Posted: May 29, 2010 12:03 pm
by campermon
Condender's #2 post: 4994 words. -LIFE

Thanks Jerome! I enjoyed the ghost stories; It took me back to the salad days of ‘Camperboy’!

I have split this first ‘proper’ post into two sections. In the first part I have expanded upon my position as regards ghosts i.e. that they are purely manifestations of the brain that do not represent objects in objective reality. I have also explained in a little more detail my objections to the two premises we are here to debate; "Some Ghost cases may represent discarnate consciousness or the remote operation of a living human consciousness". Out of necessity (I’m a busy guy!), the first section was been written before Jerome’s first main post. The second part of this post deals with the claims and evidence of Jerome’s first main post.

Ghosts are a manifestation in the Brain

At the outset I would like to state that I am in no way an expert in biology or neuroscience. On these subjects I can only claim to be an educated layman and openly welcome critical feedback (via PM / peanut gallery). If I have I have erred then I humbly apologise and ask you to correct me via the aforementioned routes ;). In my defense, I am a physics graduate and my studies have given me an excellent training in the ‘scientific method’ and the broadest of insights into the workings of the natural world. I must add that this is not an attempt to argue from a position of authority! ;)

The brain is truly a magnificent object, surely the most complex object in the known universe. According to wiki (http://en.wikipedia.org/wiki/Human_brain) this 1.5kg of soft tissues contains between “50–100 billion (1011) neurons,”. This is an impressive fact in itself, but not as awe inspiring as the fact that these neurons self organize, connect and communicate which each other via “1000 trillion (1015) synaptic connections” to achieve the common purpose of keeping you alive.

Just think about this for a few seconds; Up to 100 000 000 000 neurons self organizing to form 1000 000 000 000 000 synaptic connections. Add to the mix millions of receptor cells (http://faculty.washington.edu/chudler/facts.html) constantly feeding this network with megabits of data per second (a conservative estimate on my part based purely on the number of receptors a human body has) and we have quite a remarkable data processing machine. At this moment just try to imagine what your brain is doing; billions of photons (originating from your computer screen) are streaming into your eyes and firing the receptors in your retina causing a cascade of millions of impulses directed at your visual cortex. Your brain is filtering the extraneous visual data to extract what it is your attention is directed at i.e. the letters and words on this screen. Your brain is now decoding the shapes of the letter / words and turning them it into language, which is calling into play your memory and language centres (can you ‘hear’ the words?). That’s just the beginning. What next? Your brain is constructing meaning and understanding which in turn is firing up other parts of your brain invoking emotions (just imagine your response had I inserted the ‘C’ word here!.....no not ‘Consciousness’ ;) )and memory and on we go anon. All this to read just a few lines of text in a few seconds of time.

Now, as I said, I am a layman on the subject of the brain and there are many out there (some on these boards) who could write, with authority, more inspiring prose on this subject. In the above I clumsily attempt to illustrate how remarkably complex and ‘clever’ our brain is and to also give a hint at the extraordinary processing power it has. In spite of the astronomical numbers of neurons and connections our brains have (and the consequent room for malfunction), our brains are, in general, fairly reliable in the day to day job they do i.e. make sense of the world. To evidence this, I ask you to think about the owners of these 1.5kg’s of soft tissue masses that you may know and think about the many, many observations that you agree on; we call this objective reality. However, the brain, being a complex evolved object is likely to malfunction and at such times it presents its users with the most unusual and fascinating experiences. I invite you to watch this talk given by Jill Bolte Taylor, a neuroscientist, who describes the day she had a stroke.

http://www.ted.com/talks/jill_bolte_tay ... sight.html

During her talk Jill describes a state of bliss in which she refers to herself being in “La la land”. She goes on to describe the failure of her proprioceptive brain functions which results in the subjective experience of being almost incorporeal and “at one” with the universe around her. As the bleed further inhibits normal brain function she describes to us the feelings of being “lighter in my body”, of “peacefulness”, “euphoria” and having met her “nirvana”. How many times have we heard similar anecdotal experiences presented as evidence for the ‘paranormal’?

