Permanent Daily Savings Time: less sleep, lower productivity, worse educational outcomes

  A new analysis published in CMAJ (Canadian Medical Association Journal)  https://www.cmaj.ca/lookup/doi/10.1503/cmaj.261089 argues that eliminating the clock change is only half the decision: governments must also decide whether to adopt permanent standard time or permanent daylight saving time. Both choices have trade-offs. Permanent daylight saving time keeps evenings lighter, which may support recreation, social activity, commuting, and some economic activity.

But it also pushes sunrise an hour later, leaving more people waking, travelling to school, and commuting to work, in darkness during the winter. Permanent standard time preserves more morning light and better aligns clock time with human circadian biology, although evenings become darker earlier.

“Ending the clock change solves one problem, but it creates another decision: which time should we live on year-round?” says lead author Dr. Raymond Lam, professor of psychiatry at the University of British Columbia (UBC), Vancouver, BC. “The health evidence points to standard time, largely because morning light matters for our body clocks, sleep, and mood.”

Weighing the trade-offs

Major sleep and chronobiology organizations recommend permanent standard time. The authors note that morning light helps synchronize the body’s circadian clock, while evening light delays it. Permanent daylight saving time, therefore, works against circadian alignment during winter by reducing morning light while extending evening light.

“Our biological clocks need morning light to stay synchronized with the 24-hour day,” says Dr. Ralph Mistlberger, professor of psychology at Simon Fraser University, Vancouver, BC. “Permanent daylight saving time moves that light an hour later just when winter mornings are already darkest.”

The effects may be especially important for mood and sleep. An estimated 1% to 3% of people experience seasonal affective disorder (SAD), while as many as 15% experience milder seasonal changes in mood, sleep, appetite, and energy. The authors also point to geographic studies showing that people living farther west within a time zone — where sunrise occurs later by the clock — experience several adverse health outcomes.

Children and adolescents may be particularly vulnerable because puberty naturally shifts sleep timing later while school still starts early. Other potentially affected groups include shift and early-start workers, public transit users, pedestrians and cyclists, and people living in rural or lower-income communities with poorer lighting and transportation infrastructure.

The authors acknowledge that permanent daylight saving time has advantages. Longer evening light may make it easier to exercise, socialize, or shop after work and school.

“The attraction of permanent daylight saving time is easy to understand. People like more light after work and school,” says Dr. Patrick Baylis, associate professor at the Vancouver School of Economics at UBC. “But those evening benefits have to be weighed against evidence linking later solar time with less sleep, lower productivity, and worse educational outcomes.”

International experience also provides cautionary examples. The United States adopted permanent daylight saving time during the 1974 energy crisis but reversed the policy within a year amid opposition to dark winter mornings and concerns about children travelling to school before sunrise. Russia adopted permanent daylight saving time in 2011 and reversed it in 2014 after public dissatisfaction. Chile similarly reversed a national move to permanent daylight saving time after its 2015 experiment.

The authors of the Analysis emphasize that whichever policy governments choose, its effects should be monitored. Under permanent daylight saving time, possible measures include safer roads and pedestrian infrastructure, later or more flexible school and work start times, increased morning light exposure in schools and workplaces, and monitoring of sleep, mood, injuries, and other health outcomes. Permanent standard time would require fewer measures, mainly addressing earlier evening darkness in winter and earlier dawn in summer.

“Time policy is a public health policy,” says Dr. Alexandra Choi, medical health officer with Vancouver Coastal Health. “If governments choose permanent daylight saving time, they should plan for the consequences before the first winter — from safer morning travel and flexible start times to monitoring sleep, mental health, and injuries.”

DOI

10.1503/cmaj.261089 

How Heavily Are PhD Students Offloading Their Scientific Writing to AI?

Large language models are diffusing rapidly into science, raising concerns that delegating research writing to AI may undermine the development of expertise that scientific training is supposed to build. 

This study measures AI-generated writing in the dissertations of a near-census of US STEM PhD graduates from 2019 to 2026 and link graduates to their subsequent employment. AI writing is absent before 2023, present in 29% of dissertations filed in 2026, and rapidly growing. Use is more common among students from non-English-speaking countries and at lower-ranked programs. 

Among graduates in the same program and cohort, those whose dissertations contain AI writing are less likely to enter academic research careers and more likely to enter non-tenure-track roles or industry, with this pattern strongest among US-origin students. At the same time as AI may increase research productivity, it thus appears to also be displacing a potentially important portion of the work through which scientific expertise is developed.

Early Investments in Parents Buffer Against Future Schooling Shocks

 Do early investments in parents pay off even when treatment effects for children appear to fade out quickly? This study answers that question by leveraging a field experiment in which households with 3-5 year-old children were randomized into a parenting program, a preschool, or a control group, combined with a natural experiment (Covid-19 school closures) that occurred ten years later. 

Prior to the closures, treatment effects on academic achievement had faded to zero across all groups. Yet, with Covid-19 school closures, effects of the parenting program re-emerge: test scores in control and preschool groups drop by roughly 0.25-0.30 SD, whereas scores in the parenting group drop by only 0.11 SD (difference: p = 0.01). 

