Why is the possibility of Lechmere interrupting the ripper so often discarded?

[Newbie]

It's not something that requires a single study, but rather, I can direct you to an entire field of research, known as Signal Detection Theory, and also another well researched phenomenon known as "masking". Basically, how detectable a signal is ends up being a function of both the intensity of the signal (the distant footfalls) and the "noise" in the environment in which it is embedded. The louder noise of one's own footfalls will both produce masking (due to the similarity of the sounds they create with the signal) and will create a noisier environment than when the person stops walking. Both of those will act to make the distant footfalls less detectable.

Now, there are, of course, other factors that may reduce those negative influences, which you are alluding to. Yes, a regular, and particularly a self generated, "noise" or "mask" will be less effective than an irregular and externally generated one, but that doesn't mean they will be equivalent to no noise/no masking stimulus, which is what you are claiming. In some of my own research, we presented people with a tone, followed by a 4 second delay, followed by a 2nd tone which they had to decide if it was the same or different from the initial one. If that delay was silent, they did pretty well even if the different tone was quite similar to the original (and of course do better the more different it became), but if we filled that 4 seconds with a random sequence of 4 tones (at a constant rate, so predictable at least in their timing), the ability to detect that change between the two key tones dropped greatly, to the point they pretty much couldn't do it (Jiang, Lim, Wang, & Hamm, 2013). Not quite the same thing, but it shows that a predictable noise sequence interferes even with a simple tone matching task that one is actively paying attention to.

Also, you're presuming that Cross/Lechmere is actively seeking external footfalls, that he is trying to detect someone following him and there's nothing in his statements that indicates he was engaged in such activity. You're suggesting that footfalls, well in the distance behind him, that may very well not even have been noticeable due to masking and interference from the sounds of his own footfalls, would somehow grab his attention away from the space in front of him, that he does appear to have been attending to (both because he's travelling in that direction, and the fact we know he notices something in the darkness ahead of him - Polly's body, although his first thought is that it is a tarpaulin).

There is also an entire field on how well we do things over long periods of time (the study of vigilance). Doing something that is relatively boring (i.e. walking to work), results in a lowering of our ability to detect even very salient signals when those signals are rare (this whole field of research was prompted by the navy after WWII when the realised that the men monitoring the radar on the ships were tending to miss incoming aircraft signals near the end of their shifts much more than at the beginning - and notthing they did seemed to counter that). Anyway, Cross/Lechmere has not been "mugged" or "hassled" on his way to work on a regular basis (at least as far as we know since there is not a single mention of any such event), so there's no reason for him to be on "high alert" in the first place. His vigilance will already be low, and the further into his walk the lower it will get. He's only 7 minutes in on that day, but of course, he does that daily, and as far as we know, without anything of note really happening to make him wary. So the whole field of vigilance also points to your suggesting being unsupported (as you've not considered it).

Anyway, if you want a demonstration, just consider the gorilla in the basketball game video, which you've probably seen. People asked to count how many times the team in the white uniforms pass the ball, while the team in the black uniforms also pass a ball, will do pretty well counting the passes. But, they will completely miss a person, in a gorilla suit (which is black) walk straight through the centre of the shot, wave at the camera, and then walk off screen. If your attention is directed elsewhere, you can completely miss extremely salient signals, and so given Cross/Lechmere is likely to be directing his attention in front of him (and he appears to have been doing that given he spotted Polly in the darkness), it is very likely he would not notice weak signals coming from behind him (he's already covered that space after all; rightly or wrongly, that space will be considered as already monitored, and new information will come from the space not already traversed).

In the end, most lab based studies will be controlling for all of the other factors that are at play in "the wild", as lab based studies are trying to understand individual pieces of the puzzle. Put into "the wild" of everyday life, there will be many things at play, but the vast majority of them are forces that tell us Paul's footsteps are unlikely to have been noticed until Cross/Lechmere stops (and so no longer creates interference by reducing the auditory noise in his environment) and realises he's looking at a women in the street (and now his vigilance goes up as things are not the same repetitive everyday situation) and he monitors his environment for other chances and so now notices the distant footsteps. His description of what happens is entirely consistent with many areas of research that look at each of these things in isolation.

- Jeff

Well, you kind of gave me a study. It does not support your contention that one's own footsteps act as masking agents; instead you employ it to render suspect the ability of people to recognize the footsteps of an unexpected stranger walking behind them, either by not noticing them or confusing their footsteps with one's own.
Do you actually believe this?

