Complexity is in the eye of the beholder

Wasp_vs_Spider_Fight_(2786000021)

by Aditi Mishra – Have you ever stolen a glance or sneaked a peek? If yes; you owe a thanks to your primate heritage.

It takes less than a heartbeat for a primate to discriminate – literally. In 1996 Simon Thorpe found that mere 20 ms are enough for humans to determine whether an image has animals or not. The same group later found in 2006 that you don’t even need focus; even a fleeting glance of 120ms divided between 2 images is enough.

So how do brains do this? From what we know today, brains use simpler features of the images and of course their awesome parallel processors derived from 80 billion neurons and many times more connections between them. To give ourselves some context, IBM’s “brain-like chip” has 4096 cores while a MacBook pro has only 6. Caveat: it is still a ‘brain-like chip’, it is not the brain.

So this mass of fat-filled jelly between our ears – the source of all our joys and all our sufferings – is really powerful.

But what can you do when your processor is not as powerful but its needs are similar?

Spider_and_bee_June_2008-1

A honey bee has 100,000 times fewer neurons as compared to humans, but it has to outrun predators lunging at it in record speeds.

Being tiny has benefits, but a tiny brain is certainly not one of them. Fewer neurons implies downsizing and a paucity of neurons can severally limit the amount of parallel processing that can be accomplished. To indulge ourselves in comparisons, while thousands of neurons are involved in reward processing in the primate brain, in flies this duty has been relegated to one neuron only.

Further miniaturization is also the mother of multitasking. Thanks to fewer neurons, the same neuron has to participate in multiple pathways. Scarcity and multitasking culminates into the observation that bees can distinguish nothing more than colors and edges, in timeframes where a primate can typically distinguish even subtle facial features.

This determines your success at distinguishing a sphere hurtling towards you (where spiders excel) from a spherical spider ambushing you (where, as shown in the image above, spiders can suffer). While a fleeting glimpse is potentially enough for humans, bees need to pay attention for the same. Sadly attention is paid for with time, making the bee slower and vulnerable.

But all is not lost for the tiny bee fighting cryptic spiders; their brains have perfected doing even more with less. Partitioning attention across modalities increases the odds of bees detecting cryptic spiders.

Chittka’s lab found in 2015 that bees are better at avoiding robotic spiders hidden among flowers when they are trained to distinguish flowers by scent rather than visual cues. Simply said, given the option of discriminating flowers by their odors, bees can keep their eyes peeled for predators while searching for flowers using their antennas.

When bee eyes have too much to do, bees focus on some tasks with their antennae instead. Complexity of the task, eating without being eaten, is distributed between different senses.

Interesting, but what does could this mean for a highly visual species like us? Can we partition attention similarly? Can we harness stimuli from multiple senses to enhance our performance? Would warning labels work better if they were rougher to touch or squeaky when touched?

It might be the case, it might not be. Insects and primates had different strengths and struggles in the story of their being. The evolution that shaped them could have fashioned their brains to work differently, or not.

Regardless of this, bee brains are still an excellent study in parsimony. Understanding how tiny brains and tiny systems hedge bets in their favor gives bigger brains some food for thought. Rumination of a different kind.

References

Nityananda V, Chittka L: Modality-specific attention in foraging bumblebees. R. Soc. Open Sci. 2015, 2:150324

Spaethe J, Tautz J, Chittka L: Do honeybees detect colour targets using serial or parallel visual search? J. Exp. Biol. 2006, 209:987-993.

Nityananda V, Skorupski P, Chittka L: Can bees see at a glance? J. Exp. Biol. 2014, 217:1933-1939.

Thorpe, S., Fize, D., & Marlot, C. (1996). Speed of processing in the human visual system. Nature381(6582), 520.

Kirchner, H., & Thorpe, S. J. (2006). Ultra-rapid object detection with saccadic eye movements: Visual processing speed revisited. Vision research46(11), 1762-1776.

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