How is instinct possible?

  • Thread starter KAckermann
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In summary: We do it without thinking, but it also has to be done in a specific way. Flying is a complex behavior that is governed by evolution and it too is something that can be done in steps.
  • #1
KAckermann
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Instinct, by definition, is a hard-wired behavior. It does not have to be learned.

Therefore, it is passed on from generation to generation.

Therefore, it is encoded in DNA (as preconfigured neural structures?)

Therefore, it is a chicken and egg problem.

Does it mean that a successful (possibly essential) behavior is transcribed to DNA somehow?

How can DNA acquire a map to the physical world? When you consider that an Arctic Tern circumnavigates the planet during migration, or that a salmon knows how to get back to its place of birth, I am floored as to how this behavior could have been encoded for by chance, and equally floored by the prospect of a DNA transcription process where behavior is essentially 'recorded' in DNA.

Am I way off base here? Is there something simple that I am missing?
 
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  • #2
Yes slightly
The genetic code doesn't have to encode the learned facts - the DNA just has to encode the process of learning.
A baby has a built in genetic ability to learn language, because the animals that didn't learn it didn't communicate with their species and so didn't mate and pass on their genes.
Their DNA doesn't have to encode English - a baby would be just as good at learning Klingon.
Similairly a bird's DNA doesn't code the route to take on a migration - it codes the behaviour to follow all the other birds when they take off.
 
  • #3
Hi K,
Instinct, by definition, is a hard-wired behavior. It does not have to be learned.
Do you mean for example, how can:
- a spider 'know' how to spin a web (without having to learn it)
- a new-born dolphin 'know' how to swim and come to the surface to breath air instead of inhaling water (without having to learn it).
- etc...

Yes, these are "hard wired" and passed down through DNA. The standard paradigm goes something like this. The DNA encodes the information needed to create a brain. It is the brain (neuron structure) which is responsible for causing certain types of behavior. DNA is considered the 'code' responsible for creating the 'hardware' of the brain, and that code has in it, the information needed to create the proper neuron structure. So the neuron structure has encoded in it the 'behavior' which therefore doesn't have to be learned.

If you're asking, how can that structure get started, because the DNA has to have the proper code in order to create the brain with a specific hard wired structure (thus the chicken/egg problem) I think you only need to turn to evolution to understand how DNA can be modified through generations. Perhaps you can better phrase the question.
 
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  • #4
i'd be very surprised if salmon are encoded to a specific stream. more than likely they form an imprint based on the smell of their environment when young. even in humans, smells evoke some of the deepest memories and emotions. which makes sense, since finding food and avoiding poisons is a matter of survival.
 
  • #5
I get no satisfaction from this answer. That is worded clumsy, but I hope you know what I mean.

I can accept the learning explanation, but instinct by definition is not learned. Many are not even consciously engaged.

I can even buy the bird-folllowing-bird scenario to some degree, but even that does not explain why certain aspects of migration such as how birds 100 miles apart will begin their migration at the same time and head to the same place.

Somehow they all know where to go, and there has to be cases where a bird or a flock have begun a first migration alone without an experienced navigator.
 
  • #6
Logic says that instincts must be selected for over time, but some instincts are so complex that it's hard to stomach as a purely random manifestation.

I also have never heard of a frog that tried to fly south for the winter, and you would thing that as a random process... I don't know.

The fact that we don't know is interesting in itself.
 
  • #7
Even if a salmon does employ some kind of marker or sense, it still requires a very sophisticated set of behaviors.

Wiki says that salmon spend as much as 5 years in the open ocean, but it does not say how far they range there, only that they may travel hundreds of miles to get back to their spawning ground.

I'm surprised the salmon has not pressured itself out of existence. Them and penguins. The hell they go through just to satisfy the instinct to breed.

Now that is a powerful instinct.
 
  • #8
Instinct is just governed by evolution.
It can be done in steps to show how just because it seems complex does not mean it can't come from a simple process.