I’ll concede that Jill didn’t experience ghosts and her ordeal was due to a life threatening bleed into her brain but what her account does show is that the brain is more than capable of fooling us into experiencing events that many would classify as being ‘paranormal’.

Now back to the subject of ghosts. As I said before, I do agree with Jerome that ghosts are a real phenomena. Our point of dispute is in the nature of this phenomena. I argue that ghosts are a phenomenen associated entirely of and within the individual brain which leads me to the conclusion that ghosts are associated with hallucination. Before I discuss the commonality of and the causes of hallucinations, I must first ask the question; at what time of day do most people claim to have had seen a ghost? Night-time of course! Even a child knows that. But why should ghosts be traditionally associated with a time of darkness and, more often that not, when the observer is on their own? Could it be that our pattern seeking brains, denied of sensory input, begin to fill in the gaps? Let’s see.

Phosphenes

First of all, let’s have a look at a rather common phenomenen known as ‘phosphenes’. A phosphene is a visual experience generated in the brain in the absence of light stimulus. You can easily stimulate the production of phosphenes by rubbing your eyes (we’ve all seen the funny patterns), but the curious thing is that phosphenes will spontaneously generate themselves in the absence of any apparent stimulus;

“In general, phosphenes appear spontaneously when the viewer is subjected to prolonged visual deprivation and it has been argued that this occurrence may be related to an increased cortical excitability to the incoming visual input (see Boroojerdi et al., 2000). Phosphenes may appear with a variety of patterns: they often have a chaotic structure in the form of sparks, sometimes they appear as a glowing circle or part of it, or as a spiral moving in concentric circles”

From “Cellular mechanisms underlying the pharmacological induction of phosphenes” (http://www.ncbi.nlm.nih.gov/pmc/article ... 06998a.pdf )

The paper then goes on to explain that this phenomena is common even where there is no apparent pathology present;

“The perception of phosphenes is very common and often experienced in the absence of an identifiable pathological condition of the retina or of the visual pathways: in a large number of these cases the causes underlying phosphene generation are difficult to assess (Rosenbaum et al., 1987).”

So here we have a phenomena which produces unusual visual experiences for people who are considered to have healthy brains. So, what might happen if we add in other factors?

“More complex and picturesque spontaneous visual phenomena are often indicated as phosphenes, but when associated with emotional factors, drugs, alcohol, stress, fever or psychotic conditions, they should be referred to as visual hallucinations.”

So, with the addition of ‘stress’, for instance, the brain can manifest more intricate visuals resulting in complex hallucination. Who here, with a healthy brain( ;) ), could claim not to feel at all stressed if they were to spend the night in a dark spooky place (a morgue for instance)? Is it not possible that even with your healthy brain, producing phosphenes, and a level of stress (associated with being on your own, at night, in say, a morgue) that hallucinations may follow?

A final note on phosphenes for the moment; Phosphenes can be induced by transcranial simulation by electromagnetic fields. More of this later….

Hypnagogic Hallucination

Put your hands up if this has happened to you :- It’s late at night and you’ve crawled into bed. Your head hits that pillow and you relax, shedding the burden of an oh so busy day. You begin to drift off, leaving this conscious world, edging toward the realm of dreams. You travel that blissful path to unconsciousness wending its way, as it does, around the cul-de-sac of your day and on towards the highways of fantasy (MrsC and I appreciate sleep after having four kids! ;) ) and then. Suddenly you clearly hear someone call your name. Well, if you’ve experienced this, then you’ve had a hypnagogic hallucination. But don’t worry! You don’t have to be carted off to the asylum……yet.

Let’s see what “Complex visual hallucinations, Clinical and neurobiological insights” (http://brain.oxfordjournals.org/cgi/reprint/121/10/1819) has to say on this matter;

From the Summary;

“Complex visual hallucinations may affect some normal individuals on going to sleep and are also seen in pathological states, often in association with a sleep disturbance. The content of these hallucinations is striking and relatively stereotyped, often involving animals and human figures in bright colours and dramatic settings.”

