Saturday, October 10, 2009

The Mind - Singularly Smart

If we scientists are ever to unravel how the human mind came to be, we must first pinpoint exactly what sets it apart from the minds of other creatures. Although humans share the vast majority of their genes with chimps, studies suggest that small genetic shifts that occurred in the human lineage since it split from the chimp line produced massive differences in computational power. This rearranging, deleting and copying of universal genetic elements created a brain with four special properties. Together these distinctive characteristics, which I have recently identified based on studies conducted in my lab and elsewhere, constitute what I term our humaniqueness.

The first such trait is generative computation, the ability to create a virtually limitless variety of “expressions,” be they arrangements of words, sequences of notes, combinations of actions, or strings of mathematical symbols. Generative computation encompasses two types of operation, recursive and combinatorial. Recursion is the repeated use of a rule to create new expressions. Think of the fact that a short phrase can be embedded within another phrase, repeatedly, to create longer, richer descriptions of our thoughts– for example, the simple but poetic expression from Gertrude Stein: “A rose is a rose is a rose.” The combinatorial operation, meanwhile, is the mixing of discrete elements to engender new ideas, which can be expressed as novel words (“Walkman”) or musical forms, among other possibilities.

The second distinguishing characteristic of the human mind is its capacity for the promiscuous combination of ideas. We routinely connect thoughts from different domains of knowledge, allowing our understanding of art, sex, space, causality and friendship to combine. From this mingling, new laws, social relationships and technologies can result, as when we decide that it is forbidden [moral domain] to push someone [motor action domain] intentionally [folk psychology domain] in front of a train [object domain] to save the lives [moral domain] of five [number domain] others.

Third on my list of defining properties is the use of mental symbols. We can spontaneously convert any sensory experience—real or imagined— into a symbol that we can keep to ourselves or express to others through language, art, music or computer code.

Fourth, only humans engage in abstract thought. Unlike animal thoughts, which are largely anchored in sensory and perceptual experiences, many of ours have no clear connection to such events. We alone ponder the likes of unicorns and aliens, nouns and verbs, infinity and God.

Although anthropologists disagree about exactly when the modern human mind took shape, it is clear from the archaeological record that a major transformation occurred during a relatively brief period of evolutionary history, starting approximately 800,000 years ago in the Paleolithic era and crescendoing around 45,000 to 50,000 years ago. It is during this period of the Paleolithic, an evolutionary eyeblink, that we see for the first time multipart tools; animal bones punctured with holes to fashion musical instruments; burials with accoutrements suggesting beliefs about aesthetics and the afterlife; richly symbolic cave paintings that capture in exquisite detail events of the past and the perceived future; and control over fire, a technology that combines our folk physics and psychology and allowed our ancestors to prevail over novel environments by creating warmth and cooking foods to make them edible.

These remnants of our past are magnificent reminders of how our forebears struggled to solve novel environmental problems and express themselves in creative new ways, marking their unique cultural identities. Nevertheless, the archaeological evidence will forever remain silent on the origins and selective pressures that led to the four ingredients making up our humaniqueness. The gorgeous cave paintings at Lascaux, for instance, indicate that our ancestors understood the dual nature of pictures— that they are both objects and refer to objects and events. They do not, however, reveal whether these painters and their admirers expressed their aesthetic preferences about these artworks by means of symbols that were organized into grammatical classes (nouns, verbs, adjectives) or whether they imagined conveying these ideas equally well through sound or sign, depending on the health of their sensory systems. Similarly, none of the ancient instruments that have been found—such as the 35,000-year-old flutes made of bone and ivory— tell a story about use, about whether a few notes were played over and over again, Philip Glass–style, or about whether the composer imagined, as did Wagner, embedding themes within themes in a recursive manner.

What we can say with utmost confidence is that all people, from the hunter-gatherers on the African savanna to the traders on Wall Street, are born with the four ingredients of humaniqueness. How these ingredients are added to the recipe for creating culture varies considerably from group to group, however. Human cultures may differ in their languages, musical compositions, moral norms and artifacts. From the viewpoint of one culture, another’s practices are often bizarre, sometimes distasteful, frequently incomprehensible and occasionally immoral. No other animal exhibits such variation in lifestyle. Looked at in this way, a chimpanzee is a cultural nonstarter.

Chimps and other animals are still interesting and relevant for understanding the origins of the human mind, though. In fact, only by working out which capacities we share with other animals and which are ours alone can scientists hope to piece together the story of how our humaniqueness came to be.

The four traits below distinguish the human mind from those of animals. Uncovering the origin of the human mind will require explaining how these unique properties came about.

Generative computation enables humans to create a virtually limitless variety of words, concepts and things. The characteristic encompasses two types of operation: recursive and combinatorial. Recursion is the repeated use of a rule to create new expressions. The combinatorial operation is the mixing of discrete elements to engender new ideas.

Promiscuous combination of ideas allows the mingling of different domains of knowledge—such as art, sex, space, causality and friendship— thereby generating new laws, social relationships and technologies.

Mental symbols encode sensory experiences both real and imagined, forming the basis of a rich and complex system of communication. Such symbols can be kept to oneself or expressed to others as words or pictures.

Abstract thought permits contemplation of things beyond what we can see, hear, touch, taste or smell.

Source of Information : Scientific American September 2009

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