Thread: Biped Evolution

I was reading Ancestor's Tale the other day and it mentions that earliest hominid fossils [before most of the change in hominid brain size] push very close to the common ancestor of humans and chimpanzee/bonobos. These are considered to be bipedal from the likely position of the neck. So what do you think would be the best explanation? Do you think the molecular clock is wrong? Evolution of bipedalism was swift? The common ancestor was more human-like? The palaeontologists were wrong?

bipedalism is a physiological issue. as i know of, only finding supports bipedalism in primates is the angle between the bones tibia and femur as known as "valgus angle" (aka: tibiofemoral angle) which is only observable in homo sapiens.

I think the evolution of bipedalism occured rather rapidly compared to other such features. Since bipedalism allows for better tool manipulation, and tool manipulation is a critical part of homosapien survival, than chromosomal frequency would have undoubtedly been high.

Originally Posted by maglor

which is only observable in homo sapiens.

And H. erectus, H. heilderbergensis, H. neanderthalensis, H. rudolfensis, H. ergaster, H. habilis, Australopithecus afarensis, possibly A. africanus and H. floresiensis. Probably a few others in the past 3 Ma.

As discoveries such as the latest Ardipithecus specimen has revealed as well as even earlier hominims like Sahelanthropus and Orrorin have implied, the common ancestor of humans and chimpanzees was in all liklihood bipedal (but an inefficient walker).

In other words Chimpanzees probably evolved from a bipedal ape.

Remember that chimpanzees (especially Pan paniscus) are decent bipedal walkers when they have to be.

There are several arguments in favour of the traditional view of humans descending from knucklewalkers but generally they don't hold up to scrutiny.

our earliest homonin ancestors have evidence for being partially aboreal and therefore the adaptation for bipedal walking was in all liklihood a co-option for the gait embloyed in the trees (apes today employ an erect gait when in trees)


Not that we have enough to rule out the traditional view but the fossil evidence and modern animal behavior appears to be on the "trees-down" side

Bipedalism can go some way to define hte clade, but thats all. Personally I dont hold much store for the old argument bipedalism frees hands and allows the promotion of intelligence in some shape or form. Dawkins does not state this in any shape or form, but I do feel he gives bipedalism too much attention.
The whole idea of searching for indicators of intelligence (iu.e. distiction from 'other' apes in the gross morphological fossil record I find unconvincing. You might as well state that we are more intelligent because we have less hair.

A HUGE difference in behaviours can result from something as small as a minor alteration in a neurochemical transmitter. For my money its going to be a very minor but powerful morphological change to the brain or perhaps an alteration to a 'growth' hormone - pinea,l pituary..
Brain size is also not a good indicator or women would be less intelligent than men (my straw poll observations lean me towards they being MORE intelligent Besides measuring 'intelligence' is a game for fools, there are ws that apes are more intelligent than us, as are dolphins. Its a multidimensional question.

These are old arguments in my view and I am surprised that Dawkins gives them so much attention.

Just IMO

Zero

Use of increasingly sophisticated tools and evidence of incerementally developing culture is the evidence of intelligence, and yes average brain size of a species/individual relative to their body size is in fact an accurate means of determining intelligence to a precise enough degree in this context.

Bipedalism was never used as an indicator of intelligence, it has been offered as part of the explanation for the evolution of intelligence (freeing up the hands) but it ends there.

You've simply posited a strawman.

Also, your argument that there are ways that cetaceans and apes are more intelligent than us is untestable at best. You couldn't even offer an example.

To that effect you will probably argue something like "apes don't get into wars like humans do" which spawns two problems from the offset.

-Being able to design and manufacture the technology of warfare is an indicator of high intelligence and an ability apes and dolphins lack cognitively. The way this technology is used is a case by case demonstration of how the intelligence is employed. But since humans have the capacity to protest against this use of technology the argument that we are less intelligent due to some of the species being more belligerent refutes itself.