We then go on to learn that;

“Mauray (1848) coined the term hypnagogic hallucinations to describe his own vivid hallucinations in the state of drowsiness just before sleep.” and “Up to one-third of normal individuals may experience these hallucinations, when going off to sleep,”

The author then describes the experiences of some poor brain injured individuals who have hallucinated, amongst other things, figures in Victorian and 17th century garb, tall men with pink hands and numerous cats. Now, these examples are associated with patients who have demonstrable damage to the the brain. But common with the example of Jill Bolte (see above) we are reading about experiences (such as witnessing people in Victorian garb pushing prams in your living room) which fit very well with what is reported as ‘paranormal’ activity. What’s going on here? Let’s see what the paper says in its summary;

“Normal individuals may experience prolonged hypnagogic hallucinations prior to falling asleep. These are characterized by brilliant scenery, figures and animals, and insight is often preserved. Strikingly similar hallucinations are seen in the lesions of the visual pathways, and in brainstem and thalamic lesions affecting the ascending reticular activating system.”

At this point we need to ask the question; Why do the experiences of brain injured individuals match up so well with reports of the paranormal? Is it reasonable to claim that our immensely complex, imperfect, evolved brains (remember all the zeros in the synaptic connection count) are prone to ‘breaking down’ now again, thus replicating the ‘paranormal’ type of experiences evidenced in the above two cases of brain injury. Or is it more plausible to accept that paranormal phenomena (originating outside of the brain) has an effect such that it exactly replicates the effects of brain injury?

Let’s move on…

Things that go bump in the night….

Why do ghosts make things go ‘bump in the night’? Where does this ‘tradition’ come from? Could it be that during these quiet, sensory deprived, times our data hungry brains are amplifying every piece of auditory input, however tiny, in to something we can comprehend? Very likely, but here is an interesting phenomena I dug up during my research for this debate; “Exploding head syndrome”.

The “Journal of Neurology, Neurosurgery, and Psychiatry 1989;52:907-910 Short report Clinical features of the exploding head syndrome” (http://www.ncbi.nlm.nih.gov/pmc/article ... 9-0093.pdf) describes it thus;

“The syndrome in essence consists of an hitherto unreported benign symptom characterised by a sense of explosion in the head, confined to the hours of sleep, which is harmless but very frightening for the sufferer.”

Contained within the report is a table; “Table 2 Showing Salient features of 30 patients” describing symptoms of hearing noises ranging from ‘clash of cymbals’ to ‘crack of lightening’. The syndrome also appears to leave its victims pretty shaken up. Well wouldn’t you be frightened if you were woken up by a ‘bomb like explosion’?

The phenomena is rarely reported (the paper discusses a total of around 50 known cases), however the author suspects that it is more common;

“As a symptom it is probably fairly common. No less than fifty patients voluntarily wrote about their symptoms within 4 weeks of publication. But, as a source of complaint it is rare; many said they had been ashamed to mention it to their doctors or that their complaint had been greeted with incredulity if not frank disbelief.”

Is it possible that the tales of experiences caused by this syndrome have gotten themselves mixed up over time with the folklore of ghostly happenings and the paranormal? It seems reasonable to me.

The report does point to some suggestions as to the organic cause of this syndrome but does state that these are speculative (if anyone has any up to date research on this area, I’d love to hear!). However, there is a pattern to be found in the patient study;

“The patients are predominantly middle-aged or elderly, slightly more commonly women than men. There is little evidence of relevant past illness and no other CNS disease in evidence. The complaint is exclusively in sleep, but this may include daytime naps.”

So, are we looking at a spooky phenomena that may be explained naturally? Or do ghosts that that make things bump in the night only mainly afflict those in middle to elderly age? If so why?


