Towards consistent reporting of sample characteristics in studies investigating the biological mechanisms of romantic love [Reviewed version published in Frontiers in Pscyhology]

Abstract

In this non-systematic review, we consider the sample reporting practices of 42 studies up to and including 2021 investigating the biological mechanisms of romantic love (i.e., 31 neuroimaging studies, nine endocrinological studies, one genetics study, and one combined neuroimaging and genetics study). We summarize how they report sex/gender, age, romantic love, relationship duration/ time in love, and sample descriptors. We then outline the case for promoting comparability and the ability to determine generalizability in future studies. We conclude by presenting ideas about how best to report sex, age, romantic love characteristics, relationship status, relationship duration, time in love, type of unrequited love, sexual activity, cultural characteristics, student status, and method-relevant descriptors. If our ideas are adopted, in part or in whole, we expect the comparability of studies to increase. Adopting our ideas will also make it easier to make an assessment of the generalizability of findings.

Romantic love evolved by co-opting mother-infant bonding

“…Romantic love is sometimes referred to as “passionate love,” in the field of psychology ( Feybesse and Hatfield, 2019 ). I use the term “romantic love” because that tends to be the name conferred in the fields of biology (see Bode and Kushnick, 2021 ; Bode and Kowal, 2022 ). Romantic love precedes companionate love (see Hatfield and Walster, 1985 ), which is the love felt less intensely among individuals in an established pair bond.…”

“…Most of the human biological evidence (see Bode and Kowal, 2022 for a comprehensive list of neuroimaging, endocrinological, and genetics studies investigating romantic love) comes from cross-sectional studies using repeated measures designs of people experiencing romantic love or comparing groups experiencing romantic love with groups not experiencing romantic love (i.e., singles or people in a relationship for a long time). Seminal fMRI studies tend to ask participants in love to view an image of their loved one and compare this with viewing an image of a familiar other, although other designs and stimuli do exist (see Bode and Kowal, 2022 ).…”

“…Most of the human biological evidence (see Bode and Kowal, 2022 for a comprehensive list of neuroimaging, endocrinological, and genetics studies investigating romantic love) comes from cross-sectional studies using repeated measures designs of people experiencing romantic love or comparing groups experiencing romantic love with groups not experiencing romantic love (i.e., singles or people in a relationship for a long time). Seminal fMRI studies tend to ask participants in love to view an image of their loved one and compare this with viewing an image of a familiar other, although other designs and stimuli do exist (see Bode and Kowal, 2022 ). Endocrinological studies tend to measure circulating peptides in blood in a group of individuals experiencing romantic love and a control group of individuals not experiencing romantic love, although a small number of endocrinological studies (i.e., Marazziti et al, 1999 ; Marazziti and Canale, 2004 ; Emanuele et al, 2006 ) have identified these differences using longitudinal methods.…”

“…The scientific literature around romantic love is limited. There have only been about 45 empirical studies of the biology of romantic love ( Bode and Kowal, 2022 ). The number of studies specifically investigating the psychology of romantic love is probably in the same vicinity (although a large number do include romantic love as a variable of interest).…”

The Theory of Co-opting Mother-infant Bonding Informs a New Approach to the Science of Romantic Love (Published in Frontiers in Psychology: https://www.frontiersin.org/articles/10.3389/fpsyg.2023.1176067/full)

“…Since Bartel and Zeki's (2004) seminal comparison between romantic and maternal love, there has been three meta-analyses of fMRI studies of romantic love (Cacioppo et al, 2012b;Ortigue et al, 2010;Shih et al, 2022), more than 30 neuroimaging studies of romantic love (Bode & Kowal, 2022, May 26), 2 meta-analyses and least 12 fMRI studies into maternal love (see Rigo et al, 2019;Shih et al, 2022). Further targeted neuroimaging studies could substantially contribute to a better understanding of neurobiological and neuroendocrinological systems associated with both motherinfant bonding and romantic love.…”