Recursive language and modern imagination were acquired simultaneously 70,000 years ago
by Pensoft Publishers
The lion-man sculpture from Germany (dated to 37,000 years ago) must have been first imagined by the artist by mentally synthesizing parts of the man and beast together and then executing the product of this mental creation in ivory. The composite artworks provide a direct evidence that by 37,000 years ago humans have acquired prefrontal synthesis. Credit: JDuckeck [Public domain, commons.wikimedia.org/wiki/File:Lion_man_photo.jpg]
A genetic mutation that slowed down the development of the prefrontal cortex (PFC) in two or more children may have triggered a cascade of events leading to acquisition of recursive language and modern imagination 70,000 years ago.
This new hypothesis, called Romulus and Remus and coined by Dr. Vyshedskiy, a neuroscientist from Boston University, might be able to solve the long-standing mystery of language evolution. It is published in the open-science journal Research Ideas and Outcomes (RIO).
Numerous archeological and genetic evidence have already convinced most paleoanthropologists that the speech apparatus has reached essentially modern configurations before the human line split from the Neanderthal line 600,000 years ago. Considering that the chimpanzee communication system already has 20 to 100 different vocalizations, it is likely that the modern-like remodeling of the vocal apparatus extended our ancestors' range of vocalizations by orders of magnitude. In other words, by 600,000 years ago, the number of distinct verbalizations used for communication must have been on par with the number of words in modern languages.
On the other hand, artifacts signifying modern imagination, such as composite figurative arts, elaborate burials, bone needles with an eye, and construction of dwellings arose not earlier than 70,000 years ago. The half million-year-gap between the acquisition of the modern speech apparatus and modern imagination has baffled scientists for decades.
While studying acquisition of imagination in children, Dr. Vyshedskiy and his colleagues discovered a temporal limit for the development of a particular component of imagination. It became apparent that modern children who have not been exposed to full language in early childhood never acquire the type of active constructive imagination essential for juxtaposition of mental objects, known as Prefrontal Synthesis (PFS).
Dr. Vyshedskiy explains:
"To understand the importance of PFS, consider these two sentences: "A dog bit my friend" and "My friend bit a dog." It is impossible to distinguish the difference in meaning using words or grammar alone, since both words and grammatical structure are identical in these two sentences. Understanding the difference in meaning and appreciating the misfortune of the 1st sentence and the humor of the 2nd sentence depends on the listener's ability to juxtapose the two mental objects: the friend and the dog. Only after the PFC forms the two different images in front of the mind's eye, are we able to understand the difference between the two sentences. Similarly, nested explanations, such as "a snake on the boulder to the left of the tall tree that is behind the hill," force listeners to use PFS to combine objects (a snake, the boulder, the tree, and the hill) into a novel scene. Flexible object combination and nesting (otherwise known as recursion) are characteristic features of all human languages. For this reason, linguists refer to modern languages as recursive languages."
Unlike vocabulary and grammar acquisition, which can be learned throughout one's lifetime, there is a strong critical period for the development of PFS and individuals not exposed to conversations with recursive language in early childhood can never acquire PFS as adults. Their language is always lacking understanding of spatial prepositions and recursion that depend on the PFS ability. In a similar manner, pre-modern humans would not have been able to learn recursive language as adults and, therefore, would not be able to teach recursive language to their own children, who, as a result, would not acquire PFS. Thus, the existence of a strong critical period for PFS acquisition creates a cultural evolutionary barrier for acquisition of recursive language.
When you look at the skillfully worked Schöningen Spears that are about 300.000 years old and their purpose, then you can't believe that this spatial conception and the accompanying language of the builders is only 70.000 years old.
The spears, deformed by the load of the sediment pressure, are made from slim, straight spruce stems – except for spear IV which is made from pine wood. The spears vary in length from 1.82 to 2.25 m (5.97 to 7.38 ft), with diameters ranging from 29 to 47 mm (1.14 to 1.85 in).
They have been worked very thoroughly and are evidence of highly developed technological skills and of a workmanlike tradition. Like in today’s tournament javelins, the greatest diameter and therefore its centre of gravity is in the front third of the shaft. The tips are worked symmetrically from the base of the stems, and the end of the tips were worked beside the medullary ray, the weakest part of the stem, on purpose.
In their throwing qualities, the Schöningen Spears are equal to modern tournament javelins. During tests, athletes could throw replicas up to 70 m (230 ft). The choice of the wood is likely to be climatically determined, because during the cooler climate near the end of the interglacial, conifers grew close to the site of the finds.
More unique wooden artefacts were found at the place of discovery of the wild horse hunting camp: a charred wooden staff (skewer) as well as a wooden tool, tapered at both ends, interpreted as a throwing stick. The stone tools at the place of discovery consist of different scraper-shaped and pointed forms. Evidence of blank production is missing; much retouched debris proves the reworking of the brought-along tools.
Also among the finds are the so-called "grooved wooden tools", excavated at the place of discovery No. 12. Made from the extremely hard wooden branch-bases of the European silver fir, and noticeably incised at one end, they may have been used as a mounting for stone blades. If this interpretation is correct, they are the oldest composite tools of mankind.