What are possible individual differences in the processing of emotions? - Chapter 8

Do cognitive biases influence emotional reactivity?

Chapter 3 showed that different temperaments and personality traits are associated with different degrees of emotional reactivity. This chapter examines whether these differences are related to personality-matching biases in cognitive processing. Variation in temperament determines how we see and process the world around us, so does this mean that people divide, interpret and remember attention in a way that matches their personality? This theory is called the trait congruency hypothesis. 

What is the empirical evidence thus far?

The impact that everyday situations have on people is strongly influenced by differences or biases in how people process the same information. Unfortunately, much of the previous research is about the impact of negative traits, emotions and moods. However, there is now also a growing movement that deals with positive cognitive biases. This is interesting because it provides us with information about factors that can help to build up a resilience to stress and tension. This chapter discusses the association between natural variations in properties or temperament and fundamental biases in how information is processed. This relationship is bi-directional; temperament can cause a bias, but a bias can also cause a certain temperament.

How do personality traits, emotions and mood states interact?

A tricky problem is how to separate the effects of temperament on cognitive processing from the effects of the current mood state. Certain traits are strongly correlated with the tendency to experience certain emotions and mood states. As a result, many of the temperament influences can actually be caused by a mood state or emotions. It is likely that traits and mood states work together to determine the strength of affect-cognitive relationships.

Cognitive processing can be directly modulated by variations in properties and temperament. In addition, traits can first modulate emotions and mood states, which in turn influence cognitive processing. This is therefore an indirect connection, whereby properties influence the intensity of the mood state. Finally, properties and mood states can therefore interact with each other to strengthen cognitive biases.

Perception and attention

Various forms of arousal ensure that an organism is alert for certain information. Attention works in a much more specific way by highlighting the most important sources of information in a situation. Most attention is given to negative stimuli. Personality, however, can again modulate which stimuli (positive or negative) receive a certain amount of attention. Attention works through the posterior attention system, which consists of three subsystems: disengage the current focus, move to a new location and engage with the new location. This system is reflexive and automatic. In addition, there is the anterior attention system, which is responsible for more voluntary and flexible control of attention. The anterior system can modulate the activity of the posterior system, so that we are not always influenced by all the little things that happen around us.

Personality congruent biases

A study found that positive stimuli are processed faster than negative stimuli. In addition, it was found that people with a higher score on the extraversion trait were even faster in processing these positive stimuli. Strangely enough, no connection was found between the trait of neuroticism and the processing of negative stimuli, while this was expected. Another study also found a relationship between extraversion and positive attentional bias, even when checked for current mood.

Another study found that extroverted people were slower to disengage their attention from positive information, while introverted people were slower to move their attention away from negative information. This effect was further enhanced by the people (both introverted and extroverted) who also scored high on neuroticism. This indicates that both extraversion and neuroticism have a very interactive influence on the responses to affective stimuli.

What is the relationship between neuroticism and selective processing of negative information?

For the investigation into selective processing of negative information, a disruption task is often performed, in which people have to do an adapted Stroop test with neutral and negatively charged words. For example, people who are depressed take longer to name the color of a word that is negative than of a neutral word. People who are afraid of spiders take much longer to name the color of spider-related words than other general negative words. This therefore indicates that performance on the Stroop test is mainly disturbed when the negative words are related to the specific concerns or characteristics of a person. The same results were found in dichotic listening tasks, where negative information was offered in the unwary ear. However, these findings may also have to do with difficulty in diverting attention from negative information, rather than a tendency to pay more attention to this information.

To circumvent this problem, attentional probe paradigms were used. A few stimuli are shown at two locations on the screen, one of which is neutral and one negative. A probe is then shown at one of the two locations to which the participant must respond. It appears that the response time on the probe when it appears at the location of the negative stimulus is only accelerated in people who scored high levels of trait anxiety. These results support the hypothesis that a high score on neuroticism is accompanied by increased attention towards negative stimuli.

Another study also found that the effects of personality on processing are enhanced when people are in a frightened mood. So people who score high on neuroticism had a stronger tendency to selectively pay attention to negative material when they felt anxious.

