Take honeybees, who have a symbolic ‘language’ by which they can communicate about the precise coordinates of food sources in flowers. In this ‘dance language’, a successful scout bee returning from a good flower patch performs a repetitive sequence of movements in the dark hive on the vertical comb. These movements are keenly attended by other bees. The successful forager moves forward in a straight line for a few centimetres. Then she moves in a half circle to the left, back to her starting point, performs another straight run along the path of her first, and then circles to the right. The duration of the straight run tells other bees the distance to the food source (roughly one second of walking distance in the dance corresponds to a one-kilometre flight to the target). The direction of this run relative to gravity encodes the direction relative to the Sun – for example, if the run in the hive is straight up, this tells other bees to fly in the direction of the Sun (whereas ‘down’ means ‘fly in the opposite direction of the Sun’).
This discovery in 1945 earned the Austrian ethologist Karl von Frisch the Nobel Prize in Physiology or Medicine; in itself, such communication neither indicates nor requires consciousness. A decade later, however, one of von Frisch’s students, Martin Lindauer, peered into a beehive during the night and discovered that some bees advertised the locations of various foraging bonanzas they’d discovered the previous day. Before midnight, they ‘talked about’ locations visited the previous evening – and in the hours before sunrise, they discussed the locations they’d visited on the morning prior.
These bees retrieved their spatial memories entirely out of context, at a time when there was no possibility of foraging and so no immediate need for communication. The function is unclear. They might have ‘just thought’ about these locations spontaneously during the night. Or perhaps the communication is a strategy for consolidating their spatial memory. Scientists have since found that a bee’s memories of the previous day are strengthened when they are exposed to elements of these memories while in deep sleep. Perhaps bees not only think and ‘talk’, but dream?
The key implication of Lindauer’s discovery is that bees are capable of ‘offline thinking’ about spatial locations, and of linking these locations to a time of day, in the absence of an external trigger. That’s not what should happen if bees’ memories are merely prompted by environmental stimuli, combined with internal triggers such as hunger. Bees, then, appear to have at least one of the principal hallmarks of consciousness: representations of time and space.