1st example would be breathing. A process humans do without thinking. Anyone who can't breath dies. If a baby does not get the information on how to breath to a baby before its born it dies. Hence the baby's knowledge on how to breath is passed on from the mother before birth which must be in genes.

Step it up a level. Spiders just knowing how to make a web is the same. If they could not make a web they would die and hence not reproduce and hence not pass on the DNA holding the information to build a web.

and so on up the difficulty curve.


Migration paths will be learned by following older individuals in the migration. If they do not follow they will die and again won't pass on the genes that say "follow your parents/crowd"

I think the problem lies in that you are thinking these things come about randomly. They come about through evolution which is not random at all. Creatures will slowly evolve to particular behaviors and despite looking complex there will always be a set of small steps to something very basic. Over the very long periods of time complex actions can come about from evolution from something rather basic in comparison.
 
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  • #9
DjDukes said:
Instinct is just governed by evolution.
I think the problem lies in that you are thinking these things come about randomly. They come about through evolution which is not random at all. Creatures will slowly evolve to particular behaviors and despite looking complex there will always be a set of small steps to something very basic. Over the very long periods of time complex actions can come about from evolution from something rather basic in comparison.

It's not that, I understand things are pressured in certain directions.

I'm saying that things like migration paths are more than just learned by following, they are in the genes. If these complex behaviors are selected for, then so be it; but I wonder if there might not be additional help somewhere.

After all, the time it takes to get to some current state of instinctual behavior, if driven purely by selection, would indicated that many other attributes may have had the chance to manifest during that time. Things like changing skin color I would think would be beneficial to any species, and the fact that it occurs at all would imply that most species would eventually have this ability.

I don't know; my gut tells me it is natural selection plus something else, such as reverse transcription of some sort.
 
  • #10
As an example, let's look at elvers. These are tiny, almost transparent baby eels that come to Maine's rivers to grow in fresh water. When they are mature enough, they head out to the Sargasso Sea to breed, and their spawn comes back to Maine. The elvers have never been in a Maine river, nor do they know the smell of fresh water, having hatched in the ocean, and having spent most of their brief lives swimming the Atlantic to get here. How do they know to "come home" to waters where they can live relatively safe from predation, so that they can mature and head back to the Sargasso? It's not learned behavior. If you could see a bucket of those little glassine creatures, you'd have to wonder how such behavior could be hard-wired into such tiny little nervous systems.

As an aside: Elvers have a fair degree of protection here, in part because years ago, the Japanese were paying over $2000/lb for them live-shipped to Japan to stock eel farms. Over-fishing resulted, and strict regulations with tough penalties had to be instituted to protect enough of the returning elvers to ensure viability of the population.
 
  • #11
mgb_phys said:
Yes slightly
The genetic code doesn't have to encode the learned facts - the DNA just has to encode the process of learning.
A baby has a built in genetic ability to learn language, because the animals that didn't learn it didn't communicate with their species and so didn't mate and pass on their genes.
Their DNA doesn't have to encode English - a baby would be just as good at learning Klingon..

Steven Pinker disagrees with you. read 'the language intstinct'.
theres nothing really extraordinary about instinct. we have lots of instincts. we are born with mental modules that process visual/auditory/tactile information. we take it so much for granted that we don't even notice it but it would in fact be extremely difficult to get a computer to do what a newborn instect does easily.

babies learn language but dogs never do. yet both have the 'process of learning' encoded in their dna.
 
  • #12
KAckermann said:
Logic says that instincts must be selected for over time, but some instincts are so complex that it's hard to stomach as a purely random manifestation.

I think you'll find the cause of mutations to be the random factor in the development of an animal's instincts. The mutations are caused by the organisms interaction with the environment.

I think it's hard for you to imagine such complex instinctual "manifestations" or developments because these developments have taken place over 100s of millions of years. In some cases billions of years. It depends on the species we're talking about.

