Human beings evolved an ability to navigate a world filled with different forms of uncertainty. Every day people make plans and perform actions that involve other people, be it deciding for them, together with them or just taking into account their judgements. At the same time we have an ability for abstraction and make decisions that might not have a social content (e.g. playing a hand of poker with a computer or building an investment portfolio that would return the highest financial profit). Until recently the brain mechanisms underlying social and non-social types of choices have been examined from different theoretical angles. In the non-social domain of decision-making (for example, when playing probabilistic games), scientists have often focused on the neural code underlying value computations associated with the rewarding properties of the choice. By contrast, researchers studying social decisions (for example, playing games with a human opponent) have often focused on neural processes that may have evolved to guide social behaviour. On the one hand, non-social oriented research led to the discovery of brain regions involved in value computation and to the idea of a common currency system evaluating the motivational relevance of any kind of stimuli (Chapter 1). On the other hand, social oriented research exposed a number of brain structures specifically involved in representing intentions, emotions or actions of other people, leading to the idea of a social specific type of cognition (Chapter 2). More recently studies comparing social and non-social types of decision-making have challenged such dichotomy and suggested social decisions may also depend on valuerelated neural processes in use during non-social decisions (Chapter 3)