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Knocking down abandoned buildings has a lot of benefits for Detroit − but it’s costly for cities

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theconversation.com – Mark Skidmore, Professor of Government Finance and Policy, Michigan State University – 2025-03-07 07:16:00

Detroit has knocked down more than 20,000 homes since 2014. The process continues.
Patrick Gorski/NurPhoto via Getty Images

Mark Skidmore, Michigan State University; Camila Alvayay Torrejon, Universidad Católica del Norte, and Dusan Paredes Araya, Michigan State University

Few cities have experienced a sharper economic change of fortune than Detroit.

It was one of the fastest-growing cities in the nation between 1900 and 1950.

In the nearly 75 years since then, it has lost over 60% of its population, becoming the defining example of a postindustrial city in decline.

Chronic population loss creates a significant mismatch in the housing market. An ongoing reduction in the demand for housing leads to an oversupply of vacant properties. Vacant properties can quickly deteriorate due to neglect, arson, vandalism and crime.

A grey house with chipped steps, shuttered windows and overgrown weeds in the yard. There is a for sale sign and it is clearly in a state of disrepair.
Shuttered and repossessed homes line the streets of a middle-class neighborhood on the East side of Detroit.
Charles Ommanney via Getty Images

Rehabilitating abandoned and neglected properties is often not possible. It can take just a few years for vacant homes to transition from being habitable to blighted. What should policymakers do with the growing unwanted inventory?

One option is to do nothing and wait for real estate developers to clean up the parcels and hopefully rebuild.

In the absence of private sector action, which often fails to take hold, city officials may implement policies to remove blighted properties and stabilize neighborhoods. That’s what Detroit has been doing since 1974. As a result, 17% of the city’s land area is now composed of vacant land where houses once stood.

As a group of economists who study municipal finance of cities experiencing population decline, we took a deep look at the success of razing blighted properties in Detroit.

Detroit removes thousands of blighted homes

Between 2014 and 2019, the city demolished 20,800 blighted properties through the Detroit Demolition Program. The heaviest concentration of demolitions occurred in the lowest-valued areas of the city such as the Brightmoor, Burbank and Midwest neighborhoods.

A cluster of tiny triangles, representing demolitions, are focused in red and orange slices of Detroit. Red sections had an average sale price between $26,784 to $45,396. A shade of red slightly lighter was $45,396 to $52,339.
Location of demolitions and property sales prices in Detroit from 2009 to 2019. The heaviest concentration of demolitions occurred in the lowest-valued areas of the city, as shown in red and orange.
Alvayay Torrejón, Paredes, Skidmore (2023), CC BY-NC-ND

From 2014 to 2019, many of the demolitions were funded by the federal government’s Hardest Hit Fund. The goals of the fund are to help reduce homeowner foreclosures and stabilize neighborhoods. This fund spent US$52 million tearing down homes in Detroit.

As with any government intervention, it is critical to evaluate costs and benefits so leaders can be sure they are implementing the most effective revitalization strategy.

Costs and benefits of demolition

Research demonstrates that demolitions not only eliminate blight, they also stabilize neighborhood housing values, improve property tax compliance, reduce crime and eliminate toxic materials such as asbestos and lead paint.

From the perspective of city finances, the success of razing a property can be assessed in two ways.

First, does it increase the value of nearby properties? A study that two of us published in 2017 answered this question in the affirmative: Tearing down an abandoned building in Detroit does increase the value of nearby properties by a small amount: $162.

Second, how do changes in the value of those nearby properties affect Detroit’s property tax revenue? If property values increase, property taxes increase too, so it is possible to calculate how long it takes for the city to recoup its costs. On average, demolishing a blighted structure in Detroit costs $21,556.

In the case of Detroit during the period examined, our research shows the benefits of the program in terms of increased property values are limited and do not fully cover the demolition costs.

Even if you optimistically assume the benefits of demolition extend to properties as far as about 2½ blocks away, the increase in property tax revenue generated from the demolition is too small to cover demolition costs.