There have been actual studies conducted towards determining what is going on in the synaptic transmission of signals that make us typically ignore our own footsteps and mark that of another; it is not fully understood, but the basic reasoning is that your very own footsteps activate the same neural network over and over again and its a sound that the brain already recognizes, so an inhibitory response soon develops for that region of neurons. Another person's footsteps are suddenly activating an entirely different neural network, so in that crucial sense they are very different. It is not a matter that both disparate sounds are in competition with the brain's processing unit for attention, the brain ignores or suppresses the first, and towards the new sound it takes an active interest. The neurological terms for this is called habituation and deviance detection....both active fields of study. By now Athelwulf must be rubbing his eyes and banging his head against a desk.

Here is one study on mice conducted at Duke University in which the sounds a mouse associates with its own footsteps is suppressed through auditory cortical inhibitory neurons.

https://www.nature.com/articles/s41586-018-0520-5

Here is a study on how new auditory sounds (like Paul's footsteps) activates a stronger neural response:
Deviance Detection and Encoding Acoustic Regularity in the Auditory Midbrain
https://www.oxfordhandbooks.com/view...190849061-e-19

from an excerpt:
"Midbrain neurons are capable of responding more rapidly and strongly when a new stimulus is not matching to a previously encoded regularity; a phenomenon referred to as deviance detection."


So we need to be very clear as to which types of sounds are masking agents, and which types are not: random sounds or white noise, stimulating intermittently various neural networks are masking agents; repetitive stimuli like one's own footsteps are not competing with anything, they give no new information and the brain is not processing them. It would make no sense if the brain was that inefficient.

If we were to consider again your example of looking into a monitor for an unanticipated radar signal, one would think that this was an assignment where the individuals stared into a monitor hour after hour, day after day until fatigue set in; and one imagines the sudden radar blip on the screen was over immediately....it not being repeated over a course of a minute or so, unlike the gait of Paul trodding behind Lechmere. This is more a case of fatigue then anything else, something i doubt afflicted Lechmere or Paul that morning. Personally, i do not think it is a good analogy.

As for Lechmere only noticing Paul once he stopped, that was not the case. Lechmere describes that he was moving forward towards the body, and then stopped when he heard Paul's footsteps. " It looked like a tarpaulin sheet, but walking to the middle of the road he saw that it was the figure of a woman.
At the same time, he heard a man about forty yards away coming up Buck's Row in the direction that the witness had come from."


As for walking down Buck's row at 3:38 am being a boring jaunt, Paul would disagree with you: "Few people like to come up and down here without being on their guard, for there are such terrible gangs about. There have been many knocked down and robbed at that spot."

It was a dangerous area.....why deny it?

[Aethelwulf]

does anyone else reckon Fisherman has created a new account and is now posting under the unassuming name 'Newbie'?

it was actually meant as a joke, but having to explain it suggests it didn't work..

[JeffHamm]

Here's a very simple explanation on sound and our two ears towards the de-emphasis of discerning sounds directly in front and behind us.
https://www.scientificamerican.com/a...wo-ears-sound/

"Each ear receives information that is sent to your brain. Because your ears are not side by side, they receive different information. If someone standing to your left claps his hands, your left ear will receive this sound wave more quickly than your right one. In addition, the clap will sound louder in your left ear than in your right . Your brain uses these differences to better understand where a sound is coming from. This can also explain why—as you may have noticed—it's hard to tell the difference between a sound directly in front of or behind you, even if you are using both ears. When the sound source is exactly equidistant to both ears, they receive very similar information and your brain has fewer clues as to where the source may be."

It tells you what i have been telling you: its difficult to distinguish between a sound coming directly behind you and directly in front of you without other information.

All one has to do, though, is turn the head a bit either direction and the location becomes easily determined (because the sounds will no longer reach the two ears simultaneously). The above requires people to hold their head perfectly still and for the sound source to be positioned just so. Neither of those conditions are likely to have been met for more than a brief period, so while you're presenting valid science you're applying it to a context different from the conditions required to make it relevant.

- Jeff

[JeffHamm]

does anyone else reckon Fisherman has created a new account and is now posting under the unassuming name 'Newbie'?

No. I may not always agree with him, but I do respect his willingness to state, and stand by, his point of view.

