Investigating love from a scientific approach has slowly gained prominence today.  Most of the work is done through rigorous academic journals, or through pop psychology.  Fletcher et. al.’s textbook, The Science of Intimate Relationships, manages to look at the current literature and interweaves many disciplines to give a coherent picture of intimate relationships.  These disciplines include social psychology, developmental psychology, evolutionary psychology, anthropology, neuroscience, and sexual behavior.  Without getting bogged down with the jargon or advanced science, the book still takes an evidence-based approach in order to understand intimate relationships. 

For the purposes of this review, I will not go into the details of each theory presented in the book.  I will briefly mention the main themes, theses, or topics.  The book is composed of six parts.  Part one is the introduction in which the authors start with the disciplines to give the reader a foundation, mainly social and evolutionary psychology.  Part two investigates intimate relationships at the mind and body perspective.  The authors look at how certain emotional scripts help explain predictive behavior for the partners and why partners act and feel the way they do.  If, for example, Mary is having a bad day and she’s been in an intimate relationship with George, then George will know how to react to Mary’s emotion and behavior because they have both formed an emotional script together.

In terms of the body, the authors go through a vast amount of scholarship and explain how science has explained bodily changes and outcomes through evolution and psychology such as purpose of hormones levels in both sexes, evolutionary advantages to penis length and thickness, evolutionary advantages to orgasms, and sperm competition.  They keep up with the latest science about these topics and the debates behind them.  Yet, the authors present their own view (e.g., they argue that sperm competition did not play a huge role in hominid evolution).  They also present the latest studies by suppressing oxytocin (known as the “cuddle hormone”) in monogamous prairie voles to see if they would remain monogamous (the moles didn’t), and injecting oxytocin into promiscuous prairie voles to see if they would produce partner bonding (the moles did).  Other studies indicate that introducing oxytocin to humans has made people feel warmer towards people and less conflictual behavior.

There is also evidence that marriage negatively correlates with suicide.  Widowed men are 66 times more likely to commit suicide than married men, and widowed women are nines times more likely to commit suicide than married women.  Striking numbers indeed!

Parts Three, Four, and Five investigate the meaty part of all relationships: the beginning, duration, and end of intimate relationships respectively.  Starting with Part Three–the beginning of intimate relationships–the authors sketch out John Bowlby’s Attachment Theory.  In essence, Attachment Theory is an evolutionary theory of human social behavior and interaction.  How one is attached in infancy can explain how one interacts with others as an adult.  The authors explain: “The take-home message is that we are born to bond, but in different ways depending in part on our early social experience” (124).

Many students may initially approach physical attraction as subjective.  However, the authors give scientific accounts of universal standards that both men and women find attractive such as symmetry, waist-to-hip ratio on women, muscular athletic shape on men, and how these qualities relate to health which helps reproductive success.  Other examples include mating strategies and how the menstrual cycle depends upon when the women is most fertile.  Moreover, women are more attracted to more masculine features when she is most fertile, and women are deemed more attractive to men when she is most fertile through external features (such as a higher voice).

The authors contend that women would evolve to have a long-term mating strategy whereas men would evolve to have a short-term mating strategy.  In short, men value physical appeal more than women and are more likely to accept opportunities for casual sex.  But what is the evolutionary advantage of love?  “The standard evolutionary explanation for the origin of (romantic) love is that it evolved as a commitment device to keep parents of children together long enough to help infants survive to reproductive age” (158).  Romantic love may not be perfect in that there are cases of infidelity and divorce.  But romantic love does give our species the motivational push to invest in future offspring.  Love starts in a passionate frenzy: obsessive thoughts about the partner, intense longing for the partner, and lots of sexual activity.  After the relationship has become less frenetic, the relationship is characterized by commitment and deep companionship.  To keep and maintain a relationship, one must trust the other partner and engage in novel and exciting things. 

Part Four deals with maintaining relationships which is mainly done with communication.  It is no surprise when the authors concur with people’s intuitions that good communication helps with relationship.  Yet, the authors mention a puzzling study where “negative communication predicts relative increases in relationship satisfaction across time” (222).  To explain this, the authors mention that communication comes in two types: active and passive, and that active communication–though, at first harsh, like medicine, both negative and positive–can eventually yield positive results.  Indeed, passive communication, even in a positive way, is associated with decreasing relationship satisfaction over time.  Passive communication may resolve the tension in the short-term, but may not address the problem in the long run.  This strategy is not to say that one must continually be harshly honest in order to get the best relationship satisfaction.  Depending on the context (e.g., when the partner is stressed, whether the irritation is mild or severe, whether there is already good relational support), honesty and practical management need to be balanced in a delicate way.  Not too little support, but interestingly, not too much support either.  Why not too much support?  Possible explanations are that it lowers self-esteem, or it increases feelings of dependence to one’s partner which could increase perceptions of inequality.  The best type of support, the authors conclude, is where the support is invisible where the support is there, but not in an obvious sense.  Moreover, studies suggest that women are better at giving this invisible support.  To conclude the overall study of communication, “good communication requires the ability of both partners to ascertain, and be responsive to, the changing needs and demands specific to particular partners and interactions” (233).

When it comes to sex drives, men have stronger sex drive and are more likely to separate sex and love than women do.  This idea seems to follow the cultural conventions.  In romantic violence, “men and women initiate about the same number of violent acts in intimate relationships.  However, men use more serious forms of physical violence than women and are considerably more likely than women to inflict injuries” (270).  Relationship violence can be explained through evolutionary psychology and feminist theory by a general distal causes, and the social psychology can explain the situational, proximal causes.

Part Five deals with the ending of relationships.  With relationship dissolution, relationships and the dissolution are universal.  The common claim is that divorce happens 50% of the time (at least in America) and that this is a recent phenomenon.  However, divorce is a worldwide feature of relationships and the practice has been around since the Middle Ages in substantial numbers.  Divorce, then, seems to have been relatively tolerated throughout time.  The authors’ research explain that commitment is the trump card for relationship satisfaction.  They also offer some factors of how to recover from a relationship dissolution along with possible principled relationship therapies.  Overall, those who are oriented toward long-term mating are more likely to have the commitment and cognitive and behavioral strategies to maintain their relationships. 

Part Six is the authors’ conclusion by wrapping up what the science of love has given us and where it may lead.

This book is perfect for those who want to know more about the science of relationships without getting bogged down by the technical jargon.  However, there seems to be a glaring lacuna concerning homosexuality and the emergence of different type of relationships such as polyamory.  To get a wider field of what love is and to increase their data points, it would be advantageous if the authors would include relationships that are not part of the majority.  The science of homosexuality and polyamory is starting to gain some prominence.  It would be fruitful if the authors would look at the latest research and incorporate this into their next edition.

Despite these holes, this textbook is a great introduction to the science of intimate relationships by sketching the updated ideas and theories surrounding the field, and occasionally throw in some objections or critiques of the mainstream theories, not to cause confusion, but to show that the mainstream theories are not the end of the story.  This textbook would work well for a college class.

© 2014 Shaun Miller

Shaun Miller is a Ph. D. student in philosophy at Marquette University.  He has a BA in philosophy from Utah State University and an MA in philosophy from Texas A&M University.