These findings suggest that parenting programs can generate latent human capital that only becomes visible when complementary school inputs are removed. This result is consonant with parental and school investments acting as substitutes in skill production. Because this latent parental capacity pays off precisely when school inputs fail, standard measurement tools for early childhood programs can miss crucial state-contingent value.

Impacts of Targeted Acceleration in Middle School Math

This study focuses on an accelerated 3-year math curriculum offered in the middle schools of a large urban district that enables students to finish Algebra I and Geometry before high school. Entry to the program is based on 5th-grade math test scores, with a cutoff at the 80th percentile. Continuing eligibility requires at least a B grade in the previous year; successful completion of all three years is highly correlated with an index of non-cognitive skills. 

Following students for 6 years after high school graduation, the authors find that the impacts of admission vary widely by non-cognitive skill and gender. Marginally eligible boys with high non-cognitive skills have a 33 percentage point (ppt.) increase in the probability of completing calculus by 11th grade and a 12 ppt. increase in the probability of completing a major in STEM or business within 6 years; boys with lower noncognitive skills take more advanced math classes in high school but have no significant effects on their college outcomes. 

Like their male peers, marginally eligible girls with high non-cognitive skills are more likely to complete calculus by 11th grade (+17 ppt.). Their rate of graduating with a STEM or business major is unaffected, but they switch from social sciences to the core STEM majors (science, engineering and math). Girls in the two lower terciles of non-cognitive skill are also strongly affected by entry to the program, with higher participation in advanced math classes in high school, higher rates of entry to selective 4-year colleges, and higher rates of completing a STEM or business major (+12 ppt).

Simply telling teenagers ‘just don’t send nudes’ does not work

 Blunt warnings telling teenagers not to share sexual images are failing to protect them and can make victims of image-based sexual abuse feel blamed, ashamed and unable to seek help, according to new research from the University of Surrey. 

The study, published in Sexualities, found that current responses from schools, safeguarding services and the justice system are often fragmented, punitive and poorly equipped to address rapidly evolving threats such as sexual deepfakes and sextortion (blackmail involving sexual images). 

Researchers argue that blanket ‘just say no’ messages ignore the reality that image-sharing can form part of young people’s relationships, intimacy and social lives. By treating all sharing in the same way, these approaches can shift responsibility onto victims rather than those who violate consent. 

The research reviewed existing evidence alongside insights from a 2025 workshop involving 38 professionals from education, law enforcement, frontline services, academia, policy and the technology sector. 

Participants reported that institutions can focus more heavily on confiscating devices, preserving evidence or protecting their reputations than addressing the emotional and social harm experienced by young people. Confusing legal and safeguarding frameworks can also mean the same incident could betreated as a consensual exchange, a safeguarding concern or a criminal offence depending on who handles it. 

Dr Emily Setty, Associate Professor in Criminology at the University of Surrey, said: 

“Telling young people to ‘just don’t send nudes’ is no longer a credible safeguarding response. It ignores how digital intimacy actually works and places the burden of preventing abuse on potential victims. With AI-generated images, a young person can now be targeted even when they have never created or shared an intimate image.” 

Researchers propose an approach called ‘safe uncertainty’, which allows professionals to act decisively while considering the circumstances, relationships and needs involved in each case. Rather than relying only on rigid rules or checklists, schools and safeguarding services would examine issues such as coercion, breached trust, shame, peer pressure and the young person’s emotional safety. 

Dr Setty continued: 

“Young people who disclose abuse need to be met with care, not suspicion or a lecture about their choices. Schools and safeguarding professionals must be able to respond to the harm in front of them, even when a case does not fit neatly into an existing category. The priority should be restoring safety, dignity and trust.” 

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Journal

Sexualities

DOI

10.1177/136346072614672 

Primary school pupils who use an AI-supported learning tool learn arithmetic more quickly

Primary school pupils who use an AI-supported learning tool learn arithmetic more quickly than children who do not use such a tool. This is the finding of a multi-year study by Radboud University involving nearly eight thousand children. However, the researchers warn that it's no miracle cure, as the teacher’s role remains essential even with AI.

The researchers examined the development of numeracy skills among 7,885 Dutch primary school pupils over a three-year period, when these systems were first used between 2014 and 2017. They compared classes that used an adaptive learning system with classes that taught numeracy without such a system. Such a system automatically adapts exercises to the level of an individual pupil. Pupils are given more difficult tasks if they perform well and simpler tasks if they get stuck. On average, pupils who used the system showed more positive growth in their maths performance over the years.

Large-scale study

‘It is one of the first studies to examine the long-term effects of adaptive learning tools. Until now, research into these kinds of systems has mainly focused on short-term effects, or has been conducted on a smaller scale,’ explains Susanne de Mooij, an education researcher and one of the study’s authors.

‘Adaptive learning systems have been in use for almost fifteen years in more than half of all Dutch primary schools. Nevertheless, some fear that this type of adaptive learning tool leads to pupils learning less effectively, as digital learning materials are thought to be less effective than paper-based ones. This study shows that, in cognitive terms at least, this is not the case.’

