What makes a Happy Brain?
Neuroscience of Happiness Part 1
“Happiness is the meaning and the purpose of life, the whole aim and end of human existence.” — According to Aristotle, a philosopher who would lay an important foundation for future scientific research into happiness. Aware of the high value of happiness, what followed were the questions of how to break down this abstract concept in order to grasp what it actually means to be happy and subsequently what processes are involved in achieving it. For a long time, scientists have been finding it difficult to define and measure happiness. But faced with this challenge, they were able to borrow useful insights from Aristotle’s philosophy and conceptually distinguish two components of happiness: hedonia and eudaimonia (Kringelbach & Berridge, 2010b). Translated into modern psychological terms, the former depicts a more transient state of pleasure while the latter refers to overall well-being. This distinction alone is very interesting because it implies that these aspects of happiness are not mutually exclusive, in fact one can experience short-lived pleasures without reporting general life satisfaction or well-being and vice versa.
The neural mechanisms of pleasure were first discovered over 60 years ago, when rats in an experimental setting continuously pressed levers that initiated electrical stimulations transmitted through implanted electrodes to certain parts of their brain (Olds & Milner, 1954) — specifically the septum and nucleus accumbens (Olds, 1956). As a result, the chemical most commonly associated with these regions, dopamine, was widely established as the main neurotransmitter of pleasure (Kringelbach & Berridge, 2010a). Crucially, this implied that in order to obtain a better understanding of happiness scientists had to study the neural processes underlying pleasure, the so-called hedonic hotspots in the brain. While these have traditionally been attributed only to subcortical regions such as the nucleus accumbens, ventral pallidum or brainstem (Kringelbach & Berridge, 2010a) modern neuroimaging techniques have enabled a more nuanced understanding of the brain’s widespread circuitry of pleasure (Davidson & Schuyler, 2015), including the involvement of orbitofrontal, cingulate, medial prefrontal, and insular cortices for instance when pleasure is anticipated or remembered (Kringelbach & Berridge, 2010a). Interestingly, the neural mechanisms underlying some fundamental and generally better understood pleasures like food and sex were found to overlap with more complex higher-order pleasures such as those evoked by money, art and music or social interaction, suggesting more common ground in the underlying neural processes than previously expected (Kringelbach, 2005; Kringelbach & Berridge, 2010a).
But to relate these hedonic processes to eudaimonia, the other component of happiness, scientists were required to make progress in the use of subjective self-assessments of well-being. Along with behavioral measures, these have subsequently provided valuable insights into the psychological mechanisms underlying happiness and changes in happiness, across contexts and individuals. At the same time, individuals’ self-reports have helped establish large-scale evidence of how well-being is distributed around the world and influenced by factors such as money or social interaction (Kahneman et al., 1999). In fact, this research has empirically shown how hedonia and eudaimonia correlate in happy people, with those rating their overall well-being as high also reporting a positive hedonic mood (Kringelbach & Berridge, 2010b).
