We have this issue in one of our experiments where rats have to press a lever in order to receive chocolate milk. The problem is two fold and confounded. The rats develop a bias to both the location of the lever (whether it is the left or right lever) and also to the smell of the lever (whether the lever smells rewarding, based on the rats recent performance). We are already using lcds in our rat experiments but the rats don’t interact with them. Our levers are also already hooked up to usb. So it seems natural to try a touch screen lcd to replace the levers. Through this I could create “levers” on screen and change their location and sideness in order to overcome any potential bias in the rat. The problem is that the rats are constantly in search and destroy mode, and there is no chance that a regular lcd touch screen will last very long.
Can anyone think of a way to get around this issue, that is both cheap and reliable/robust?
I don’t know how modern touch screens work but I do know how Hewlett-Packard tried to implement one about 25 years ago. It never caught on because it was so rare (and HP used their own weird Basic) that nobody wrote any software for it. It was not actual touch but required breaking an infra-red grid across the screen. It could be fooled as well by ‘going in’ at one place and ‘coming out’ at another, then it recorded the ‘out’ not the ‘in’ as the ‘touch’. Suggest then having a screen covered with glass (as some good laptops do) that the rats can’t get through and surround that with a bezel containing a photo-emitter and receptor grid. I expect this could be made a lot tighter than HP’s that I think was about an inch spacing (or maybe 2cm). I can’t remember the model.
The iPhone/iPod Touch’s screen seems pretty resilient to me. If you can find a source for similar screens, that might work. You could try using an actual iPod Touch with a custom app to do what you need, but you’d probably have to be reliant on controlling it over a wireless network, which might not give you the reliability you’d need. You’d also be paying for a lot of capabilities you don’t actually need…
ETA: I’m also not sure how responsive that type of screen would be to the “touches” a rat would do…
There’s several touch-screen technologies. Wiki link.. Some require to be touched by skin, others by anything pointy, while others as was mentioned work with light.
Most are pretty durable, however. They are used in all kinds of public terminals and are typically more reliable than buttons (or levers). Of course, noone tries to gnaw at them, but I imagine gnawing a flat surface isn’t easy.
There are very tough plastic touchscreen “skins” available that are designed to mitigate the beating and poking that many undergo. Place one of these self adhering skins over the place the rats will touch.