The prototypical UK blood donor, homophily and blood donation: Blood donors are like you, not me.

Background And Objectives: Homophily represents the extent to which people feel others are like them and encourages the uptake of activities they feel people like them do. Currently, there are no data on blood donor homophily with respect to (i) people's representation of the average prototypical UK blood donor and (ii) the degree of homophily with this prototype for current donors, non-donors, groups blood services wish to encourage (ethnic minorities), those who are now eligible following policy changes (e.g.

Introducing IOS as an extended interactive version of the 'Inclusion of Other in the Self' scale to estimate relationship closeness.

The study of relationship closeness has a long history in psychology and is currently expanding across the social sciences, including economics. Estimating relationship closeness requires appropriate tools. Here, we introduce and test a tool for estimating relationship closeness: 'IOS'.

Communicating the move to individualized donor selection policy: Framing messages focused on recipients and safety.

Background: Men-who-have-sex-with-men (MSM) have been deferred from donating blood. However, recent evidence supports the adoption of donor screening based on individuals' sexual behavior over population-based criteria. We explore how best to frame communications about adopting this change to minimize any potential negative consequences (e.

Contextualised strong reciprocity explains selfless cooperation despite selfish intuitions and weak social heuristics.

Humans frequently cooperate for collective benefit, even in one-shot social dilemmas. This provides a challenge for theories of cooperation. Two views focus on intuitions but offer conflicting explanations.

People prefer coordinated punishment in cooperative interactions.

Human groups can often maintain high levels of cooperation despite the threat of exploitation by individuals who reap the benefits of cooperation without contributing to its costs. Prominent theoretical models suggest that cooperation is particularly likely to thrive if people join forces to curb free riding and punish their non-contributing peers in a coordinated fashion. However, it is unclear whether and, if so, how people actually condition their punishment of peers on punishment behaviour by others.