  Honesty plays a crucial role in any situation where organisms exchange
information or resources. Dishonesty can thus be expected to have damaging
effects on social coherence if agents cannot trust the information or goods
they receive. However, a distinction is often drawn between prosocial lies
('white' lies) and antisocial lying (i.e. deception for personal gain), with
the former being considered much less destructive than the latter. We use an
agent-based model to show that antisocial lying causes social networks to
become increasingly fragmented. Antisocial dishonesty thus places strong
constraints on the size and cohesion of social communities, providing a major
hurdle that organisms have to overcome (e.g. by evolving counter-deception
strategies) in order to evolve large, socially cohesive communities. In
contrast, 'white' lies can prove to be beneficial in smoothing the flow of
interactions and facilitating a larger, more integrated network. Our results
demonstrate that these group-level effects can arise as emergent properties of
interactions at the dyadic level. The balance between prosocial and antisocial
lies may set constraints on the structure of social networks, and hence the
shape of society as a whole.
