(2) THE HERO IS INTRODUCED, AND (3) THE SITUATION CHANGES

The new breed of intelligent creatures rapidly spread throughout the whole world and exploited every mode of livelihood. The power of adaptation to the particular kind of life each group chose to pursue soon came to be expressed in a bewildering variety of specializations in structure, some for living on the earth or burrowing in it, others for living in trees or even for flight; others, again, for an aquatic existence. Some mammals became fleet of foot and developed limbs specially adapted to enhance their powers of rapid movement. They attained an early pre-eminence and were able to grow to large dimensions in the slow-moving world of the dawn of the Age of Mammals. (Pp. 27-28)

But danger lurks, as it often does in Eden. So the “inevitable penalty” is levied on all who succumb to the temptation to specialize. “They became definitely committed to one particular kind of life, and in so doing they sacrificed their primitive simplicity and plasticity of structure, and in great measure also their adaptability to new conditions” (p. 28). Clearly there is little value in the purely material for, as Elliot Smith warns, impressive specializations are actually “confessions of weakness,” while primitive traits, thought by some biologists to be degraded, are signs of virtue.

It is important to keep in mind . . . that the retention of primitive characters is often to be looked upon as a token that their possessor has not been compelled to turn aside from the straight path and adopt protective specializations, but has been able to preserve some of the plasticity associated with his primitiveness, precisely because he has not succumbed or fallen away in the struggle for supremacy. It is the wider triumph of the individual who specializes late after benefitting from the many-sided experience of early life, over him who in youth becomes tied to one narrow calling. (Pp. 34-35)

Truly a golden mean, the road to evolutionary success is paved with the nonmaterial. But without a brain to compensate for physical simplicity, such an evolutionary path would lead nowhere. It is the brain, then, that is the key to the retention of primitive traits and to the plasticity signified by the “wider triumph.” But perhaps I am giving away the story.

Like many mythical heroes, then, it is precisely because of its humble origins that a primitive mammal can become something better. It is only because it “took advantage of its insignificance to develop its powers evenly and gradually without sacrificing in narrow specialization any of its possibilities of future achievement” (p. 28) that, eventually, it turns into a human. For Elliot Smith, as for Darwin (Landau et al. 1982, p. 507), it was an “immense advantage” to have sprung from a creature of such small significance. Measuring it at about the size of a squirrel, Elliot

usually feature four important episodes: terrestriality, or a shift from the trees to the ground; bipedalism, or the acquisition of upright posture; encephalization, or the development of the brain, intelligence, and language; and civilization, the emergence of technology, morals, and society. Although the order of these events may vary among accounts,

structure can be represented by nine basic actions or “functions,” each of which can be filled in several ways. (Events that are latent or continuing from a previous stage are shaded in light gray.) The views of Elliot Smith are represented below Darwin and Keith.

Smith models this ancestral creature very closely along the lines of the modern tree shrew: moving in the trees and on the ground, occasionally it sits back on its haunches, using its forepaws to feed on fruits and insects. Of “lively disposition and great agility” (Smith, 1924, p. 29), nevertheless this creature is not a primate. Not until it forsakes completely its mammalian birthplace does it give birth to the new order.

The move up into the trees is thus a pivotal episode in Elliot Smith’s narrative, even more momentous, as we shall see, than the subsequent shift back down. Again, it is by the power of “intelligent adaptation” that Elliot Smith’s hero enters the arboreal realm. There, new selective pressures act on the neopallium and in particular the areas devoted to the sense of sight. Though well-developed even in primitive mammals, until now vision had been subservient to the more ancient reptilian sense of olfaction.

This was due not only to the fact that the sense of smell had already installed its instruments in and taken possession, so to speak, of the cerebral hemisphere long before the advent in this dominant part of the brain of any adequate representation of the other senses, but also, and chiefly, because to a small land-grubbing animal the guidance of smell impressions, whether in the search for food or as a means of recognition of friends or enemies, sexual mates or rivals, was much more serviceable than all the other senses. Thus the small creature’s mental life was lived essentially in an atmosphere of odours; and every object in the outside world was judged primarily and predominantly by smell. The senses of touch, vision, and hearing were merely auxiliary to the compelling influence of smell. (P. 29-30)

Once in the trees, however, all this changes. Unable to respond to the arboreal demand for improved agility, smell “calls to its help the senses of vision and touch and what may be called the labyrinth sense” (1927, p. 13). Thus a “more equable balance” is brought about in the structure of the brain as large portions of the brain are “given up” to other senses.