It is likely that personal traits influence the threshold above which attention is given to negative, dangerous stimuli. When the threat is very strong, these personal traits have much less effect and the impending stimulus attracts everyone's attention.

Do personality traits influence the orienting or the holding of attention?

An important theoretical problem is whether the findings in the attentional probe task show that attention is being drawn towards the threat, or that the results reflect a struggle to disengage from the threatening material.

Posner found evidence that anxiety- related differences are caused by disengaging the attention of an impending stimulus. In this experiment, people were given a cue in the form of a neutral or angry face, either on the left or on the right of the screen. After this, the target stimulus appeared, sometimes at the same location as the cue, sometimes just on the other side. When the target appeared at the same location, there were no differences between the low and high anxiety groups. However, when the target appeared on the other side, it turned out that the people who scored high on anxiety took longer to respond to the target when the cue was an angry facial expression. However, these results cannot indicate whether attention is also drawn more quickly to the threatened stimuli.

A different kind of experiment is needed to solve this problem. A number of studies have found that people who are socially anxious are more likely to detect angry faces and people who are afraid of spiders or snakes are more likely to detect spider and snake-related stimuli. This indicates that a general tendency to detect a threat can be reinforced by individual differences in personality. Other studies did not find these results, but the influences of these individual differences might be stronger with specific phobias, but not with more general variations in trait anxiety.

Research is also often done that uses attentional blink. This means that a series of stimuli is displayed in rapid succession. When a stimulus is shown immediately (within 500ms) after another target stimulus, this second stimulus escapes attention. However, when this second stimulus is affectively salient (for example, its own name), the attentional blinking effect is canceled out. It appears that even when this second stimulus is strongly negative, the attentional blinking effect is greatly reduced and the words are often noticed. It is striking that patients with damage to the amygdala do suffer from the attentional blink, regardless of the valence of the second stimulus. This indicates that the effect is driven by influences from the amygdala.

Subsequent research found that attentional blink occurs for both happy and anxious faces, but that people who score higher on trait anxiety suffer significantly less from attentional blink on anxious faces. This pattern indicates that attention is more quickly assigned to negative stimuli as trait anxiety and neuroticism increase.

In summary, it seems that personal traits (especially neuroticism) have an important influence on the functioning of the posterior attention system. Anxious or neurotic people (especially when they score low on extraversion) are slow in disengaging the attention from threatening locations. Extroverts (especially if they score high on neuroticism) are slower to move their attention away from rewarding locations. In addition, there is some evidence that people who score high on trait anxiety are more likely to direct attention towards threatening stimuli and less likely to miss threat-related stimuli under difficult processing conditions.

Personality traits and attentional control

A number of studies have investigated the role of personality traits in modulating the anterior attention system. It was found that anxious people with poor attention control had difficulty with moving their attention away from threatening locations. Anxious people with good attention control, however, were better able to shift attention from threatening to safe locations. This indicates that control over attention differs between people and that this is independent of the degree of anxiety or neuroticism.

Memory

Temperament can affect the type of material that is best remembered. For example, extrovert people remember more positive words than negative or neutral ones. Neurotic people, on the other hand, remember more negative words. These effects were still found to be significant when checked for current mood state. However, when a certain mood state is actively caused, this mood state becomes a stronger predictor of the kind of words that are being remembered.

What are the effects of depression and anxiety on recall?

Temperament can affect autobiographical memory. For example, it has been found that depressed people tend to recall more negative autobiographical memories. It appears to be more difficult to demonstrate selective memory for negative material in people who score high on anxiety. This is striking because measurements for depression and anxiety often correlate strongly with each other.

It is generally found that only when superficial coding is needed, there is a selective bias that is caused by trait anxiety. When a deeper analysis is needed to perform a task, there was no question of a selective memory advantage. These findings indicate that depression and anxiety have different influences on explicit memory. Because depression is associated with mood state control problems and excessive worrying about negative events, it seems that individual differences in depression are related to the selective retrieval of negative memories.

What is the influence of mood repair strategies on selective retrieval of memories?