-Chimpanzees in fact *do* engage in gang warfare. They assemble armies and invade neighbouring chimpanzee territories

Originally Posted by ProcInc

Bipedalism was never used as an indicator of intelligence, it has been offered as part of the explanation for the evolution of intelligence (freeing up the hands) but it ends there.

You've simply posited a strawman.

I understand the appropriate technical term for this is 'bollocks'. zerozero clearly states "Personally I dont hold much store for the old argument bipedalism frees hands and allows the promotion of intelligence in some shape or form." (My emphasis) He most certainly does not describe it as an indicator of intelligence.

Having incorrectly accused him of raisin a strawman, you then do exactly that creating and demolishing an argument that he has come nowhere near making. I too would like to know in what ways he things apes and whales are more intelligent than humans, but lets ask him - don't put carefully selected words in his mouth.

(And welcome to the forum.)

I am new to this forum and I must say there are some good incisive thinkers here, I shall have to be more careful with my P&Qs.

I come from a psychiatric profession and there was a time that people like Eysenk and Binet used to talk about measuring intelligence. This has become popular and there are many IQ tests and various tests still around - e.g. Mensa.

Personally I dont give much store to any of these things. There are so many dimesions to the question as to make any answer feeble from some other perspective. I feel its often frequntly misleading to extrapolate from cognitive tests of these kinds.

In the past scientisits have raised various markers as markers of 'inteliigence' to differentiate us from apes and most of these have been eroded to a degree (but not completely) by subsequent study.
Obviously there is something radically different about the human species in comparison to other animals, but I feel this is both multidemnsional and cultural.
We are Belyaev foxes who have undergone a process of self imposed artificial selection which has changed our own genetic future. We are becoming stranger and stranger - IMO nad the gradient is now increasing. I also hold that the sharp division between conscious and unconscious is getting more defined as we increasingly live artificial existences seperated from our own natural being by our own values.
A human being can be born that never has a blade of grass between their toes, never catches or grows its own food, rarely looks up at the sky or sees an animal, and thinks of little else but X box fantasies, what to wear and whats on the telly. This 'conciousness' has a set of values which are almost indigestible to the inherited brain, which has evolved to handle utterly diffferent data. This produced a marked division and an inconsistency of behaviours.
The process seems to have began least 30,000 years (MIN) depending on which marker you elect to use for measurement.

My point about dolphins was sloppily made (apols). It was really two points in my mind that I conflated wrongly. Firstly I feel that many higher mammals have an awareness near or equal to ours and I credit them with emotions (its only in the past twenty years or so that such a statement is not very controversial) . I personally have been impressed with Dolphins seals, squid, pigs, dogs - some of my best friends are squids and they have a far deeper appreciation of color that say Van Gogh.

My second point is that mans 'intelligence' is frequently overestimated (by man himself). We possess certain intelligent attributes which we handle very badly, very inconsitently, though obviously with many successes too.
If we are 'reasoning' beings, in the sense that our cognition is fundamentally a 'rational process' then why is it we are clearly so utterly useless at reasoning except perhaps under strict labority conditions? Just watch daytime television to see my proof
We share much more in common with animals than Descartes and the founders of rationalism gave us credit for (Desmond Morris) . Three days without food and lets see how rational our behaviour is then.

As I said my points about the Dolphins etc was not clarified. I was taking a bit of a political pop at the 'superiority' of the species that is trashing the planet.

I said nothing about warfare.

you make several interesting points, some of which I should like to comment on after due consideration, but I felt this one merited immediate attention.

Originally Posted by ZeroZero

Three days without food and lets see how rational our behaviour is then.

I am confident that in such a situation my behaviour would attain a level of rationality normally absent from it.