To understand why, imagine drawing a circle around the razed property with a radius of about 0.125 miles, which is how we defined 2½ city blocks, and then examining the change in property value and tax revenue of the properties within the circle. While removing a blighted property is a win in many other ways, it doesn’t have much effect on neighboring home values.

Our findings indicate that vacant lots also have a negative effect on the property values of surrounding homes. For example, for homes within 2½ city blocks, the net effect of a demolition without redevelopment is an increase in neighboring home prices of $162. In this case, it would take 50 years for money collected via property taxes to equal the costs of demolition. It’s hard to say what happens if the lot is redeveloped because so few are.

If you measure the effect using smaller rings around the razed property, full cost recovery times get even longer.

State and federal assistance

Yet over the long run, these demolitions are essential for maintaining quality of life and positioning the city for future redevelopment. Some would argue that it is the role of government to pay for programs like this in struggling cities. Under President George W. Bush, for example, the U.S. Department of Housing and Urban Development implemented the Neighborhood Stabilization Program, which included funds for the demolition of blighted structures.

The federal Hardest Hit Fund covered many of the demolitions in Detroit from 2014 to 2019. When that program ended, city voters showed their enthusiasm for removing blighted properties by approving Proposal N, a $250 million Detroit-funded plan to continue the demolition program.

However, additional property taxes to cover demolition costs may further put the city at competitive disadvantage in the region, nationally and globally. Detroit already has among the highest property taxes in the country.

Allowing the state to foot the bill would keep property taxes affordable, but support for such programs is mixed in the state Capitol in Lansing due to resource constraints and the fact that other Michigan cities such as Flint have also struggled with declines in population.

Lessons learned from Detroit’s razing

Detroit and other postindustrial American cities such as Cleveland, Ohio, and Gary, Indiana, have experienced population declines in recent decades, but these challenges are by no means exclusively a United States phenomenon.

Throughout history, cities such as Rome have experienced enormous drops in population. Paris lost population in medieval times. Some ancient cities such as Carthage and Petra have been fully abandoned.

In the coming years, Japan, Korea and a number of European countries are on track to experience significant population decline. Many resource-dependent cities in China have the same problem.

That means lessons learned from Detroit may be helpful to policymakers in other places. Many leaders in Detroit did not imagine that the population would decline over decades, and they didn’t plan for that happening.

Other cities have an opportunity to prepare. They can start by diversifying their economies and city revenue streams so that government has the funding to step in and ensure that quality of life is maintained as population shrinks.The Conversation

Mark Skidmore, Professor of Government Finance and Policy, Michigan State University; Camila Alvayay Torrejon, Assistant professor of Economics, Universidad Católica del Norte, and Dusan Paredes Araya, Adjunct Professor of Economics, Michigan State University

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Are twins allergic to the same things?

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theconversation.com – Breanne Hayes Haney, Allergy and Immunology Fellow-in-Training, School of Medicine, West Virginia University – 2025-04-14 07:42:00

If one has a reaction to a new food, is the other more likely to as well?
BjelicaS/iStock via Getty Images Plus

Breanne Hayes Haney, West Virginia University

Curious Kids is a series for children of all ages. If you have a question you’d like an expert to answer, send it to curiouskidsus@theconversation.com.


Are twins allergic to the same things? – Ella, age 7, Philadelphia


Allergies, whether spring sneezes due to pollen or trouble breathing triggered by a certain food, are caused by a combination of someone’s genes and the environment they live in.

The more things two people share, the higher their chances of being allergic to the same things. Twins are more likely to share allergies because of everything they have in common, but the story doesn’t end there.

I’m an allergist and immunologist, and part of my job is treating patients who have environmental, food or drug allergies. Allergies are really complex, and a lot of factors play a role in who gets them and who doesn’t.

What is an allergy?

Your immune system makes defense proteins called antibodies. Their job is to keep watch and attack any invading germs or other dangerous substances that get inside your body before they can make you sick.