Someone's motives are of great importance in determining what kind of memories are retrieved. From this perspective, memories are seen as dynamic aspects of a developing individual, whereby they are actively retrieved to maintain or change a current mood state. The self-regulation of mood states is therefore an important motive.

There is evidence that recalling certain types of memories can regulate mood states. When a sad mood state is caused and people are then asked to recall two strong emotional memories, the first memory is often a sad one (mood congruence). The second reminder is determined by how high someone scores on depression: depressed people recall a sad reminder, but non-depressed people tried to recall a positive reminder to improve their mood. It is clear that these differences and the use of 'mood repair strategies' can play an important role in the mood-congruence effects of memory.

Interpretation and judgment

Based on the differences in temperament, we could expect strong effects of personal traits on the interpretation of ambiguous situations ("Are they laughing at me or with me?"). Indeed, it has been found that when people are told a series of homophones (words that sound the same but can have different meanings; die - dye), those who score high on trait anxiety are more likely to interpret the negative meaning. However, this effect can also be caused by a response bias; maybe both meanings come to mind, but frightened people express the negative meaning sooner.

To get around this problem, a priming task was used with homographs (words with the same spelling that have different meanings; arms, stroke, etc.). There is no question of a response, so it was found that there is indeed a difference in interpretation; there was a greater priming effect for the negative meaning among anxious participants.

Research with homophones on extraversion and neuroticism found that extroverted people were more likely to interpret ambiguous information in a positive way, while neurotic people were more inclined to interpret ambiguous information in a negative way.

What are the estimates of risk?

When people judge how likely it is that a certain event will occur in the future, they usually use the ease with which they can form a mental model of the event as a benchmark. This is called the availability heuristic or simulation heuristic. In general, it appears that people who score high on extraversion predict that positive events are more likely. People who score high on neuroticism predict that negative events are more likely.

If people can come up with a reason more quickly why a certain event would occur, they also estimate this event as more likely. People high on neuroticism come quicker to a reason why a negative event would occur and also saw such an event as more likely. The likelihood of positive events is underestimated by these people. Conversely, another study also found that extroverted people were more likely to expect positive events to occur. This effect is independent of the current mood.

These results therefore indicate that stable personal traits such as extraversion and neuroticism cause biased affective assessments. These characteristics can influence the current interpretation of ambiguous events and the estimated probability of future events.

Neural reactivity

Fundamental differences in the reactivity of the approach and avoidance systems would underlie personality building. For example, extraversion would strongly correlate with psychophysiological reactivity to positive events (reward signals) and neuroticism with psychophysiological reactivity to negative events (punishment signals). Results found indicate that hypertonic activation of the limbic system is involved in neuroticism, with a constant low tolerance for aversive stimuli.

Neuroimaging studies

fMRI studies found that reactivity due to positive stimuli strongly correlated with the score that a participant had on extraversion in both cortical and subcortical areas. Activation due to negative stimuli strongly correlated with scores on neuroticism in left frontal and temporal cortical areas. These findings indicate that there are indeed individual differences in brain activation associated with certain personality traits.

The direction of causality is not always clear in studies on cognitive biases and neural factors. For example, different patterns of brain activation may result in different subjective interpretations of the same objective experience. However, it can also be the other way around that the brain processes themselves are biased by differences in cognitive interpretations.

It was also found that the amygdala is active in everyone, regardless of personality traits, in response to anxious stimuli. The amygdala response to positive stimuli (happy faces) was very inconsistent. It turned out that the activation in this case depended on the score for extraversion; a higher score on extraversion meant a higher (approach-related) activation of the amygdala. These individuals are more likely to use approach related neural systems, which are associated with positive emotions due to reward related stimuli. Neuroticism appears to be able to modulate the strength of amygdala activation in response to negative stimuli.

A fMRI study found that the degree of ACC activation due to positive stimuli varied as a function of extraversion, but did not vary as a function of positive mood. In contrast, the ACC response to negative words varied significantly as a function of negative mood, but did not vary as a function of neuroticism. These results show that solid personality traits and more short-lived mood states can have different effects. It is speculated that negative mood modulates the activation of the ACC, thereby improving sensory selection and stimulus anticipation. This fits well with the findings of improved cognitive processing for negative stimuli. In contrast, the fact that ACC activation on positive words is a function of extraversion suggests that there is a neural mechanism for more long-lasting and consistent differences between people.

