He’d long wanted to take a peek at the anatomy ... Dissection revealed that aye-ayes have an extra thumb, which researchers call a pseudo-thumb. The small structure made of bone and cartilage ...

An extra thumb, huh? I don’t know, that could be pretty cool ... like a carpenter who’s using a hammer all day long. And people have this expression, they say it’s like the hammer becomes an extension ...

but scientists don’t actually know if the human brain can meaningfully support an added body part or the long-term consequences of the extra cognitive load. A user’s view of the Third Thumb.

Press down with one foot and the thumb will make a grasping movement. Lift up to let go of the pressure, and your extra thumb will return to the normal, relaxed position on your hand. Clode's ...

The average user wore the thumb for just under 3 hours a day. To understand how the extra thumb affected people’s brains, the researchers gave them an MRI scan before and after the experiment.

Nobody is seen shaking hands with a third thumb, because that might feel creepy. Cole sees two general paths for her extra thumb. There are utilitarian purposes, making it like a watch or power tool.