The problems in social representations of scientific theories are blindingly obvious. As audiences simply absorb, in an impoverished and lessened form, the information and ideas which stem from scientific research, as depicted on television or in newspapers, real knowledge is diluted, distilled, and yet is often accepted as truth by the general population. According to Massimiano Bucchi (1998) the media is a ‘dirty messenger’ for science wherein factual and scientific information is represented in a simpler, weaker or distorted way to a lay public who merely find science ‘too difficult’.
The current article ‘It’s not you dear, it’s me: the genetic reason why some men are just born to cheat’ provides an excellent example of how knowledge is elaborated and manipulated at the popular level and given greater concreteness and relevance. This report will to some degree critically evaluate the above mentioned article as printed in The Times newspaper, September 2, 2008 issue, and will consider the conclusions reached by its author Mark Henderson, the Science Editor for the publication. Additionally, it will draw upon other existing sources in the literature in order to substantiate or falsify the claims made.
In evaluating a piece of journalistic writing such as the one presented by Henderson, it is crucial to consider the accompanying linguistic arrangement of the articles content, and particularly, the articles title, since it is this that will firstly seduce the reader, drawing him into the commentary. The heading ‘the genetic reasons why some men are just born to cheat’ is a somewhat misleading one. Key words, such as ‘genetic’ are de-contextualised and are carelessly linked with words related to cheating and the notion of infidelity. In fact, the central study (Walum, Westberh, Henningsson, Reiss, Igl, Ganiban, Spotts, Pedersen, Eriksson & Lichtenstein, 2008) that is referred to in this article and what underpins the very foundation of the commentary, does not deal with infidelity, but rather marital quality, dissatisfaction and crisis.
The Henderson article goes on to make a number of claims and suggests that man’s tendency to be unfaithful may be influenced by his genes, the basic unit of heredity transmission from one generation to the next. Further to this, those men who inherit a specific genetic variant 334, which may affect the hormone receptor for vasopressin are more likely to have weaker relationships, and marital problems than men who do not.
This claim is not as unrealistic as one might expect, since a wealth of previous empirical research has identified different genes that influence a social behaviours in a number of species, including flies (Greenspan & Ferveur, 2000), mice (Pfaff, 1999), birds (Clayton, 2000b), fish (Hofmann & Fernald, 2000), ants (Krieger & Ross, 2002), and bees (Robinson, 2002b) as well as humans. Perhaps more relevant the current discussion is a study of 1600 pairs of female twins carried out by the Twin Studies Research Unit at St Thomas’ Hospital, London. It revealed that genetic factors have a significant impact on how likely women are to cheat on their partners and how many sexual partners they are likely to have (Cherkas, Oelsner, Mak, Valdes & Spector, 2002). Findings such as these undoubtedly lend weight to Henderson’s assertions which he courageously expresses in the article without any real explanation of the scientific implications.
To clarify, genes do not specify behaviour directly, but instead encode molecular products that build and govern the functioning of the brain through which behaviour is expressed. Brain development, brain activity and behaviour all depend on both inherited and environmental influences and research suggests that social information can alter brain gene expression and behaviour (Shanahan & Hofer, 2005). Furthermore, all tissues and organs in the body consist of cells.
The specialised functions of cells and how they interact determine the functions of those organs. One particular cell, the nerve cell consists of several common parts, such as the soma, dendrites and axon. It is within the neuronal membrane of these cells, inside a centrally located spherical nucleus where chromosomes, which contain the genetic material deoxyribonucleic acid (DNA), are located. Human DNA consists of 20,000 to 25,000 genes in total and it is the ‘reading’ of the DNA that is known as gene expression. The final product of gene expression is the synthesis of molecules called proteins, the building blocks of which are amino-acids.
Henderson implicates a particular hormone called vasopressin and its receptors in his presentation of reasons for why men might commit infidelity but fails to provide any useful definition of these key terms. Vasopressin is a 9 amino-acid peptide that is synthesized principally by the magnocellular neurons of the paraventricular and supraotic nuclei in the hypothalamus, and released into the bloodstream from within the brain, from the dendrites, stomata, and axon terminals of neurosecretory neurons in the posterior pituitary gland. The gene for vasopressin is found on chromosome 20 in humans (Vincent & Fuhong, 2008) with its cell surface receptors distributed in various brain regions (Landgraf & Neumann, 2004).
The peptide vasopressin, along with the similarly structured hormone, oxytocin, is released within the brain following chemical depolarization of target cells and then exerts its effect by binding to receptors. Three specific receptors for vasopressin have been identified – V1 (or AVPR1a), V2, and V3 – however the binding process occurs more rapidly for AVPR1A receptors (Vincent & Fuhong, 2008).
Henderson reports that vasopressin and AVPR1A play an important role in social behaviour, pair bonding and sexual attachment and whilst these claims can be empirically supported by a number of studies involving neuropeptide receptor mapping for example, vasopressin is best known for its effects on water regulation, body temperature, and is known to be involved with insulin release (Mutlu & Factor, 2004), and memory (Weingartner, Gold & Ballenger, 1981).
However, a large body of work firmly establishes a role for vasopressin and its receptors in social behaviours such as social recognition (Bluthe & Dantzer, 1992) communication (Goodson, 1998) aggression (Ferris, 2005), infant mother attachments and paternal care (Wang, Ferris &De Vries, 1994). It is the study of pair bonding in voles, a mouse sized rodent that is posed by Henderson as the backbone in previous research on infidelity. Pair-bonding is the monogamous relationship between sexual partners and the study of such bonds in voles provides an example of the evolution of social behaviour associated with changes in gene regulation that influence patterns of gene expression (Insel & Young, 2000).
By using a partner preference test, Getz and Carter (1996) found that prairie voles, that tend to live in pairs, are monogamous and show well-established behavioural preferences for their familiar partner (Williams, Catania & Carter, 1992) in contrast to their close cousin, the meadow vole, a highly promiscuous species of vole. Henderson reports that male prairie vole’s brains contain higher levels of vasopressin than meadow voles. Whilst this claim is supported (Carter & Getz, 1993) it is the development of specific agonists and antagonists for oxytocin and vasopressin receptors that have allowed for a better understanding of the specific contributions to physiology and behaviour that each peptide makes.
Pharmalogical studies as well as gene knock outs and transgenic animal studies, which involve the deliberate introduction of external or foreign DNA into the genome of an animal, have directly implicated oxytocin and vasopressin in the regulation of social behaviours. For example, a vasopressin antagonist administered to usually monogamous male prairie voles was found to block the development of partner preference and its associated aggression. Presumably, the vasopressin antagonist prevents the binding of the vasopressin and its receptor AVPR1A and therefore blocks the behavioural consequences of mating. Henderson’s reporting of another study in which ‘scientists enhanced the gene for the vasopressin receptor in meadow voles’, transforming them from promiscuous rodents to ‘loyal and attentive spouses’ further suggests that vasopressin levels are implicated in pair bonding behaviours.