Diversity Equity and Inclusion (DEI) underpinned by evolutionary psychology.

Insights from Psychological Studies on How Inside and Outside Groups Form Naturally.

I believe that at the start of 2025, HR stands at an inflection point in its history. We will either evolve into a profession, or we will be lumped in with “bureaucracy”, the cutting of which is very in vogue.

This idea that I have been propagating, shared by many others I have met over my career and reflected in recent negative news, is that without evidence based practice, rigorous application and measurable impact, HR as we know it, will not survive.

So, we are at a moment in time coursing with opportunity to evolve further into being a valued profession and discipline, based on craft, experimentation and empiricism.

In my search to define what that looks like in practice, I have been considering what is the measurable impact that we should look to have? For my money, two “KPIs” that our work has to be evidenced against are “Business Performance” and “Colleague Happiness”.

We have been given the keys to Talent and Learning & Organizational Development, one definitive business performance driver, and one that might increase your chances of success.

We have also been given the keys to Colleague Happiness, from policy, to practice, from technology to process, from “culture” to experience, from promises to ethics.

I have not worked out yet how you directly link the work we do in these spaces to real world outcomes and attribute accurate performance and happiness uplifts.

For now, what I know is that if HR is to evolve to actually deliver greater colleague happiness and business performance, we have to base our hypotheses about human life in our organizations; what matters, why something happens and whether we can do anything about it, on strong scientific foundations where we have them, and real world experimentation where we need to build them.

Once we have established practice, method and knowledge of what has a causal relationship with what, and what of that can be affected, we develop it into an apprentice-able craft, with the right construct in place to ensure that as science and practice advances, the craft can be updated.

I suspect that this will mean much of our thinking, method and task will have to be reimagined for the 21st Century.

People have asked me what that might look like in practice, vs. what we have to work with today.

Fair question I suppose, it’s easy enough to tear things with weak foundations down, much harder to build things anew.

At this point there are many more questions than answers, but I hope to inspire. I’m not clever enough to have all the answers.

Sorry For the sojourn. Back to the topic I lured you in with.

Why DEI?

I have been thinking about DEI as a topic to explore for a while. It is very pertinent in today’s socio-political context, with many companies and government bodies in the world’s biggest economies actively cutting back their staff and commitments to DEI, and a popular trend conflated with a drive for organizational efficiency and reducing bureaucracy.

I also believe that in some context’s it is observable that Diversity, or the lack of it, affects business outcomes, and in every context, Equity and Inclusion are real world perceivable entities that you need to make choices about, to create psychological safety or the psychological context you believe will create your greatest chance of success for a given task.

For example, red teaming and blue teaming for innovation might not have all the components of psychological safety. The very nature of entrepreneurship is a more direct relationship between task or context failure and personal consequences.

Whereas for a multi-disciplinary interdependent team delivering on behalf of the wider business, psychological safety (for which Equity & Inclusion are required) is paramount as a hygiene factor for collaboration on complex work.

I have already written about why I believe that psychological safety, the ability to share your viewpoint and how confident you are in it, with someone else at work safely, and vice versa, has been proven to increase our chances of success with complex tasks. I have also written about how it’s a fundamental but not exclusive component of individual, team and organizational success.

Which means DEI looks to be pretty damn important if you or those you employ are doing anything complex.

DEI is also an area of HR which many people feel is “fluffy” or “political” or “ideological”, so a great test bed to see if empiricism and scientific findings can be applied to HR thinking and practice, thereby convince you, the observer, that I am onto a real idea when I herald a new era for HR.

I apologise for the fact that it is a faint outline at the moment... I hope that through this discussion, and each discussion that I have with every one of you, it becomes clearer to all of us. Thank you for teaching me.

So, if we can create a spark of this thinking in DEI, it’s a challenge to us to then apply this approach across our HR knowledge, method and craft. This will require many experts to go much deeper than I have the knowledge or capacity to.

Once I settled DEI as the example, I needed to find someone who knows way more than me about DEI in large organizations and would have an informal conversation about the science that could sit behind it.

