Olivia: Most people think of migration as a steady flow, like a river. But what if it’s more like an avalanche? A small trickle that, once it starts, gathers mass and speed until it’s an unstoppable, self-accelerating force. That’s the explosive idea we’re unpacking today. Jackson: An avalanche. That’s a powerful image. It’s not just a line of people, it’s a system with its own momentum. Olivia: Exactly. And this idea comes from a really provocative and influential book, Exodus: How Migration Is Changing Our World by Paul Collier. Jackson: Right, and Collier isn't your typical migration scholar. He's a top-tier development economist, famous for his work on global poverty. What's fascinating is that his own family history is steeped in this – his grandfather was a German immigrant who faced intense racism in Britain during WWI, even had to change his name. So he comes at this with both data and a very personal understanding of the stakes. Olivia: Precisely. And that personal stake is why he tries to cut through the noise. He argues that for decades, the debate has been hijacked by emotion and taboo, preventing any real, rational conversation. He wants to change that. Jackson: I can see why it’s a minefield. It feels like you can’t even ask questions without being labeled. Olivia: And Collier says this acceleration, this avalanche, is driven by two simple things that most policy ignores: a massive income gap and something he calls the diaspora effect. Jackson: Okay, 'diaspora effect' sounds academic. What does it actually mean in human terms?

Olivia: In the simplest terms, it’s a landing pad. The first person to migrate to a new country faces enormous costs—finding a job, a place to live, navigating a new culture, all alone. But once a community from their home country—a diaspora—is established, the costs for the next person plummet. Jackson: Ah, I see. You have a network. Someone can give you a couch to sleep on, tell you where to find work, translate for you. It makes the whole terrifying leap much more manageable. Olivia: Exactly. Collier uses his own family's story to illustrate this. His grandfather migrated from a poor village in Germany to the booming industrial city of Bradford in England. But he didn't just move to Bradford; he moved to a specific neighborhood called 'Little Germany.' He was surrounded by people who spoke his language and shared his culture. Jackson: So the diaspora acts like a magnet, pulling more people over and making it easier for them to arrive. And the bigger the diaspora gets, the stronger the magnetic pull. Olivia: That’s the feedback loop. A bigger diaspora lowers migration costs, which increases the rate of migration, which in turn makes the diaspora even bigger. It’s a self-reinforcing cycle. Left unchecked, Collier argues, this doesn't just lead to a steady flow; it leads to an accelerating one. Jackson: That makes so much sense, but it’s rarely part of the public conversation. Which brings me back to the taboo. Why is this topic so toxic? In liberal circles, isn't the default just 'migration is good, and anyone who questions it is a bigot'? Olivia: Collier argues that history has poisoned the well. He points to figures like the British politician Enoch Powell, whose infamous 'Rivers of Blood' speech in the 1960s was so virulently racist that it effectively shut down any mainstream discussion of immigration for forty years. Jackson: It indelibly linked any opposition to immigration with racism. Olivia: Correct. So for decades, the only 'permissible' opinion in polite society was to lament popular opposition to it. He even points to a more recent example, when former Prime Minister Gordon Brown was caught on a hot mic calling a voter who raised concerns about immigration a 'bigot.' Jackson: Wow. And that just reinforces the idea that you can't have a legitimate concern; you can only have a prejudice. Olivia: And that’s Collier’s entry point. He’s saying we have to get past this paralysis. We need to analyze migration, not just politicize it. We need to look at the actual effects, not just our feelings about them. Jackson: Okay, so the conversation is broken. But let's get to the core of his argument. What are the actual effects on the countries people move to? Most of the debate is about jobs and wages, right?

