Neurobiological underpinning of trait emotional intelligence

The neurobiological underpinning of ability EI was discussed in our previous blog.  Here we present research about the trait EI –  brain relationship. The research is grounded in theoretical assumptions on emotional processes, their influence on decision-making and brain areas involved in their normal and pathological functioning. Central to this are two assumptions: (i) the role of hemispheric lateralization in emotions and (ii) the somatic marker hypothesis.

The role of hemispheric lateralization in emotions has been the subject of interest for several decades (Harmon-Jones et al., 2010). The asymmetric involvement of prefrontal cortical regions in positive affect (or approach motivation) and negative affect (or withdrawal motivation) was suggested over 70 years ago based on lesion studies of individuals who had suffered damage to the right or left anterior cortex. The findings were later supported by research, which mainly employed the Wada test. The test involves injecting amytal into one of the internal carotid arteries and suppressing the activity of one hemisphere. Injections in the left side produced depressed affect, whereas injections in the right side produced euphoria. These findings have been also confirmed in non-human animals, ranging from great apes and reptiles to chicks, amphibians and even spiders. Summarizing the research on frontal lateralization, Harmon-Jones et al. (2010) concluded that there is robust evidence for the claim that greater left as compared to right frontal activity is associated with approach motivational processes, whereas the reverse hypothesis (withdrawal-right-frontal-region) in the motivational direction model was not as extensively investigated.

Support for a frontal asymmetry in relation to the level of trait emotional intelligence comes from the study by Mikolajczak et al. (2010). They showed that higher trait EI scores were associated with a greater relative left-sided frontal activation determined with EEG during a resting eyes open/closed condition. The effect size for the global score was 0.82, which is considered to be a large effect according to Cohen’s norms for social sciences. The strongest relationships were obtained with the factors ‘‘sociability” and ‘‘self-control”. Mikolajczak et al. (2010, p. 179) concluded: “[…] it seems that the construct of trait emotional intelligence might be particularly well-suited to capture the socio-emotional dispositions affected by frontal EEG asymmetries”.

The second theory that shaped research into the trait EI-brain relationship was the somatic marker hypothesis which suggests that several brain structures and operations are required for the normal function of decision-making (Damasio, 1999). Central in this process is the amygdala triggering somatic states activated by primary[1] and secondary[2] inducers. Representations of these states can be sub-conscious (brainstem) or perceived as a feeling when brought to the level of insular (SI, SII) and posterior cingulate cortices. All of these somatic states, which can be either positive or negative, are then summed into one overall somatic state providing a substrate for biasing our decision-making. When this process is carried out in the striatum, the person acts without a conscious decision to do so. In contrast, decision-making is under volitional control when this process takes place at (i) the level of the lateral orbitofrontal cortex - the person favors a plan of action and (ii) at the anterior cingulate - the person executes a plan of action. Thus, the conceptual nexus between the somatic marker hypothesis and emotional intelligence is mainly in the way the latter is defined – an array of interrelated emotional, personal and social competencies determining the ability to actively and effectively cope with daily demands.

Support for the somatic marker hypothesis comes from lesion studies. Bar-On et al. (2003) showed that only patients with lesions in the somatic marker circuitry revealed low emotional intelligence and poor judgment in decision-making as well as disturbances in social functioning, in spite of normal levels of cognitive intelligence  and the absence of psychopathology. Further support was provided by neuroimaging studies employing different methods such as EEG (Craig et al., 2009) and fMRI - showing also activity in support of the neural efficiency hypothesis (Killgore and Yurgelund-Todd, 2007). Voxel-based morphometry correlations between the level of the EI interpersonal factor and regional gray matter density were reported for an anatomical cluster that included the right anterior insula and the medial prefrontal cortex (Takeuchi et al, 2011). Similar brain areas in relation to trait EI were also observed in studies using resting-state functional connectivity (Takeuchi et al., 2013a) and diffusion tensor imaging (Takeuchi et al., 2013b).

In a recent review paper by Hogeveen et al. (2016), a miniature meta-analysis was conducted to determine whether any brain regions have been ‘reliably’ associated with EI. Regions-of-interest were manually constructed based on the relevant neuroimaging tables reported in the reviewed papers, and these regions-of-interest were placed on a glass brain for visualization. The resulting figure revealed a striking level of inconsistency in brain regions that have been associated with EI using traditional measures. To overcome these problems, the authors tried to map different emotional intelligence factors with findings obtained in lesion studies. The table below summarizes the obtained findings.

