Biology and being ‘green’

Dr Chris Hand

Why do some of us take action on the environment, and some not? Is it connected to masculinity?

We are becoming more and more aware that how we consume affects the environment. This awareness is reinforced by policy (such as introducing charges for single use plastic bags and coffee cups, and requiring rubbish to be sorted for recycling) as well as the media – the BBC’s Blue Planet episode on plastic pollution in the oceans, for example.

Is being eco-friendly ‘unmanly’?

However, changing our behaviour can involve costs, which raises a question: why do some people accept these costs while others are more reluctant? The question of what drives pro-environmental behaviour has been explored for some time. Alongside altruism and a sense of shared responsibility, the literature on pro-environmental consumption suggests a number of other possibilities. One is that going ‘green’ is, for some people, a status-marking activity. A second is that (some) men subconsciously see pro-environmental behaviours as ‘unmanly’, which puts them off adopting these behaviours.

The idea that pro-environmentalism was ‘unmanly’ has been explored using methods such as scenario experiments and surveys before. However, the Understanding Society Innovation Panel provided an alternative approach. Wave F contained a set of questions on pro-environmental behaviours (such as turning lights off when leaving the room and taking your own shopping bag when going shopping) developed from a list used by DEFRA. It also contained data on a suggested biomarker for pre-natal exposure to testosterone and oestrogen: the lengths of our fingers.

Testosterone and ‘digit ratio’

The ratio of the index finger to the ring finger (the ‘digit ratio’) has been suggested as an indicator of relative exposure to testosterone and oestrogen before we are born. Greater exposure to testosterone results in a comparatively longer ring finger, whilst greater exposure to oestrogen is associated with a longer index finger. This in turn seems to be related to how we think and act. The digit ratio has been found to be associated with a range of features such as competitiveness and altruism as well as with aspects of personality. It has also been found among men to be associated with purchase of goods with a more ‘masculine’ image (Regular Coke as opposed to Diet Coke in one study and colour of clothes in another) as well as to courtship related consumption. 

Based on these findings and the prior literature, there are two possible expectations as to how the digit ratio might relate to pro-environmental behaviour. First, if pro-environmentalism is seen as unmanly and a more masculine digit ratio is associated with goods with a more masculine image, we might also expect it reduce pro-environmental behaviour. Conversely, a more feminine digit ratio might increase it. However, if pro-environmental behaviour is used to signal status, and a more masculine ratio is associated with greater competitiveness, it could also be associated with greater pro-environmental behaviour.

We tested the relationship between pro-environmental behaviour and the digit ratio using data from Understanding Society – and controlled for the effects of age, education and household income. The results were published in Biology and being green: The effect of prenatal testosterone exposure on pro-environmental behaviour.

More complex than we thought

In contrast to earlier studies, the pro-environmental behaviour score for men was not that much lower than for women; the difference was statistically significant, but with a very small effect size. The results also suggested that both a more ‘masculine’ digit ratio and a more ‘feminine’ digit ratio among men are associated with greater engagement in pro-environmental behaviour. (A ‘neutral’ ratio was associated with lesser engagement; in other words, the relationship is roughly u-shaped.) Among women though, there was no significant relationship.

The results suggest that the relationship between gender and pro-environmental behaviour is rather more nuanced and complex than the ‘green is feminine’ stereotype would imply. Perhaps men with a more ‘masculine’ digit ratio don’t see pro-environmental behaviour as a threat to their gender identity – or perhaps they are more competitive or status-seeking, and this manifests itself in greater (reported) pro-environmental activity. If it’s the latter, we might find that promoting recycling and other behaviours in a way which appeals to that sense of competition or status-seeking is more successful than targeting altruistic or social motives.

We need to see further studies to understand men’s motivations in this area better – but the Understanding Society data provided a crucial first step, and a larger sample than is found in many digit ratio studies.


Dr Chris Hand

Chris Hand is an Associate Professor of Marketing at Kingston Business School