For example, it was found that when drugs are used that promote memory after training, they lead to an even better memory improvement than the training itself. This effect is not immediately visible, but it is visible 24 hours later. This pattern suggests that the drugs selectively influence consolidation.

Adrenaline and cortisol (stress hormones) play an important role in the consolidation of memory. The amygdala is important for mediating this influence; we know this because lesions on the amygdala can block the effects of these hormones on consolidation. These findings have also been confirmed in humans, including the administration of adrenaline after performing a memory task. This promoted consolidation for all incentives.

So, it seems that emotionally arousing stimuli are better consolidated in the long-term memory. This effect is linked to a number of hormones and is further regulated by the amygdala. In addition, the amygdala-hippocampal network (which is active in coding) has a direct impact on consolidation. The only problem is that memory is often tested only once (if consolidation is already well under way), so we do not know whether arousal mainly affects consolidation, or encoding.

What are the effects of retrieval?

There is some evidence that activation of the amygdala and areas in the anterior temporal pole are specifically involved in retrieving affective information. For example, it was found that different neural networks were involved in retrieving neutral information and retrieving affective information. To retrieve both positive and negative images, there was activation in the right anterior temporal pole and the left amygdala. These areas were not active when retrieving neutral images. The problem with this study was that the amygdala might not have been activated for the retrieval process, but rather because of the emotional response to the retrieved memories.

Do mood states influence memory?

The viewing of emotional stimuli may cause a certain mood, which then affects memory, rather than the influence of stimulus or event characteristics. When we are in a certain mood, we tend to notice things that are consistent with that mood and we also remember more things from the past that fit the mood.

We discuss two phenomena here: mood-congruent memory and mood-dependent memory . Mood-congruent effects occur when we recall primarily negative events from our past when we are in a depressed mood, or when we recall primarily positive events from our past when we are in a happy mood. Thus, recall is facilitated for information that is affectively congruent with our current mood state. Mood-dependent memory will be facilitated when there is a match between mood at encoding and mood at retrieval. If we hear a story while we are in a sad mood, then we should be more likely to remember details of that story some time later when we are once again in a sad mood as opposed to being in a happy mood. 

Mood-congruent memory

Mood-congruent memory can occur with both encoding and retrieval. The influence of mood on encoding is often tested by causing a mood and then letting people learn a list of positive and negative words. Later, when these people are in a neutral mood, they look at what words they remember. Indeed, it is found that words that correspond to the mood in which the person was during learning are better remembered. The explanation for this can be found in the associative network model, which predicts that information corresponding to the mood is more salient and processed at a deeper level than other information.

The influence of mood on the collection seems less clear. People are often asked to learn a list of positive and negative words while in a neutral mood. After this the individual is asked to retrieve as many words as possible when they are in a positive or negative mood. The results of this are varied: some studies find no effect, others do.

The studies on autobiographical memories provide a clearer picture. A mood is evoked here, after which people are asked to recall events from their own lives. The findings here are generally that people retrieve more events that match their mood, although some studies found the opposite.

The problem with these studies is that the events that are retrieved are often also consistent with the mood at the time the event occurred. So, it may just as well be that the effects are caused by the influence of mood at the time of encoding. In addition, the current mood can distort the memory, reconstructing them in such a way that they fit in better with the current mood. The latter can be an adaptive function, since appraisals of the current affective situation can be a better guide to future behavior than if the memory were a perfect reflection of the past.

A number of factors influence whether mood congruence occurs. For example, the question is whether the material is referenced to the self or to another and whether the person is aware that the information matches the mood or not. In addition, the intensity of the mood and the material is important. For example, it has been found in a study that when the intensity of the material is low, there is even mood inconsistency. When mood and material are noticed (so are intense), deeper associations are formed, which benefits memory.

The mood inconsistency effects found are more difficult to explain. It is possible that cognitive control strategies are at work that are involved in regulating moods. So, retrieving mood incongruent information can be an attempt to change the mood.

An effect has also been found where encoding influences how words are "colored". When people are in a certain mood and learn a list of neutral words, these words get a meaning through the affective background (the mood). As a result, more words were correctly remembered, which complements the theory that emotionally charged stimuli are better remembered.

Mood dependent memory

As discussed earlier, mood-dependent memory ensures that material learned in a certain mood is better retrieved when someone is back in the same mood. This therefore involves consistency between the votes at the time of coding and the time of retrieval.

A study by Bower gave a very strong effect of mood-dependent memory, but the results were never well replicated. However, researchers agree that there are certain circumstances in which mood-dependent memory almost always occurs. For example, the effects are much more common in real-life situations than in the laboratory. In these situations, the affective nature of the situation is much more salient and intense. In addition, affective situations from real life are often more connected to the life goals of a person, so that they are previously evaluated and interpreted as significant.

It is likely that a stronger mood during encoding results in a stronger association with the material. So, if the mood when retrieving is the same as the mood when encoding, the mood itself is a good indication. This explains why the effect is strongest when the mood is intense, there is then a clear context for learning the material. The effect also occurs when context, instead of mood, location or aroma, is used.

When other indications are almost non-existent, voting is an important cue. However, when there are many other strong indications, mood is a bit disappointing. So, this explains why the effect is less or not present when the mood is not very intense: it then falls away against the other cues from the environment.

Eich stated that mood-dependent memory effects are reliable and consistent, as long as moods are strong and stable and when people are involved in actively generating the target events that should be remembered later. This is almost always the case in everyday social situations, so this is a good explanation for the fact that the effect occurs more often in real life than in the laboratory.

