In the research, some blindfolded volunteers were holding a stick that was submitted to external impacts, and all the participants were able to localise the impact with an almost perfect accuracy, as if the touch took place directly on their arm. This behaviour is due to the somatosensory system ability to use rapidly and efficiently the tool as a tactile extension of the body. In addition, using electroencephalography (EEG), the researchers discovered that the position of the impact on the tool is decoded through the neural dynamic of the primary somatosensory cortex end the hind parietal regions: the same ones that activate when the contact is directly on the body. The research demonstrates that tools, thanks to the somatosensory system, expand the boundaries of our body at the neuronal level. Rather than limited to the skin, the somatosensory processing stretches the contact to the tool we are using. This enables us to use a tool like a non-neural extended sense organ, which can efficiently scan the surroundings as if it were a limb.
The peculiarity to use tools as instruments to extend the body abilities has represented an important step in human evolution. Even if nowadays we know about several animals that can use utensils, none of them has reached the human perfection level when performing this ability. But now we have scientific proof of what we had already known empirically: the tools we use become a particularly precise extension of our hands. Those of us who make pipes, as well as all artisans and artists dealing with small-sized objects, know very well what this means. The file, the knife, the sanding band running on our finger, the intensity and direction of the contact between briar and sanding pad, even the tool on the lathe we use to drill, are not felt like barriers between our hands and the object we are shaping, on the contrary, they give our fingers exceptional function without losing sensibility.
However, a specification is needed; also this one is every good craftsman’s empiric asset: tools with same functions have remarkably different performances. Every Sicilian knows the popular saying “tools make the master”. So, if we can, we try to snap up an old Swiss lathe rather than a shining new one, 90% made in China for sure despite its European name. And this principle is valid for any other tool. You don’t economise on tools. They represent an essential investment to grant our production final quality.
