Please, Share.

Neuroscience: The Real Algorithm

In the late 16th century, the word share entered into the English language, breaking away from its Old English root scearu, meaning “a cutting, a shearing; a part or division, a piece cut off.”

By 1590, it had settled into a more familiar definition: to divide one’s own and give part to others.

If you were born in the 1990s or earlier, you probably didn’t need an etymology lesson to understand what sharing meant.

If you're anything like me, you learned it from a mother’s stern glare and a swift backhand to the head:

“Share with your sister.”

Some of you might not remember a time when sharing had only one definition, rooted in empathy, fairness, and most importantly, sacrifice.

Some of you might not remember a time when sharing didn’t have an icon either.

However, if you were born on or after October 31, 2006, you will have interacted with a starkly different definition of the word share, and you probably don’t even realize it.

What was so special about Halloween 2006?

That was the day Facebook (now Meta) introduced the "Share" button to its platform.
A small product update that didn’t just change how content moved online, it changed the meaning of sharing altogether.

Now, it’s no uncommon for language to produce homophones. (words that sound alike but have different meanings)

For example, A bat can be a wooden club used in baseball or a nocturnal creature who inspires Bruce Wayne.

But the split definition of the word share doesn’t just divide linguistic real estate. It creates neurological fault lines that shift the way people interact with each other and the world at large.

Oxytocin vs. Dopamine- Relationships vs. Habits

At the core of this divide is a difference in neurochemical loops.

Prosocial sharing: Giving to others without expectation activates the oxytocin system, a neuropeptide released by the hypothalamus and distributed throughout the brain, particularly in areas like the ventromedial prefrontal cortex (vmPFC), amygdala, and nucleus accumbens (NAcc).

Oxytocin fosters trust, empathy, and social bonding. It’s often called the moral molecule because it doesn’t just reward helping behaviour. It increases the desire to help again (Zak et al., 2007).

Social media sharing, by contrast, is built on dopaminergic circuitry, particularly the nucleus accumbens and ventral striatum. Dopamine thrives on anticipation and novelty.

The short-term high of a post getting attention. But unlike oxytocin, dopamine doesn’t care about connection. It rewards repetition, regardless of whether the behaviour is meaningful, hollow, or even harmful.

One builds relationships. The other builds habits.

Feedback Mechanisms: Intrinsic Satisfaction vs. Social Validation

The reinforcement loops between the two forms of sharing couldn't be more different.

Prosocial sharing is powered by intrinsic feedback: a quiet sense of moral satisfaction, emotional resonance, or shared connection. You don’t need a like button to feel the impact of giving your lunch to someone who’s hungry. This kind of reward is delayed but deep, processed through the vmPFC’s integration of empathy, memory, and values.

Social media sharing is designed for external validation: It is fast, visible, and quantifiable. The reward is variable. One post gets 50 likes, another gets two. This inconsistency is what keeps dopamine flowing. The loop is immediate, shallow, and addictive. It rewards you for visibility, not connection.

TLDR:

Oxytocin says, “That was good. Let’s connect again.”
Dopamine says, “That was exciting. Do it again, and do it bigger.”

How Sharing Shapes the Brain

What we do repeatedly, we become.

Prosocial sharing builds a brain attuned to empathy, trust, and emotional regulation. It reduces stress, in part due to oxytocin’s cortisol-lowering effect, and increases feelings of belonging and meaning (Heinrichs et al., 2003). Over time, those who share in this way become more emotionally grounded, not because they have more, but because they feel more connected.

Social media sharing, on the other hand, reinforces performance over presence. It rewards attention-seeking, not authenticity. The more we chase likes and shares, the more our brain wires itself to depend on them. Self-worth becomes fragile, tied to numbers. We begin to see others not as people to connect with, but as audiences to impress, or competition to outperform.

You stop asking, “Who needs this?”
And start asking, “Will this get traction?”

Conclusion

Look, I dont know if science can replace a swift backhand to the head.

And I highly doubt we can derail the social media train from “sharing” things into oblivion.

But understanding how these behaviours work at a fundamental level can hopefully give agency to your actions and give you back some control over your mood and well-being.

Works Cited

• Heinrichs, M., Baumgartner, T., Kirschbaum, C., & Ehlert, U. (2003). Social support and oxytocin interact to suppress cortisol and subjective responses to psychosocial stress. Biological Psychiatry, 54(12), 1389–1398. https://doi.org/10.1016/S0006-3223(03)00465-7
  
  

• Zak, P. J., Stanton, A. A., & Ahmadi, S. (2007). Oxytocin increases generosity in humans. PLoS ONE, 2(11), e1128. https://doi.org/10.1371/journal.pone.0001128