If you were under the impression that the opposite of a cynic is an easily hoodwinked person of low mental horsepower, then Jamil Zaki, a professor of psychology and director of Stanford’s Social Neuroscience Lab, has news for you. The idea that cynics are somehow more astute is the first of many notions demolished in this succinct, uplifting book.

Cynics perform less well in cognitive tests and “have a harder time spotting liars than non-cynics”. They are wrong more often than optimists, and the damage to their wellbeing, and to society, is higher than that incurred by their hopeful counterparts. Like an autoimmune disease, what starts out as a misguided defensive reaction ends up causing self-harm. (Zaki is careful early on to distinguish between “big-c” Cynics of the ancient philosophical tradition, and the cynicism “most of us know today” – which can be summarised as a lack of faith in our fellow humans.)

Zaki has been studying “human goodness”, and illuminating how connection, empathy and kindness operate in the world for the past 20 years. His team have found that most people are basically pretty decent, valuing “compassion over selfishness”. Donating money lights up the brain just like eating chocolate, and “helping others through stress soothes our own”. This is a refreshing contrast to the modern, highly individualised conception of “self-care”, which, unmoored from community and solidarity, has mutated into the sad fetishism of bubble baths and misinterpretation of party invitations as demands for “emotional labour”.

Cynicism is bad for us on several levels. Cynics are sicker, more depressed, drink more and die younger than their less cynical counterparts. On a societal level, “study after study finds that cynical beliefs eat away at relationships, communities, economies, and society itself”. Conversely, people who live in high-trust communities are longer-lived, healthier and happier – benefits Zaki translates into the equivalent of a 40% pay rise. And yet, over a 50-year period, cynicism has risen dramatically. The proportion of Americans agreeing that “most people can be trusted” fell by 20% between 1972 and 2018. Zaki’s data focuses on the US, but his findings can certainly be applied more widely.

This “trust recession” has serious social consequences. Zaki introduces various juicy phenomena linked to cynicism, including populism, conspiracy theories and political polarisation. He rejects the notion that cynicism is a radical, stick-it-to-the-man worldview, reframing it as a “tool of the status quo” wielded by propagandists to foment distrust and increase elite control. He explores how and why an apparently ordinary California woman fell prey to QAnon, touching on the psychology underlying our most basic existential needs. He makes a link to attachment theory – ideas about how the way we are attuned towards caregivers from infancy can set the pattern for our adult lives and relationships. Zaki also highlights the fact that economic inequality – regardless of the total overall wealth in a nation – erodes trust. People who live in more unequal places “tend to be polarised, hostile, stressed, lonely, materialistic and mistrustful.”

Much of Hope for Cynics chimes with the late epidemiologist Hans Rosling’s work. Like Rosling, Zaki claims our perceptions of how terrible the world is and the statistics themselves are wildly mismatched. Bad news gets far more clicks than good, after all. For example, data shows that public perception of rates of violent crime has risen steadily since 1990, while actual figures show rates of violent crime falling overall.

Yet both Zaki and Rosling’s arguments raise the same gnawing doubt. Despite the buoyancy of their message, the world is nevertheless full of people experiencing horrific, avoidable suffering. This demands feeling and action from the rest of us. By settling into a sense that the world isn’t all that bad, really, we risk slumping into inexcusable inaction.

Zaki addresses this, saying he has worried that hope might be “the sweetener that helps oppression go down easier”. But it feels like an inadequate afterthought given what is happening presently in Gaza, Sudan and Congo. Perhaps his invocation of “hope mixed with fury” strikes a better balance. As much as being eternally optimistic could induce stagnation, the paralysis that despair invites can be far worse. Zaki’s choice of epigraph by Rebecca Solnit offers a way forward: “Hope is not a lottery ticket you can sit on the sofa and clutch … [It] is an axe you break down doors with in an emergency.”