In order to comprehend the intricacies of human cognition and social interaction, it is crucial to explore the underlying cognitive processes that support them. This chapter delves into one of the core cognitive abilities – the ‘theory of mind’ (ToM), which allows individuals to infer the thoughts, beliefs and intentions of others. ToM plays a vital role in understanding the complexities of social interaction and contributes to our ability to empathise and communicate effectively. Within the context of psychiatry, investigating ToM impairments is particularly important as they are associated with several mental disorders, such as autism spectrum and schizophrenia. By examining these impairments, researchers aim to uncover the specific neuronal networks and cognitive mechanisms that underlie social cognitive abilities, as well as identify commonalities and differences between patient groups. Gaining a deeper understanding of ToM and its role in various disorders will not only provide valuable insight into the complexities of human cognition but also guide the development of more effective interventions and treatments for affected individuals.

Cognitive abilities in animals can range from simple learning mechanisms to complex mechanisms including causal reasoning, imagination, foresight, and perspective taking. These complex cognitive abilities are thought to have evolved in primates in response to socio-ecological challenges faced by their ancestors. Corvids, a group of large-brained birds, are thought to have evolved comparable cognitive abilities in response to similar socio-ecological pressures. Cephalopods, including octopus, cuttlefish, and squid, also exhibit a subset of complex cognitive abilities despite having evolved independently. Here, we discuss the evolutionary pressures that might have facilitated the emergence of complex cognition in these diverse animal groups. By identifying the cognitive similarities between diverse taxa and recognizing the likely drivers for their emergence, we can derive a more comprehensive understanding of cognitive evolution.