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Author Topic:   What you see with your own eyes vs what scientists claim
Modulous
Member
Posts: 7801
From: Manchester, UK
Joined: 05-01-2005


Message 91 of 165 (447672)
01-10-2008 11:51 AM
Reply to: Message 87 by sinequanon
01-10-2008 11:07 AM


You've also combined it with your bizarre excuse that you won't bother with a citation because I wouldn't be satisfied with it. I don't recall you ever accepting that as a valid excuse from anyone.
We disagree. You think a cite is necessary. I don't. I don't think the following really qualifies for requiring a citation in an ecology journal.
a) there are learned behaviours
b) there are unlearned behaviours
c) the current consensus is that a complex (abe: unlearned!) behaviour that is efficient or optimum is almost certainly the result of evolution.
Because these are general points, it is unlikely a single paper will go into them. They are found on a body of work that started with their respective pioneers, so any single cite is unlikely to do everything that you are demanding. I'd have to get a whole body of evidence together and compile into a convincing whole. Essentially to complete the task to my own satisfaction, let alone yours, would require writing a discussion paper or managing to find just the right one. For example, this paper states that
quote:
The Baldwin effect is sometimes referred to as the simple notion that, through evolution, unlearned can replace learned behavior.
but even that paper doesn't really cover it.
You however do think it requires a citation.
I think the statements are uncontroversial, pretty much the foundation of the work being done and accepted by the intended readers and so don't require citation.
In fact, I think our positions and arguments are now out there and repeating them is surely a waste of time and memory, don't you? You think this presents a problem. I am not convinced by your argument that it is, you remain unconvinced by my argument that it isn't. Unless we have something new to say - let's not bother, eh?
I have even offered concession on this point, yet you have decided not to take it. I offer again, let us grant that this was sloppy wording or improper citation and move on. Even if you were entirely right about this point, I don't see any thing particularly noteworthy. In a world of dodgy ethical practices, fraud, people talking about subjects clearly out of their field I feel we can discuss much more interesting things. So, any more examples to look at?
Edited by Modulous, : No reason given.

This message is a reply to:
 Message 87 by sinequanon, posted 01-10-2008 11:07 AM sinequanon has not replied

Modulous
Member
Posts: 7801
From: Manchester, UK
Joined: 05-01-2005


Message 92 of 165 (447675)
01-10-2008 12:13 PM
Reply to: Message 89 by sinequanon
01-10-2008 11:36 AM


For example, if your capability and behaviour changed as a result of ingesting a drug, would you say that was learned behaviour?
Well, that really depends. Let me give you a straight answer in example form for ease, I would consider falling over when drunk to be unlearned behaviour. I would consider talking to a rock on acid to be a learned behaviour (though the impulse to communicate might be unlearned...but in both cases there is usually a complex web of learned and unlearned behaviour at work).
They fail to consider prey loss decreasing when a bird drops prey from a greater height. Why?
Well, they might have considered it, but the proposal would run against the 'evidence of their eyes' - when birds drop things from higher up, it takes longer for them to retrieve them. Fortunately, in the spirit of science, they go observe it for themselves. They found that prey loss increases with height.

This message is a reply to:
 Message 89 by sinequanon, posted 01-10-2008 11:36 AM sinequanon has replied

Replies to this message:
 Message 93 by sinequanon, posted 01-10-2008 12:23 PM Modulous has replied

sinequanon
Member (Idle past 2865 days)
Posts: 331
Joined: 12-17-2007


Message 93 of 165 (447679)
01-10-2008 12:23 PM
Reply to: Message 92 by Modulous
01-10-2008 12:13 PM


Well, that really depends. Let me give you a straight answer in example form for ease, I would consider falling over when drunk to be unlearned behaviour. I would consider talking to a rock on acid to be a learned behaviour (though the impulse to communicate might be unlearned...but in both cases there is usually a complex web of learned and unlearned behaviour at work).
It sounds as if you agree that the new aspects of the behaviour are not learned. i.e what you could do after that you couldn't do before, is not learned. Agreed?
Well, they might have considered it, but the proposal would run against the 'evidence of their eyes' - when birds drop things from higher up, it takes longer for them to retrieve them. Fortunately, in the spirit of science, they go observe it for themselves. They found that prey loss increases with height.
That was for one drop. The likelihood of the prey breaking also increases, so fewer drops would be needed. How do they know that wouldn't outweigh the benefit of shorter retrieval?
Edited by sinequanon, : Changed 'longer retrieval' to 'shorter retrieval'

