Dr Rick

No.

<strong> Insects and humans both have sex drives. Insects act upon their drives instinctively, but humans act upon their drives through learned behaviors. Insects mate to propagate, whereas humans mate for a veritable plethora of reasons. Insects cannot choose how they respond to their sex drives as their actions are dictated by instincts and reflexes. Adult humans can make choices in how they respond to their sex drives because they have no instincts, though reflexes may impose some limitations on their choices.

It is my opinion that adult human behavior is governed by drives, reflexes, and learning. Insect behavior is governed by drives, reflexes, and instincts; I do not know if insects learn any of their behaviors.

Do you agree or disagree with any of this? Can insects learn? Do you think adult humans have instincts, and if so, can you define and describe them? What is your definition of instinct?

I've posed several questions; respond to any single one or more as you wish and time allows.

I am sorry for the spelling errors. I'm posting in a bit of a hurry from a hospital computer, and it does not have a spell-checker.

Rick

[ March 15, 2002: Message edited by: rbochnermd ]</p>

Dr Rick

We don' t need them, and they probably became a hinderance to our most recent ancestors and were eliminated through selective pressures.

Instincts may increase the chances of survival and successful reproduction in those animals that possess them by providing them with behavioral patterns that they can not learn but nonetheless enhance gene propagation. For example, the ancestors of most migratory birds did not possess the cognitive skills to reason that they needed to prepare for the winter, so selective pressures favored those which had the instinct to migrate and this instinct was passed to subsequent generations.

The downside to instincts is that they limit adaptability by pre-determining responses. They do not allow for as much adaption as cognition does. Humans are highly cognitive and have the capacity to learn all of the behaviors that are essential for survival and reproduction. The advantage cognition confers over instinct is that it allows for adaption to a wider variety of circumstances and environments. As a result, migratory birds have fewer options in preparing for the winter months than humans, and it is the later's adaptabiltiy that underlies much of its reproductive success. Instincts would hinder this adaptability and were likely eliminated through selective pressures. Migratory birds, on the other hand, do not have the cognitive ability to adapt their behaviors as well as humans, so selective pressures have favored the continuation of instincts in those animals.

Peez

Perhaps the problem is a semantic one. Some definitions from introductory biology texts: I suppose that we need to be clear on what a behaviour is: Using these definitions, I cannot escape the conclusion that humans have instincts. I don't want to get into a debate on the nature of free will, but humans do mate. This is not something we do because someone taught us to, we inherit this behaviour. To choose, perhaps, a simpler example, human males get an erection when they receive certain stimuli. They do not learn this behaviour, it is inherited. As for insects, we must distinguish between ultimate and proximate causes. The ultimate reason that insects, and humans, mate is to reproduce (even if the human consciously does not want to have children). The proximate reason in insects is that a certain set of stimuli leads to mating behaviour. In humans things are more complex, but it may be argued to boil down to the same thing. I do not think that learning and instinct are mutually exclusive, that is I agree that human behaviour is governed to a large degree by learning, but I believe that instinct plays a roll as well. FWIW, I do not know of any example of insects learning. I have covered this above and out of order, sorry. Better late than never. Don't worry about it, I have atrocious spelling, and only a spell check makes me look good. I put in [sic] because I would want such errors pointed out to myself, not to complain or put anyone down.


Peez

Dr Rick

Instincts are behaviors that are inherited, but that does not mean that all inherited behaviors are instinctive. If the above are meant to be the definitions of instinct, the first is circular and is more of a conclusion rather than a definition, and the second is incomplete in that it fails to distinguish instincts from other inherited behaviors. Autonomic and reflexive behaviors are "inherited and typical," but they are distinct from instincts, at least in mammals, because these behaviors arise from the lower portions of the mammalian nervous system.

These are not just semantic differences; instincts in organisms with complex nervous systems arise from areas that are distinct from those that operate autonomic and reflexive behaviors. Instincts are operative in mammals and other "higher" animals when they are awake and the cerebrum or its equivalent is functioning, but autonomic and reflexive behavior can and does occur when a mammal or bird is asleep or even "brain dead."

Destroy the cerebrum of a migratory bird, and it will instinctively migrate no more, though reflexive and autonomic behaviors will still potentially be operable.

