Quiz of the Day
International Day of Friendship
Thursday, 30 July 2026
The science and psychology of friendship — what makes bonds last, and why they matter more than you think
1. The International Day of Friendship was established by the UN in 2011, originally proposed by which country based on its 'Día de la Amistad' tradition?
- Paraguay
- Mexico
- Argentina
- Bolivia
Paraguay's Dr. Ramón Artemio Bracho founded World Friendship Day in 1958, inspired by the idea that friendship could be a force for peace. The concept spread across South America before the UN adopted it. Paraguay celebrates it on July 30 with parties and the exchange of friendship bracelets — a tradition that became globally influential.
2. Research consistently shows that having close friendships is associated with longer life expectancy. By approximately how much does social isolation increase the risk of premature death?
- 75%
- 29%
- 10%
- 50%
A 2015 meta-analysis found social isolation increases mortality risk by about 29% — comparable to smoking 15 cigarettes a day. The Harvard Study of Adult Development, tracking men for 80+ years, found that the quality of relationships at age 50 was a better predictor of health at 80 than cholesterol levels.
3. Psychologist Robin Dunbar proposed a famous limit on the number of stable social relationships humans can maintain. What is 'Dunbar's Number'?
- 100
- 50
- 150
- 250
Dunbar derived his figure from the correlation between primate brain size and social group size. He found humans consistently form groups of around 150 — visible in hunter-gatherer bands, military companies, village sizes, and optimal business team sizes. Beyond 150, organisations need formal hierarchies rather than personal relationships to function.
4. Which of the following is NOT a type of friendship identified by Aristotle in his Nicomachean Ethics?
- Friendships of loyalty
- Friendships of pleasure
- Friendships of utility
- Friendships of virtue
Aristotle described three friendship types: utility (useful to each other), pleasure (enjoyable company), and virtue (admiring each other's character). He considered virtue-based friendship the highest form and the only truly durable kind. Utility and pleasure friendships dissolve when the usefulness or pleasure ends — a 2,400-year-old insight that holds up in modern psychology.
5. The 'mere exposure effect' in psychology describes which phenomenon relevant to friendship formation?
- Childhood friendships are strongest
- People tend to like those they see repeatedly
- Friends who share hobbies form stronger bonds
- People become friends during shared crises
Robert Zajonc's research showed that mere repeated exposure to a stimulus — a person, face, or sound — increases positive feelings toward it. This explains why proximity drives friendship formation: office colleagues, neighbours, and classmates become friends partly because we see them often. The effect works even when exposures are below conscious awareness.
6. Which neurochemical, sometimes called the 'bonding hormone,' is released during positive social interactions and strengthens friendship bonds?
- Oxytocin
- Dopamine
- Serotonin
- Cortisol
Oxytocin, produced in the hypothalamus and released by the pituitary gland, promotes trust, bonding, and social memory. It's released during hugs, laughter, and positive social interactions — but also in conflict with out-group members. Research suggests it promotes in-group bonding partly by increasing out-group suspicion — a less flattering aspect of the 'love hormone.'
7. A landmark 2017 study found that friendship quality declines significantly in which decade of life for many people?
- Their 30s
- Their 40s
- Their 50s
- Their 20s
The 30s typically bring career pressures, parenthood, and geographic dispersion that erode friendships. Sociologists call this the 'friendship recession.' Studies show adults in their 30s have fewer close friends than at any other life stage. Research on 'friendship investment' shows that maintaining old friendships requires deliberate effort, not just proximity.
8. The famous phrase 'It takes a village to raise a child' reflects which anthropological insight about social bonds?
- Extended social networks beyond the nuclear family support child development
- Neighbours play a more important role than grandparents
- Government welfare services replace kin
- Mothers cannot raise children without fathers
The phrase's anthropological basis is 'alloparenting' — non-parents caring for children. In traditional societies, grandmothers, aunts, friends, and community members all shared childcare. Research finds children with larger networks of caring adults develop better social and cognitive skills. The nuclear family model of parents raising children alone is historically atypical.
9. Cross-sex friendships (friendships between people of different genders) became more common in Western societies following which social change?
- Universal suffrage
- Women entering the workforce
- Smartphone adoption
- The sexual revolution
The workplace integration of women and men from the 1960s-70s onwards created routine mixed-sex non-romantic contact on an unprecedented scale, normalising cross-sex friendships. Research suggests these friendships are often complicated by differing perceptions — studies found men tend to overestimate romantic interest from female friends more than the reverse.
10. The 'Best Friends Forever' (BFF) concept suggests intense, exclusive friendships. Research into young women's friendships found these 'best friend' pairs are associated with what outcome?
- Lower long-term wellbeing than broader friendship networks
- More social exclusivity and bullying
- Higher self-esteem but more anxiety
- Greater emotional competence and resilience
Studies of adolescent girls found that those with a 'best friend' — even one extremely close companion — developed better emotional regulation and coping skills than those with only peripheral friendships. However, research also shows that adults benefit from broader networks of moderate-quality friendships rather than dependency on one intense bond.
11. Which 18th-century philosopher wrote that 'Friendship is a single soul dwelling in two bodies'?
- David Hume
- This is actually from Aristotle
- John Locke
- Immanuel Kant
The quote — 'What is a friend? A single soul dwelling in two bodies' — is attributed to Aristotle, not an 18th-century philosopher. It's one of philosophy's most quoted friendship observations. Aristotle devoted more pages to friendship in his ethics than to any other virtue, viewing it as essential to the good life and political community.
12. Online friendships have been studied extensively. Research generally finds they are:
- Harmful to overall wellbeing compared to face-to-face contact
- More meaningful due to deliberate effort required
- Less emotionally meaningful than offline friendships
- Equally meaningful to offline friendships when maintained actively
Multiple studies have found that regularly maintained online friendships — through video calls, messaging, and shared online activities — provide comparable emotional support to in-person friendships. The key variable is maintenance quality, not medium. However, passive social media browsing (watching others' updates without interaction) consistently correlates with lower wellbeing.
13. In many cultures, there are formal rituals for declaring close friendship. The German concept of 'Duzen' involves what transition?
- Becoming godparents to each other's children
- Moving from formal 'Sie' to informal 'Du' address
- A public declaration of friendship at a celebration
- Exchanging meaningful gifts
German (like many European languages) distinguishes formal and informal pronouns. The ritual of 'Brüderschaft trinken' (drinking brotherhood) — linking arms and drinking simultaneously before switching to informal address — marks the transition to genuine friendship. In modern Germany this is less common, but the linguistic distinction still encodes the depth of social relationship.
14. The 'loneliness epidemic' is described as a public health crisis. Which country became the first to appoint a dedicated 'Minister for Loneliness' in 2018?
- Sweden
- United Kingdom
- Canada
- Denmark
The UK appointed Tracey Crouch as the world's first Minister for Loneliness in January 2018. The appointment was partly triggered by research showing 9 million Britons regularly felt lonely — a figure exacerbated by urbanisation, social media use, and the breakdown of traditional community structures. The COVID-19 pandemic further intensified global loneliness.
15. Research into 'friendship chemistry' — the feeling of immediate connection with someone — has found it most commonly occurs when:
- People are in a vulnerable emotional state
- People meet through mutual friends
- People are highly similar in values but have complementary personalities
- People share exactly the same personality type
The 'similarity-attraction effect' is well-established — we like people similar to us in values, attitudes, and interests. But complementarity in personality (introverts and extroverts pairing well) is equally documented. The combination of shared values and different social strengths appears to create the most enduring friendships: agreeing on what matters while each bringing different skills.