This message is a reply to:
 Message 92 by Modulous, posted 01-10-2008 12:13 PM Modulous has replied

Replies to this message:
 Message 95 by Modulous, posted 01-10-2008 1:22 PM sinequanon has replied
 Message 97 by Percy, posted 01-10-2008 1:41 PM sinequanon has replied

riVeRraT
Member (Idle past 416 days)
Posts: 5788
From: NY USA
Joined: 05-09-2004


Message 94 of 165 (447689)
01-10-2008 1:09 PM
Reply to: Message 1 by sinequanon
01-07-2008 7:53 AM


Magicians do tricks all the time, and what we see isn't really what happened.

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 Message 1 by sinequanon, posted 01-07-2008 7:53 AM sinequanon has not replied

Replies to this message:
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Modulous
Member
Posts: 7801
From: Manchester, UK
Joined: 05-01-2005


Message 95 of 165 (447696)
01-10-2008 1:22 PM
Reply to: Message 93 by sinequanon
01-10-2008 12:23 PM


It sounds as if you agree that the new aspects of the behaviour are not learned. i.e what you could do after that you couldn't do before, is not learned. Agreed?
On reflection I wouldn't say they were strictly speaking 'new', I'd say they were 'modified'. The same goes for brain damage I suppose.
However, moving back towards the original point, where we were talking about a certain type of behaviour. I may not have mentioned it every time, but I tried to repeat it as much as I could stomach without sounding repetitive. And the behaviour in context was optimum or efficient behaviour, like the behaviour of the crows under discussion.
I grant that it might be possible for a drug (or brain damage) to induce specific behaviour that is more optimum or efficient in principle, it is just highly improbable and definitely highly improbable if all the observed members of a seemingly random group exhibit the behaviour.
If a bird scientist observed humans and thought it worth mentioning, with no evidence, that one possible reason that certain humans can play good poker is because they are on drugs or brain damaged - they would get an appropriately amused twitter I'm sure you'd agree.
The likelihood of the prey breaking also increases, so fewer drops would be needed. How do they know that wouldn't outweigh the benefit of longer retrieval?
Finding this out was part of the test. They observed that the crows drop lower and more often when there are many birds around, and higher and less often as the number of birds decreased. As you say 'That was for one drop.', and that was what they were talking about 'one drop'. For each drop, the higher it is dropped from the greater the chance of breaking the nut but the higher chance of theft. The authors postulated that if natural selection was at play, or if the birds were able to learn how, the birds would have found some optimum.
Edited by Modulous, : No reason given.

This message is a reply to:
 Message 93 by sinequanon, posted 01-10-2008 12:23 PM sinequanon has replied

Replies to this message:
 Message 99 by sinequanon, posted 01-10-2008 2:15 PM Modulous has replied

Taz
Member (Idle past 3292 days)
Posts: 5069
From: Zerus
Joined: 07-18-2006


Message 96 of 165 (447697)
01-10-2008 1:27 PM
Reply to: Message 94 by riVeRraT
01-10-2008 1:09 PM


riverrat writes:
Magicians do tricks all the time, and what we see isn't really what happened.
Funny how you mentioned magicians. The people that they fool the most are scientists, you know.

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 Message 94 by riVeRraT, posted 01-10-2008 1:09 PM riVeRraT has not replied

Percy
Member
Posts: 22394
From: New Hampshire
Joined: 12-23-2000
Member Rating: 5.2


Message 97 of 165 (447704)
01-10-2008 1:41 PM
Reply to: Message 93 by sinequanon
01-10-2008 12:23 PM


sinequanon writes:
The likelihood of the prey breaking also increases, so fewer drops would be needed. How do they know that wouldn't outweigh the benefit of shorter retrieval?
You're thinking of a different question than the one they were actually attempting to answer. The question you seem to think they were asking is, "Does increasing drop-height increase the likelihood that they'll lose the walnut before they can break and eat it?"
As stated in the excerpt you quoted in your Message 89, the question they were actually asking was, "Do crows adjust drop height with respect to potential kleptoparasitism?"
I think your question is at least as interesting, but it definitely seems outside the paper's topic area, which was the factors affecting prey-dropping behavior, not the success-rate of various prey dropping strategies.
--Percy