Does the type of mood state make a difference to the memory?

The above research shows that valence of the mood makes no difference, but intensity does indeed. Furthermore, Levine and Pizarro state that it is necessary to look at what purpose an emotion serves. This is not just a matter of arousal or valence, but depends on what someone achieves with an emotion. According to this theory, emotions should improve memory for the details that are most relevant to the motivations associated with discrete emotions. There is some confusion between emotions and moods, but it seems logical that different moods are also related to different adaptive functions.

Are positive and negative mood states associated with different information-processing strategies?

There is a line of research that states that different moods are associated with different information processing strategies. For example, happy people rely more on general knowledge and stereotypes. After all, a happy mood is a result of achieving a goal, so there is no immediate problem that needs to be solved. Negative moods, on the other hand, lead to more detailed evaluation of information. After all, these moods are caused by important goals being threatened or failing.

For positive moods, assimilation is used, with active cognitive elaboration of stimuli being done by internal schemes and knowledge structures. This is especially good when exploration and creativity are important. With negative moods, on the other hand, accommodation is used. This is an adaptive process that focuses on the requirements of the environment. This entails careful and detailed perception and analysis of stimuli, when no mistakes may be made.

This also affects memory. When people are told a story that fits certain events in the script (for example, a story about a restaurant where the waitress puts the menus on the table) and other events don't (that someone puts his tennis racket away), people "remember" those script-typical material better, even when it had not been presented. People who were in a negative mood are more accurate in naming what was and was not in the story. This shows that positive mood leads to more confidence in general knowledge, causing errors to slip into the memory.

Another study shows that people in a happy mood have a better memory for a story as a whole, while angry or sad people could remember more details of the story. In addition, sad people remembered more information related to negative outcomes than the angry people. Angry people remembered more information about goal states than the sad people. This indicates that people in different negative mood states tend to recall different types of information.

What are the different theoretical accounts of mood state and memory interactions?

Associative network models

The central idea behind associative network theories is that all the concepts and facts that we have in our long-term memory are stored as nodes in a complex network. For example, the concept of "dog" is stored as a node alongside things such as animal, bark, bite, "Fido", etc. The idea is that when a certain node is activated, a wave passes through the network, causing strongly related concepts to be activated more strongly than hardly related concepts. Such a network is a good explanation for semantic priming effects . This means that the processing of a concept is faster if we have processed a related concept just before that.

Bower stated that moods can also be stored as nodes in such a network, along with other 'cognitive' concepts. So, for every concept a series of affective states (emotions and moods experience in association with the concept) can be linked to this core concept. This means that when a certain concept is activated, a certain mood can also be activated (or vice versa; a concept is activated by voting). This model can therefore explain both mood congruence and mood dependent memory .

It is assumed that certain emotion nodes (sadness) inhibit other emotion nodes (joy), making it more difficult, for example, to retrieve concepts associated with joy when you are sad.

The model assumes fairly general predictions about mood congruence, while other research shows that the effect on memory differs per mood. This differentiation cannot be properly made by an associative network . In addition, the effects of motivation on mood congruence are not discussed . People do not just experience passive affective states, they use a range of strategies to regulate these and to maintain or achieve positive moods. One such strategy is distraction, where people try to think of something else. As a result, the activation wave is disturbed by the model, thereby inhibiting the activation of concepts related to the negative mood.

Affect infusion model (AIM)

When motivations are present to regulate emotions, mood incongruity effects often occur. The Affect Infusion Model (AIM) is intended to provide a clearer specification of the circumstances in which mood conflict is or is not likely to occur. The model assumes that mood-related predictions of associative network models only occur under circumstances that allow an open and unbiased search and processing strategy.

AIM identifies four processing strategies. The choice of a strategy depends on the characteristics of the task, the person and the situation as a whole. Two of the strategies (direct access and motivated) involve closed and targeted processing, which limit the possibility of affect infusion (the process whereby affectively salient information is involved in cognitive and behavioral processes). The two other strategies, on the other hand (heuristic and substantive), require a more open and constructive processing style, which means there are more possibilities for affect infusion. The various strategies therefore largely determine the characteristics of affect-cognitive relationships.

AIM comes to the unexpected conclusion that affect infusion mainly occurs when more in-depth processing is needed. This is because these strategies promote the careless use of affective information. When the situation requires a simple, pre-existing response, affective information has virtually no impact on cognitive processing. Furthermore, AIM assumes that if all other circumstances remain the same, people will opt for the simplest processing strategy, which requires the least effort.

These four processing strategies are as follows:

1. Direct access strategy: is about the direct retrieval of a pre-programmed response, is used when the task is known.
2. Motivated strategy: driven by a specific motivational goal, characterized by a highly focused and selective search for information. Negative moods can trigger this strategy to "fix" the mood.
3. Heuristic strategy: used when there is no motivational pressure and when the task is simple and familiar. Affect infusion only occurs when people use affect as a heuristic cue
4. Substantive processing strategy: used when the task is difficult or complex, or when it is new and there is no motivational goal to guide the processing. Affect infusion occurs because constructive, creative processes are needed.

In summary, the most important prediction of AIM is the presence of mood conflict effects when heuristic and substantive processing strategies are used, and the absence of affect infusion when direct access or motivated processing is used. AIM thus expands the associative network models by specifying the circumstances under which affect infusion and therefore also mood congruent and mood dependent memory effects occur.