The expert. Rachel Sadka .

After graduating in Physics and Natural Sciences from 英国伦敦大学学院 and teaching Maths through Teach First in one of the poorest school catchments in London, Rachel has spent over 12 years at 安永 working with countless clients, developing their DEI, Culture and Social Sustainability strategies, driving their implementation agendas and measuring their impact.

She works at Board and C-Suite level across the largest, most complex and most successful organisations in the world. Daily.

I approached her and asked,

“If you had to take an empirical perspective on DEI, what would it be?

I quickly followed up with,

Not in a truly scientific way, I can’t ask of your time like that, but perhaps you could give us examples that operate on a broad base of scientific knowledge, to point our thinking in the right direction.

To make the point.”

Rachel’s thoughtful response highlighted that evolutionary psychology explains how deeply ingrained social behaviours shape workplace dynamics and calls on the burgeoning field of evolutionary psychology as an example of how we can use empiricism as a basis for understanding why and how people act the way they do in certain contexts, and contemplates what might affect it for the better.

Introduction.

Humans are social creatures, wired to form groups and affiliate with others. From early human tribes to modern organizations, group affiliations define our social landscape.

However, the mechanisms behind group formation, loyalty, and conflict are not always intuitive.

Drawing on detailed psychological studies and thought experiments, we can explore why and how all of us humans naturally form "inside" and "outside" groups, the role of categorization in our lives and the implications for human behaviour.

More importantly, we can offer experiment-able insights on how organizations can leverage this knowledge to foster inclusion, reduce division, and align employees toward shared goals. In other words, things to set you on the road to experimentation, which might increase your chances of success.

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The Natural Occurrence of Group Affiliations.

Robbers Cave.

Group identity plays a central role in shaping human behaviour.

One of the most famous experiments exploring this is the Robbers Cave Experiment by Muzafer Sherif. In this study, 22 boys were split into two groups at a summer camp, unaware of each other's existence initially. Over time, they formed strong group bonds and identified as the "Rattlers" and the "Eagles." However, when the groups were introduced to one another, hostility quickly emerged. Small provocations like tearing down a flag escalated into full-blown conflict, with raids, theft, and fights occurring between the groups.

The Robbers Cave Experiment demonstrates that group identity forms rapidly and can lead to intense loyalty and competition. Even in a neutral environment like a summer camp, the presence of a rival group triggered territorial and defensive behaviours. This underscores the human tendency to affiliate with an "in-group" while perceiving others as "outsiders," even when the groups are arbitrarily created.

Overestimators vs. Underestimators

One of the most striking studies on group behaviour was conducted by psychologist Henri Tajfel. In his experiment, teenage boys were randomly assigned to groups labelled "overestimators" and "underestimators" based on a trivial dot-counting task. Despite the groups being entirely arbitrary, participants consistently favoured their own group in assigning rewards and penalties.

Tajfel’s study revealed that "groupness" does not require a shared history, deep bonds, or even meaningful differences. Simply being labelled as part of a group is enough to trigger favouritism and discrimination against others. This highlights how minimal conditions can create a sense of in-group loyalty and out-group hostility.

If forming groups is Human Nature, what can we do to ensure DE&I in our Organization?

