An introduction to Evolutionary Psychology

What does it tell us about behaviour?

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What is evolutionary psychology?

Perhaps unsurprisingly, evolutionary psychology builds on Darwin’s theory of evolution by natural selection and applies it to human psychology. It proposes that the neural mechanisms which underpin human psychology and behaviour are a product of evolution.

Psychological processes such as emotions, thought, language and communication skills are said to be innate and inherited from our ancestors, who developed these adaptations through solving problems crucial to their survival. As such, it proposes that many human characteristics and behaviour are seen universally across different societies and cultures.

The survival and advancement of our species is at the root of evolutionary psychology. When our ancestors were able to solve problems and develop these adaptations, they were at an advantage and benefitted from better health and a longer lifespan, which allowed them to reproduce more and pass on these adaptations to the next generation. In addition to problem solving, being able to interact with groups was key to survival. Our ancestors recognised the need to co-operate with others for mutual survival, and so developed a wide range of social skills, such as language, empathy and altruism, to support communication and therefore survival, resulting in humans evolving in groups.

Although evolutionary psychology is a predominantly ‘nature’ approach, suggesting that many characteristics are innate and therefore universal, it recognises that social and cultural influences have a role in shaping and differentiating human behaviour and psychology, particularly with regards to language, morals, social norms and rules. This therefore suggests that social groups and our cultures can continue to shape our behaviours into the modern day.

What does evolutionary psychology tell us about behaviour?

Evolutionary psychology suggests two main motivations for human behaviour: meeting basic physiological needs and having successful social interaction. In addition to these motivations for human behaviour, it can also offer an explanation to some problematic behaviours through comparing today’s environment with the one in which our neural mechanisms evolved.

  • The importance of physiological needs

    According to evolutionary psychology, the need to survive and reproduce is core to human behaviour and our neural mechanisms have adapted to maximise this opportunity. This indicates that needing to meet basic physiological needs in order to maintain good health and extend survival is a key motivation which underpins much of human behaviour.

    As the country went into lockdown, supermarket shelves were stripped bare, with people stockpiling things they considered essential to their survival, such as foods with a longer shelf-life, things which could be frozen and (weirdly) toilet paper. This surge in panic-buying and over-buying essentials is a prime example of the innate need to survive taking over; whether consciously or unconsciously, people chose the route of self-preservation, ensuring they had plenty of what they may need at the expense of others rather than just taking what they know they will need and leaving enough for others.


  • The necessity of social interaction

    Our neural mechanisms developed so that we could continue to survive as a species through being able to problem solve and successfully communicate with one another. This latter point is of particular interest, as it indicates that the presence of others was not only key to human evolution, but that it plays an instrumental role in human psychology and behaviour. Social interaction was key to survival, and this knowledge is something which is ingrained in our innate neural mechanisms. This can provide an explanation as to why people tend to adopt group behaviours and norms.

    Humans are social creatures and depend on social interaction for survival, and so it is important for them to match the attitudes, beliefs and behaviours of their peers so that they ‘fit in’ and are accepted into the social group. This acceptance not only allows humans to work together for survival but also provides a degree of social protection for all those within the group against outsiders and outsider groups. Here, evolutionary psychology can tie into social psychology, as it indicates that the presence of others is important in shaping how we behave.


  • Rational behaviours becoming problematic

    Evolutionary psychology can offer an explanation for a range of inappropriate or problematic behaviours through its ‘mismatch’ principle. ‘Mismatch’ highlights the fact that the environment in which our neural mechanisms evolved was very different from the modern-day environment.

    Because of this difference, when our internal mechanisms encourage a particular behaviour in response to a situation, this behaviour will likely be more suited to our ancestors’ world (in which the mechanisms evolved) rather than today’s. Although this response was once perfectly rational and key to survival, it may now be deemed inappropriate or problematic in the modern world.

    For example, our ancestors learned to seek out and take advantage of foods high in fat and sugar in order to fight starvation and support survival, foods which were not easy to obtain in their time. In today’s world, however, these foods are easy to come by and are often readily available. Although this makes the need to take advantage of these foods redundant, humans still have this innate response. If followed, this impulse can lead to high levels of consumption of foods high in fat and sugar, which not only carries the risk of a wide range of health-related issues, but is also counterproductive to what the impulse was developed for – survival.


What does evolutionary psychology tell us about behaviour?

The notion that human behaviour is a product of innate and inherited neural mechanisms suggests there is little room for change. However, we think there are two key elements within this approach which can be utilised to support behaviour change:

  • The importance of meeting basic physiological needs; and
  • The necessity of social interaction

Interventions can be framed so that they appeal to these motivations (both consciously and unconsciously) and therefore resonate with people and make an impact, leading to positive change. 

  • Change through physiological needs

    Humans have an innate need to survive, reproduce and pass on the most favourable genes to the next generation and so are likely to engage with behaviours which maximise this opportunity. This adaptability for the benefit of survival may be key to supporting behaviour change. If behaviour change interventions are framed in-line with the physiological needs essential to survival, people may be more likely to join or take part in the intervention and therefore adopt the proposed behaviour change; this would be a result of their innate need to be at an advantage and have a better chance of both survival and reproduction.

    Take the challenge of trying to encourage more mothers to breastfeed for longer as an example. Interventions to encourage this could focus on how breastfeeding supports the health of both mother and baby, which taps into the physiological need to have advantages in health and wellbeing in order to support and extend survival. This benefits the mother’s opportunity to pass on her genes to the next generations both through her own survival and that of her child. We took this approach of emphasising the health advantages of breastfeeding with our For You & Baby campaign – read more about it here.


  • Change through social needs

    In addition to physiological needs, the need for social interaction is key to supporting survival. Humans need to fit in with social groups so that they can survive through cooperation and group protection, which means that they will adapt their internal beliefs and behaviours so to be accepted into a social group. As such, behaviour change interventions that aim to achieve change through influencing wider social norms and affecting change at a societal level will likely have more success than those interventions which try affect change at the individual level.

    For example, enabling mothers to breastfeed in public is a key step to supporting them to breastfeed for longer. From the research we conducted for our For You & Baby campaign, we know that many mothers do not feel comfortable to breastfeed in public and that some have unfortunately received judgement from others when doing so. Why? Because it isn’t the social norm.

    However, if more and more mothers feel supported to and therefore able to breastfeed in public, with the support of community organisations, it will increasingly become the norm. Those who initially opposed it will begin to become accustomed to seeing mothers breastfeed in public and their peers gradually being more accepting of this. In order to fit in with this norm, those who initially opposed it will begin to change their negative behaviours when seeing a mother breastfeed in public, which will in-turn have an impact on their internal beliefs. Alongside this, you have the added benefit of mothers feeling increasingly confident and comfortable to breastfeed in public, therefore encouraging them to breastfeed for longer.



Although evolutionary psychology is a predominantly ‘nature’ approach, proposing that the processes making up human behaviour and psychology are innate, there are certain principles which can be applied to and used for behaviour change. The fact that we are social creatures whose survival drives our behaviour means that there are ways in which our environments and social groups can be reshaped by interventions to facilitate changes in behaviour.

There are many approaches to consider when working to understand human behaviour, all of which have a unique position on the factors and contexts that influence behaviour, how it can be changed and the degree to which this is possible.

As behaviour change experts, we pride ourselves on our wide breadth of knowledge around behavioural theory, and use this knowledge to make a positive impact and enact real, social change.

If you’re interested in finding out more about the many behavioural theories we adopt and how we can help you to make change happen, then get in touch with our team today