Instincts are distinguished from learned behaviors in that they are not only inherited but also guide actions to an end not known to the organism.

<strong> Agree

<strong> Humans inherit the urge (or stimulus or drive) to mate, but not mating behavior. The urge to mate is an innate stimulus, but it is not "what [a human] does...in response to stimuli in its environment;" the urge to mate is only the stimulus, arising from the internal environment, whereas the act of mating is what actually constitutes behavior. A stimulus or urge compels an organism to respond but is not behavior and so cannot properly be labeled as an instinct. A behavior is a response to a stimulus, and in the case of humans, mating behavior is a response that is learned, not instinctive.

Humans and some of the other Great Apes are not born with the knowledge of how to perform intercourse even though they inherit a sex drive; they must be taught how to mate. Humans learn about mating from a variety of sources depending on social and family circumstances. If humans must learn the behavior of mating, that means it must be acquired, and acquired behaviors are not inherited and so cannot be instinctive.

It might be tempting to argue that human mating behavior is obviously innate and inherited, as it seems so ubiquitous, but it is not. Humans mate in a variety of different ways and sometimes not at all despite the urge to do so. Humans growing-up in the Western world require "sex education" in school or have to be told of "the birds and the bees." In some communities, particularly religious ones, the knowledge is imparted in special and now atavistic church-sponsored courses for soon-to-be wed couples. In third world countries, where living-space is tight, children can observe adults, especially their parents, copulating. Without acquiring the behavior through learning, humans do not know how to mate.

This lack of inherited mating behavior is not without precedent. Gorillas are another of the Great Apes that are born with the urge to mate but not the innate behavior to satisfy the urge. Gorillas in the wild can observe adult gorillas copulating and so learn the behavior, but those born in captivity have been found not to know how to mate if they are kept separate from mating couples; this has been one of the obstacles to breeding gorillas in captivity.

The lack of an inherited behavior corresponding to a specific drive is not unprecedented, either; we are born with a "hunger" drive, and infants have a reflex for suckling, but beyond that one behavior, the actions that satisfy the hunger urge are learned and not inherited.

<strong> It is a reflex; human males can be stimulated to erection even if the connections between the brain and spinal cord have been severed. Erections arise through spinal and intrinsic nerve tracts below the cerebral cortex. Visual stimuli can lead to erection because these lower tracts are "tapped" into the cerebral cortex and can intercept some of the signals in the higher brain centers, but these reflexes can operate independently from the cortex; mammalian instincts cannot.


<strong> Humans mate for a variety or reasons, and often without any intention of reproducing. They can and do often mate while simultaneously blocking reproduction. That humans can and do block reproduction strongly suggests that human mating sometimes occurs for reasons other than reproduction.

<strong> Instincts and learned behaviors are distinctly different. They can co-exist in the same organism, but only the latter of the two is found in adult humans. The examples provided to demonstrate instincts in adult humans are actually drives and learned behaviors (mating) and reflexes (erections), not instincts.

Rick

[ March 21, 2002: Message edited by: rbochnermd ]</p>

Peez

That depends on your definition of instincts. Please explain. It defines instinct, though it is not presented as such. I see no circularity: it states that any behaviour that is the product of natural selection is an instinct. What is circular about that? That does not make it incomplete, it only makes it different from some other definitions. I don't think that you understand. What I was giving was two published definitions of instinct. I am not saying that these represent the consensus of ethologists, and I am certainly not claiming that these are the only possible definitions for this term. By those definitions, "autonomic and reflexive" behaviours, if they are inherited and typical, are instincts. It is that simple. By the way, what do you mean by the "lower" portion of the mammalian nervous system? Only if you define them that way. You see, it really is a semantic argument. Again, depending on how one defines instinct, the "reflexive and autonomic" behaviours are still instincts. This might be true, depending on how one defines instinct. That is open to debate, but in any event this still rests on a particular definition of "instinct." Um, are you suggesting that they "need to be told" so that they will be able to mate? I was never taught how to mate in sex education! What they "need to be told" is the consequences of mating. With all due respect, what evidence do you have of this? I am not saying that it is false, merely that it is unsupported.

This lack of inherited mating behavior is not without precedent. Gorillas are another of the Great Apes that are born with the urge to mate but not the innate behavior to satisfy the urge. Gorillas in the wild can observe adult gorillas copulating and so learn the behavior, but those born in captivity have been found not to know how to mate if they are kept separate from mating couples; this has been one of the obstacles to breeding gorillas in captivity.