Summing up my position on ghosts…

I have become conscious that, as well as possibly boring the reader with my waffle ;) , I am using up valuable word space with which I will need discuss my objections to the aforementioned points of debate and critique the evidence Jerome brings to the table. But before I move on, I would urge you to have a read of “Psychobiology of Altered States of Consciousness” (http://www.mp.uni-tuebingen.de/mp/filea ... 05-ASC.pdf ). I will not discuss this article further than quoting the abstract and summing up my position that ghosts are manifestations of the brain. From the article;

” The article reviews the current knowledge regarding altered states of consciousness (ASC) (a) occurring spontaneously, (b) evoked by physical and physiological stimulation, (c) induced by psychological means, and (d) caused by diseases. The emphasis is laid on psychological and neurobiological approaches. The phenomenological analysis of the multiple ASC resulted in 4 dimensions by which they can be characterized: activation, awareness span, self-awareness, and sensory dynamics. The neurophysiological approach revealed that the different states of consciousness are mainly brought about by a compromised brain structure, transient changes in brain dynamics (disconnectivity), and neurochemical and metabolic processes. Besides these severe alterations, environmental stimuli, mental practices, and techniques of self-control can also temporarily alter brain functioning and conscious experience.”

What I hope to have shown in the preceding is that paranormal experience can be adequately explained by understanding the mechanisms of the brain through neuroscience. We have seen that the brain can create the range of ‘paranormal’, ‘ghostly’ experiences either through damage or as a natural consequence of it being the highly complex, evolved, input greedy object it is. Why should we look to fanciful theories when the object of our investigation is that 1.5kg mass of wet stuff encased in our heads? I will address this in the following, where I am on more steady ground because it involves a bit of physics! ;)

My objections to the idea that "Some Ghost cases may represent discarnate consciousness..”

Having witnessed the discussions on ‘consciousness’ in the philosophy forum, I don’t want to dwell too much on this! Let’s just go with what wiki says:

“Consciousness is variously defined as subjective experience, or awareness, or wakefulness, or the executive control system of the mind.”
(http://en.wikipedia.org/wiki/Consciousness)

My challenge to Jerome, also open to anyone else on this forum, is to provide valid evidence that any of the defined actions, as described in the wiki quote, can take place without a physical substrate.

There’s nothing more for me to say on this point until the production of valid evidence to support the claim!

My objections to the idea that “Some Ghost cases may represent [...] the remote operation of a living human consciousness”

I must admit that if there is any alternative for the explanation of paranormal events that I would like to believe in that this is it. To start off with, let’s look at “Extra Sensory Perception” (ESP). The idea that our brains are able to extract objective information from the environment through mechanisms other than the common five (ESP) does appeal to me. However, the failure of research to conclusively demonstrate perception of objective reality through senses other than sight, smell, taste, touch and feel consigns this alternative to the scientific trash can. I don’t wish to bore you, and I haven’t the time to trawl through papers and critiques of this area, so I will simply refer you to “James Randi’s One Million Dollar Paranormal Challenge” (http://www.randi.org/site/index.php/1m-challenge.html). Thus far, no one has won the prize (or I believe, passed the preliminary tests) for demonstrating this ability.

I admit that ESP is not strictly on topic, but the lack of valid evidence to support it does indicate that we will not find an example of a consciousness operating remotely in this case.

How about brains influencing other brains directly over distance? Well, I would ask myself first of all is how this could be done? What sort of mechanism could transfer information, via space, directly from one electrochemical object (i.e. brain) to another? What springs to mind ( :nono: ) is magnetic fields. Why? Well, oscillating magnetic fields will induce currents in the brain and thus excite neural activity. So we could be onto a winner because this effect is demonstrated by ‘transcranial magnetic stumulation’ (TMS). This is outlined by wiki quite nicely; ( http://en.wikipedia.org/wiki/Transcrani ... timulation ).

Unfortunately, when we dig down into the physics, it appears that this mechanism does not help. Why? For that we need to look at the magnitude of the fields involved and the way they spread out though space. To answer both these questions, wiki will be out friend.

From the wiki article on TMS we learn that coils in contact with the head emit oscillating magnetic fields with a strength of about 2 Tesla. To put this into context, http://en.wikipedia.org/wiki/Tesla_%28unit%29 informs us that;

• 31 µT (3.1×10−5 T) - strength of Earth's magnetic field at 0° latitude (on the equator)
• 5 mT - the strength of a typical refrigerator magnet
• 1 T to 2.4 T - coil gap of a typical loudspeaker magnet
• 9.4 T - Modern high resolution research magnetic resonance imaging system“


OK, so 2T doesn’t sound much, but remember the coils involved in TMS are in close vicinity to the skull. Also, we must not forget that magnetic fields diminish in inverse proportion to the distance squared from their source. Check out the ‘Biot-Savart Law’ which is adequately explained here: http://en.wikipedia.org/wiki/Biot%E2%80%93Savart_law. In other words, it takes a very large field to have any influence (on the brain) over any sort of reasonable distance; several metres for instance.

