Nicholas Money, Miami University

Mold growth in your home can be unsettling. Blackened spots and dusty patches on the walls are signs that something is amiss, but it is important to distinguish between mold growth that is a nuisance and mold growth that may be harmful.

There are more than 1 million species of fungi. Some are used to produce important medications. Others can cause life-threatening infections when they grow in the body.

Microscopic fungi that grow in homes are a problem because they can trigger asthma and other allergies. In my work as a fungal biologist, however, I have yet to encounter robust scientific evidence to support claims that indoor molds are responsible for other serious illnesses.

What are molds?

Molds are microscopic fungi that grow on everything. This may sound like an exaggeration, but pick any material and a mold will be there, from the leaves on your houseplant to the grain in your pantry and every pinch of soil on the ground. They form splotches on the outside of buildings, grow in crevices on concrete paths and roads, and even live peacefully on our bodies.

Molds are important players in life on Earth. They’re great recyclers that fertilize the planet with fresh nutrients as they rot organic materials. Mildew is another word for mold.

Fungi, including molds, produce microscopic, seed-like particles called spores that spread in the air. Mold spores are produced on stalks. There are so many of these spores that you inhale them with every breath. Thousands could fit within the period at the end of this sentence.

When these spores land on surfaces, they germinate to form threads that elongate, and they branch to create spidery colonies that expand into circular patches. After mold colonies have grown for a few days, they start producing a new generation of spores.

Where do indoor molds grow?

Molds can grow in any building. Even in the cleanest homes, there will be traces of mold growth beneath bathroom and kitchen sinks. They’re also likely to grow on shower curtains, as well as in sink drains, dishwashers and washing machines.

Molds grow wherever water collects, but they become a problem in buildings only when there is a persistent plumbing leak, or in flooded homes.

There are many species of indoor molds, which an expert can identify by looking at their spores with a microscope.

The types of molds that grow in homes include species of Aspergillus and Penicillium, which are difficult to tell apart. These are joined by Cladosporium and Chaetomium, which loves to grow on wet carpets.

Stachybotrys is another common fungus in homes. I’ve found it under plant pots in my living room.

When does mold growth become a problem?

Problematic mold growth occurs when drywall becomes soaked through and mold colonies develop into large, brown or black patches. If the damaged area is smaller than a pizza box, you can probably clean it yourself. But more extensive mold growth often requires removing and replacing the drywall. Either way, solving the plumbing leak or protecting the home from flooding is essential to prevent the mold from returning.

In cases of severe mold growth, you can hire an indoor air quality specialist to measure the concentration of airborne spores in the home. Low concentrations of spores are normal and present no hazard, but high concentrations of spores can cause allergies.

During air testing, a specialist will sample the air inside and outside the home on the same day. If the level of spores measured in indoor air is much higher than the level measured in the outdoor air, molds are likely growing somewhere inside the home.

Another indication of mold growth inside the home is the presence of different kinds of molds in the outdoor and indoor air. Professional air sampling will identify both of these issues.

Why are indoor molds a problem?

Indoor molds present three problems. First, they create an unappealing living space by discoloring surfaces and creating unpleasant, moldy smells. Second, their spores, which float in the air, can cause asthma and allergic rhinitis, or hay fever.

Finally, some molds produce poisonous chemicals called mycotoxins. There is no scientific evidence linking mycotoxins produced by indoor molds to illnesses among homeowners. But mycotoxins could cause problems in the most severe cases of mold damage – usually in flooded homes. Irrespective of mycotoxin problems, you should treat mold growth in these more severe situations to prevent allergies.

The mold called Stachybotrys has been called the toxic black mold since its growth was linked to lung bleeding in infants in Cleveland in the 1990s. This fungus grows on drywall when it becomes soaked with water and produces a range of mycotoxins.

Black mold spores are sticky and are not blown into the air very easily. This behavior limits the number of spores that anyone around will likely inhale, and it means that any dose of the toxins you might absorb from indoor mold is vanishingly small. But the developing lungs of babies and children are particularly vulnerable to damage. This is why it is important to limit mold growth in homes and address the sources of moisture that stimulate its development.

Knowing when indoor molds require attention is a useful skill for every homeowner and can allow them to avoid unnecessary stress.

Nicholas Money, Professor of Biology, Miami University

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

Roger J. Kreuz, University of Memphis

How will the internet evolve in the coming decades?

Fiction writers have explored some possibilities.