Salmon have been around along time. Or, at least their predecessors have. We're talking about probably over 250 million years. Every generation during every one of those 250 million years is subject to environmental adversities and challenges.

Each generation there is a modification in the gene pool of the species because a certain feature was advantageous for a certain number and helped that portion of that generation survive. And the modification or "mutation" remains while the individuals without it do not.

Let's say a Salmon's generation cycle is about 7 years. Multiply these changes by 7 into 250,000,000, = 35,714,286 generations of evolutionary development... and development of instinct.

36 million generations represents enough time to develop some pretty complex instincts.
 
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  • #13
KAckermann said:
Logic says that instincts must be selected for over time, but some instincts are so complex that it's hard to stomach as a purely random manifestation.

This is a standard misconception that probably stems out of creationist's fallacious arguments against evolution. A complex instinct didn't just randomly spring into existence in a couple of individuals after which those individuals were selected, but the instinct itself gradually evolved from simpler behaviours, each of the steps being favorable for the individual in question.
 
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  • #14
What instincts do all humans share?
 
  • #15
The Dagda said:
What instincts do all humans share?

One common instinct is to "google".
 
  • #16
baywax said:
One common instinct is to "google".

I just googled that and it said on wiki that it's a common misconception that googling is an instinct?

Now I'm just confused?

Is it true that if you type Google into Google it can break the internet?
 
  • #17
The Dagda said:
What instincts do all humans share?

the language instinct
 
  • #18
granpa said:
the language instinct

The instinct to learn language you mean. Ok got that one from before what else?
 
  • #19
The Dagda said:
What instincts do all humans share?

All of them, by definition.
 
  • #20
yerpo said:
All of them, by definition.

? :confused:
 
  • #21
The Dagda said:
? :confused:

Just google the question you're asking... here's what I got from the infamous Wikipedia

Instincts in humans can also be seen in what are called instinctive reflexes. Reflexes, such as the Babinski Reflex (fanning of the toes when the foot is stroked), are seen in babies and are indicative of stages of development. These reflexes can truly be considered instinctive because they are generally free of environmental influences or conditioning.

Additional human traits that have been looked at as instincts are:
sleeping,
altruism,
disgust,
face perception,
language acquisitions,
"fight or flight" and
"subjugate or be subjugated".

Some experiments in human and primate societies have also come to the conclusion that a sense of fairness could be considered instinctual, with humans and apes willing to harm their own interests in protesting unfair treatment of self or others.[1][2]

http://en.wikipedia.org/wiki/Instinct
 
  • #22
I'd like to add here that there are physiological reactions that are inheritable - not instinctual. For example (probably due to some Native American heritage on both sides of my family) I cannot be poisoned by mushrooms. I am acutely sensitive to the taste of alkaloids and experience a most revolting gut-wrenching bitterness at exposure levels that most people can't detect. I found this out when participating in a genetics program as a biology student. While undergoing genetic screening with a whole bunch of other "guinea pigs" we had to file through a station at which you were told to touch a piece of blotter paper to your tongue, and write down your impression. Every single person in front of me (that I could see) simply went through the station and shrugged (or less) and wrote something on their clip-board. When I tasted the paper, I retched and thought I might puke - it was that bad.
 
  • #23
turbo-1 said:
I'd like to add here that there are physiological reactions that are inheritable - not instinctual. For example (probably due to some Native American heritage on both sides of my family) I cannot be poisoned by mushrooms. I am acutely sensitive to the taste of alkaloids and experience a most revolting gut-wrenching bitterness at exposure levels that most people can't detect. I found this out when participating in a genetics program as a biology student. While undergoing genetic screening with a whole bunch of other "guinea pigs" we had to file through a station at which you were told to touch a piece of blotter paper to your tongue, and write down your impression. Every single person in front of me (that I could see) simply went through the station and shrugged (or less) and wrote something on their clip-board. When I tasted the paper, I retched and thought I might puke - it was that bad.

