Why studying bees can teach us about human loneliness | Sarah Kocher | TEDxNewEngland

Key Concepts

• Social Brain: The set of molecular and neurobiological processes that regulate social interactions, shaped by evolution to enhance survival and reproduction.
• Social Behavior: Interactions within groups of organisms, crucial for individual success in finding food, avoiding predators, and securing mates.
• Model Systems: Organisms commonly used in research (e.g., fruit flies, mice) for controlled experiments, but often limited in behavioral variation.
• Comparative Approach: Studying differences between groups of organisms to understand underlying mechanisms, contrasting with traditional methods of studying similar individuals.
• Same Differences: Traits that are shared among social organisms and not found in non-social ones, highlighting what makes sociality unique.
• Hormone Binding and Transport: Biological processes involving hormones that are implicated in regulating social behavior.
• Gene Expression: The process by which information from a gene is used in the synthesis of a functional gene product, such as a protein.
• Gene-Environment Interaction: The interplay between an organism's genetic makeup and its environment, which influences behavior.
• Social Deprivation: The lack of social interaction, which can have significant negative impacts on development and behavior.

The Importance of Social Bonds and the Social Brain

The video emphasizes the profound impact of social bonds on health and well-being, drawing parallels between the benefits of strong social connections and quitting smoking. It highlights that even brief positive social interactions can boost happiness, and acts of altruism or helping others activate reward centers in the brain. Conversely, the loss of social connections, or loneliness, significantly increases the risk of mortality, with loneliness increasing a person's risk of death by 26% annually.

This underscores the fundamental nature of humans as social creatures, a trait shared by many other species across the animal kingdom, including insects, vertebrates, and microbes. For these species, social interactions are intrinsically linked to individual success, aiding in crucial activities like foraging, predator avoidance, and reproduction.

Understanding the Mechanisms of Social Behavior

A central challenge in biology is the incomplete understanding of the mechanisms underlying social behavior. This knowledge gap hinders the development of effective interventions when these mechanisms falter or when individuals struggle with social interactions. The speaker posits that understanding the core molecular and neurobiological processes regulating social interactions could revolutionize our approach to diagnosing and treating human social disorders.

The Evolutionary Shaping of the Social Brain

Social interactions are tightly linked to evolutionary success, defined as an organism's ability to survive and reproduce. Natural selection has therefore shaped the brains of various species, from humans and primates to bees, to better navigate their social environments. This evolutionary fine-tuning of neural structures and functions is what scientists refer to as the "social brain." The speaker's lab aims to understand the mechanisms driving the evolution and development of this social brain, with the goal of identifying general principles applicable to human social disorders.

Methodological Approaches to Studying Social Behavior

Limitations of Traditional Model Systems

The conventional scientific approach involves comparing similar entities and conducting controlled experiments by manipulating a single variable while keeping others constant. This is exemplified by lab studies using genetically similar organisms like fruit flies or mice, where drug effects can be precisely measured by comparing a treated group to a placebo group. However, this method limits the study of variation.

In the context of social behavior, relying on model systems with a narrow behavioral range, like mice which exhibit limited social behaviors such as mating and maternal care, restricts the scope of research questions. To understand the origins of sociality, it is crucial to compare individuals that live in social groups with those that do not. Current model systems often lack this necessary behavioral diversity, making it difficult to identify the fundamental components required for social behaviors to emerge.

The Power of Contrasting Differences: A New Approach

The speaker proposes an alternative approach: contrasting things that are different, rather than solely comparing similar ones. This is illustrated with the analogy of learning to bake excellent cookies. Comparing 20 nearly identical chocolate chip cookie recipes offers limited insight compared to analyzing 20 vastly different recipes with varied ingredients and flavors. By contrasting these diverse recipes, one can identify "same differences" – commonalities that contribute to a good cookie. For instance, comparing a dark chocolate walnut cookie with a white chocolate macadamia nut cookie might lead to the conclusion that "sweet and crunchy" is a desirable dessert characteristic.

This comparative approach can be applied to biology. To understand adaptation to extreme environments, one could compare animals in the Arctic (cold, icy, limited vegetation; e.g., polar bears, arctic foxes, seals) with those in deserts (hot, limited water, sparse vegetation; e.g., camels, fennec foxes, kangaroo rats). This comparison reveals distinct adaptations: Arctic mammals have thick fur and fat for insulation, while desert mammals have thin fur and concentrated fat (like camel humps) to avoid overheating. Desert animals often have large ears for heat dissipation (fennec fox), while Arctic animals have small ears to retain heat (arctic fox). Desert animals are often nocturnal to avoid the sun, while Arctic animals can be active day or night.