In his 2019 novel “Fall,” science fiction author Neal Stephenson imagined a near future in which the internet still exists. But it has become so polluted with misinformation, disinformation and advertising that it is largely unusable.

Characters in Stephenson’s novel deal with this problem by subscribing to “edit streams” – human-selected news and information that can be considered trustworthy.

The drawback is that only the wealthy can afford such bespoke services, leaving most of humanity to consume low-quality, noncurated online content.

To some extent, this has already happened: Many news organizations, such as The New York Times and The Wall Street Journal, have placed their curated content behind paywalls. Meanwhile, misinformation festers on social media platforms like X and TikTok.

Stephenson’s record as a prognosticator has been impressive – he anticipated the metaverse in his 1992 novel “Snow Crash,” and a key plot element of his “Diamond Age,” released in 1995, is an interactive primer that functions much like a chatbot.

On the surface, chatbots seem to provide a solution to the misinformation epidemic. By dispensing factual content, chatbots could supply alternative sources of high-quality information that aren’t cordoned off by paywalls.

Ironically, however, the output of these chatbots may represent the greatest danger to the future of the web – one that was hinted at decades earlier by Argentine writer Jorge Luis Borges.

The rise of the chatbots

Today, a significant fraction of the internet still consists of factual and ostensibly truthful content, such as articles and books that have been peer-reviewed, fact-checked or vetted in some way.

The developers of large language models, or LLMs – the engines that power bots like ChatGPT, Copilot and Gemini – have taken advantage of this resource.

To perform their magic, however, these models must ingest immense quantities of high-quality text for training purposes. A vast amount of verbiage has already been scraped from online sources and fed to the fledgling LLMs.

The problem is that the web, enormous as it is, is a finite resource. High-quality text that hasn’t already been strip-mined is becoming scarce, leading to what The New York Times called an “emerging crisis in content.”

This has forced companies like OpenAI to enter into agreements with publishers to obtain even more raw material for their ravenous bots. But according to one prediction, a shortage of additional high-quality training data may strike as early as 2026.

As the output of chatbots ends up online, these second-generation texts – complete with made-up information called “hallucinations,” as well as outright errors, such as suggestions to put glue on your pizza – will further pollute the web.

And if a chatbot hangs out with the wrong sort of people online, it can pick up their repellent views. Microsoft discovered this the hard way in 2016, when it had to pull the plug on Tay, a bot that started repeating racist and sexist content.

Over time, all of these issues could make online content even less trustworthy and less useful than it is today. In addition, LLMs that are fed a diet of low-calorie content may produce even more problematic output that also ends up on the web.

An infinite − and useless − library

It’s not hard to imagine a feedback loop that results in a continuous process of degradation as the bots feed on their own imperfect output.

A July 2024 paper published in Nature explored the consequences of training AI models on recursively generated data. It showed that “irreversible defects” can lead to “model collapse” for systems trained in this way – much like an image’s copy and a copy of that copy, and a copy of that copy, will lose fidelity to the original image.

How bad might this get?

Consider Borges’ 1941 short story “The Library of Babel.” Fifty years before computer scientist Tim Berners-Lee created the architecture for the web, Borges had already imagined an analog equivalent.

In his 3,000-word story, the writer imagines a world consisting of an enormous and possibly infinite number of hexagonal rooms. The bookshelves in each room hold uniform volumes that must, its inhabitants intuit, contain every possible permutation of letters in their alphabet.

Initially, this realization sparks joy: By definition, there must exist books that detail the future of humanity and the meaning of life.

The inhabitants search for such books, only to discover that the vast majority contain nothing but meaningless combinations of letters. The truth is out there –but so is every conceivable falsehood. And all of it is embedded in an inconceivably vast amount of gibberish.

Even after centuries of searching, only a few meaningful fragments are found. And even then, there is no way to determine whether these coherent texts are truths or lies. Hope turns into despair.

Will the web become so polluted that only the wealthy can afford accurate and reliable information? Or will an infinite number of chatbots produce so much tainted verbiage that finding accurate information online becomes like searching for a needle in a haystack?

The internet is often described as one of humanity’s great achievements. But like any other resource, it’s important to give serious thought to how it is maintained and managed – lest we end up confronting the dystopian vision imagined by Borges.