Conversely, although the firstnation people had developed a genetic warning system with regard to certain foods, they were totally new to booze. Consequently, this was taken advantage of... along with their lack of anti-bodies that fight Small Pox... to the point of diminishing what was once quite a large North American population.

Personally, I must have genes that regulate my gag reflex to "Cherry Jack"... (some kind of sick winey kind of booze)
 
  • #24
Well, considering this is a pressing issue in the Neurodevelopmental Biology community that has yet to be answered, I suggest to you that you will receive no simple answer as to how an instinct is coded for. To begin with Neurodevelopment is dependent on plenty signaling mechanisms that code for the massive amount of differentiation in the CNS. I'd hypothesize, as I really don't know a lot about the subject, that instinctual behaviors, such as FAPs, are resultant of the intrinsic nature of the neural network of an organism. Neural development is not exactly replicable in the sense of one hundred percent spatial conservation across individuals in a population, but it is similar in a sense, for instance cells regulate the amount of synapses of different types of neurons that connect to them, in terms of overall surface area. So I'd expect that these genes are responsible for the overall development of the organism's instincts would be those that code for the signaling proteins in the pathways that would control cytoskeletal elements, or the other large number of pathways that may be implicated by my previous very blanket-like statement.

Genes do code for instincts, but not in a very 1:1 type of way. For instance, look at autism, specifically Fragile X. The loss of a single protein causes major defects in physical appearance, retardation, problems with blood glucose regulation, and I'm sure, much more which has not been yet elucidated or that I'm forgetting.
 
  • #25
The brain uses DNA methylation to store memories, so that they can be copied as well. That is probably the basis of fear instincts as well in our more primitive brains.

DNA methylation is a type of chemical modification of DNA that can be inherited and subsequently removed without changing the original DNA sequence. As such, it is part of the epigenetic code and is also the most well characterized epigenetic mechanism.[citation needed] Because Methylation is a common capability of all viruses for self non-self identification the epigentic code could be a persistent remnant of ancient viral infection events.[1]

DNA methylation involves the addition of a methyl group to DNA — for example, to the number 5 carbon of the cytosine pyrimidine ring — in this case with the specific effect of reducing gene expression. DNA methylation at the 5 position of cytosine has been found in every vertebrate examined. In adult somatic tissues, DNA methylation typically occurs in a CpG dinucleotide context; non-CpG methylation is prevalent in embryonic stem cells.[2][3]

In plants, cytosines are methylated both symmetrically (CpG or CpNpG) and asymmetrically (CpNpNp), where N can be any nucleotide but guanine. Some organisms, such as fruit flies, exhibit virtually no DNA methylation.

Research has suggested that long term memories in humans may be stored via DNA methylation

http://en.wikipedia.org/wiki/DNA_methylation
 
  • #26
The Dagda said:
The brain uses DNA methylation to store memories, so that they can be copied as well. That is probably the basis of fear instincts as well in our more primitive brains.



http://en.wikipedia.org/wiki/DNA_methylation

Is there any evidence for a DNA methylation based memory mechanism? I mean, I understand how methylation is implicated in long term changes of functionality in the brain in response to sensory information, but is it memory with respect to learning or is it a plasticity in functionality due to a stimuli? I understand the basis behind LTP and what have you, but I never heard of a methylation based mechanism. Please elucidate this concept!

Thanks.
 
  • #27
If I had to guess, it influences the expression of genes that control axon formation.
 
  • #28
kingdomof said:
Is there any evidence for a DNA methylation based memory mechanism? I mean, I understand how methylation is implicated in long term changes of functionality in the brain in response to sensory information, but is it memory with respect to learning or is it a plasticity in functionality due to a stimuli? I understand the basis behind LTP and what have you, but I never heard of a methylation based mechanism. Please elucidate this concept!

Thanks.