In such a situtation I can no longer afford to amble along in the self indulgent fashion afforded by western middle class life. I need to act promptly, decisively and effectivley to secure food. I shall employ all of my experience, knowledge, intellect, reason, rhetorical skills and coercive powers to achieve that goal. Rational? I'll make Descartes look like a mentally retarded pygmy shrew with tertiary syphillis.

In such a circumstance self-actualisation means maintaining my existence. Base and peak of Maslow's heirarchy merge and the merging element is reason.

Yes Opholite but would you eat your children? OK maybe after two weeks or so - depending on their A level results you would select priorities (but you get my serious point).
I suppose it boils down to what you would define as 'rational'. I am talking of entertaining propositions and considering them in an objective manner, then working out their consequences before acting. Mankind has a habit of resulting to barbarism s soon as there is no plate for him at the table. You could define this as 'good' in the sefish gene context.

You are defining barbarism as the cessation or reduction of cooperative behaviour in a hostile situation. That appears to me to be a clearly rational adaptation to a changed environment. Now I am not proposing that all homo sapiens would display this rationality. However, I do not believe that the majority of humanity display such ratioanlity at any time. Perhaps that was your initial point.

I wouldn't be surprised if dolphins and chimps are both smarter than us in some areas, although we're definitely much more intelligent overall than chimps.
While we might be much larger brained than chimps, the fact that they are much larger brained than hyenas doesn't stop hyenas from outperforming them in some tests of cooperation ability:
Hyenas cooperate better than chimps, study finds
Spot*ted hye*nas may not be smarter than chimp*anzees, but a study in*di*cates the much-maligned, dog-like creat*ures beat out our ape rel*a*tives in co*op*er*a*tive prob*lem-solv*ing tests.

Cap*tive pairs of spot*ted hye*nas that needed to tug two ropes in un*ison to ob*tain some food co*op*er*at*ed suc*cess*fully and learn*ed the ma*neu*vers quickly with no train*ing, re*search*ers said. Ex*pe*ri*enced hye*nas even helped in*ex*pe*ri*enced part*ners do the trick.

Faced with si*m*i*lar tasks, chim*panzees and oth*er pri*ma*tes of*ten re*quire ex*ten*sive train*ing, and coop*era*t*ion may not be easy, said Chris*tine Drea, an ev*o*lu*tion*ary an*thro*po*l*o*gist at Duke Un*ivers*ity in Dur*ham, N.C.

Drea’s re*search, pub*lished on*line in the Oc*to*ber is*sue of the jour*nal An*i*mal Be*hav*ior, sug*gests so*cial car*ni*vores like spot*ted hye*nas that hunt in packs may be good mod*els for in*ves*ti*gat*ing co*op*er*a*tive prob*lem solv*ing and the ev*o*lu*tion of so*cial in*tel*li*gence.

She per*formed the ex*pe*ri*ments in the mid-1990s but strug*gled to find a jour*nal that was in*ter*est*ed in non-pri*mate so*cial cog*ni*tion. “No one wanted an*y*thing but pri*mate cog*ni*tion stud*ies back then,” Drea said.

“But what this study shows is that spot*ted hye*nas are more ad*ept at these sorts of coop*era*t*ion and prob*lem-solv*ing stud*ies in the lab than chimps are. There is a nat*u*ral par*al*lel of work*ing to*geth*er for food in the lab*o*r*a*to*ry and group hunt*ing in the wild.”

Drea and co-author Al*lisa N. Cart*er of the Un*ivers*ity of Cal*i*for*nia at Berke*ley ar*ranged to have pairs of spot*ted hye*nas put in a large pen where they faced a choice be*tween two iden*ti*cal plat*forms 10 feet high. Two ropes dan*gled from each plat*form. When both ropes on a plat*form were pulled down hard in un*ison—a si*m*i*lar ac*tion to bring*ing down large prey—a trap door opened and spilled bone chips and a sticky meat*ball.

The double-rope de*sign pre*vented a hy*e*na from solv*ing the task alone, and the choice be*tween two plat*forms en*sured that a pair would not solve ei*ther task by chance.

