This absorbing exploration of nostalgia raises questions about its slippery nature, and shows how it has been chillingly deployed in politics, from the cold war to Trumpism

In the 1970s there were American press reports of an Iowa man who was tormented by his yearning for the 16-year stretch of time that ran from 1752 to 1768. His misery was the result of not being able to find anyone who shared this deep nostalgia for a period when electricity was still a rumour and America was proud to think of itself as British.

But does this really count as nostalgia? Is it not, actually, a bid for attention, a way for the man from Iowa to signal that, while his body might be tethered to the cornfields, his mind is free to roam in exquisite pastures where gentlemen routinely wear wigs and night-time travel is best reserved for a full moon? Agnes Arnold-Forster doesn’t say, but deploying the anecdote allows her to draw attention to the slipperiness of the very concept of nostalgia. Is it a legitimate and trans-historical emotion, like sadness or rage? Or could it be rather a cultural confection, a passing fancy expressive of a particular time and place (in the case of the man from Iowa, this would be Gerald Ford’s post-Vietnam America)? Most fundamentally of all, can you feel nostalgic for a time or a place that you never actually experienced yourself?

How can you change your life for the better today? Learn not just to appreciate happiness – but to anticipate it

Be honest: there are times when you have felt schadenfreude, or “delight in another’s misfortunes”. But what about v orfreude ? I recently came across this lovely word, which my German-speaking friend translated as “the anticipation of joy”. It struck me as such a hopeful concept – surely we could all do with less schadenfreude and more vorfreude . So what exactly is anticipatory joy, how do we cultivate it and will it make us happier?

“The idea is to find joy in the lead-up to an event,” says Sophie Mort , a clinical psychologist and mental health expert at the meditation and mindfulness app Headspace . “For example, we often feel joy and excitement when planning a trip, thinking about going on a date or anticipating a special meal.” It’s easy to look forward to holidays and special occasions, but a joy-filled life is also about everyday occurrences. Rory Platt, a writer at the personal development company The School of Life , says: “The trick lies in filling our calendar with lots of little moments to look forward to – like tiny baubles that, when seen from a distance, combine to make a more glittering future.”

The Harvard professor reveals how everyday rituals can help us cope with pressure, unlock our emotions and define our identities – but can also become unhelpful and divisive

Michael Norton studied psychology and was a fellow at the MIT Media Lab before becoming professor of business administration at Harvard Business School. Known for his research on behavioural economics and wellbeing, Norton published his first book, Happy Money: The New Science of Smarter Spending , with Elizabeth Dunn , in 2013. For his latest, The Ritual Effect: The Transformative Power of Our Everyday Actions , out on 18 April, Norton spent more than a decade surveying thousands of people about the role of ritual in their lives.

Rituals seem a tricky subject for scientific study. How do you categorise them and measure their effect?
It felt very daunting at first, because you can’t randomly assign people to families and have them do different rituals, then follow up in 12 years. At first I was going to study obvious things like weddings and funerals, but when we surveyed people, we found that they had all these other things they made up – in their families, with a significant other, with people at work. That opened it up a lot. We could look at these kinds of rituals and see when people do them. We could measure their emotions, we could really start to get traction on what these things are doing in our lives.

A supermarket is using eye-tracking technology to find what messaging encourages take-up of unpackaged fruit and veg

With thick black frames and hidden cameras, the glasses look designed for espionage or the metaverse but instead the eye-tracking headgear is being deployed to get inside shoppers’ heads as part of the drive to cut plastic packaging from the weekly food shop.

It is an unlikely scene. Hooked up with the glasses a shopper is being tailed around a Waitrose produce department by a researcher carrying a large tablet that displays live footage of them picking up banal things such as potatoes, apples and bananas.

From Rafael Nadal’s ball-bouncing to families’ Christmas traditions, what purpose does ritualistic behaviour serve?

The adjective “ritual”, from Latin via French, means related to religious rites. (A rite, according to the OED, is “a prescribed act or observance in a religious or other solemn ceremony”.) As soon as it appeared, however, the word “ritual” could be used in a derogatory fashion to denote things empty of authentic spiritual content. In his Ecclesiastical History (1570), for example, the martyrologist John Foxe complained about two epistles erroneously (so he argued) attributed to the third-century pope Zephyrinus: they contained “no manner of doctrine” but only “certain ritual decrees to no purpose”. Today one may disparagingly speak of some writer’s “ritual genuflection” to fashionable norms, to accuse them of a kind of moral and intellectual cosplay.