An allergy happens when your body mistakes some usually harmless substance for a harmful intruder. These trigger molecules are called allergens.

diagram of Y-shaped antibodies sticking to other molecules
Y-shaped antibodies are meant to grab onto any harmful germs, but sometimes they make a mistake and grab something that isn’t actually a threat: an allergen.
ttsz/iStock via Getty Images Plus

The antibodies stick like suction cups to the allergens, setting off an immune system reaction. That process leads to common allergy symptoms: sneezing, a runny or stuffy nose, itchy, watery eyes, a cough. These symptoms can be annoying but minor.

Allergies can also cause a life-threatening reaction called anaphylaxis that requires immediate medical attention. For example, if someone ate a food they were allergic to, and then had throat swelling and a rash, that would be considered anaphylaxis.

The traditional treatment for anaphylaxis is a shot of the hormone epinephrine into the leg muscle. Allergy sufferers can also carry an auto-injector to give themselves an emergency shot in case of a life-threatening case of anaphylaxis. An epinephrine nasal spray is now available, too, which also works very quickly.

A person can be allergic to things outdoors, like grass or tree pollen and bee stings, or indoors, like pets and tiny bugs called dust mites that hang out in carpets and mattresses.

A person can also be allergic to foods. Food allergies affect 4% to 5% of the population. The most common are to cow’s milk, eggs, wheat, soy, peanuts, tree nuts, fish, shellfish and sesame. Sometimes people grow out of allergies, and sometimes they are lifelong.

Who gets allergies?

Each antibody has a specific target, which is why some people may only be allergic to one thing.

The antibodies responsible for allergies also take care of cleaning up any parasites that your body encounters. Thanks to modern medicine, people in the United States rarely deal with parasites. Those antibodies are still ready to fight, though, and sometimes they misfire at silly things, like pollen or food.

Hygiene and the environment around you can also play a role in how likely it is you’ll develop allergies. Basically, the more different kinds of bacteria that you’re exposed to earlier in life, the less likely you are to develop allergies. Studies have even shown that kids who grow up on farms, kids who have pets before the age of 5, and kids who have a lot of siblings are less likely to develop allergies. Being breastfed as a baby can also protect against having allergies.

Children who grow up in cities are more likely to develop allergies, probably due to air pollution, as are children who are around people who smoke.

Kids are less likely to develop food allergies if they try foods early in life rather than waiting until they are older. Sometimes a certain job can contribute to an adult developing environmental allergies. For example, hairdressers, bakers and car mechanics can develop allergies due to chemicals they work with.

Genetics can also play a huge role in why some people develop allergies. If a mom or dad has environmental or food allergies, their child is more likely to have allergies. Specifically for peanut allergies, if your parent or sibling is allergic to peanuts, you are seven times more likely to be allergic to peanuts!

two boys in identical shirts side by side look at each other
Do you have an allergy twin in your family?
Ronnie Kaufman/DigitalVision via Getty Images Plus

Identical in allergies?

Back to the idea of twins: Yes, they can be allergic to the same things, but not always.

Researchers in Australia found that 60% to 70% of twins in one study both had environmental allergies, and identical twins were more likely to share allergies than fraternal (nonidentical) twins. Identical twins share 100% of their genes, while fraternal twins only share about 50% of their genes, the same as any pair of siblings.

A lot more research has been done on the genetics of food allergies. One peanut allergy study found that identical twins were more likely to both be allergic to peanuts than fraternal twins were.

So, twins can be allergic to the same things, and it’s more likely that they will be, based on their shared genetics and growing up together. But twins aren’t automatically allergic to the exact same things.

Imagine if two twins are separated at birth and raised in different homes: one on a farm with pets and one in the inner city. What if one’s parents smoke, and the others don’t? What if one lives with a lot of siblings and the other is an only child? They certainly could develop different allergies, or maybe not develop allergies at all.

Scientists like me are continuing to research allergies, and we hope to have more answers in the future.


Hello, curious kids! Do you have a question you’d like an expert to answer? Ask an adult to send your question to CuriousKidsUS@theconversation.com. Please tell us your name, age and the city where you live.