Roger J. Kreuz, Associate Dean and Professor of Psychology, University of Memphis

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

Rinanda Shaleha, Penn State

In an era where digital devices are everywhere, the term “screen time” has become a buzz phrase in discussions about technology’s impact on people’s lives. Parents are concerned about their children’s screen habits. But what if this entire approach to screen time is fundamentally flawed?

While researchers have made advances in measuring screen use, a detailed critique of the research in 2020 revealed major issues in how screen time is conceptualized, measured and studied. I study how digital technology affects human cognition and emotions. My ongoing research with cognitive psychologist Nelson Roque builds on that critique’s findings.

We categorized existing screen-time measures, mapping them to attributes like whether they are duration-based or context-specific, and are studying how they relate to health outcomes such as anxiety, stress, depression, loneliness, mood and sleep quality, creating a clearer framework for understanding screen time. We believe that grouping all digital activities together misses how different types of screen use affect people.

By applying this framework, researchers can better identify which digital activities are beneficial or potentially harmful, allowing people to adopt more intentional screen habits that support well-being and reduce negative mental and emotional health effects.

Screen time isn’t one thing

Screen time, at first glance, seems easy to understand: It’s simply the time spent on devices with screens such as smartphones, tablets, laptops and TVs. But this basic definition hides the variety within people’s digital activities. To truly understand screen time’s impact, you need to look closer at specific digital activities and how each affects cognitive function and mental health.

In our research, we divide screen time into four broad categories: educational use, work-related use, social interaction and entertainment.

For education, activities like online classes and reading articles can improve cognitive skills like problem-solving and critical thinking. Digital tools like mobile apps can support learning by boosting motivation, self-regulation and self-control.

But these tools also pose challenges, such as distracting learners and contributing to poorer recall compared with traditional learning methods. For young users, screen-based learning may even have negative impacts on development and their social environment.

Screen time for work, like writing reports or attending virtual meetings, is a central part of modern life. It can improve productivity and enable remote work. However, prolonged screen exposure and multitasking may also lead to stress, anxiety and cognitive fatigue.

Screen use for social connection helps people interact with others through video chats, social media or online communities. These interactions can promote social connectedness and even improve health outcomes such as decreased depressive symptoms and improved glycemic control for people with chronic conditions. But passive screen use, like endless social media scrolling, can lead to negative experiences such as cyberbullying, social comparison and loneliness, especially for teens.

Screen use for entertainment provides relaxation and stress relief. Mindfulness apps or meditation tools, for example, can reduce anxiety and improve emotional regulation. Creative digital activities, like graphic design and music production, can reduce stress and improve mental health. However, too much screen use may reduce well-being by limiting physical activity and time for other rewarding pursuits.

Context matters

Screen time affects people differently based on factors like mood, social setting, age and family environment. Your emotions before and during screen use can shape your experience. Positive interactions can lift your mood, while loneliness might deepen with certain online activities. For example, we found that differences in age and stress levels affect how readily people become distracted on their devices. Alerts and other changes distract users, which makes it more challenging to focus on tasks.

The social context of screen use also matters. Watching a movie with family can strengthen bonds, while using screens alone can increase feelings of isolation, especially when it replaces face-to-face interactions.

Family influence plays a role, too. For example, parents’ screen habits affect their children’s screen behavior, and structured parental involvement can help reduce excessive use. It highlights the positive effect of structured parental involvement, along with mindful social contexts, in managing screen time for healthier digital interactions.

Consistency and nuance

Technology now lets researchers track screen use accurately, but simply counting hours doesn’t give us the full picture. Even when we measure specific activities, like social media or gaming, studies don’t often capture engagement level or intent. For example, someone might use social media to stay informed or to procrastinate.

Studies on screen time often vary in how they define and categorize it. Some focus on total screen exposure without differentiating between activities. Others examine specific types of use but may not account for the content or context. This lack of consistency in defining screen time makes it hard to compare studies or generalize findings.

Understanding screen use requires a more nuanced approach than tracking the amount of time people spend on their screens. Recognizing the different effects of specific digital activities and distinguishing between active and passive use are crucial steps. Using standardized definitions and combining quantitative data with personal insights would provide a fuller picture. Researchers can also study how screen use affects people over time.

For policymakers, this means developing guidelines that move beyond one-size-fits-all limits by focusing on recommendations suited to specific activities and individual needs. For the rest of us, this awareness encourages a balanced digital diet that blends enriching online and offline activities for better well-being.

Rinanda Shaleha, Doctoral student in the College of Health and Human Development, Penn State

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