The lack of an inherited behavior corresponding to a specific drive is not unprecedented, either; we are born with a "hunger" drive, and infants have a reflex for suckling, but beyond that one behavior, the actions that satisfy the hunger urge are learned and not inherited.[/b][/quote]Once again, one could include "urges" in the definition of behaviour. Sorry to be repetitive, but the definitions of "instinct" that I gave clearly define this term independently of what parts of the nervous system (or, indeed, if any parts of the nervous system) are involved. I agree, but even this depends on how you define these terms. Not if you define "instinct" as I have. These are only not instincts if you define "instincts" so as not to include them. It is a semantic argument.

Peez

Dr Rick

I certainly do not wish to debate semantics, and you are right: a disagreement over definitions would be just that. If one wishes to define instinct in such a way that it includes heartbeats or digestive tract peristalsis, then of course humans possess these "instincts." If there is utility in equating autonomic functions with avian migrations and mating rituals, then your definition might even serve some purpose.

My freshman biology course covered a lot of physiology and anatomy, but very little about animal behavior and nothing about human behavior, so it is not surprising that an elementary biology text would provide cursory definitions of instinct.

Most sociologists, psychologists, and behavioralists do not concern themselves with the autonomic nervous system when evaluating human behavior, so neither do I.

[ March 25, 2002: Message edited by: rbochnermd ]</p>

Peez

Implying that "my" definition does not serve any purpose? First, it is not my definition, I simply took it from a biology text book. Second, I would not necessarily agree that it serves no purpose, but that is beside the point. Indeed, I do not usually have time to teach much animal behaviour in my biology courses, though I would like to. By the way, why do you consider these definitions "cursory?" I note that you have not given a source for your own, or did I miss it? I believe that most biologists who study animal behaviour do not use the term "instinct," though I could be wrong. Certainly the colleague who I consulted (who studies animal behaviour) does not use it, and it is nowhere to be found in the first animal behaviour text that I consulted (Animal Behavior, Fifth Edition, Drickamer et al 2002, McGraw- Hill). That book only uses "innate" defined as "Behavior that has either a fixed genetic basis or a high degree of genetic programming." I guess that they find that definition serves some purpose, even if used for another term.

Peez

Jubal

Survivability is not the only factor in deciding whether a member is genetically viable, but also desirability. For example, if a lion is found to have a taste for human blood, he will be tracked down and killed. The reason there is no mass extermination of lions in the area is that it's easier to live around a partially domesticated dominant predator than it is to either have to cope with a new one or deal with the consequences of changing the local ecosystem. To make a possibly better example, male wolves are able to coexist, but they have a heirachy of sorts. If an overambitious subordinate male misbehaves he may be driven into exile or even murdered, thus eliminating him from the genepool; however, if the alpha is too ruthless, he will eventually be challenged and defeated.

What I am suggesting here is that natural selection alone is not responsible for the state of our species, but also peer selection. I believe that this works better than the usual strawman appreciation of evolution.

[ March 25, 2002: Message edited by: Swan-eater ]</p>

Peez

If I understand you correctly, I agree. In order to pass on your genes, you have to survive and reproduce. Actually, you only need to reproduce, but you need to survive long enough to do that. However, you seem to be saying that natural selection does not include any selection resulting from interactions with other members of the same species. This is not how natural selection is usually understood. Rather, selection arising from selection caused by one's peers is natural selection, unless you use some definition with which I am unfamilar. Thus what you are calling "peer selection" (not to be confused with kin selection, if I understand you) is a form of natural selection. Just a little nit pick.

Peez

Jubal

Creationists have a poor understanding of natural selection. It would be easier to introduce a new term than it would be to get them to change their understanding of an old one on which they have built so many of their assumptions. I think they'd be far more willing to hear of a concept they have not yet heard of than they would be to face the possibility that they've had something wrong. Just tending to some practical concerns.

Also, with this, you can juxtapose the effects human social constructions on our genome with the domestication of wild animals, which has been proven effective in practice: <a href="http://drbeetle.homestead.com/dog.html" target="_blank">http://drbeetle.homestead.com/dog.html</a>