And since curiosity has no age limit – adults, let us know what you’re wondering, too. We won’t be able to answer every question, but we will do our best.The Conversation

Breanne Hayes Haney, Allergy and Immunology Fellow-in-Training, School of Medicine, West Virginia University

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AI-generated images can exploit how your mind works − here’s why they fool you and how to spot them

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theconversation.com – Arryn Robbins, Assistant Professor of Psychology, University of Richmond – 2025-04-11 07:43:00

A beautiful kitchen to scroll past – but check out the clock.
Tiny Homes via Facebook

Arryn Robbins, University of Richmond

I’m more of a scroller than a poster on social media. Like many people, I wind down at the end of the day with a scroll binge, taking in videos of Italian grandmothers making pasta or baby pygmy hippos frolicking.

For a while, my feed was filled with immaculately designed tiny homes, fueling my desire for minimalist paradise. Then, I started seeing AI-generated images; many contained obvious errors such as staircases to nowhere or sinks within sinks. Yet, commenters rarely pointed them out, instead admiring the aesthetic.

These images were clearly AI-generated and didn’t depict reality. Did people just not notice? Not care?

As a cognitive psychologist, I’d guess “yes” and “yes.” My expertise is in how people process and use visual information. I primarily investigate how people look for objects and information visually, from the mundane searches of daily life, such as trying to find a dropped earring, to more critical searches, like those conducted by radiologists or search-and-rescue teams.

With my understanding of how people process images and notice − or don’t notice − detail, it’s not surprising to me that people aren’t tuning in to the fact that many images are AI-generated.

We’ve been here before

The struggle to detect AI-generated images mirrors past detection challenges such as spotting photoshopped images or computer-generated images in movies.

But there’s a key difference: Photo editing and CGI require intentional design by artists, while AI images are generated by algorithms trained on datasets, often without human oversight. The lack of oversight can lead to imperfections or inconsistencies that can feel unnatural, such as the unrealistic physics or lack of consistency between frames that characterize what’s sometimes called “AI slop.”

Despite these differences, studies show people struggle to distinguish real images from synthetic ones, regardless of origin. Even when explicitly asked to identify images as real, synthetic or AI-generated, accuracy hovers near the level of chance, meaning people did only a little better than if they’d just guessed.

In everyday interactions, where you aren’t actively scrutinizing images, your ability to detect synthetic content might even be weaker.

Attention shapes what you see, what you miss

Spotting errors in AI images requires noticing small details, but the human visual system isn’t wired for that when you’re casually scrolling. Instead, while online, people take in the gist of what they’re viewing and can overlook subtle inconsistencies.

Visual attention operates like a zoom lens: You scan broadly to get an overview of your environment or phone screen, but fine details require focused effort. Human perceptual systems evolved to quickly assess environments for any threats to survival, with sensitivity to sudden changes − such as a quick-moving predator − sacrificing precision for speed of detection.

This speed-accuracy trade-off allows for rapid, efficient processing, which helped early humans survive in natural settings. But it’s a mismatch with modern tasks such as scrolling through devices, where small mistakes or unusual details in AI-generated images can easily go unnoticed.

People also miss things they aren’t actively paying attention to or looking for. Psychologists call this inattentional blindness: Focusing on one task causes you to overlook other details, even obvious ones. In the famous invisible gorilla study, participants asked to count basketball passes in a video failed to notice someone in a gorilla suit walking through the middle of the scene.

YouTube video
If you’re counting how many passes the people in white make, do you even notice someone walk through in a gorilla suit?

Similarly, when your focus is on the broader content of an AI image, such as a cozy tiny home, you’re less likely to notice subtle distortions. In a way, the sixth finger in an AI image is today’s invisible gorilla − hiding in plain sight because you’re not looking for it.

Efficiency over accuracy in thinking

Our cognitive limitations go beyond visual perception. Human thinking uses two types of processing: fast, intuitive thinking based on mental shortcuts, and slower, analytical thinking that requires effort. When scrolling, our fast system likely dominates, leading us to accept images at face value.

