Hand Signals of Design

The human hand turns out to have much more capability for complex movement than scientists thought.

Watch a good pianist or someone skilled at sign language, and you will undoubtedly be impressed with the extremely rapid yet precise movements of the human hand. Each of us typing at a computer experiences some of that ability, too. And simple everyday tasks—opening a jar, turning a steering wheel, buttoning a shirt or blouse—could be seen as amazing feats, when considered in slow motion. Can science explain these things in simple terms?

Scientists at the University of Chicago decided to test an “oft replicated finding” that hand kinematics can be described in 8 to 10 dimensions of volitional control. Anything beyond that was judged to be “noise” over which the brain had no control. What they found, to their surprise, was “unexpected complexity of everyday manual behaviors” that punch through the limits earlier scientists had set. In Nature Communications today (16 July 2020), they begin with some of the wonders of the human hand-brain connection:

From picking up a coffee cup to playing the piano, humans can engage in a wide range of manual behaviors, highlighting the staggering flexibility of the hand, whose 27 bones and 39 muscles give rise to >20 biomechanical degrees of freedom (DOF) for volitional movement. This versatility is also supported by a sophisticated neural system: the hand is one of the most densely innervated regions of the human body, and the hand representation in sensorimotor cortex is disproportionately large. In addition, although primate motor cortex lacks a clear somatotopic organization, it nonetheless seems to contain a specialized module for hand control.

So “How does the brain control an effector as complex and versatile as the hand?” The team of five did some checking on human subjects in two tasks: grasping, and performing sign language. They monitored the positions of reflective dots on the hands as the subjects performed the motions. What they found is that the sum is greater than the parts:

Illustra Media

The complexity of hand movements might be interpreted as evidence against the general notion that motor control occupies a low-dimensional manifold. Another possibility, however, is that the hand is a uniquely complex effector and constitutes an exception to this rule. Indeed, the kinematics of the hand are higher dimensional than are those of other effectors. Moreover, a subdivision of primate M1 has direct access to motoneurons that innervate muscles, particularly muscles of the hand, which could be construed as anatomical support for the notion that hand control is special. A common argument in support of low-dimensional motor control is that the brain needs to simplify the problem of controlling a complex effector, such as a hand, to solve it. Note, however, that control signals required for a 29 DOF effector still occupy a neural manifold whose dimensionality is much lower than that of the possible neural space spanned by the activity of all neurons modulated by the task.

The hand, indeed, turns out to have “unexpected complexity” even in everyday manual tasks: not just 8 to 10 degrees of freedom, but at least 29. And the brain can handle that, no problem! Is the hand quicker than the eye? Look at what the brain handles in vision:

Recent advances in large-scale neuronal recordings suggest that high-dimensional representations are possible if not common: sensory representations of natural scenes in primary visual cortex exceed 500 dimensions, an order of magnitude more than the implied representations of hand postures. Nonetheless, visual percepts are highly intuitive and allow for the accurate, rapid, and effortless identification of complex objects. In comparison, motor control is positively straightforward!

One doesn’t often encounter exclamation points in scientific papers. The fact that this paper ends with a bang (!) indicates that the scientists were impressed!

This paper illustrates well a Law of Scientific Papers often seen at Creation-Evolution Headlines: The more complexity is discussed, the less talk about evolution. There was no mention in this paper of evolution, Darwin, or natural selection. The authors mentioned nonhuman primates, but not in any sense of relationship; rather, they only discussed common neuromotor abilities in control of the hand. Although apes can grasp things well, one doesn’t see them translating speech into another language by means of hand signs, or playing the piano, or building complex machines with hand tools. Human hands are unique in the living world for their flexibility to perform numerous creative acts under the control of the eye and exceptional human brain.