Applying the Comparative Approach to Social Behavior

The same principle applies to understanding social behavior. By comparing animals that live in social groups with those that do not, researchers can identify traits common to social organisms and absent in non-social ones. These "same differences" highlight what makes social organisms unique and have been shaped by natural selection to evolve the social brain.

Sweat Bees as a Model System for Social Behavior Research

The speaker's lab utilizes this comparative approach with sweat bees, a group of wild bees that exhibit a wide behavioral range, including both social and solitary individuals within the same species. Some sweat bees live in hierarchical social groups with a queen and workers, while others reproduce independently. The fact that sweat bees have evolved social behavior multiple times throughout their evolutionary history provides a rich source of natural variation for studying genes, brains, and behaviors.

Genetic and Hormonal Correlates of Sociality

By comparing social and solitary sweat bees, researchers have identified a core set of genes shaped by natural selection during the gain and loss of social behavior. Some of these genes are involved in hormone binding and transport into the insect brain. Social sweat bees have been found to have higher levels of a particular hormone in their brains compared to solitary sweat bees.

Further research in ants, which diverged from bees over 180 million years ago, also reveals a correlation between variation in brain hormone levels and natural variation in social behaviors. The known role of hormones in regulating social behaviors in vertebrates suggests potential overarching commonalities in the mechanisms governing social behavior across vast evolutionary distances.

Conserved Mechanisms Across Species

Evolutionary biology demonstrates that genes regulating insect brains often perform similar functions in vertebrate brains. Humans share a significant percentage of their genes with other species, including cows (80%) and fruit flies and bees (nearly 50%). The speaker's research has found that some mechanisms regulating social variation in bees are also associated with variation in human social behavior. Specifically, genes that differ between social and solitary sweat bees of the same species show significant overlap with genes linked to autism in humans. This highlights conserved mechanisms that shape social behavior variation from insects to mammals.

The Role of Environment and Gene-Environment Interactions

The video acknowledges that behavior is not solely determined by genes but also by environmental experiences. Childhood environments and parenting styles, for instance, can profoundly influence adult social skills. Therefore, a comprehensive understanding of the social brain requires investigating not only genes but also how they interact with the environment and how these interactions are encoded in the brain.

Studying Social Experience in Bumblebees

The research extends to examining how social and non-social individuals respond to social experiences. Experiments are being conducted to determine if social individuals are more sensitive to their social environments than solitary counterparts and to identify brain regions most affected by these differences.

In bumblebees, which are all social, isolating individuals from the colony alters their social interactions. Insects use antennae for sensory input, and antennal contact is crucial for information exchange. Bumblebees typically engage in "antennal handshakes" – brief face-to-face antennal contact. However, bumblebees isolated during a sensitive early life period exhibit less specific and more unpredictable interactions, akin to an inappropriate greeting.

Isolated bumblebees also show greater variation in brain development compared to those reared in social groups. A set of genes with varying expression levels based on social experience has been identified, including genes involved in hormone binding and transport into the brain.

Broader Implications of Social Experience

Social experiences significantly impact behavior across a wide range of animals. Isolation can lead to increased aggression and decreased sociability in species like spiders, mice, and primates. In humans, early life social deprivation is linked to a higher risk of neurodevelopmental and mental disorders. Studying the effects of social experience provides a complementary perspective on how the social brain develops.

Building Research Resources and Future Directions

Conducting these studies requires building resources from scratch, as organisms like sweat bees are not readily available commercially. This involves fieldwork to find and study them in their natural habitats. Despite the challenges, this work yields valuable insights into pathways associated with social variation.

Future research will focus on understanding how these pathways function, how they respond to different environmental inputs, and how social and solitary individuals differ in their responses. The ultimate goal is to identify the core mechanisms that make social organisms unique and to uncover the fundamental blueprint of the social brain.

Conclusion: Learning from Variation

Social interactions are vital for numerous species, and their breakdown can have severe consequences. By studying animals that naturally vary in their social behaviors, researchers can gain novel insights into the "same differences" that define social organisms. This approach offers a deeper understanding of the fundamental blueprint of the social brain, with potential applications across species, from insects to humans. The key takeaway is the immense value of studying existing variation in the natural world with an open mind.