Adding to this issue is the tendency to seek information that confirms your beliefs or reject information that goes against them. This means AI-generated images are more likely to slip by you when they align with your expectations or worldviews. If an AI-generated image of a basketball player making an impossible shot jibes with a fan’s excitement, they might accept it, even if something feels exaggerated.

While not a big deal for tiny home aesthetics, these issues become concerning when AI-generated images may be used to influence public opinion. For example, research shows that people tend to assume images are relevant to accompanying text. Even when the images provide no actual evidence, they make people more likely to accept the text’s claims as true.

Misleading real or generated images can make false claims seem more believable and even cause people to misremember real events. AI-generated images have the power to shape opinions and spread misinformation in ways that are difficult to counter.

Beating the machine

While AI gets better at detecting AI, humans need tools to do the same. Here’s how:

  1. Trust your gut. If something feels off, it probably is. Your brain expertly recognizes objects and faces, even under varying conditions. Perhaps you’ve experienced what psychologists call the uncanny valley and felt unease with certain humanoid faces. This experience shows people can detect anomalies, even when they can’t fully explain what’s wrong.
  2. Scan for clues. AI struggles with certain elements: hands, text, reflections, lighting inconsistencies and unnatural textures. If an image seems suspicious, take a closer look.
  3. Think critically. Sometimes, AI generates photorealistic images with impossible scenarios. If you see a political figure casually surprising baristas or a celebrity eating concrete, ask yourself: Does this make sense? If not, it’s probably fake.
  4. Check the source. Is the poster a real person? Reverse image search can help trace a picture’s origin. If the metadata is missing, it might be generated by AI.

AI-generated images are becoming harder to spot. During scrolling, the brain processes visuals quickly, not critically, making it easy to miss details that reveal a fake. As technology advances, slow down, look closer and think critically.The Conversation

Arryn Robbins, Assistant Professor of Psychology, University of Richmond

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Trump’s nomination for NASA leader boasts business and commercial spaceflight experience during a period of uncertainty for the agency

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theconversation.com – Wendy Whitman Cobb, Professor of Strategy and Security Studies, Air University – 2025-04-10 07:54:00

Jared Isaacman, the nominee for next NASA administrator, has traveled to orbit on two commercial space missions.
AP Photo/John Raoux

Wendy Whitman Cobb, Air University

Jared Isaacman, billionaire, CEO and nominee to become the next NASA administrator, faced questions on April 9, 2025, from members of the Senate Committee on Commerce, Science, and Transportation during his confirmation hearing for the position.

Should the Senate confirm him, Isaacman will be the first billionaire – but not the first astronaut – to head NASA. Perhaps even more significant, he will be the first NASA administrator with significant ties to the commercial space industry.

As a space policy expert, I know that NASA leadership matters. The head of the agency can significantly shape the missions it pursues, the science it undertakes and, ultimately, the outcome of America’s space exploration.

A man with short dark hair wearing a black jumpsuit with an American flag patch and the Polaris mission insignia.
Jared Isaacman speaks at a news conference in 2024, before his Polaris Dawn mission.
AP Photo/John Raoux, File

An unconventional background

At 16 years old, Isaacman dropped out of high school to start a payment processing company in his basement. The endeavor succeeded and eventually became known as Shift4.

Though he found early success in business, Isaacman also had a love for aviation. In 2009, he set a record for flying around the Earth in a light jet, beating the previous record by more than 20 hours.

While remaining CEO of Shift4, Isaacman founded another company, Draken International. The company eventually assembled the world’s largest fleet of privately owned fighter jets. It now helps to train U.S. Air Force pilots.

In 2019, Isaacman sold his stake in Draken International. In 2020, he took Shift4 public, making him a billionaire.

Isaacman continued to branch out into aerospace, working with SpaceX beginning in 2021. He purchased a crewed flight on the Falcon 9 rocket, a mission that eventually was called Inspiration4. The mission, which he led, represented the first private astronaut flight for SpaceX. It sent four civilians with no previous formal space experience into orbit.

Following the success of Inspiration4, Isaacman worked with SpaceX to develop the Polaris Program, a series of three missions to help build SpaceX’s human spaceflight capabilities. In fall 2024, the first of these missions, Polaris Dawn, launched.