The first ex*pe*ri*ment sought to de*ter*mine if three pairs of cap*tive hye*nas could solve the task with*out train*ing. “The first pair walked in to the pen and fig*ured it out in less than two min*utes,” Drea said. “My jaw lit*er*ally dropped.”

Drea and Cart*er stud*ied the ac*tions of 13 com*bina*t*ions of hy*e*na pairs and found that they syn*chro*nized their tim*ing on the ropes, re*veal*ing that the an*i*mals un*der*stood the ropes must be tugged in un*ison. They al*so showed that they un*der*stood both ropes had to be on the same plat*form. Af*ter an an*i*mal was ex*perienced, the num*ber of times it pulled on a rope with*out its part*ner pre*s*ent dropped sharp*ly, in*di*cat*ing the an*i*mal un*der*stood its part*ner’s role.

“One thing that was dif*fer*ent about the cap*tive hy*e*nas’ be*hav*ior was that these prob*lems were solved largely in si*lence,” Drea said. Their non-verbal com*mu*nica*t*ion in*clud*ed match*ing gazes and fol*low*ing one anoth*er. “In the wild, they use a vo*cal*iz*a*tion called a whoop when they are hunt*ing to*geth*er.”

Hyenas have an un*pleas*ant re*pu*ta*tion as some*what dirty and cow*ardly sca*ven*gers, though in fact they often hunt live prey as well. Al*though they re*semble dogs, hy*enas are more closely re*lated to mon*gooses and civ*ets.

In sec*ond and third ex*pe*ri*ments, Drea found that so*cial fac*tors af*fect*ed the hye*nas’ per*for*mance in both pos*i*tive and neg*a*tive ways. When an au*di*ence of ex*tra hye*nas was pre*s*ent, ex*perienced an*i*mals solved the task faster. But when dom*i*nant an*i*mals were paired, they per*formed poor*ly, even if they had been suc*cess*ful in pre*vi*ous tri*als with a sub*or*di*nate part*ner.

“When the dom*i*nant fe*males were paired, they did*n’t play nicely to*geth*er,” Drea said. “Their ag*gres*sion to*ward each oth*er led to a fail*ure to coop*erate.”

When an an*i*mal un*fa*mil*iar with the feed*ing plat*forms was paired with a dom*i*nant, ex*perienced an*i*mal, the dom*i*nant an*i*mals switched so*cial roles and sub*mis*sively fol*lowed the lower-ranking, naïve an*i*mal, Drea said. Once the naïve an*i*mal be*came ex*perienced, they switched back.

It was*n’t a big sur*prise that the an*i*mals were strongly in*clined to help each oth*er ob*tain food, said Kay Ho*le*kamp, a zo*ol*o*gist at Mich*i*gan State Un*ivers*ity who stud*ies spot*ted hye*nas.

Re*search*ers have fo*cused on pri*ma*tes for dec*ades with an as*sump*tion that high*er cog*ni*tive func*tion*ing in large-brained an*i*mals should en*a*ble or*gan*ized team*work. But Drea’s study sug*gests so*cial car*ni*vores, in*clud*ing dogs, may be very good at co*op*er*a*tive prob*lem solv*ing, even though their brains are com*par*a*tively smaller.

“I’m not say*ing that spot*ted hye*nas are smarter than chimps,” Drea said. “I’m say*ing that these ex*pe*ri*ments show that they are more hard-wired for so*cial coop*era*t*ion.”


A pair of cap*tive hye*nas co*oper*ate to get some food. (Im*age cour*tesy Chris*tine Drea)
From here.

The reason is fairly obvious: it is a very realistic scenario for wild hyenas to have to grip something (prey) with their mouths and yank in a cooperative manner to get food. Not so for a chimp, and thus hyenas have evolved to perform well at such tasks, while chimps have not (and their greater intelligence didn't happen to provide such abilities as a consequence).