- Jeff

[Newbie]

this sound stuff is getting a bit desperate. why don't you just give the actual evidence that points to lechmere being a serial killer, not the smoke and mirrors nonsense as above

No, I'm trying to keep it simple here....just sticking with the auditory information before us.

The information about sound and neural processing from your perspective is smoke and mirrors; from my perspective it is akin to casting pearls before swine.

The failure of Lechmere and Paul to identify each others footsteps is informative in itself. I'm glad most people are not incurious like you.

And yet, all i get in terms of any response is an attempt to explain it away using a theory on one's own footsteps canceling out that of others. This does not coincide with any current scientific understanding about habituation and how our brains prioritize information that is novel, but i appreciate the effort on JeffHamm's part to engage the topic.

You, on the other hand, are a complete waste of my time; you just stupidly bleat out your old song about smoke and mirrors whenever something disagrees with your perspective and then you go into your avoidance routine pretending that another's positions are beneath you. Why are you even here?


BTW, unlike Christer i can be a mean sob....his fault for growing up in Scandinavia.

[JeffHamm]

Great!

Then you can provide me with a study on how repetitive auditory signals (& i don't mean someone operating a jackhammer) 'cancels' out less intense but novel auditory information that is perceptible, absent any other sound.

That is all that i am asking. If not, you are using a scientifically unverified idea to support a position - and you need to move away from it.

As of now, the 'cancels out' idea doesn't wash.

A much better mode of argument would be along the lines of the soles of shoes of typical workmen in late Victorian England were not likely to produce sounds along that road that were perceptible beyond close range.

It's not something that requires a single study, but rather, I can direct you to an entire field of research, known as Signal Detection Theory, and also another well researched phenomenon known as "masking". Basically, how detectable a signal is ends up being a function of both the intensity of the signal (the distant footfalls) and the "noise" in the environment in which it is embedded. The louder noise of one's own footfalls will both produce masking (due to the similarity of the sounds they create with the signal) and will create a noisier environment than when the person stops walking. Both of those will act to make the distant footfalls less detectable.

Now, there are, of course, other factors that may reduce those negative influences, which you are alluding to. Yes, a regular, and particularly a self generated, "noise" or "mask" will be less effective than an irregular and externally generated one, but that doesn't mean they will be equivalent to no noise/no masking stimulus, which is what you are claiming. In some of my own research, we presented people with a tone, followed by a 4 second delay, followed by a 2nd tone which they had to decide if it was the same or different from the initial one. If that delay was silent, they did pretty well even if the different tone was quite similar to the original (and of course do better the more different it became), but if we filled that 4 seconds with a random sequence of 4 tones (at a constant rate, so predictable at least in their timing), the ability to detect that change between the two key tones dropped greatly, to the point they pretty much couldn't do it (Jiang, Lim, Wang, & Hamm, 2013). Not quite the same thing, but it shows that a predictable noise sequence interferes even with a simple tone matching task that one is actively paying attention to.

Also, you're presuming that Cross/Lechmere is actively seeking external footfalls, that he is trying to detect someone following him and there's nothing in his statements that indicates he was engaged in such activity. You're suggesting that footfalls, well in the distance behind him, that may very well not even have been noticeable due to masking and interference from the sounds of his own footfalls, would somehow grab his attention away from the space in front of him, that he does appear to have been attending to (both because he's travelling in that direction, and the fact we know he notices something in the darkness ahead of him - Polly's body, although his first thought is that it is a tarpaulin).

There is also an entire field on how well we do things over long periods of time (the study of vigilance). Doing something that is relatively boring (i.e. walking to work), results in a lowering of our ability to detect even very salient signals when those signals are rare (this whole field of research was prompted by the navy after WWII when the realised that the men monitoring the radar on the ships were tending to miss incoming aircraft signals near the end of their shifts much more than at the beginning - and notthing they did seemed to counter that). Anyway, Cross/Lechmere has not been "mugged" or "hassled" on his way to work on a regular basis (at least as far as we know since there is not a single mention of any such event), so there's no reason for him to be on "high alert" in the first place. His vigilance will already be low, and the further into his walk the lower it will get. He's only 7 minutes in on that day, but of course, he does that daily, and as far as we know, without anything of note really happening to make him wary. So the whole field of vigilance also points to your suggesting being unsupported (as you've not considered it).