EMOTIONAL COMPONENT	BRAIN AREA INVOLVED
Recognizing Emotional States in the Self and Others Emotional Awareness	Anterior Insula (AI) Anterior Cingulate Cortex (ACC) Ventromedial Prefrontal Cortex (vmPFC)
Emotion Recognition	Amygdala Ventromedial Prefrontal Cortex (vmPFC)
Using Emotions to Facilitate Thought and Behavior Empathy and Prosocial Behavior	Ventrolateral Prefrontal Cortex (vlPFC)
Emotional Memory	Medial temporal lobes that encompass the amygdala, hippocampus, and perirhinal cortex
Understanding How Emotions Shape One's Own Behavior and the Behavior of Others	Ventromedial Prefrontal Cortex (vmPFC)
Emotion Regulation	Ventromedial Prefrontal Cortex (vmPFC)

These neurobiological findings have been used as evidence to distinguish EI abilities from cognitive intelligence. According to Hogeveen et al. (2016), such a separation seems untenable since the latest advances in psychology and neuroscience have reliably suggested that emotion and cognition are very much integrated in the brain and together they shape goal-directed behavior. In this direction points a recent study by Yao et al. (2017, published online) utilizing voxel-based morphometry  to investigate the neural structures underlying critical thinking disposition in relation to the level of emotional intelligence. The central finding was that: “Specifically, critical thinking disposition was associated with decreased GMV of the temporal pole for individuals who have relatively higher emotional intelligence rather than lower emotional intelligence. The results of the present study indicate that people who have higher emotional intelligence exhibit more effective and automatic processing of emotional information and tend to be strong critical thinkers.”

References

Bar-On, R. (2003). Exploring the neurological substrate of emotional and social intelligence. Brain, 126(8), 1790–1800. https://doi.org/10.1093/brain/awg177

Craig, A., Tran, Y., Hermens, G., Williams, L. M., Kemp, A., Morris, C., & Gordon, E. (2009). Psychological and neural correlates of emotional intelligence in a large sample of adult males and females. Personality and Individual Differences, 46(2), 111–115. https://doi.org/10.1016/j.paid.2008.09.011

Damasio, A.R. (1999) The feeling of what happens: body and emotion in the making of consciousness. New York: Harcourt Brace.

Harmon-Jones, E., Gable, P. A., & Peterson, C. K. (2010). The role of asymmetric frontal cortical activity in emotion-related phenomena: A review and update. Biological Psychology, 84(3), 451–462. https://doi.org/10.1016/j.biopsycho.2009.08.010

Hogeveen, J., Salvi, C., & Grafman, J. (2016). “Emotional Intelligence”: Lessons from Lesions. Trends in Neurosciences, 39(10), 694–705. https://doi.org/10.1016/j.tins.2016.08.007

Killgore, W. D., & Yurgelun-Todd, D. A. (2007). Neural correlates of emotional intelligence in adolescent children. Cognitive, Affective, & Behavioral Neuroscience, 7(2), 140–151.

Mikolajczak, M., Bodarwé, K., Laloyaux, O., Hansenne, M., & Nelis, D. (2010). Association between frontal EEG asymmetries and emotional intelligence among adults. Personality and Individual Differences, 48(2), 177–181. https://doi.org/10.1016/j.paid.2009.10.001

Takeuchi, H., Taki, Y., Nouchi, R., Sekiguchi, A., Hashizume, H., Sassa, Y., … Kawashima, R. (12/2013a). Resting state functional connectivity associated with trait emotional intelligence. NeuroImage, 83, 318–328. https://doi.org/10.1016/j.neuroimage.2013.06.044

Takeuchi, H., Taki, Y., Sassa, Y., Hashizume, H., Sekiguchi, A., Fukushima, A., & Kawashima, R. (2011). Regional gray matter density associated with emotional intelligence: Evidence from voxel-based morphometry. Human Brain Mapping, 32(9), 1497–1510. https://doi.org/10.1002/hbm.21122

Takeuchi, H., Taki, Y., Sassa, Y., Hashizume, H., Sekiguchi, A., Nagase, T., … Kawashima, R. 

(05/2013b). White matter structures associated with emotional intelligence: Evidence from diffusion tensor imaging. Human Brain Mapping, 34(5), 1025–1034. https://doi.org/10.1002/hbm.21492

Yao, X., Yuan, S., Yang, W., Chen, Q., Wei, D., Hou, Y., … Yang, D. (2017). Emotional intelligence moderates the relationship between regional gray matter volume in the bilateral temporal pole and critical thinking disposition. Brain Imaging and Behavior. https://doi.org/10.1007/s11682-017-9701-3

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[1] Primary inducers are unconditioned stimuli that are innately set as pleasurable or aversive, or conditioned stimuli. When conditioned stimuli are present in the immediate environment, a somatic response is automatically generated.

[2] Secondary inducers are units generated by recall or by thought, eliciting a somatic response when brought to memory.