This message is a reply to:
 Message 93 by sinequanon, posted 01-10-2008 12:23 PM sinequanon has replied

Replies to this message:
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Archer Opteryx
Member (Idle past 3598 days)
Posts: 1811
From: East Asia
Joined: 08-16-2006


Message 98 of 165 (447705)
01-10-2008 1:44 PM
Reply to: Message 1 by sinequanon
01-07-2008 7:53 AM


What you see with your own eyes vs What theologians claim
sinequanon:
I would always believe the evidence of my own eyes.
Then you are an atheist, because God, even by the accounts of theological "experts", cannot be seen. And you just told us you have no use for experts.
Thank you for playing, Mr Non.

This message is a reply to:
 Message 1 by sinequanon, posted 01-07-2008 7:53 AM sinequanon has not replied

sinequanon
Member (Idle past 2865 days)
Posts: 331
Joined: 12-17-2007


Message 99 of 165 (447714)
01-10-2008 2:15 PM
Reply to: Message 95 by Modulous
01-10-2008 1:22 PM


I grant that it might be possible for a drug (or brain damage) to induce specific behaviour that is more optimum or efficient in principle, it is just highly improbable and definitely highly improbable if all the observed members of a seemingly random group exhibit the behaviour.
If a bird scientist observed humans and thought it worth mentioning, with no evidence, that one possible reason that certain humans can play good poker is because they are on drugs or brain damaged - they would get an appropriately amused twitter I'm sure you'd agree.
Absolutely not. Performance enhancing drugs are very common in sport and games. It's one thing for which officials do look out.
So this evolved/learned description that you called a dichotomy has now changed to something you think is only highly probable?
Finding this out was part of the test. They observed that the crows drop lower and more often when there are many birds around, and higher and less often as the number of birds decreased. As you say 'That was for one drop.', and that was what they were talking about 'one drop'. For each drop, the higher it is dropped from the greater the chance of breaking the nut but the higher chance of theft. The authors postulated that if natural selection was at play, or if the birds were able to learn how, the birds would have found some optimum.
No. Read the conclusion. Their model predicts energy maximisation.
quote:
Our model predicted that if birds maximize the energy obtained from each dropped food item, they should take into account the intensity of kleptoparasitism, the likelihood of each item breaking given its hardness and previous weakening, and the hardness of the substrate. American crows adjusted the height from which they dropped walnuts as our model predicted, if they were accounting for each of these factors.
quote:
This suggests that these crows have evolved or learned to maximize the energy obtained from each dropped walnut.
For kleptoparasitism they tested one drop, which does not test energy maximisation, and then said the results agreed with their model.

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 Message 95 by Modulous, posted 01-10-2008 1:22 PM Modulous has replied

Replies to this message:
 Message 101 by Modulous, posted 01-10-2008 4:42 PM sinequanon has replied

sinequanon
Member (Idle past 2865 days)
Posts: 331
Joined: 12-17-2007


Message 100 of 165 (447716)
01-10-2008 2:25 PM
Reply to: Message 97 by Percy
01-10-2008 1:41 PM


The question you seem to think they were asking is, "Does increasing drop-height increase the likelihood that they'll lose the walnut before they can break and eat it?"
No. My point is that I do not see how the question they answered ties in with their conclusion that crows are maximising energy.

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Replies to this message:
 Message 102 by Modulous, posted 01-10-2008 5:20 PM sinequanon has replied

Modulous
Member
Posts: 7801
From: Manchester, UK
Joined: 05-01-2005


Message 101 of 165 (447730)
01-10-2008 4:42 PM
Reply to: Message 99 by sinequanon
01-10-2008 2:15 PM