Anyway, to back up the specific claims of human vs chimp:
Almost Human, and Sometimes Smarter
Tetsuro Matsuzawa, a Kyoto primatologist, described a young chimp watching as numbers 1 through 9 flashed on the computer screen at random positions. Then the numbers disappeared in no more than a second. White squares remained where the numbers had been. The chimp casually but swiftly pressed the squares, calling back the numbers in ascending order — 1, 2, 3, etc.

The test was repeated several times, with the numbers and squares in different places. The chimp, which had months of training accompanied by promised food rewards, almost never failed to remember where the numbers had been. The video included scenes of a human failing the test, seldom recalling more than one or two numbers, if any.

“Humans can’t do it,” Dr. Matsuzawa said. “Chimpanzees are superior to humans in this task.”

From here.

I doubt you could train a hyena to sit in front of a monitor and really perform a task like that, and we are obviously far ahead in other areas, such as language abilities.

Dolphins vs humans:
Some quotes I found (without a source, but I can contact the poster to request them if people are interested-as a note, the poster has been accused of "cherry picking" in the past, and as I have not looked into it I can not attest to whether or not this is true):
Dr Sam Ridgeway[9] recorded the ERPS (Event Related Electrical Potential) from a dolphin brain and compared them with similar experiments in humans and monkeys. Only dolphins and humans were comparable in sharing properties of ERPS known to be 'decision' related. In short, the enlarged areas of the cetacean brain operate at levels of complexity previously found only in our own brains.

Television scenes are representations of the real world and, as humans, we respond to them as we might to the real world but understand that they are not the real world. A cat might respond to a television image of a moving bird in the same way it would respond in the real world, failing to discriminate between the representation and the real world. In other cases, the cat or other animals might simply ignore the television scene, seemingly failing to recognize that anything meaningful or relevant is occurring. The latter behavior has been reported, for example, for language-trained chimpanzees, who only learned to respond appropriately to television scenes after long periods of watching their human companions responding. In contrast, all four of our dolphins, on the very first occasion that they were exposed to television, responded spontaneously and appropriately to televised images of people gesturing to them. They responded in the same way as they did to live people, faithfully carrying out the gestural instructions conveyed by the image. The dolphins understood, however, that the television scene was not the real world. For example, if the trainer tossed a ball in the air and then gestured to the dolphin to imitate the action, the dolphin did not attempt to retrieve the ball in the television scene, but used one in its real world.

Where I had found this info I thought there was something where dolphins performed superior to humans, but in my quick skim through using the color coding the author provided for info on different animal species I did not find it.
Either way, both of the above seem extraordinary by animal standards.

Non-primate non-cetacean animals can also be very intelligent however; a few quotes about grizzly bear no. 146, named "the Mud Lake bear" from Learning to Talk Bear by Roland Cheek:
The camera lay upon the ground, dented with tooth marks. Part of the frame was missing where the bear had ripped open and sprung the door, its film cartridge gone. The carefully prepared “set” was vandalized: the logs and rocks overturned, brush flattened, snares tripped. The bait-a road-killed deer carcass hung in a a tree-was gone. The Mud Lake Bear had struck again.
“It's his modus operandi,” Rick Mace said as he handed me the camera, a compact Olympus Infinity stamped No. 12. “He usually appears at night and always rips up our trap site.”
I turned the camera over and over, staring at the tooth marks. Johannes Brahms could not have tuned into a Beethoven symphony with more rapt attention than I honed into Mace's sonata.
“We suspected the Mud Lake Bear, of course, but can you believe it? We found the film cartridge off to one side, smashed, but we were able to develop enough film for a positive I.D.”
Mace gets paid for trapping and monitoring grizzly...