Olivia: This is where Collier drops his most controversial idea. He says the economic effects—the impact on wages and jobs for the native population—are trivial. They're a rounding error. The real story, the one we're missing, is social. Jackson: What does he mean by social? Like, culture, food, music? Olivia: Deeper than that. He’s talking about trust. Cooperation. The invisible threads that hold a society together. He proposes what he calls an 'inverse-U shape' for the impact of migration. Jackson: An inverse-U? Like a hill. It goes up, peaks, and then comes down. Olivia: Exactly. He argues that a moderate level of migration is fantastic. It brings new ideas, cultural variety, and economic dynamism. Society goes up the hill. But, if the rate of migration is too high for too long, and the diaspora grows very large without integrating, you can tip over the peak and start heading down the other side. Jackson: Down how? What starts to break? Olivia: Something he calls 'mutual regard.' It's a powerful concept. It’s more than just respect; it’s the baseline empathy we feel for fellow members of our community. It's the feeling that makes you willing to pay taxes to fund schools for children you'll never meet, or healthcare for elderly people you don't know. It’s the 'we're all in this together' feeling. Jackson: And he’s saying that too much, too-fast migration can weaken that? Olivia: It can. When a society becomes highly fragmented into separate, non-interacting groups, that shared sense of identity can fray. And when it frays, the willingness to contribute to the common good can decline. He uses the story of California as a stark case study. Jackson: Tell me. Olivia: California is one of the richest places on Earth, but for years its public services have been in a state of collapse. Its once-great public school system plummeted in rankings, its public universities were starved of funds. Collier points out that this collapse in public services coincided with two things: a massive influx of immigration, creating a very diverse but also highly stratified society, and a tax strike by the state's high-income earners. Jackson: Proposition 13, the cap on property taxes. Olivia: The very one. Collier's provocative suggestion is that these two things might be linked. As the sense of a shared community weakened, so did the willingness of the fortunate to pay for the less fortunate. The empathy engine stalled. Jackson: This is the part of the book that gets critics fired up, isn't it? It sounds like he's blaming immigrants for the decline of the welfare state. How does he square that with the clear benefits of diversity? Olivia: He’s very careful to say it’s not about blame, and it's not about diversity being inherently bad. It’s about the rate and scale of migration overwhelming a society's capacity to absorb and integrate newcomers. He leans on the work of Harvard political scientist Robert Putnam, whose research found that in highly diverse communities, trust declined not just between ethnic groups, but within them as well. People of all backgrounds tended to "hunker down," retreating into their private shells. Jackson: So it’s a speed and scale problem. The social fabric can only stretch so fast before it starts to tear. Olivia: That's the argument. It’s not an argument against migration, but an argument for managing it. For finding that sweet spot at the top of the inverse-U curve. Jackson: That is a much more complex picture than we're usually given. It moves the goalposts from economics to something much more fundamental about how we live together. Olivia: And this brings us to the most overlooked parts of the story—the effects on those who stay behind, and, most surprisingly, on the migrants themselves.

Jackson: This is what I’m really curious about. Aren't migrants the clear winners? They move from a poor country to a rich one, their income can multiply overnight. It seems like a no-brainer. Olivia: Economically, yes. Collier is adamant: migrants are the single biggest economic winners from migration. The productivity jump is massive. He calls it the closest thing the world economy has to a free lunch. But psychologically? Maybe not. Jackson: What do you mean? Olivia: He highlights a stunning natural experiment. New Zealand runs a visa lottery for people from the Pacific island nation of Tonga. It’s random, so it’s a perfect way to compare those who win and get to migrate with those who lose and stay behind. Jackson: Okay, so what happened? Olivia: The results were staggering. The Tongan migrants who moved to New Zealand saw their incomes increase by nearly 400 percent. A life-changing amount of money. But when researchers measured their self-reported happiness, the migrants were significantly less happy than the ones who stayed in Tonga. Jackson: Wait, what? That’s completely counterintuitive. You leave everything for a better life, you get the money, but you lose your happiness? Why? Olivia: Collier points to the immense psychological costs. You're torn away from your family, your friends, your culture. You might go from being a respected member of your community to a low-status worker in a foreign land. The cultural dislocation is profound. The money is real, but so is the pain of what's lost. Jackson: Wow. That's heartbreaking. It reframes the entire narrative. It's not just a story of economic triumph; it's a story of deep personal sacrifice. Olivia: And the story for those left behind is just as complex. The common term is 'brain drain'—the idea that the poorest countries lose their best and brightest. Collier says this is a real concern, especially for small, poor nations. He gives the example of Haiti, which has lost around 85 percent of its educated people to emigration. Jackson: Eighty-five percent. How does a country even function after that? It's like a hidden form of foreign aid, but flowing from the poor to the rich. The poor country pays to educate a doctor or engineer, and the rich country gets the benefit. Olivia: That’s exactly how Collier frames it. He argues that remittances—the money migrants send home—are a lifeline, but they don't make up for the loss of human capital. Remittances can help a family survive, but they don't build the institutions a country needs to thrive. Jackson: So the people who could build those institutions are the very ones who are leaving. It's another one of those feedback loops. Olivia: A tragic one. And it’s why he argues that migration policy can't just be about the desires of the migrant or the needs of the host country. It has to consider the impact on the societies being left behind.

Olivia: So when you put it all together, Collier's ultimate point is that migration isn't a simple transaction. It's a complex system with powerful feedback loops. And by focusing only on the individual migrant's economic gain, or the host country's labor needs, we miss the systemic effects on social trust in host nations and the hollowing out of the countries left behind. Jackson: It forces you to ask a really tough question. The question isn't 'is migration good or bad?' but 'how much is best, and for whom?' It moves it from a moral absolute to a question of managing incredibly difficult trade-offs. Olivia: He’s not offering easy answers, because there aren't any. He's offering a new framework for thinking. He’s trying to break the taboo so we can have an honest, evidence-based conversation about one of the most powerful forces shaping our world. Jackson: And it feels more urgent than ever to have that conversation. It’s not about building walls or having open borders; it’s about being smart and humane at the same time. Olivia: Exactly. And that's a much harder, but more honest, conversation to have. We'd love to know what you think. Does this framework change how you see the issue? Let us know your thoughts on our social channels. It’s a topic that touches all of us. Jackson: This is Aibrary, signing off.