To finish, I’ll point you to a recent paper investigating the production of our old friends ‘phosphenes’, which in this case may explain the phenonmema of ‘ball lightening’, via TMS induced by lightening strikes; “Transcranial stimulability of phosphenes by long lightning electromagnetic pulses” (http://arxiv.org/PS_cache/arxiv/pdf/100 ... 1153v2.pdf). The paper hypothesizes that the phenomena of ‘ball lightening’ (a phenomena notoriously difficult to recreate) may be caused by phosphenes induced in brains by multiple lightening strikes. I’m not going to go into the details of the paper, merely comment that it appears to take multiple lightening strikes (think of the energy involved here) to induce a magnetic field that will have any effect on a brain that is not in direct danger of being fried by the strike (the paper quotes “20-100m horizontal distance” away). I find it highly unlikely that brains could generate the potentials required to emit magnetic waves over these distances.

Even if it were possible that brains were communicating over distances of several metres via the mechanism of magnetic fields, it would be readily apparent. For example, TV sets and other sensitive electrical equipment would be in constant peril of being damaged, not to mention the fact that using a plotting compass would be futile.

In conclusion, it seems that magnetic fields cannot be a mechanism by which brains may operate influence other brains remotely and I cannot even begin to conceive of a possible mechanism that might allow psychokinetic ability. I will leave it to Jerome to propose a physical mechanism. ;) Oh yes, and some valid evidence to show that it has actually occurred!

Thus ends part one of my post.

Response to Jerome

Well, where do I start Jerome? ;) As I said at the beginning, reading those stories took me back to my ‘salad days’! In particular, that time when I realized that there were no answers to be found in book section 130-139!

My first impressions of your post seem to concur with some who are following this in the peanut gallery i.e. there’s a lot of anecdote! I’m not going to pick apart every nook and cranny of your post, but attempt to give a ‘holistic’ response in the main. I will then focus on any crucial points in which you have failed to give the forum anything of substance to support them. So, I’ll think I’ll begin with a general moan about the quality of evidence supplied by the poltergeist stories you shared with us.

My problem with the paranormal investigations

First of all, thanks to Jerome for sharing the documents with regard to the “Cardiff Responsive Case” from which you quoted in your post. The following quote, by the author Professor David Fontana of Cardiff University, neatly sums up one of my problems with paranormal investigations;

“Although a frequent observer of the consequences of the disturbances detailed above, I did not see any of them actually taking place”

So..erm..I’ll leave that one there!

The next case I’d like to briefly look at is the “South Shields poltergeist”. As a first step I looked up the web site that Jerome referenced in his post; http://www.mikehallowell.com/shieldspolt/page2.html . As the good investigator that I am, I immediately sought out a link button that would take me to ‘Evidence’. I looked hard, but in vain. It appeared that if I were to gain any information about this case I’d have to buy their rather sensational sounding book. Not easily beaten, I found a review here; http://www.newsmonster.co.uk/paranormal ... exist.html .

The review quotes a few of the ghostly experiences the householders endured for example;

"It was like ice even with the heating on,” said Sabrina. “It was dull no matter how bright the lights were and there was a horrid smell. It was like living in a mortuary."

And the usual poltergeist antics such as;

“Die bitch”, “RIP”, and “Go bitch now to your mam” appeared unbidden on the message board. They were followed by the appearance of arcane Satanic-looking symbols.”

OK, standard fare so far. The following, however, struck me as potentially good evidence;

“Chilling text messages then began appearing on Marianne’s phone. One warned her: “Going to die today, going to get you.” Another read: “I can get you when you awake and I’ll come for you when you asleep bitch.”

