Mental Evolution in Man 9

Mental Evolution in Man 9

To lead off with a few instances which have been already selected for

substantially the same purpose by Mr. Darwin:—

 

“Houzeau relates that, while crossing a wide and arid plain in Texas,

his two dogs suffered greatly from thirst, and that between thirty and

forty times they rushed down the hollows to search for water. These

hollows were not valleys, and there were no trees in them, or any other

difference in the vegetation; and as they were absolutely dry, there

could have been no smell of damp earth. The dogs behaved as if they

knew that a dip in the ground offered them the best chance of finding

water, and Houzeau has often witnessed the same behaviour in other

animals.”

 

I have myself frequently observed this association of ideas between

hollow ground and probability of finding water in the case of

setter-dogs, which require much water while working; and it is evident

that the ideas associated are of a character highly generic.

 

Further, Mr. Darwin writes:—“I have seen, as I dare say have others,

that when a small object is thrown on the ground beyond the reach of

one of the elephants in the Zoological Gardens, he blows through his

trunk on the ground beyond the object, so that the current reflected on

all sides may drive the object within his reach. Again, a well-known

ethnologist, Mr. Westropp, informs me that he observed in Vienna a bear

deliberately making with his paw a current in some water, which was

close to the bars of his cage, so as to draw a piece of floating bread

within his reach.”[38]

 

In _Animal Intelligence_ it will be seen that both these observations

are independently confirmed by letters which I have received from

correspondents; so that the facts must be accepted. And they imply a

faculty of forming generic ideas of a high order of complexity. Indeed,

these are not unlike the generic ideas of intelligent water-dogs

with reference to water-currents, which induce the animals to make

allowance for the force of the current by running in the opposite

direction to its flow before entering the water. Dogs accustomed to

tidal rivers, or to swimming in the sea, acquire a still further

generic idea of uncertainty as to the direction of the flow at any

given time; and therefore some of the more intelligent of these dogs

first ascertain the direction in which the tide is running by placing

their fore-paws in the stream, and then proceed to make their allowance

for driftway accordingly.[39]

 

Lastly, Mr. Darwin writes:—“When I say to my terrier in an eager voice

(and I have made the trial many times), ‘Hi, hi, where is it?’ she at

once takes it as a sign that something is to be hunted, and generally

first looks quickly all around, and then rushes into the nearest

thicket, to scout for any game, but finding nothing, she looks up into

any neighbouring tree for a squirrel. Now, do not these actions clearly

show that she had in her mind a general idea, or concept, that some

animal is to be discovered and hunted?”[40]

 

From the many instances which I have already given in _Animal

Intelligence_ of the high receptual capabilities of ants, it will here

be sufficient to re-state the following, which is quoted from Mr. Belt,

whose competency as an observer no one can dispute.

 

“A nest was made near one of our tramways, and to get to the trees the

ants had to cross the rails, over which the waggons were continually

passing and re-passing. Every time they came along a number of ants

were crushed to death. They persevered in crossing for some time, but

at last set to work and tunnelled underneath each rail. One day, when

the waggons were not running, I stopped up the tunnels with stones; but

although great numbers carrying leaves were thus cut off from the nest,

they would not cross the rails, but set to work making fresh tunnels

underneath them.”

 

These facts cannot be ascribed to “instinct,” seeing that tram-cars

could not have been objects of previous experience to the ancestors

of the ants; and therefore the degree of receptual intelligence, or

“practical inference,” which was displayed is highly remarkable.

Clearly, the insects must have appreciated the nature of these repeated

catastrophes, and correctly reasoned out the only way by which they

could be avoided.

 

As this is an important branch of my subject, I will add a few more

illustrations drawn from vertebrated animals, beginning with some

from the writings of Leroy, who had more opportunity than most men of

studying the habits of animals in a state of nature.[41]

 

He says of the wolf:—“When he scents a flock within its fold, memory

recalls to him the impression of the shepherd and his dog, and balances

that of the immediate neighbourhood of the sheep; he measures the

height of the fence, compares it with his own strength, takes into

account the additional difficulty of jumping it when burdened with his

prey, and thence concludes the uselessness of the attempt. Yet he will

seize one of a flock scattered over a field, under the very eyes of the

shepherd, especially if there be a wood near enough to offer him a hope

of shelter. He will resist the most tempting morsel when accompanied

by this alarming accessory [the smell of man]; and even when it is

divested of it, he is long in overcoming his suspicions. In this case

the wolf can only have an abstract idea of danger—the precise nature

of the trap laid for him being unknown.... Several nights are hardly

sufficient to give him confidence. Though the cause of his suspicions

may no longer exist, it is reproduced by memory, and the suspicion is

unremoved. The idea of man is connected with that of an unknown danger,

and makes him distrustful of the fairest appearances.”[42]

 

Leroy also well observes:—“Animals, like ourselves, are _forced_ to

make abstractions. A dog which has lost his master runs towards a group

of men, by virtue of a general abstract idea, which represents to him

the qualities possessed in common with these men by his master. He then

experiences in succession several less general, but still abstract

ideas of sensation, until he meets the particular sensation which he

seeks.”[43]

 

Again, with regard to the stag, this author writes:—“He exhausts every

variety and every design of which the action of flight consists. He

has perceived that in thickets, where the passage of his body leaves a

strong trace, the dogs follow him ardently, and without any checks; he

therefore leaves the thicket and plunges into the forests where there

is no underwood, or else skirts the high-road. Sometimes he leaves that

part of the country altogether, and depends wholly on his speed for

escape. But even when out of hearing of the dogs, he knows that they

will soon come up with him; and, instead of giving himself up to false

security, he avails himself of this respite to invent new artifices

to throw them out. He takes a straight course, returns on his steps,

and bounding from the earth many times consecutively, throws out the

sagacity of the dogs.... When hard pressed he will often drop down in

the hope that their ardour will carry them beyond the track, and should

it do so he retraces his steps. Often he seeks the company of others

of his species, and when his friend is sufficiently heated to share

the peril with, he leaves him to his fate and escapes by rapid flight.

