The Psychology of Automation

It’s easy to overlook the power of human motivation in automation systems.

I’m going to assume you don’t work in a lights-out factory. That’s pretty rare. Almost all automation systems interact with people on a regular basis, and even though we have high fidelity control over our automation processes, people are notoriously difficult to predict, let alone control.

For instance, consider a process with a reject station. Finished parts are measured and parts that don’t meet specification are diverted down a chute. Good parts continue down the line.

Question: how big do you make the reject bin? Naively you might want to make it as big as possible so the operator doesn’t have to waste time emptying it. Unfortunately that means it’s just as easy to make bad parts as it is to make good parts. You’d be better off to make the reject chute only hold 3 parts, and put a full sensor on the chute that throws a fault and stops the machine when it’s fully. Then it’ll be a pain in the ass to make bad parts, and the operator will have a lot more motivation to do something about it. While you’re at it, put the reject chute on the other side of the machine so they have to walk around the machine to empty it.

Consider a machine with an e-stop button. It’s a big red button with a mushroom head that’s supposed to be easy to hit. However, I’ve seen a lot of machines where the consequence of hitting that button was major downtime because the part tracking got screwed up or the machine just didn’t recover gracefully. I once watched a pallet get bumped out of the track and it was riding along the rail of the conveyor. I hit the e-stop just before it was about to damage some equipment. I was scolded for my efforts: “never hit the e-stop,” he said. That’s the wrong motivation. You want operators to press the button when they see something wrong, so make it easy to recover.

Consider an inventory tracking system. You want people to record stuff they’ve consumed, and what cost account they’ve consumed it against. What motivation does a person standing there with a bolt in their hand have to look up that bolt in your inventory system and mark it consumed? Very little. What if you lock the door to the store room and make them request an item before you unlock the door? That’ll help, but chances are some people who don’t know exactly what they want will click the first item on the list, and just go in and browse. What if you make the inventory storage system so convoluted that the only way to find an item is to look up the storage location in the computer? Well, that might work (until your inventory system breaks).

Like water, people tend to take the easiest path down hill. You’re better off digging a channel where you want it to go than expecting it to get there under its own power. Use gravity to your advantage. Make it harder to do things the wrong way and easier to do things the right way.

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