Anyway, if you want a demonstration, just consider the gorilla in the basketball game video, which you've probably seen. People asked to count how many times the team in the white uniforms pass the ball, while the team in the black uniforms also pass a ball, will do pretty well counting the passes. But, they will completely miss a person, in a gorilla suit (which is black) walk straight through the centre of the shot, wave at the camera, and then walk off screen. If your attention is directed elsewhere, you can completely miss extremely salient signals, and so given Cross/Lechmere is likely to be directing his attention in front of him (and he appears to have been doing that given he spotted Polly in the darkness), it is very likely he would not notice weak signals coming from behind him (he's already covered that space after all; rightly or wrongly, that space will be considered as already monitored, and new information will come from the space not already traversed).

In the end, most lab based studies will be controlling for all of the other factors that are at play in "the wild", as lab based studies are trying to understand individual pieces of the puzzle. Put into "the wild" of everyday life, there will be many things at play, but the vast majority of them are forces that tell us Paul's footsteps are unlikely to have been noticed until Cross/Lechmere stops (and so no longer creates interference by reducing the auditory noise in his environment) and realises he's looking at a women in the street (and now his vigilance goes up as things are not the same repetitive everyday situation) and he monitors his environment for other chances and so now notices the distant footsteps. His description of what happens is entirely consistent with many areas of research that look at each of these things in isolation.

- Jeff

[Mark J D]

does anyone else reckon Fisherman has created a new account and is now posting under the unassuming name 'Newbie'?

That's a disgustingly cheap shot.

M.

[Newbie]

I have also done a little bit of research on what material likely composed Buck's row circa 1888. It seems to have been laid with granite setts: most all of White Chapel roads were laid in this fashion, having to do with transporting goods from the docks along the Thames. I can not determine the typical surface material for these roads at this time.

http://www.glias.org.uk/journals/8-a.html

Table 4:	Types of pavings in use in London Districts in the 1890s
(miles, unless otherwise stated)
District	Granite	Wood	Asphalt
Bermondsey	16	0.5
Camberwell	4
Chelsea		4.4
Greenwich	4	0.5
Fulham	0.06	4.5	0.176
Hammersmith	0.14
Holborn	9.2	1.2	2.23
Kensington	5.2	196,314 sq yds
Mile End Old Town	5.5
Lambeth	1.75	8
Newington	3.14	0.5	0.25
Paddington	1.09	8.08
Plumstead	2
St. George in the East	14
St. Giles	9	0.75
St. George’s, Hanover Square	5	12
St. James, Westminster	0.75	3.5	5.25
St. John, Hampstead	0.5	1.25
St. Leonard, Shoreditch	15	0.25	1
St. Martin-in-the-Fields	1	3.75	1
Whitechapel	18 miles of road	**	0.5
St. Mary, Islington	12	0.5	0.5
St. Mary, Battersea	For tram tracks
St.Olave		4,326 sq yds
Westminster		135,500 sq yds	48,055 sq yds
Woolwich	2

[Al Bundy's Eyes]

does anyone else reckon Fisherman has created a new account and is now posting under the unassuming name 'Newbie'?

Not a chance. If Christer wanted to say something, he'd come out and say it.

[Aethelwulf]

Here's a very simple explanation on sound and our two ears towards the de-emphasis of discerning sounds directly in front and behind us.
https://www.scientificamerican.com/a...wo-ears-sound/

"Each ear receives information that is sent to your brain. Because your ears are not side by side, they receive different information. If someone standing to your left claps his hands, your left ear will receive this sound wave more quickly than your right one. In addition, the clap will sound louder in your left ear than in your right . Your brain uses these differences to better understand where a sound is coming from. This can also explain why—as you may have noticed—it's hard to tell the difference between a sound directly in front of or behind you, even if you are using both ears. When the sound source is exactly equidistant to both ears, they receive very similar information and your brain has fewer clues as to where the source may be."

It tells you what i have been telling you: its difficult to distinguish between a sound coming directly behind you and directly in front of you without other information.

this sound stuff is getting a bit desperate. why don't you just give the actual evidence that points to lechmere being a serial killer, not the smoke and mirrors nonsense as above

[MrBarnett]

does anyone else reckon Fisherman has created a new account and is now posting under the unassuming name 'Newbie'?

Nope. A very different writing style.

