The Multifaceted Effects of Serotonin Transporter Polymorphism (5-HTTLPR) on Anxiety, Implicit Moral Attitudes, and Harmful Behaviors

Abstract

Morality is fundamentally human in nature. Regardless, and even when moral norms seem to work toward the common goal of human cooperation, which morally contentious behaviors are permitted and which are prohibited vary across populations. Because of this occurrence, much scientific debate has revolved around the notion that this phenomenon might be explained by the interaction between genes and environment. Alongside, whether the principles cementing the bases of morality are intuition- or reason-based is another question that has been raised. However, previous research addressing these topics used explicit measures to probe moral attitudes, thus being the participants able to intentionally modify or disguise their honest responses. What’s more, while the 5-HTT gene was found to be associated with anxiety, morality, and even cultural structures, a single genotype–phenotype linkage cannot be established without considering the multifaceted effects of the 5-HTT gene on gene–behavior interactions. In order to explore the role of genetics on modeling moral attitudes and behaviors, we genotyped the 5-HTTLPR in 114 healthy volunteers and subsequently assessed their explicit justice sensitivity (Justice Sensitivity Inventory) and moral permissibility judgments, as well as their implicit moral attitudes [moral implicit association task (mIAT)]. Results revealed that 5-HTTLPR short-allele carriers had significantly lower mIAT reaction times when answering correctly and were less compliant on harming another person even when harm or death would inevitably occur anyway to this other individual. With these preliminary results, we can first see how it does not have to be a matter of vouching for a rationalist versus an intuitionist model of moral judgment, but rather being moral judgment an outcome of the different variants of the 5-HTTLPR polymorphism affecting the way in which individuals engage contrastingly with moral issues.

Action Modulates the Conscious Reasoning Process of Moral Judgment: Evidence From Behavior and Neurophysiology

“…The few participants who agree with the doing harm resolution for consequentialism have to recruit cognitive control to overcome emotional interference, leading to longer reaction times to judgment for the doing harm condition than for the allowing harm condition. Therefore, our behavior data concerning participant's selection and reaction time may strongly support the dual-processing theory in that moral judgments are the product of two competing processing systems; one is a fast and automatic emotional system driving deontological judgments, and the other is a slow and controlled cognitive system favoring utilitarian judgments (Greene et al, 2001(Greene et al, , 2004(Greene et al, , 2008Martínez et al, 2020).…”

A genome-wide association study of social trust in 33,882 Danish blood donors

“…The genes SLC6A4 26 , 27 , OXTR 24 , 28 – 30 , CD38 29 , 31 and AVPR1A 32 have previously been associated with social trust or related social behavior phenotypes through genetic studies of different kinds. To test whether these observations replicated in our data, we generated regional association plots centered around these genes.…”

“…Several studies have also explored candidate genes that, based on their previously observed function, are likely to play a part in pro-social and trust behaviors. Albeit inconsistent, results have drawn attention to the genes encoding the serotonin transporter ( SLC6A4 ) 26 , 27 , the oxytocin receptor ( OXTR ) 24 , 28 – 30 , CD38 29 , 31 , and the arginine vasopressin receptor 1A ( AVPR1A ) 32 .…”

Association of COMT, BDNF and 5-HTT functional polymorphisms with personality characteristics

“…The short variant draws less serotonin back to the presynaptic neuron. When it is set again to the long (L) version, there is an overload of serotonin in the synaptic cleft that keeps stimulating, in this way, the serotonin receptors [66]. Afterwards a single nucleotide polymorphism (SNP) A → G (rs25531) has been disclosed inside the sixth repeat of the S-and L-variants.…”