Absolutely not. Performance enhancing drugs are very common in sport and games. It's one thing for which officials do look out.
We're not talking about improving physical traits through drugs, we're talking about adopting optimum strategies. What behaviour is changed to form some kind optimum way of running when a sprinter takes steroids?
So this evolved/learned description that you called a dichotomy has now changed to something you think is only highly probable?
Yes, you've heard of tentativity right? We're talking science here; there's no need to list all the philosophically possible causes - just the ones that are actually suggested by the evidence.
No. Read the conclusion. Their model predicts energy maximisation.
Yes, that is what their model predicts. What's 'no' about what I said?
quote:
They observed that the crows drop lower and more often when there are many birds around,
OK, so the paper says that crows drop lower when there are many birds around:
quote:
As predicted, there was a significant negative relationship between drop height and kleptoparasite intensity, indicating that crows dropped walnuts from greater heights when the potential for kleptoparasitism was lower.
And the paper also shows that the higher that walnuts are dropped the less drops it takes
quote:
By dropping nuts experimentally, we found that the number of drops required to crack a walnut decreased with height of drop, regardless of species
And the paper thus stated
quote:
For each drop, the higher it is dropped from the greater the chance of breaking the nut but the higher chance of theft.
I also said
quote:
Thee authors postulated that if natural selection was at play, or if the birds were able to learn how, the birds would have found some optimum.
And the abstract states:
quote:
Complex and energetically expensive foraging tasks should be shaped by natural selection to be efficient... When faced with multiple prey types and dropping substrates, and high rates of attempted kleptoparasitism, crows adjusted the height from which they dropped nuts in ways that decreased the likelihood of kleptoparasitism and increased the energy obtained from each nut.
I'm not sure why that would prompt you to say 'no' and then tell me what part of the conclusion says.
For kleptoparasitism they tested one drop, which does not test energy maximisation, and then said the results agreed with their model.
They didn't just test 'one drop'. They observed the rate of kleptoparasitism by measuring the rate of kleptoparatisism of the first drop of all the English walnuts at the Birch Lane site. If you think that this constitutes some kind of methodological issue then I'll happily hear you out. However, the data they did collect does agree with their model (mostly). The birds do take into account the chances that their prey will be stolen in selecting a height.

This message is a reply to:
 Message 99 by sinequanon, posted 01-10-2008 2:15 PM sinequanon has replied

Replies to this message:
 Message 103 by sinequanon, posted 01-10-2008 5:22 PM Modulous has replied

Modulous
Member
Posts: 7801
From: Manchester, UK
Joined: 05-01-2005


Message 102 of 165 (447738)
01-10-2008 5:20 PM
Reply to: Message 100 by sinequanon
01-10-2008 2:25 PM


The likelihood of the prey breaking also increases, so fewer drops would be needed. How do they know that wouldn't outweigh the benefit of shorter retrieval?
And then later,
My point is that I do not see how the question they answered ties in with their conclusion that crows are maximising energy.
If a walnut has 100 energy, and the probability of losing prey looks like this:

metres probability of losing
5 90
4 45
3 15
2 8
1 6
And if the number of drops required looks like this:

metres number of drops required
5 1
4 2
3 5
2 7
1 10
Then the probability of still possessing the walnut after it cracks open:

metres probability
5 10
4 0.552=30
3 0.855=44
2 0.927=56
1 0.9410=54
So, on average, a walnut dropped at 5 metres nets 10 units of energy (10% of 100). Likewise, dropping the walnut from 1 metre will average out as 54 units for each walnut. The optimum height to drop is 2 metres, since each walnut then effectively gives 56 units of energy. If 2 metres is chosen then the subject has maximised the amount of energy they get from the walnuts.
Obviously this is a simplified account, but that is how it ties into the idea that crows are maximising energy.
Edited by Modulous, : No reason given.

This message is a reply to:
 Message 100 by sinequanon, posted 01-10-2008 2:25 PM sinequanon has replied

Replies to this message:
 Message 104 by sinequanon, posted 01-10-2008 5:42 PM Modulous has replied

sinequanon
Member (Idle past 2865 days)
Posts: 331
Joined: 12-17-2007


Message 103 of 165 (447739)
01-10-2008 5:22 PM
Reply to: Message 101 by Modulous
01-10-2008 4:42 PM


We're not talking about improving physical traits through drugs, we're talking about adopting optimum strategies. What behaviour is changed to form some kind optimum way of running when a sprinter takes steroids?
No idea. I do not think their purpose is to work on the brain or the nervous system. Drugs which do, alter behaviour.
They didn't just test 'one drop'. They observed the rate of kleptoparasitism by measuring the rate of kleptoparatisism of the first drop of all the English walnuts at the Birch Lane site.
Semantics. We are agreed it can take many drops to break a nut and thereby obtain the energetic value. Their test took into account only one of them, i.e the first drop.
If you think that this constitutes some kind of methodological issue then I'll happily hear you out. However, the data they did collect does agree with their model (mostly). The birds do take into account the chances that their prey will be stolen in selecting a height.
The number of drops required to break the nut was missing from their test as an independent variable. But it is a critical variable in measuring energy expended. Without it, their conclusion that the crows maximised energy with regard to kleptoparasitism is flawed.
And the paper thus stated
quote:
--------------------------------------------------------------------
For each drop, the higher it is dropped from the greater the chance of breaking the nut but the higher chance of theft.
I can't find this "quote" anywhere in the paper by the way.

