The Nature of the Hand

The Hand: A built-in mechanism of self-preservation provides this complex apparatus with the ability to sustain a lifetime of use. 

Hands are a perceptual organ, playing a crucial role in gathering information about the world. 

Fingers can tell us whether a surface is smooth or rough...

wet or dry...

hot or cold...

soft or hard...

Hands contain nociceptors, which are implicated in pain responses... 

The hand is not just a neutral observer, it is an instrument of value. 

With respect to gathering sensory information, the hand allows us to receive proprioceptive information... the position of our fingers and wrists - and kinesthetic information - the tension in our muscles... 

Through a combination of touch and proprioception, when our fingers bend against a surface, we infer curvature...

When muscles tense while lifting an object, we can even discern its weight, and even its approximate shape from kinesthesia...

Our haptic senses also interact with vision and other modalities. We see an object and spontaneously imagine what it would be like to touch it..

Haptic senses, because they often exploit bodily movement, may present space in a way that is more decidedly external. When we see an image and imagine reaching for it or exploring it with our hands, we convert the visual information into an action that is quite literally extended in the world. This may contribute to our impression that things are meant to be touched. 

Do Not Touch Me

Paolo Veronese 

Musée des Beaux-Arts, Grenoble, France

When we see something as graspable, we imagine what it will feel like when we take hold of it. 

This is what J.J. Gibson called an affordance: an immediate registration of an object's potential for interaction. This takes us beyond the purely sensory aspects of the hand to an entirely distinct feature: Hands are things with which we act. 

The evolution of the prehensile thumb and the bipedal gate has made us especially skilled at manipulating our world. Hands are a sine qua non for the manufacture of artifacts, which are distinctively human. 

Hands allow us to do many things that other creatures do with their mouths...

Hands and haptic imagery are also important for thinking and problem solving. The most obvious case of this is calculation. Here, we perform operations with our hands that we perform in our heads. 

When we see someone grasping something, we spontaneously imagine grasping the object ourselves. It is difficult to observe someone doing something with his or her hands without feeling an impulse to do it ourselves. 

We use hands to greet one another... which promotes trust

to console... a hand on the shoulder can bring comfort

to caress...

and to fight!

Hands bind us together, and set us apart. Touching another person and being touched have strong psychological effects. 

Hands play a poetic role in our lives, going beyond mere communication, adding an aesthetic dimension. 

Gestures can provide emphasis, indicate content, and serve as cognitive crutches for the speaker... as well as the listener-observer. 

Some gestures do not always translate cross-culturally...

North American "Okay" sign

Something less polite in Brazil

Gestures can also be expressive of positive feelings, such as when we applaud...

or offer a fetchingly curled "come hither" expression...

or make a sweeping "be gone!" motion...

It is no surprise that many researchers think language originated in gesture. 

Without hands, without fingers to type, I would not be able to write this article, nor would Matteo Baccarini, Andrew J. Bremner, Massimiliano L. Cappuccio, Andy Clark, Jonathan Cole, Dorothy Cowie, Natalie Depraz, Rosalyn Driscoll, Harry Farmer, Shaun Gallagher, Nicolas P. Holmes, Daniel D. Hutto, Angelo Maravita, Filip Mattens, Richard Menary, Jesse J. Prinz, Zdravko Radman, Matthew Ratcliffe, Etiennne B. Roesch, Stephen V. Shepherd, Susan A. J. Stuard, Manos Tsakiris, and Michael Wheeler been able to contribute to The Hand, an Organ of the Mind. 

Many thanks to Richard A. Berger and Arnold-Peter C. Weiss for helping me to understand that hand surgery was not in the cards for me...