Testosteron und Kooperation

Eine interessante Studie zur Wirkung von Testosteron auf Frauen:

Collaboration can provide benefits to the individual and the group across a variety of contexts. Even in simple perceptual tasks, the aggregation of individuals‘ personal information can enable enhanced group decision-making. However, in certain circumstances such collaboration can worsen performance, or even expose an individual to exploitation in economic tasks, and therefore a balance needs to be struck between a collaborative and a more egocentric disposition. Neurohumoral agents such as oxytocin are known to promote collaborative behaviours in economic tasks, but whether there are opponent agents, and whether these might even affect information aggregation without an economic component, is unknown. Here, we show that an androgen hormone, testosterone, acts as such an agent. Testosterone causally disrupted collaborative decision-making in a perceptual decision task, markedly reducing performance benefit individuals accrued from collaboration while leaving individual decision-making ability unaffected. This effect emerged because testosterone engendered more egocentric choices, manifest in an overweighting of one’s own relative to others‘ judgements during joint decision-making. Our findings show that the biological control of social behaviour is dynamically regulated not only by modulators promoting, but also by those diminishing a propensity to collaborate.

Quelle: Testosterone disrupts human collaboration by increasing egocentric choices (Full Text, PDF)

Aus der Diskussion in der Studie:

Our finding that testosterone increased egocentric choices accords with a broader literature concerning testosterone’s role in social choice, and in particular with an interpretation of that literature which proposes that testosterone’s role is to increase dominance or status-related behaviours [18,19]. High social status is associated with elevated testosterone in humans [13,19], chimpanzees [34] and other mammals [35]. A greater drive for social status leading to greater assertiveness during social interactions might reasonably be expected to impair an individuals’ ability to appropriately weight the opinion of another, consistent with our findings. Indeed, the increased egocentricity in an individual’s choices that we observe could be interpreted as a form of signalling, whereby the individual is signalling their dominance in the context of a collective decision. Increased dominance can be detrimental to collaborative decision-making, as shown previously during reasoning tasks where high variance in the verbal contributions of group members (i.e. groups with highly dominant individuals) led to a significantly attenuated performance benefit from collaboration [6]. Other possible effects of testosterone previously related to its role in status-related behaviour [18] may also contribute to less effective information aggregation in our dyads, for example in reducing trustworthiness ratings of faces [17] and decreasing the ability to infer emotional states through photographs of eyes [16]. In addition to potential status-related effects of testosterone, our finding of increased egocentricity has interesting parallels with testosterone’s role in sexual and reproductive behaviours, where testosterone relates to more self-orientated behaviour as evident in reduced parenting and increased courtship in birds [31,32], rodents [36] and rural Senegalese men [37]. Importantly, our task involves no conflict over resources as accurate integration of information is in the best interest of the dyad members, which suggests that the effects of testosterone we observed are not caused by it rendering individuals more selfish.

Und etwas später:

Social animals reap benefits from collaboration across a wide variety of tasks, ranging from those involving information aggregation (as seen here), reasoning [6] or the division of resources such as food or money [1–3]. Indeed, the potential benefits frominformation aggregation, for example, are used to support the use of juries (i.e. groups of observers) in the criminal justice system [5]. However, collaborating too freely is not always beneficial, and therefore the biological mechanisms controlling the balance between more collaborative and self-oriented behaviours must dynamically tune behaviour to the social environment. While a previous focus has been on factors promoting collaboration [9–11], here we highlight an opposing biological influence that increases self-orientated or status-related behaviours at the expense of collaboration. Our data show that the humoral agent testosterone modulates the delicate trade-off between collaboration and a more egocentric disposition.

Es scheint also, als würde Testosteron eine gewisse Wirkung haben, die sich in der Zusammenarbeit, zumindest bei Frauen auswirkt. Interessant ist, dass die Forscher hier selbst betonen, dass es in der Sache um nichts ging und das dies vielleicht Auswirkungen gehabt haben könnte. Eine andere Studie in der es um Verhandlungen ging, hat im Gegensatz dazu feststellt, dass Frauen, die Testosteron erhielten, fairer waren und daher besser miteinander verhandeln konnten.

Aus einer Besprechung der Studie in der Süddeutschen:

Bei dieser Abwägung sorgt Testosteron dafür, dass die eigenen Interessen nicht zu kurz kommen, wie die Forscher zeigten. In Zweierteams sollten sich die Probandinnen einigen, welches von zwei Bildschirm-Mustern die stärkeren Kontraste aufwies. Die Muster wurden kurz hintereinander präsentiert, und die Unterschiede waren sehr gering.

Dabei waren die Probandinnen ohne Testosteron deutlich im Vorteil. Sie diskutierten unvoreingenommener darüber, was jede von ihnen wahrgenommen hatte, und waren eher bereit, sich die Meinung der Partnerin anzuhören. In der Testosteron-Gruppe hingegen war eine solche Abstimmung die Ausnahme. Frauen, zuvor eine Hormonpille geschluckt hatten, ließen sich kaum von ihrer Meinung abbringen. Das egozentrische Verhalten führte zu deutlich schlechteren Trefferquoten als in der Placebo-Gruppe.

Wie eine frühere Studie gezeigt hat, kann Testosteron jedoch auch die Bereitschaft zur Kooperation erhöhen – aber nur, wenn sich die Beteiligten dadurch materielle Gewinne oder gesellschaftliches Ansehen erhoffen. Testosteron führt nämlich auch dazu, dass Menschen solche Verdienste stärker schätzen. In den Londoner Versuchen hingegen gab es keinerlei Belohnung für die richtige Antwort.

Es scheint also, also würde Testosteron insbesondere das Festhalten an der eigenen Meinung fördern, was eine Kooperation ohne besonderes Ziel erschweren kann. Ohne Testosteron schien die Bestätigung der eigenen Meinung egaler zu sein, was dann die Zusammenarbeit förderte. Es wäre interessant inwiefern das Ergebnis inbesondere bei Frauen auftritt oder aber auch auf Männer übertragbar ist.