Greater success at large schools

The effects found are modest, De Mooij emphasises. ‘We have found small effects, but generally a positive trend. Moreover, the positive effect is particularly evident in large schools and in vulnerable schools with many pupils from less advantaged socio-economic backgrounds. There is often greater variation between pupils in such settings. Adaptive technology can then help to better tailor teaching to individual needs,’ says De Mooij.

This means that an adaptive learning tool is primarily something that supports teachers, rather than replacing them. ‘A teacher cannot adapt the lesson content to thirty pupils at the same time. But with a tool like this, you can improve pupils’ maths skills whilst also reducing a teacher’s workload.’ The researchers emphasise that the teacher always remains in control: ‘The teacher draws up the lesson plan, decides what pupils learn and oversees what happens in the classroom. Such learning technology is fed solely by the data stored in the system, whereas a teacher has access to much more information.’

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Journal

Learning and Instruction

DOI

10.1016/j.learninstruc.2026.102480 

Busy college students less likely to be depressed, and get better grades

 When it comes to mental health, it may not be how much time you have that matters, but rather, how you feel about the time you have.

That’s one key takeaway of a new University of Colorado Boulder study examining the relationship between time and mental health.

The study of 646 undergraduates, published in the Journal of American College Health, found that those with the busiest schedules were significantly less likely to be depressed, and—contrary to some common assumptions—they got better grades. Those who felt a chronic sense of rush or “time pressure” had higher rates of anxiety and depression, regardless of what their schedules looked like.

Additionally, those who scored higher on measures of mindfulness (the ability to be present and aware in the moment) appeared to be able to take on a heftier schedule without compromising their mental health.

“We have a tendency to think, ‘Oh, things will get better, and I won’t be stressed if I can just take some things off of my plate,’” said first author Caitlin McKimmy, a doctoral candidate in the Department of Psychology and Neuroscience. “These data show that it’s not that simple — that outside of what is actually on our calendar we need to heal our relationship with time.”

Time pressure vs. time scarcity

Previous research shows that people can experience time differently, depending on what they’re doing with it.

One study found that people who give their time away, through things like volunteering or helping friends, tend to feel less stressed about time than those who spend time on themselves or waste time. Other research has shown that when someone is fully immersed in a task they care about, also known as a “flow state,” time seems to speed by.

Deep breathing and other mindfulness practices have been shown to increase one’s sense that their time is abundant.

For the new study, McKimmy, a busy mother of two, wanted to examine the impact of two distinct elements of time: “time pressure” (or the subjective sense of rush); and “time scarcity” (the objective lack of non-committed hours).

In her survey, she gathered data on how many hours per week the student participants spent in class, preparing for class, working a job, commuting and doing other activities. Survey questions also assessed how much time pressure they felt, how anxious or depressed they were and their level of mindfulness.

The participants agreed to provide their GPAs and access to their academic records.

McKimmy was surprised to find that time scarcity was strongly associated with both better grades and lower rates of depression.  Heightened time pressure, on the other hand, was strongly associated with more anxiety, depression and lower grades.

Importantly, those short on time didn’t necessarily feel time pressure.

“You can have a very busy person who has a harmonious relationship with time and someone else who, objectively speaking, has a calendar with some space in it but is really stressed out about time,” McKimmy said.

When asked what they would do with it if they did have more time, students listed self-care, including mental healthcare, as No. 1.

What causes what?

McKimmy stresses that the findings don’t prove that staying busy causes people to be happier. It could be that those with better mental health naturally seek out more experiences while those struggling with low mood say no more. There could also be shared underlying factors that influence both how someone perceives time and their mental health. For instance, some research suggests that depression itself can influence perception of time, potentially making it feel unmanageable.

What we can infer from these data, she said, is that the common less-is-more narrative may not always hold.

For instance, while a student might be inclined to skip taking a part-time job, for fear it might hurt their GPA, the study found no evidence that adding more to a schedule will hurt academic performance or mental health. While someone might retreat socially when their grades or work start to slip, this could potentially backfire, leading to a monotonous schedule—that can make time crawl by—and a sense of loneliness, warns McKimmy.

“These data support the idea that doing more and being engaged can not only lead to better mental health but could also support academic and professional success,” she said.

This is not to say that there’s no such thing as being overscheduled, she stressed. Often, for reasons they can’t control, people have less free time than is ideal.

Notably, the study showed that people who scored higher on measures of mindfulness had less negative mental health impacts when they were stressed about time.

“There appears to be something about attuning to the present moment that protects you against the negative impact of time pressure,” she said.

Her advice to those feeling stressed about their schedule: If you must fill it, try to fill it with things in line with your passions and values; try to be in the moment, not thinking about the future or past.

If you notice you are feeling stressed, take a moment to focus on your breath and ground yourself in your body and in the moment.

“The amount of time we have in our week isn’t super malleable,” she said. “But the way we think about time is.”

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Journal

Journal of American College Health

DOI

10.1080/07448481.2026.2681092