1. Acknowledge, Understand and Normalize Group Affiliations. Train leaders and employees to recognize that forming ‘in-groups’ and therefore ‘out-groups’, ?is a natural part of human behaviour. This is not inherently negative—it builds trust, loyalty, and collaboration within teams. However, it’s important to raise awareness that group affiliations can unintentionally exclude others and create division, so we have to work as individuals and groups to check and balance negative trends in our behaviour. And we have to be able to check and balance each other.
2. Encourage Cross-Team Collaboration. Introduce structured activities or even better, align around work delivery that promotes collaboration across departments, helping employees by setting common goals and aligning with organizational (the meta-group) rather than group level priorities. Also acknowledge that collaboration at an individual to individual level is a costly exercise, so the value back from the collaboration has to be worth it. Across larger numbers of people and number of groups, if the overhead required to manage collaboration effectively rises exponentially, so must the return. Which in turn means that the choice on WHAT to collaborate on in large organizations is a strategic one. With collaboration everywhere being an impossibility, collaboration needs to be facilitated where it adds the most value (in my experience often around the most complex high value work in your organization, where interdependent expertise needs to be woven together to make the whole more than the sum of its parts), with most other work being designed to be driven in siloes and independently.
3. Lead by Example. Encourage leaders to actively model inclusivity by engaging with various teams and ensuring no one feels excluded from decision-making processes. This can be as simple an experiment as blocking time with each team / team member in the leaders diary on a regular basis, being the facilitative force to ensure teams are feeding each other with opportunities and risks, or actively arranging individuals and teams in mixed expertise groups if the context would value from it and facilitating those teams to act effectively as a unit and across organizational siloes.
4. Recognize How Easily Divisions Form. Train employees to understand that group biases can arise even without meaningful differences. Leaders should be particularly vigilant about creating inclusive spaces where no one feels "othered." This can be measured and practice. Holding space requires us to do less, not more. We are all accountable to help everyone be heard safely, though the leader of others is more accountable.
5. Create an Organizational Level "In-Group". Build a strong sense of organizational identity by embedding aspirations, culture and values that everyone can align with. Shared goals and a common mission unite employees, where everyone can see their part in a real play, creates a single, inclusive "in-group", at a total organizational level.
6. Reward Collaboration. Design systems that reward teamwork across groups rather than fostering competition, ensuring that collaboration becomes the norm rather than an exception. This is easily done, and from my experience, rarely done. The hard part is not the HR reward mechanisms. The hard part is defining the strategic outcome we are aiming for in the future, everyone’s part in it, and then measuring progress against it so that we can apply the right reward mechanisms to them as individuals, teams and organizations.

https://en.wikipedia.org/wiki/Realistic_conflict_theory

https://en.wikipedia.org/wiki/Henri_Tajfel

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Cooperation is More Natural than Chaos. The Flaws in Lord of the Flies

In contrast to the Robbers Cave findings, William Golding’s novel Lord of the Flies depicts a darker, more chaotic view of human nature. Stranded on a deserted island, a group of British schoolboys descends into savagery, with violence and murder taking hold as societal norms collapse. However, critics argue that this scenario is overly simplistic and unrealistic.

Why People Don’t Behave Like That

Real-world cases, such as children stranded in survival situations, often reveal cooperation rather than chaos. In the Robbers Cave Experiment, while initial hostility emerged, researchers found that shared goals, such as fixing a broken truck, reduced conflict. Additionally, in real life, pre-existing relationships and social bonds heavily influence group dynamics, which Golding’s narrative overlooks.

If cooperation is Human Nature, how can we leverage it to ensure DE&I in our Organization?

1. Emphasize Shared Goals. We said it before with in & out groups, so you get to kill two birds with one stone if you get this right. Organizations can also reduce insider / outsider divisions by clearly defining shared values and goals. When employees work toward a clear and real common purpose, it unites them and increases the chances of cooperation across our biased human divisions.
2. Address Unconscious Bias. Leaders must be aware that exclusion often stems from unacknowledged biases or assumptions about others. Training should include tools for recognizing and mitigating these biases and there should be a fair way of notifying one of an unconscious bias with an objective viewpoint and facilitation where needed (cough cough, role of HR?). If we are naturally cooperative once we understand how we are actually all working towards the same goal, we don’t want our unconscious biases, which are highly idiosyncratic to each individual, possibly irrespective of context, to get in the way.
3. Create Opportunities for Bonding. Use team-building exercises that help employees connect across departments, fostering trust and understanding outside their immediate groups. You heard it here. Team building exercises are valuable. Though team building is just one component of cooperation. For effective cooperation or collaboration, we know that we need to have; dependable team mates, real and shared purpose & strategic direction, clear and adhered to team governance, clear and respected roles & responsibilities, clear ways of working, good stakeholder requirements gathering and managing, and psychological safety. Plus a leader who ensures that all stays in place.

