An organism may use misinformation, knowingly (through deception) or unknowingly (as in the case of camouflage), to gain advantage in a competitive environment. From an evolutionary perspective, greater tactical deception occurs among primates closer to humans, with larger neocortices. In humans, the onset of deceptive behaviours in childhood exhibits a developmental trajectory, which may be regarded as 'normal' in the majority and deficient among a minority with certain neurodevelopmental disorders (e.g. autism). In the human adult, deception and lying exhibit features consistent with their use of 'higher' or 'executive' brain systems. Accurate detection of deception in humans may be of particular importance in forensic practice, while an understanding of its cognitive neurobiology may have implications for models of 'theory of mind' and social cognition, and societal notions of responsibility, guilt and mitigation. In recent years, functional neuroimaging techniques (especially functional magnetic resonance imaging) have been used to study deception. Though few in number, and using very different experimental protocols, studies published in the peer-reviewed literature exhibit certain consistencies. Attempted deception is associated with activation of executive brain regions (particularly prefrontal and anterior cingulate cortices), while truthful responding has not been shown to be associated with any areas of increased activation (relative to deception). Hence, truthful responding may comprise a relative 'baseline' in human cognition and communication. The subject who lies may necessarily engage 'higher' brain centres, consistent with a purpose or intention (to deceive). While the principle of executive control during deception remains plausible, its precise anatomy awaits elucidation.

Relations between an early interest in violent fantasy and children's social understanding, antisocial and emotional behavior, and interactions with friends were investigated in 40 "hard-to-manage" preschoolers and 40 control children matched for gender, age, and school and ethnic background. Children were filmed alone in a room with a friend, and tested on a battery of cognitive tests, including false-belief, executive function, and emotion understanding tasks. Teachers reported on their friendship quality. At age 6 years, the children's understanding of the emotional consequences of antisocial and prosocial actions was studied. The hard-to-manage group showed higher rates of violent fantasy; across both groups combined, violent fantasy was related to poor executive control and language ability, frequent antisocial behavior, displays of anger and refusal to help a friend, poor communication and coordination of play, more conflict with a friend, and less empathic moral sensibility 2 years later. The usefulness of a focus on the content of children's pretend play-in particular, violent fantasy-as a window on children's preoccupations is considered.

No abstract

Lying and deception are common human activities and may occur in a wide variety of clinical contexts. These behaviours implicate higher neural systems within the brains of humans and other primates. Recent functional neuroimaging studies suggest that prefrontal and anterior cingulate cortices are particularly engaged during certain forms of deception, hence, that executive processes support deceit. Congruent with the latter position is the finding that lies take longer to execute than truthful responses. To date, no functional neuroimaging study has demonstrated brain regions exhibiting greater activation during truth telling (compared with lying). Although the latter may reflect a Type II error, it also supports the hypothesis that truthfulness comprises a relative baseline in human cognition and communication. Those psychiatric disorders particularly associated with the practice of deception are varied both in aetiology and the degree to which deceit is central to their conceptualisation. Nevertheless, the deceiving human is likely to be engaging components of their cognitive executive system, a proposal with implications for societal notions of responsibility and mitigation. A successful lie denotes a functioning executive.

No abstract