Brainless Decision-Making

Ed Yong's blog at Discover magazine has an interesting post on slime mold and its decision-making capability. You may be shocked -- I certainly was -- to discover that slime mold with no brain uses a similar decision-making technique to what humans do when offered choices...

A couple arrive at a fancy restaurant and they’re offered the wine list. This establishment only has two bottles on offer, one costing £5 and the other costing £25. The second bottle seems too expensive and the diners select the cheaper one. The next week, they return. Now, there’s a third bottle on the list but it’s a vintage, priced at a staggering £1,000. Suddenly, the £25 bottle doesn’t seem all that expensive, and this time, the diners choose it instead.
Businesses use this tactic all the time – an extremely expensive option is used to make mid-range ones suddenly seem like attractive buys. The strategy only works because humans like to compare our options, rather than paying attention to their absolute values. In the wine example, the existence of the third bottle shouldn’t matter – the £25 option costs the same amount either way, but in one scenario it looks like a rip-off and in another, it looks like a steal. The simple fact is that to us, a thing’s value depends on the things around it. Economists often refer to this as “irrational”.
But if that’s the case, we’re not alone in our folly. Other animals, from birds to bees, make choices in the same way. Now, Tanya Latty and Madeleine Beekman from the University of Sydney, have found the same style of decision-making in a creature that’s completely unlike any of these animals – the slime mould, Physarum polycephalum. It’s a single-celled, amoeba-like creature that doesn’t have a brain.

Go read the rest of the post to discover the details of the experiments. They are fascinating... and humbling. Science has so many ways to chip away at our ego that wants so badly to tell us that we are "special".

At the posting, Ed Yong includes this video of an experiment with slime mold. This particular slime mold showed craftiness but also a bludering inability to find its food...