THE HAND AS METAPHOR

Hands are very special creations of Almighty God, which we should care for and use for good deeds. The Bible often uses the metaphor of the “Hand of God” to illustrate his masterful skill as an artisan:

When I look at your heavens, the work of your fingers, the moon and the stars, which you have set in place, what is man that you are mindful of him, and the son of man that you care for him? (Psalm 8:2-4)

Because they do not regard the works of the Lord or the work of his hands, he will tear them down and build them up no more. (Psalm 28:5)

For you, O Lord, have made me glad by your work; at the works of your hands I sing for joy. (Psalm 92:4)

Of old you laid the foundation of the earth, and the heavens are the work of your hands. (Psalm 102:25)

He has shown his people the power of his works, in giving them the inheritance of the nations. The works of his hands are faithful and just; all his precepts are trustworthy; they are established forever and ever, to be performed with faithfulness and uprightness. (Psalm 111:6-8)

The Lord will fulfill his purpose for me; your steadfast love, O Lord, endures forever. Do not forsake the work of your hands. (Psalm 138:8)

I remember the days of old; I meditate on all that you have done; I ponder the work of your hands. (Psalm 143:5)

They have lyre and harp, tambourine and flute and wine at their feasts, but they do not regard the deeds of the Lord, or see the work of his hands. (Isaiah 5:12)

But now, O Lord, you are our Father; we are the clay, and you are our potter; we are all the work of your hand. (Isaiah 64:8)

And, “You, Lord, laid the foundation of the earth in the beginning, and the heavens are the work of your hands” (Hebrews 1:10)

The Hand of God metaphor is also used of God’s sovereignty in dealings with man, including judgment:

Then the magicians said to Pharaoh, “This is the finger of God.” But Pharaoh’s heart was hardened, and he would not listen to them, as the Lord had said. (Exodus 8:19)

And he gave to Moses, when he had finished speaking with him on Mount Sinai, the two tablets of the testimony, tablets of stone, written with the finger of God. (Exodus 30:18)

For there was a deathly panic throughout the whole city. The hand of God was very heavy there. (I Samuel 5:11)

The hand of God was also on Judah to give them one heart to do what the king and the princes commanded by the word of the Lord. (II Chronicles 30:12)

Have mercy on me, have mercy on me, O you my friends, for the hand of God has touched me! (Job 19:21)

There is nothing better for a person than that he should eat and drink and find enjoyment in his toil. This also, I saw, is from the hand of God, for apart from him who can eat or who can have enjoyment? (Ecclesiastes 2:24-25)

But all this I laid to heart, examining it all, how the righteous and the wise and their deeds are in the hand of God. Whether it is love or hate, man does not know; both are before him. (Ecclesiastes 9:1)

It is a fearful thing to fall into the hands of the living God. (Hebrews 10:31)

Human hands are frail, but the hand of God is mighty! This metaphor should bring people to repentance and awe.

O Lord God, you have only begun to show your servant your greatness and your mighty hand. For what god is there in heaven or on earth who can do such works and mighty acts as yours? (Deuteronomy 3:24)

And the Lord brought us out of Egypt with a mighty hand and an outstretched arm, with great deeds of terror, with signs and wonders. (Deuteronomy 26:8)

so that all the peoples of the earth may know that the hand of the Lord is mighty, that you may fear the Lord your God forever.” (Joshua 4:24)

Likewise, when a foreigner, who is not of your people Israel, comes from a far country for the sake of your great name and your mighty hand and your outstretched arm, when he comes and prays toward this house, hear from heaven your dwelling place and do according to all for which the foreigner calls to you, in order that all the peoples of the earth may know your name and fear you, as do your people Israel, and that they may know that this house that I have built is called by your name. (II Chronicles 6:32-33, prayer of Solomon at dedication of the temple)

“O Lord, God of our fathers, are you not God in heaven? You rule over all the kingdoms of the nations. In your hand are power and might, so that none is able to withstand you. (II Chronicles 20:6)

“The hand of our God is for good on all who seek him, and the power of his wrath is against all who forsake him.” (Ezra 8:22)

I will bring you out from the peoples and gather you out of the countries where you are scattered, with a mighty hand and an outstretched arm, and with wrath poured out. (Ezekiel 20:34)

And now, O Lord our God, who brought your people out of the land of Egypt with a mighty hand, and have made a name for yourself, as at this day, we have sinned, we have done wickedly. (Daniel 9:24)