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The Role of Categorization

Categorization is a foundational aspect of human cognition. As linguist S.I. Hayakawa famously said, “When we name something, we are classifying.” This innate ability to categorize helps us process the world efficiently but also leads to stereotyping and group distinctions.

The Whorfian hypothesis suggests that the way we linguistically label and categorize shapes our thoughts. However, experiments show that categorization is not limited to humans or even language. For instance, pigeons trained to recognize images of cows vs. cars demonstrate that categorization occurs even without verbal labels.

Categorization is a natural cognitive process, but it also contributes to dividing the world into "us" and "them." It shows how deeply rooted group distinctions are, even when they serve no practical purpose beyond simplifying our perception of the world.

If categorization is Human Nature, how can we guide it to ensure DE&I in our Organization?

1. Teach Sensitivity to Group Dynamics. Employees should be trained to notice when divisions form, even around arbitrary characteristics like job titles, seniority, or physical proximity. This awareness can prevent exclusionary behaviours. Again an objective viewpoint and facilitation where needed (cough cough, role of HR?), would likely add value. Exclusionary behaviours over arbitrary characteristics, increases the chances of innovation and talent being stifled.
2. Focus on Behaviours Over Labels. Encourage employees to focus on shared experiences and collaboration rather than labels like "new hires" or "management." Make space and time for people to understand each other socially and professionally. Find ways to encourage exploration of other and reaching of mutual respect on a component of how we are and how we live our lives, rather than the label we operate under.
3. Promote Cross-Group Engagement. Offer mentoring programs, job-shadowing opportunities, or team rotation to break down silos and encourage inter-group understanding. As practical as it can be and again so rarely done. It might be a lot of work, but it’s also a sure-fire way to reduce the negative affect of our natural human categorization of others.

https://en.wikipedia.org/wiki/Pigeon_intelligence

Key Conclusions

The Natural Occurrence of Group Affiliations.

Studies like the Robbers Cave Experiment and Tajfel’s minimal group paradigm demonstrate that humans quickly form group affiliations, even under arbitrary conditions. Loyalty to the in-group and hostility toward the out-group are natural outcomes of this process.

In Practice: Encourage leaders to recognize this tendency and manage it constructively by promoting awareness, empathy, and cross-group collaboration.

Cooperation is More Natural than Chaos. The Flaws in Lord of the Flies

While group loyalty can lead to conflict, shared goals and cooperation can help bridge divides. The Robbers Cave Experiment showed that tasks requiring interdependence reduced hostility, providing a hopeful insight into resolving group conflicts.

In Practice: Embed organizational values and goals to create a unifying "in-group." By aligning employees around a shared purpose, organizations can foster real inclusion and enhance collaboration.

The Role of Categorization

Categorization, while a useful cognitive tool, also leads to the perception of differences and divisions. Whether through arbitrary labels or social constructs, this process plays a critical role in how humans define "us" versus "them."

In Practice: Train employees to recognize and challenge exclusionary dynamics, encouraging engagement and collaboration across all levels of the organization.

Finally, the role of HR is to objectively educate, measure, manage and intervene where needed to ensure Diversity, Equity and Inclusion can drive business performance in the way we need them to.

Conclusion

Understanding how and why we form inside and outside groups is crucial for navigating social dynamics and mitigating conflict. Whether in classrooms, workplaces, or global politics, the mechanisms of group affiliation and categorization shape our interactions. By recognizing these tendencies and leveraging shared values and goals, organizations can create a truly inclusive environment—one where every employee feels united behind a common purpose and aligned through organizational values. Real inclusion is not about eliminating groups but about creating one united in-group for all employees.

The whole becomes more than the sum of its parts.

The widening of my perspective, though sometimes difficult or even painful, has always been positive.

?I wish you the most wonderful 2025!

?Happy New Year.

?Meir

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