Sure.

http://www.newscientist.com/article/mg20026845.000-memories-may-be-stored-on-your-dna.html

Memories may be stored on your DNA

REMEMBER your first kiss? Experiments in mice suggest that patterns of chemical "caps" on our DNA may be responsible for preserving such memories.

To remember a particular event, a specific sequence of neurons must fire at just the right time. For this to happen, neurons must be connected in a certain way by chemical junctions called synapses. But how they last over decades, given that proteins in the brain, including those that form synapses, are destroyed and replaced constantly, is a mystery.

Now Courtney Miller and David Sweatt of the University of Alabama in Birmingham say that long-term memories may be preserved by a process called DNA methylation - the addition of chemical caps called methyl groups onto our DNA.

Many genes are already coated with methyl groups. When a cell divides, this "cellular memory" is passed on and tells the new cell what type it is - a kidney cell, for example. Miller and Sweatt argue that in neurons, methyl groups also help to control the exact pattern of protein expression needed to maintain the synapses that make up memories.

They started by looking at short-term memories. When caged mice are given a small electric shock, they normally freeze in fear when returned to the cage. However, then injecting them with a drug to inhibit methylation seemed to erase any memory of the shock. The researchers also showed that in untreated mice, gene methylation changed rapidly in the hippocampus region of the brain for an hour following the shock. But a day later, it had returned to normal, suggesting that methylation was involved in creating short-term memories in the hippocampus (Neuron, DOI: 10.1016/j.neuron.2007.02.022)...
 
  • #29
first, in regard to the bird migration topic, i think we would have to know: if you took a bird egg and raised the bird for a couple years then released it (and it didnt join a group) would it still fly to the same spot as the rest of its species?

im sure that is known, but i do not. so, if the bird did not fly to the same spot, i think that would mean it has nothing to do with instinct, rather it is socially learned, in the form of following the old wise bird that followed the old wise bird that followed... and then the original old wise bird most likely figured it out from observing its environment, as in, movement and position of the sun in the sky. birds are very keen observers of the sun, they sit and stare at it during sunsets. hopefully someone here has studied birds and can shed some light on my speculation.

now for human instincts, i have thought about this a few times since a friend told me he had a college 'professor' that claimed we have no instincts. one i came up with that i think is pretty solid is: if a baby was born in a cave and it could see the opening where the light comes from, and you never let it see you leave or enter the cave, when left alone and able to move by itself it would surely move toward the light (energy) as opposed to into the dark cold cave.

the point I am trying to make there is that for the sake of survival the baby moves toward warmth, not to mention our other many connections to light and the sun.

also, another one i just considered is, babies being able to swim, has this not been shown to be an instinct? i don't know. :)
 
  • #30
The Dagda said:
I just googled that and it said on wiki that it's a common misconception that googling is an instinct?

Now I'm just confused?

Is it true that if you type Google into Google it can break the internet?

If you type Google into Google you will travel in time to the future at a speed and time comparative to your central processing unit.
 

1. How is instinct developed?

Instinct is developed through a combination of genetic programming and learning. Animals are born with certain innate behaviors that are passed down through genetics, but they also have the ability to learn and adapt their behaviors based on their environment.

2. Can instinct be taught or learned?

While instinct itself cannot be taught, animals can learn to modify their instincts through experience and observation. For example, a bird may have the instinct to build a nest, but it can learn to build a better nest through trial and error.

3. How do animals know what behaviors to perform instinctively?

Animals have specific neural pathways and structures in their brains that are responsible for instinctive behaviors. These pathways are developed through genetics and allow animals to perform certain behaviors without conscious thought.

4. Are instincts the same for all animals?

No, instincts can vary greatly among different species and even within the same species. Some animals may have instincts for hunting and foraging, while others may have instincts for social behaviors or survival tactics.

5. Can instincts be overridden by learned behaviors?

Yes, in some cases, learned behaviors can override instinctive behaviors. For example, a domesticated dog may have the instinct to chase prey, but through training, it can learn to ignore this instinct and follow commands from its owner.

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