...In the spring of 1987, about the time when Riley's proposed study got off the ground, the coming four-year-old lost his collar. And it wasn't until the following spring, as veteran biologists (who learned grizzly trapping via Chuck Jonkel's Border Grizzly Project) swarmed into the area, that the now nearly grown, unusually dark-colored grizzly was captured again.
It was a near-thing. The process used a cubby set, a pile of logs stacked into a V-shape. The bait is laid inside the tip of the V and a snare is placed in front. The dark-colored male was held by just four toes...

...Biologists snared the Mud Lake Bear for the last time in June of 1989. This time the mature bruin blundered into a blind trail set. It completed his education, a doctorate in trap distaste. He began writing his thesis within the month...

Biologists wheeled a culvert trap into position near the woods and baited it with their ripest road-killed deer. During the night, the Mud Lake Bear tripped the trap's gate without entering. Again the device was set. The following night the bear turned over not only the heavy culvert, but it's trailer, too, making no attempt to retrieve the bait. Again, the trap was set. On the third night, Number 146 pushed the awkward contrivance through two barbed-wire fences and, tiring of the sport, decamped for the Swan Range's high country.

The book goes on to explain that there was a fight between number 144 and the Mud Lake Bear in which the Mud Lake Bear lost his collar. After this fight bear 144 changed course and did not go to a food rich area he had visited at that time of year each year of his life, suggesting he had lost the fight (he didn't lose his collar though) and that the Mud Lake Bear was now the dominant male.
For this reason researchers thought it was important to put a new radio collar on him.

We flag-hang orange flagging ribbon-on our way from a baited set so we can follow the trail when we return to check it,” said biologist Tim Manley, then a Study trapper. “We could always tell when the Mud Lake Bear was there ahead of us. Every piece of flagging ribbon was down. We put up plastic signs, too, warning people away from the sets. And those signs would be ripped down. He'd invariably trigger our snares, steal the bait, knock over the remote cameras, and generally tear up the site.
Shawn Riley claimed the Mud Lake Bear “ate cameras.” And if the Olympus that Rick Mace showed me was any indication, it certainly appeared so.
“It was his standard operating procedure,” Mace said, “to come to a set during the night and tear it up. He always left a trashed trap site as his calling card.”
All through the rest of the 1990 and 1991, biologists returned to their carefully planned and constructed sets to find them ripped asunder, the bait stolen. When 1992's spring and summer trapping season opened with the same result's, Mace turned his men loose on their nemesis.
“I told them their number one priority was to catch that bear. I said the Mud Lake Bear could tell us a lot about bear behavior and use of the area-if only we could put a collar on him. But he was too smart. He wouldn't just avoid a set, he'd destroy it. Then we'd have to start all over planning the set and laying it out.”
“And you never caught him?”
The project leader shook his head. “We never caught him. We'd make a cubby set and put other snares around it. When he trashed them, we began making trail sets leading to our bait. At one time we had twenty-two snares set around one bait that was hanging from a center tree. And Number 146 triggered every single snare and got the bait anyway.”
When I shook my head in disbelief, Mace said, “Roland, it looked to us like he picked up rocks and limbs in his mouth and dropped them on the triggers. Sometimes he pushed a sapling into a snare to spring it. However he did it, he tripped all twenty-two snares, then took the bait at his leisure.” The man shook his head again and repeated, “We never did get him.”
“So how about this year?” I asked.
The answer was subdued. “He's not out there.”
As of September, the Mud Lake Bear hadn't destroyed one 1993 set. Neither did the study team have a heat-sensor triggered photograph of an unusually dark-colored grizzly taken by remote cameras. For study purposes, Mace at last declared the Mud Lake Bear “dead.”...

I am not sure how much of an understanding the bear really had of how traps work; his understanding could have simply gone so far as "destroy everything man made", and basic knowledge of how to do it (bite things, like the camera, until the film came out, and for the snares throw objects at them until it goes off).
Either way, that a wild animal figures such things out does suggest they have a reasonable level of reasoning abilities.
Another famous grizzly was the Giefer grizzly, a problem animal who raided people's houses for food. He had a radio collar, but was nonetheless able to evade all attempts from professional government hunters to kill him despite their being armed with telemetry allowing them to track him. This again suggests a decent level of intelligence.