Which role do genes play in individual differences in emotionality?

It has long been known that genes make an important contribution to individual differences in personality. Thus genetic factors contribute 40-60% to the explained variance of extraversion and neuroticism. Because there are so many different genes that underlie personality, there are probably no specific genes that are responsible for emotional disorders such as depression or anxiety. There may be genes that are underlying certain behavioral dimensions, such as neuroticism, extraversion, etc.). A strategy to investigate this would be to analyze how variations in some genes affect specific behavioral dimensions or personality traits.

To find the genes that influence this, there must be looked at polymorphic genes. These are genes of which there is a variant (allele ) that can be linked to a specific trait. This polymorphism must be relevant to the trait, so if high scores on neuroticism are associated with low levels of serotonin, alleles that result in reduced serotonin are clear candidates.

What is the relationship between serotonin and variation in emotional reactivity?

The serotonin transport gene (5-HTT) has two variants: S and L. Everyone has two variants of the gene, one that comes from the father and one from the mother. This means that someone can be homozygous for S (S / S), homozygous for L (L / L) or heterozygous (S / L). It appears that when someone carries at least one S allele (i.e. S / S or S / L), this already leads to significantly higher scores on neuroticism.

If polymorphism of the 5-HTT gene is associated with neuroticism, it should also be associated with individual differences in how the brain responds to anxiety-related stimuli. People who carry the S allele also have a greater activation of the amygdala in response to frightened and angry faces than people who do not carry the allele. In addition, greater activation of the vmPFC was found among carriers of the S allele when negative information was processed.

However, it appears that the difference in activation of the amygdala in S-allele carriers is actually due to a reduced activation with neutral stimuli, rather than an actually increased activation with negative stimuli. Nevertheless, over time, S-allele carriers experience a relatively greater activation of the amygdala in response to negative stimuli than L-homozygotes.

It was also found that a reduction of serotonin in the brain leads to an increase in reactivity of the right amygdala in response to anxious faces, as a function of individual differences in sensitivity to threat. The reduction in serotonin did not have the same effect on everyone, but those with a high score on neuroticism (and therefore probably an S allele) became very reactive for aversive stimuli.

Other studies have looked at polymorphism in the human tryptophan hydroxylase-2 gene (hTPH2) in terms of amygdala activation by negative stimuli. This gene influences the amount of serotonin that is produced in the brain. The different alleles here are G and T.

It appears that carriers of the T-allele showed more bilateral activation of the amygdala in response to anxious and sad facial expressions than G-homozygotes (checking for the genotype of 5-HTT). However, it was also found that carriers of the T allele had a higher activation of the amygdala in response to happy faces. The explanation for this is that the gene modulates the activation of the amygdala as a more general function of arousal rather than negative valence.

What is the relationship between dopamine and variation in emotional reactivity?

Early research was done into genetic polymorphisms of the dopamine D4 receptor gene (D4DR). Here again a distinction is made between an L and an S allele. The study found that those who carried the L allele scored significantly higher on novelty seeking compared to the S-homozygotes. These L allele carriers also scored higher on extraversion, but lower on conscientiousness. These studies provide evidence for a link between polymorphism of the D4DR gene and novelty seeking.

An important characteristic of people who score highly on extraversion is that they are sensitive to rewards. Dopamine very strongly involved in the reward system in the brain. The dopamine D2 receptor gene (D2DR) in particular seems to be important for this. The A1 allele in particular is associated with lower amounts of D2 receptors in the brain and therefore with clinical disorders of reward sensitivity and alcoholism.

A fMRI study therefore showed that the reward response was higher among those who scored high on extraversion than those who scored low on it. Wearing an A1 allele indeed caused a reduced reward response. A reduced amount of D2DR receptors in the brain therefore leads to a reduced sensitivity to rewards.