it seems attractive to suggest that the similarities between numerical and perceptual absences could help reveal the neural basis of not only experiences of absence but conscious awareness more broadly. Jean-Paul Sartre testified that nothingness was at the heart of being, after all.

it’s harder to have self-reflective insight into our experiences of absence than our experiences of presence.

Classic evidence for this comes from the ‘feature positive effect’, which describes how a presence of something is easier to detect than its absence. For example, when four-month-olds are familiarised with the letter ‘F’, they will be surprised when the next symbol to appear is an ‘E’, which has an extra stroke at the bottom. But when the order is... See more

The brain’s sensory systems are geared towards detecting the presence of objects, rather than their absence: when an object encroaches on your visual field, generally speaking, neurons in your visual cortex are activated. Moreover, this bias towards detecting objects has been reflected in scientific interest in the topic: most neuroscientific... See more

Understanding, and using, zero requires a move away from the physical world into the abstract world of concepts, which may be why children take longer to master zero, compared with other countable numbers