Frequently the quarry is thus changed, and this artifice is one the

success of which is most certain.”[44]

 

“Often (when not being hunted at all), instead of returning home in

confidence and straightway lying down to rest, he will wander round the

spot; he enters the wood, leaves it, goes and returns on his steps

many times. Without having any immediate cause for his uneasiness, he

employs the same artifices which he would have employed to throw out

the dogs, if he were pursued by them. This foresight is an evidence of

remembered facts, and of a series of ideas and suppositions resulting

from those facts.”[45]

 

It is remarkable enough that an animal should seek to confuse its

trail by such devices, even when it knows that the hounds are actually

in pursuit; but it is still more so when the devices are resorted

to in order to confuse _imaginary_ hounds which may _possibly_ be

on the scent. Perhaps to some persons it may appear that such facts

argue on the part of the animals which exhibit them some powers of

representative thought, or some kind of reflection conducted without

the aid of language. Be it remembered, therefore, I am not maintaining

that they do not: I am merely conceding that the evidence is inadequate

to justify the conclusion that they do; and all I am now concerned with

is to make it certain that in animals there is a _logic_, be it a logic

of recepts only, or likewise what I shall afterwards explain as a logic

of _pre-concepts_.

 

Again, Leroy says of the fox:—“He smells the iron of the trap, and

this sensation has become so terrible to him, that it prevails over

every other. If he perceives that the snares become more numerous, he

departs to seek a safe neighbourhood. But sometimes, grown bold by a

nearer and oft-repeated examination, and guided by his unerring scent,

he manages, without hurt to himself, to draw the bait adroitly out of

the trap.... If all the outlets of his den are guarded by traps, the

animal scents them, recognizes them, and will suffer the most acute

hunger rather than attempt to pass them. I have known foxes keep their

dens a whole fortnight, and only then make up their minds to come out

because hunger left them no choice but as to the mode of death....

There is nothing he will not attempt in order to save himself. He will

dig till he has worn away his claws to effect his exit by a fresh

opening, and thus not unfrequently escapes the snares of the sportsman.

If a rabbit imprisoned with him gets caught in one of the snares, or if

by any other means one should go off, he infers that the machine has

done its duty, and walks boldly and securely over it.”[46]

 

Lastly, this author gives the case, which has since been largely

quoted—although its source is seldom given—of crows which it is

desired to shoot upon their nests, in order to destroy birds and eggs

at the same time. The crows will not return to their nests during

daylight, if they see any one waiting to shoot them. If, to lull

suspicion, a hut is made below the rookery and a man conceal himself

in it with a gun, he waits in vain if the bird has ever before been

shot at in a similar manner. “She knows that fire will issue from the

cave into which she saw a man enter.” Leroy then goes on to say:—“To

deceive this suspicious bird, the plan was hit upon of sending two men

into the watch-house, one of whom passed on while the other remained;

but the crow counted and kept her distance. The next day three went,

and again she perceived that only two returned. In fine it was found

necessary to send five or six men to the watch-house in order to put

her out of her calculation.”

 

Now, as Leroy is not a random writer, and as his life’s work was that

of Ranger at Versailles, we must not lightly set aside this statement

as incredible, more especially as he adds that the “phenomenon is

always to be repeated when the attempt is made,” and so is to be

regarded as “among the very commonest instances of the sagacity of

animals.”[47] If it is once granted that a bird has sagacity enough to

infer that where she has observed two men pass in and only one come

out, therefore the second man remains behind, it is only a matter

of degree how far the differential perception may extend. Of course

it would be absurd to suppose that the bird counts out the men by

any process of notation, but we know that for simple ideas of number

no symbolism in the way of figures is necessary. If we were to see

three men pass into a building and only two come out, we should not

require to calculate 3-2=1; the contrast between the simultaneous

sense-perception of A+B+C, when receptually compared with the

subsequently serial perceptions of A and B, would be sufficient for

the spontaneous inference that C must still be in the building. And

this process would in our own case continue possible up to the point at

which the simultaneous perception was not composed of too many parts to

be afterwards receptually analysed into its constituents.[48]

 

In this connection also I may state that, with the assistance of

the keeper, I have succeeded in teaching the Chimpanzee now at the

Zoological Gardens to count correctly as far as five. The method

adopted is to ask her for one straw, two straws, three straws, four

straws, or five straws—of course without observing any order in the

succession of such requests. If more than one straw is asked for, the

ape has been taught to hold the others in her mouth until the sum is

completed, so that she may deliver all the straws simultaneously. For

instance, if she is asked for four straws, she successively picks up

three straws and puts them in her mouth: then she picks up the fourth,

and hands over all the four together. This method prevents any possible

error arising from her interpretation of vocal tones, which might well

arise if each straw were asked for separately. Thus there can be no

doubt that the animal is able to distinguish receptually between the

numbers 1, 2, 3, 4, 5, and understands the name for each. Further than

this I have not attempted to take her. I may add that her performance

has been witnessed by the officers of the Zoological Society and also

by other naturalists, who will be satisfied with the accuracy of the

above account. But the ape is capricious, and, unless she happens to be

in a favourable mood at the time, visitors must not be disappointed if they fail to be entertained by an exhibition of her learning.