This message is a reply to:
 Message 101 by Modulous, posted 01-10-2008 4:42 PM Modulous has replied

Replies to this message:
 Message 105 by Modulous, posted 01-10-2008 6:25 PM sinequanon has replied

sinequanon
Member (Idle past 2865 days)
Posts: 331
Joined: 12-17-2007


Message 104 of 165 (447747)
01-10-2008 5:42 PM
Reply to: Message 102 by Modulous
01-10-2008 5:20 PM


And if the number of drops required looks like this:
Are these actual values? If so, which graph did you use and how did you work them out?
Are you satisfied with your working?

This message is a reply to:
 Message 102 by Modulous, posted 01-10-2008 5:20 PM Modulous has replied

Replies to this message:
 Message 106 by Modulous, posted 01-10-2008 6:33 PM sinequanon has replied

Modulous
Member
Posts: 7801
From: Manchester, UK
Joined: 05-01-2005


Message 105 of 165 (447764)
01-10-2008 6:25 PM
Reply to: Message 103 by sinequanon
01-10-2008 5:22 PM


No idea. I do not think their purpose is to work on the brain or the nervous system. Drugs which do, alter behaviour.
Right, so we're back to
quote:
If a bird scientist observed humans and thought it worth mentioning, with no evidence, that one possible reason that certain humans can play good poker is because they are on drugs or brain damaged - they would get an appropriately amused twitter I'm sure you'd agree.
Last time you disagreed because of performance enhancing drugs in athletics. I think we can now agree that a drug that makes you good at poker and a drug that builds muscle mass to increase speed/strength are different categories.
Semantics. We are agreed it can take many drops to break a nut and thereby obtain the energetic value. Their test took into account only one of them, i.e the first drop.
They tested prey breakability. Their model predicted that the optimum strategy for harder nuts is to drop them from higher heights. The crows dropped harder species of nut from higher heights.
They tested substrate hardness. They predicted that the optimum strategy for dealing with softer surfaces is to increase the height to drop from. It also predicted that the optimum strategy is to prefer harder surfaces. The crows dropped from higher onto soft surfaces and preferred hard surfaces.
They tested the height of successive drops. They predicted that the height from which the walnut is dropped on successive drops will lower as the probability that the walnut will break goes up. They observed this behaviour in the crows.
quote:
At Birch Lane 11.9% of 337 English walnuts dropped once were dropped again by the same crow (mean = 3.42 1.87 drops). The maximum number of repeated drops observed at Birch Lane was 17, although at other sites crows dropped English walnuts up to 50 times before cracking them (data not shown). As predicted by our model, drop height decreased significantly with successive drops (Figure 3). Attempted kleptoparasitism did not change with successive drops (df = 4, Kruskal-Wallis H = 4.0, p =.41), indicating that this variable is unlikely to explain the relationship between drop height and successive drop number.
They tested prey mass and breakability. They predicted that the optimum strategy is to drop heavier walnuts from lower heights. The crows did not follow this behaviour.
They tested prey loss. They predicted that as the risk of kleptoparasitism increases the optimum strategy is to lower the height to drop. This behaviour was replicated by the crows.
Thus, with the exception of taking mass into consideration, the crows followed the optimum behaviour in adjusting height to account for various variables, maximising the chances of getting at the sweet nut, and thus maximising the energy per walnut.
The number of drops required to break the nut was missing from their test as an independent variable. But it is a critical variable in measuring energy expended. Without it, their conclusion that the crows maximised energy with regard to kleptoparasitism is flawed.
The paper did not discuss the amount of energy the crow expends, though that would be interesting too. They were talking about the amount of energy gained from the walnuts.
I can't find this "quote" anywhere in the paper by the way.
I was comparing my quotes with theirs to show how I didn't seen any contradiction with what I said with what the paper showed. Sorry for any confusion.
Edited by Modulous, : No reason given.

This message is a reply to:
 Message 103 by sinequanon, posted 01-10-2008 5:22 PM sinequanon has replied

Replies to this message:
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