God came from Teman, and the Holy One from Mount Paran. Selah. His splendor covered the heavens, and the earth was full of his praise.His brightness was like the light; rays flashed from his hand; and there he veiled his power. (Habakkuk 3:3-5)

Humble yourselves, therefore, under the mighty hand of God so that at the proper time he may exalt you. (I Peter 5:6)

The power of God’s mighty hand was with Jesus when he walked the Earth:

And on the Sabbath he began to teach in the synagogue, and many who heard him were astonished, saying, “Where did this man get these things? What is the wisdom given to him? How are such mighty works done by his hands? (Mark 6:2)

But if it is by the finger of God that I cast out demons, then the kingdom of God has come upon you. (Luke 11:20)

And it shall come to pass that everyone who calls upon the name of the Lord shall be saved.’ “Men of Israel, hear these words: Jesus of Nazareth, a man attested to you by God with mighty works and wonders and signs that God did through him in your midst, as you yourselves know— this Jesus, delivered up according to the definite plan and foreknowledge of God, you crucified and killed by the hands of lawless men. (Acts 2:21-23)

Numerous passages state that Jesus was exalted to sit at the right hand of God the Father:

The Lord says to my Lord: “Sit at my right hand, until I make your enemies your footstool.” (Psalm 110:1, prophetic of Messiah)

“But from now on the Son of Man shall be seated at the right hand of the power of God.” (Luke 22:69, Jesus to the Sanhedrin)

And he said, “Behold, I see the heavens opened, and the Son of Man standing at the right hand of God.” (Stephen’s testimony as he was being martyred)

He is the radiance of the glory of God and the exact imprint of his nature, and he upholds the universe by the word of his power. After making purification for sins, he sat down at the right hand of the Majesty on high. (Hebrews 1:3)

And now, the mighty hand of God is outstretched to every man, woman and child, to show mercy and to save. His hand-eye coordination is flawless!

Now I know that the Lord saves his anointed; he will answer him from his holy heaven with the saving might of his right hand. (Psalm 20:6)

For he stands at the right hand of the needy one, to save him from those who condemn his soul to death. (Psalm 109:31)

Behold, the Lord’s hand is not shortened, that it cannot save, or his ear dull, that it cannot hear; but your iniquities have made a separation between you and your God, and your sins have hidden his face from you so that he does not hear. For your hands are defiled with blood and your fingers with iniquity; your lips have spoken lies; your tongue mutters wickedness. (Isaiah 59:1-3)

as he spoke by the mouth of his holy prophets from of old, that we should be saved from our enemies and from the hand of all who hate us; to show the mercy promised to our fathers and to remember his holy covenant (Luke 1:70-72, Zechariah, in the “Benedictus” blessing)

For Christ has entered, not into holy places made with hands, which are copies of the true things, but into heaven itself, now to appear in the presence of God on our behalf. (Hebrews 9:24)

Those who have repented and trusted the Lord for salvation should use their hands to bless others, worship God and do good.

I will lift up my hands toward your commandments, which I love, and I will meditate on your statutes. (Psalm 119:48)

Let us lift up our hearts and hands to God in heaven: (Lamentations 3:41)

and we labor, working with our own hands. (Paul, I Corinthians 4:12)

The eye cannot say to the hand, “I have no need of you,” nor again the head to the feet, “I have no need of you.” On the contrary, the parts of the body that seem to be weaker are indispensable, (I Corinthians 12:21-22)

Let the thief no longer steal, but rather let him labor, doing honest work with his own hands, so that he may have something to share with anyone in need. (Ephesians 4:28)

and to aspire to live quietly, and to mind your own affairs, and to work with your hands, as we instructed you, (I Thessalonians 4:11)

I desire then that in every place the men should pray, lifting holy hands without anger or quarreling; (I Timothy 2:8)

Therefore lift your drooping hands and strengthen your weak knees, and make straight paths for your feet, so that what is lame may not be put out of joint but rather be healed. (Hebrews 12:12-13)