If you tickle a rat's belly, it squeals with laughter. However, we are unable to perceive this laughter as its frequency, around 50 kHz, exceeds the range of human hearing. Neuroscientist Jaak ...

In humans, emotions can bias our thinking and decision-making. For instance, depressed or anxious people tend to be more pessimistic than happier people, expecting bad things to happen and paying more ...