[Newbie]

Here's a very simple explanation on sound and our two ears towards the de-emphasis of discerning sounds directly in front and behind us.
https://www.scientificamerican.com/a...wo-ears-sound/

"Each ear receives information that is sent to your brain. Because your ears are not side by side, they receive different information. If someone standing to your left claps his hands, your left ear will receive this sound wave more quickly than your right one. In addition, the clap will sound louder in your left ear than in your right . Your brain uses these differences to better understand where a sound is coming from. This can also explain why—as you may have noticed—it's hard to tell the difference between a sound directly in front of or behind you, even if you are using both ears. When the sound source is exactly equidistant to both ears, they receive very similar information and your brain has fewer clues as to where the source may be."

It tells you what i have been telling you: its difficult to distinguish between a sound coming directly behind you and directly in front of you without other information.

[Aethelwulf]

I would agree that he would be more interested in what was ahead....now that we are moving towards agreement that he was not wrapped in thought;where we disagree again is the ears focusing on 'ahead' sounds. The eye's yes, the ears no (they'll pick up any sound entering them all the same). One focuses one's listening on sounds - not ahead, nor behind. Sounds do not get ignored because they are coming from behind.....again, there is noevolutionary basis to this line of reasoning.....although i have not checked on research involved in this capacity as of yet. One would certainly expect newsounds coming from behind to get our attention.

And then there is not just one person, but two: Paul was also engaging the world with his sensory apparatus and Lechmere was supposedly 50 yards or so ahead of him - and yet we get no recognition of any undue sounds from him.

The Laws of physics have no say in personal decisions based on options

does anyone else reckon Fisherman has created a new account and is now posting under the unassuming name 'Newbie'?

[Newbie]

He had lived in the Whitechapel area for quite a long time, it's not like he moved in from the West End. And, he had moved long enough that his route to work would be well established. Generally, people are going to be more attentive to what is ahead of them, given they've already been through and evaluated what is behind. As such, even if he is scouting for danger, which his testimony doesn't imply but we can consider it all the same, then he's going to be more focused on what is up ahead (hence spotting Polly at a distance in the first place, even if he misidentified what he first saw).

Stepping back from Polly, etc, for a guilty Cross/Lechmere, requires he knows he can do all that movement without being seen otherwise his personal risk becomes undeniably huge. And if he knows he can't be seen, leaving the scene becomes the far less riskier option as he has complete control over that option, while allowing Paul to approach, and then to engage Paul to look at the body when he appears to try and just get past, is to follow the highest risk and most foolish path. It's not defying the laws of physics, so it's not impossible, but not all possible options are probable. Our difference in that latter evaluation appear to reflect our differences in the risk assessment. I cannot see how remaining and moving away from the body could ever be evaluated as less risky than fleeing the scene, particularly as leaving at a quite walking pace is unlikely to arouse Paul's suspicions until he eventually arrives at the body, and only then if Paul chooses to examine her (and not just presume she's passed out). And by that time, he would be far enough away, and never seen well enough to be identified or recognized, that he's removed the risk he was facing. Clearly, you evaluate that differently than I do, and so you come to a different conclusion. That's the nature of things, if we disagree on the starting point (risk assessment), it's hardly surprising we get to different conclusions as to what follows. The commonality is that we are both following what we believe to be the path with least risk, so I guess we agree that he would choose things that reduce his risk, we just disagree on what the risks are.

- Jeff

I would agree that he would be more interested in what was ahead....now that we are moving towards agreement that he was not wrapped in thought;where we disagree again is the ears focusing on 'ahead' sounds. The eye's yes, the ears no (they'll pick up any sound entering them all the same). One focuses one's listening on sounds - not ahead, nor behind. Sounds do not get ignored because they are coming from behind.....again, there is noevolutionary basis to this line of reasoning.....although i have not checked on research involved in this capacity as of yet. One would certainly expect newsounds coming from behind to get our attention.

And then there is not just one person, but two: Paul was also engaging the world with his sensory apparatus and Lechmere was supposedly 50 yards or so ahead of him - and yet we get no recognition of any undue sounds from him.

The Laws of physics have no say in personal decisions based on options

[Newbie]

And here is an excerpt from an article in A dictionary of Every-day wants ©1872 on shoe and boot care:

http://historicaltidbits.blogspot.com/2016/10/boots-shoe-care.html

"If shoes be treated in this manner, and a row of round-headed shoe nails be driven around the edge of the soles, they will wear like copper, and always set easy to the feet. Boots and shoes should be treated as suggested, and worn a little several months before they are put to daily service."