It is this shift of power from smell to vision which signifies “the birth of the Primates and the definite branching off from the other mammals of the line of Man’s ancestry” (1924, p. 31). Depicted as a struggle, the relationship between the olfactory region and other parts of the primate brain was the focus of one of Elliot Smith’s earliest scientific papers, “On the morphology of the brain in the Mammalia” (1903). Though he claims, in this paper, to be concerned only with demonstrating the affinities between the brains of lemurs and anthropoids (monkeys, apes, and

humans), Elliot Smith does not restrict himself merely to problems of taxonomy (1903, p. 425):

After seeking for some explanation for all the apparently conflicting features of the Prosimian brain, the following tentative working hypothesis as to the ancestry of the Lemurs shaped itself in my mind, and I insert it here merely as a slender bond connecting certain facts scattered through these notes.

The brain of the Primates was derived from some Insectivore-like type, the cerebral hemispheres of which attained a precocious development and, as one of the expressions of their greatness, bulged backward over the cerebellum. In consequence of this great extension of the “physical organ of the associative memory of visual, auditory, and tactile sensations,” the sense of smell lost the predominance which it exercised in the primitive mammal (and in all the Orders of recent mammals), and the olfactory parts of the brain rapidly dwindled. . . .

In the keen struggle for existence, the Lemurs ceased to keep pace with the other Primates so far as the increase in the size of the brain is concerned. They became more specialized, and their brain probably shrunk, thus leading to a retraction of the occipital pole of the hemispheres.

With the diminution of the size of the neopallium the sense of smell comes to play a more important part, and a secondary re-enlargement of the olfactory region occurs. The blotting out of the rhinal fissure may be an indication of this phenomenon.

By following the rise and fall of the olfactory organs in relation to the neopallium, Elliot Smith sketches his storyline.

But it is by emphasizing the role of vision that Elliot Smith raises our interest.

The high specialization of the sense of sight awakened in the creature the curiosity to examine the objects around it with closer minuteness and supplied guidance to the hands in executing more precise and more skilled movements than any that the Tree Shrew attempts. Such habits not only tended to develop the motor cortex itself, trained the tactile and kinaesthetic senses, and linked up their cortical areas in bonds of more intimate associations with the visual specialization within or alongside the motor cortex of a mechanism for regulating the action of that cortex itself. Thus arose an organ of attention which co-ordinated with the activities of the whole neopallium so as the more efficiently to regulate the various centres controlling the muscles of the whole body. (1924, p. 32)

Just as the senses are “awakened” by vision, the great prefrontal area is “called into life.” Through the “guidance” of vision, the mammalian brain

is transformed into an organ of even greater plasticity and power: the mind.

Given such an active role (and vision not only guides but “usurps” and “cultivates” the mind and the body), vision might appear to have a mind of its own. Indeed, expanding the prefrontal area allows for the crossing of the optic tracts and, hence, stereoscopic vision. “Thus the fuller cultivation of the results of the visual powers provides a new stimulus and new means for enhancing vision itself” (1924, p. 146). But the primates also profit from such self-interested deeds, for it is by virtue of stereoscopic vision that the prosimian evolves into a monkey. Nor do the benefits stop there. So as to gain “a more advantageous position by being raised higher from the ground” (1929, p. 28), vision brings about the upright posture which, in turn, brings us apes and the next episode.

Despite the increased power of adaptation,

The primates at first were a small and humble folk, who led a quiet life, unobtrusive and safe in the branches of trees, taking small part in the competition for size and supremacy that was being waged upon the earth beneath them by their carnivorous, ungulate and other brethren. But all the time they were cultivating the equable development of all their senses and limbs, and the special development of the more intellectually useful faculties of the mind that in the long run were to make them the progenitors of the dominant Mammal – the Mammal destined to obtain supremacy over all others, while still retaining much of the primitive structure of limb that his competitors had sacrificed. (1924, p. 34)

Set above in a literal sense by virtue of their arboreality, the first primates are truly superior, for they have maintained their original mammalian purity of design while developing their special powers. It is by virtue of the primitive primate limb structure that vision is first able to attain its influence. Only in those animals whose limbs have not been subjected to “precocious specialization” can vision cultivate one of its most important powers, muscular skill. Not only does skill enhance the ability to learn by experience, which we have seen to be a basic mammalian property, it also develops the ability to experiment. “Hence it is perhaps no exaggeration to say that high intelligence is largely one of the results of the attainment