Perhaps, then, we are long overdue a defence of the value of ritual, in all its style-over-substance glory? That is what the Harvard business professor Michael Norton aims to provide in his book, an amiable and diverting-enough essay in the genre of airport-friendly smart thinking. Though he notes the power of longstanding social rituals such as the wedding or the funeral, Norton’s interest is mostly in the other kind: “idiosyncratic behaviours that can emerge spontaneously”. From Rafael Nadal’s interminable routine of ball-bouncing and shirt-pulling before every serve, to a romantic couple giving each other ladybird-themed presents, the message is that rituals can not only optimise athletic performance but enrich our lives in general, cementing relationships, encouraging attention to the moment, and – perhaps most importantly for the target audience – tricking one’s employees into being more happily productive.

Picking nuggets from psychology and social science research to build this case, Norton also describes his own research into the topic, which consists of a mixture of large-scale surveys (about what kind of personal rituals people perform as they groom, exercise or retire to sleep) and lab tests, in which people are taught rituals and then asked to collaborate on tasks. It turns out that the imposition of arbitrary rituals alone (clapping, chanting, whatever) helps a group of strangers become a team.

In this story it is precisely the emptiness of rituals that makes them valuable as “emotional catalysts”, when they are not actually exercises in magical thinking, such as rain ceremonies. (Other animals may be prone to magical thinking, too: pigeons have been observed to repeat a nonsensical action that once was rewarded with food in the hope it will work again.) But when is a ritual not a ritual? Norton discusses family “rituals” such as choices about specific food or Johnny Mathis records at Christmas, but it seems more natural to speak of these as invented traditions. (That preserves the author’s point that we can come to value these traditions very deeply through what he calls “the Ikea effect”: if you build it, you love it more.)

I was tickled to learn that the concert pianist Sviatoslav Richter always carried a pink plastic lobster backstage with him before a performance, but was this really a ritual or just a superstition? Meanwhile, if I do something habitually but without any particular drama – for example, drinking two cups of coffee before writing a book review – that is not a ritual either. As Norton notes, the “essence” of a ritual is how it is performed, not what is done. Perhaps one synthesis of such arguments might be that the idea of “ritual” itself is a spectrum, at one end of which lies mere habit, at the other end ceremony.

Alas, rituals have a dark side, too, and not just when they are explicitly satanic. The most troubling finding in this book is the obverse of the ritual-as-social-glue: it turns out that groups brought together with newfangled rituals in a research setting automatically view others taught different rituals as an out-group, less worthy of respect. In this light, Earth’s long history of religious wars looks less like a series of battles over actual doctrine than just another strand of us against them. Even so, the book’s overall point perhaps offers a reason for cautious optimism: in a disenchanted world, attention to tiny rituals can clear a little space for everyday magic.

Psychologist Chris French has spent decades studying paranormal claims and mysterious experiences, from seemingly-impossible coincidences to paintings that purportedly predict the future. Ian Sample sits down with French to explore why so many of us end up believing in, what he terms, ‘weird shit’, and what we can learn from understanding why we’re drawn to mysterious and mystic phenomena

The late Nobel laureate advocated deliberate thinking, but what rules now is haste and gut instinct. His passing should give us pause

Here is a simple maths problem: together a bat and ball cost £1.10. The bat costs one pound more than the ball. How much is the ball?

It doesn’t take long for most people to answer 10p. And most people get it wrong. If you are in the minority that pauses long enough to realise that the ball costs 5p and the bat £1.05, congratulations, smartypants. If you recognised the question as an exercise in misdirection to expose the foibles of human intuition, you are probably familiar with the work of Daniel Kahneman , psychologist and Nobel laureate, who died last week.

Rafael Behr is a Guardian columnist

The Israeli-American’s first book, Thinking, Fast and Slow, was a worldwide bestseller with revolutionary ideas about human error and bias

Daniel Kahneman, a psychologist who pioneered theories in behavioural economics that heavily influenced the discipline, and won him a Nobel prize, has died at age 90.

Kahneman, who wrote bestselling book Thinking, Fast and Slow , argued against the notion that people’s behaviour is rooted in a rational decision-making process – rather that it is often based on instinct.

Beyond simply feeling decrepit, perception of being older can affect health by encouraging unhealthy eating and reducing exercise

Two nights of broken sleep are enough to make people feel years older, according to researchers, who said consistent, restful slumber was a key factor in helping to stave off feeling one’s true age.

Psychologists in Sweden found that, on average, volunteers felt more than four years older when they were restricted to only four hours of sleep for two consecutive nights, with some claiming the sleepiness made them feel decades older.