Yes Ophilite I see where you are coming from. It makes sense and helps me clarify my understanding of my position.
I think I am referring to something that might be called 'civilised behaviour' and calling it rational. what I think I mean is that in such extreme conditions the 'rules' by which we delude ouselves govern our behehaviour go out of the window and our heriditory behaviour patterns kick in with a strength few can resist.
I am also kicking against the Cartesian/rationalist position that we are fundamentally a reasoning being. We can reason, often quite poorly, but this is a side application of cognition and not fundamental to it, like many philosophers infer.
The folk model goes soemthing like this. Humans are different from animals because they can reason, reasoning is a process of examining propositions and seeing if they are verifiable. Human beings are fundamentally reasoning things al a 'cogito ergo sum'. I am a thinking thing, my mind is an apparatus for thinking and reasnoning, Reason is at the heart of my cognition. My behaviour is governed by my reasoning processes.
Its also curious to me that their can be different takes on what is the 'rational' thing to do. Different frames of refence that can grab the psyche and drive behaviour. I suppose this is because reason starts with axioms that cannot be defined without the argument construct (thats why they are axioms).

C Elrod:
I think we are agreement - these are typical examples of the sorts of experiments I feel can’t really infer evidence about 'intelligence' (whatever that might be .
A supermarket checkout can process food items and produce a total invoice far faster than a human (OK I mean at least one human - me) . Therefore: Supermarket checkouts are more intelligent than humans.
Human beings are useless at finding their way around caves in the dark - bats are more 'intelligent' than us in this way.

Lets imagine you have two black boxes A & B. Inside one is an animal X (do you remember Fred Flinstone's household gadgets?).
Inside the next box is a human being or perhaps simply any other species.
Both boxes are rigged up so that you can input a stimuli P .
Your definition of 'intelligent behaviour' is to get an output from the box of Q, perhaps within the time frame T.
You run a battery of tests and collect data. Box B is faster and produces more ‘correct’ outputs.
Does Box b contain a more intelligent animal?
Well suppose the task involved catching fish and we have dolphins and humans.
The Dolphin having been adapted to swim under water catches more fish (OK so its a box with a swimming pool inside and goldfish)
The human is compelled to use a rod and line and wait for the fish to come to him. This is hidden from you as you cannot see into the box. This obviously skews the result, the human is physically (not mentally) less adapted to the task BUT this is unknown to you and is not compensated for in your experiment.
Now suppose that its not a fishing exercise but a pattern recognition exercise, and this pattern for arbitrary reasons resembles a shoal of fish swimming underwater. As the experiment designer you have not realised this. The dolphin recognises the pattern before the human. Does this make the dolphin more intelligent than species B?

I would hold that there are many different definitions of the term intelligence and they are all inadequate, all we can do is test for the ability to solve the problem in question. Even then there is opportunity for many hidden and unaccounted variables (such as physical adaptiveness at gross and micro levels) to interfere with the results.

Again small changes in neurochemistry can also have immense effects on behaviours . Its unlikely that such changes could be preserved in the fossil record and our current state of understanding of cognition is not really enough to qualify the likely effects IMO.
Perhaps there are experiments that are so carefully designed as to rule out such anomalies, but I do find much of the debate niave. Firstly we need a proper definition of intelligence which entails all or even just most forms of intelligence. Then this definition needs to be expressed in a non homocentric form (otherwise you end up testing which biped or ape or animal has the most humanoid intelligence). Then you need to design an experiment that compensates not only for the physical differences of the species involved, but also for cultural and inherited variables.


All in all it’s a fools errand, like perpetual motion IMO.


Zero
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