Polaris Dawn added more accomplishments to Isaacman’s resume. Isaacman, along with his crewmate Sarah Gillis, completed the first private spacewalk. Polaris Dawn’s SpaceX Dragon capsule traveled more than 850 miles (1,367 kilometers) from Earth, the farthest distance humans had been since the Apollo missions.

A rocket launching into a dark sky, leaving behind a cloud of smoke.
The Polaris Dawn mission launched on a SpaceX Falcon 9 rocket in September 2024.
AP Photo/John Raoux

The next adventure: NASA

In December 2024, the incoming Trump administration announced its intention to nominate Isaacman for the post of NASA administrator.

As NASA administrator, Isaacman would oversee all NASA activities at a critical moment in its history. The Artemis program, which has been in progress since 2017, has several missions planned for the next few years.

This includes 2026’s Artemis II mission, which will send four astronauts to orbit the Moon. Then, in 2027, Artemis III will aim to land on it.

Four astronauts in blue NASA jumpsuits standing in front of a conical metal capsule.
If the mission proceeds as planned, the Artemis II crew will fly in an Orion crew capsule, pictured behind them, around the Moon in 2026.
Kim Shiflett/NASA via AP, File

But, if Isaacman is confirmed, his tenure would come at a time when there are significant questions about the Artemis program, as well as the extent to which NASA should use commercial space companies like SpaceX. The agency is also potentially facing funding cuts.

Some in the space industry have proposed scrapping the Artemis program altogether in favor of preparing to go to Mars. Among this group is the founder of SpaceX, Elon Musk.

Others have suggested canceling NASA’s Space Launch System, the massive rocket that is being used for Artemis. Instead, they argue that NASA could use commercial systems, like SpaceX’s Starship or Blue Origin’s New Glenn.

Isaacman has also dealt with accusations that he is too close to the commercial space industry, and SpaceX in particular, to lead NASA. This has become a larger concern given Musk’s involvement in the Trump administration and its cost-cutting efforts. Some critics are worried that Musk would have an even greater say in NASA if Isaacman is confirmed.

Since his nomination, Isaacman has stopped working with SpaceX on the Polaris Program. He has also made several supportive comments toward other commercial companies.

But the success of any of NASA’s plans depends on having the money and resources necessary to carry them out.

While NASA has been spared major cuts up to this point, it, like many other government agencies, is planning for budget cuts and mass firings. These potential cuts are similar to what other agencies such as the Department of Health and Human Services have recently made.

During his confirmation hearing, Isaacman committed to keeping the Artemis program, as well as the Space Launch System, in the short term. He also insisted that NASA could both return to the Moon and prepare for Mars at the same time.

Although Isaacman stated that he believed NASA had the resources to do both at the same time, the agency is still in a time of budget uncertainty, so that may not be possible.

About his relationship with Musk, Isaacman stated that he had not talked to Musk since his nomination in November, and his relationship with SpaceX would not influence his decisions.

Additionally, he committed to carrying out space science missions, specifically to “launch more telescopes, more probes, more rovers.”

But since NASA is preparing for significant cuts to its science budget, there is some speculation that the agency may need to end some science programs, like the Hubble space telescope, altogether.

Isaacman’s future

Isaacman has received support from the larger space community. Nearly 30 astronauts signed a letter in support of his nomination. Former NASA administrators, as well as major industry groups, have signaled their desire for Isaacman’s confirmation.

He also received the support of Senator Ted Cruz, the committee chair.

Barring any major development, Isaacman will likely be confirmed as NASA administrator by the Senate in the coming weeks. The Committee on Commerce, Science, and Transportation could approve his nomination once it returns from a two-week break at the end of April. A full vote from the Senate would follow.

If the Senate does confirm him, Isaacman will have several major issues to confront at NASA, all in a very uncertain political environment.The Conversation

Wendy Whitman Cobb, Professor of Strategy and Security Studies, Air University

This article is republished from The Conversation under a Creative Commons license. Read the original article.

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