All appeared to be from the poltergeist and arrived seemingly from nowhere. None could be traced to a mobile phone, computer or landline. Once again, there appeared to be no ‘rational’ explanation. “

So, this could possibly be some tangible evidence of paranormal activity i.e. a phone with received text messages which were apparently not routed through a service provider. I can find no mention on the internet of this particular phone having being subject to professional forensic analysis or the service provider being involved in the investigation. If these messages were genuine poltergeist activity it should have been big news. I suspect that in some data centre somewhere there is a log showing the origin of these messages, if indeed they were even sent to the phone.

I don’t know what else I can say about this case apart from the fact that it appears to be replete with anecdote and blurry images. I’m not particularly impressed with the investigators, who seemed to miss collecting footage of one apparition because they were so ‘stunned’;

““The entity strode slowly but purposefully from the bathroom and walked across the landing into the master bedroom,” says Mike. “As it passed the door to Robert's room, it paused and stared icily at me. Its face, devoid of all features such as eyes, was cold and menacing. It felt like it was burrowing into my soul. It was large – maybe two metres in height – and midnight black. It was a three-dimensional silhouette that radiated sheer evil.”

Mike was so stunned by what he saw that he didn’t manage to switch the camera on in time.”

I admit that I “LOL’d” as I read that bit! Mike goes on to say;

“”It was gutting,” says Mike. “We all saw it but we didn’t get the proof we needed.””

Yes Mike, but that didn’t stop you from presenting anecdote in the place of evidence (‘proof’) did it?

Now, it would be unfair of me to say much more on this case because I haven’t read the book. But, I strongly suspect that the ‘evidence’ the authors supply will be mix of personal and second hand anecdote. Entertaining though it is (I do love a good ghost story), I’m afraid that’s not good enough. I want valid, quantifiable evidence! Next!

With regards to the Rosenheim case (http://en.wikipedia.org/wiki/Rosenheim_Poltergeist) I will refer the reader to The_Metatrons commentary in the peanut gallery ( paranormal/peanut-gallery-existence-of-ghosts-apparitions-t6933-100.html#p228934 ) which sums up the sloppy science / reporting of this case.

The fact that two Max Planck Institute physicists were involved in this case doesn’t impress me. Scientists are notoriously easy to deceive in paranormal investigations. One classic example is ‘Project Alpha’ (http://en.wikipedia.org/wiki/Project_Alpha ). What amuses me most about this project was that James Randi actually told the investigators how to safeguard themselves against being tricked! By coincidence (or maybe there are hidden forces are at play here…), the JREF has just posted a couple of videos of an interview Randi recently had with one of the tricksters;

Part 1: http://www.youtube.com/user/JamesRandiF ... 9n7i9_kAFw

Part 2: http://www.youtube.com/user/JamesRandiF ... Mj38lF2U5k

Having read through the numerous poltergeist cases that Jerome has presented I cannot find anything in them that could be termed ‘evidence’ in the scientific sense. Entertaining as they are, the purpose of this debate is not to tell ghost stories. We are here to discuss the evidence that may support that "Some Ghost cases may represent discarnate consciousness or the remote operation of a living human consciousness". Before I move on I must get my LOLsworth from that Professor David Fontana quote;

“Although a frequent observer of the consequences of the disturbances detailed above, I did not see any of them actually taking place”

PKE?

It is clear that acceptance of anecdote as ‘evidence’ by the parapsychologists is leading them down a slippery slope to disaster. For in treating anecdote as scientific evidence they now have to form an explanatory hypothesis. To quote from Jerome’s post;

“So what do modern parapsychological researchers think cause this? Most seem to agree that people are involved – probably the popular explanation now is the RSPK or Recurrent Spontaneous Psycho-Kinesis theory, which put poltergeists down to a mysterious force named PKE. What is PKE? Psycho-Kinetic Energy (PKE) is an energy supposedly generated by the human mind that is able to move objects at a distance. The RSPK hypothesis suggests that this talent can occasionally occur spontaneously and without warning humans develop the ability to unconsciously chuck stuff around, resulting in a poltergeist haunting. I likened this theory to being as the equivalent of "a nervous breakdown occurring outside the victim's head."”

In hypothesizing this, the parapsychologists are getting themselves into some serious hot water. For example, what is this ‘energy’ they refer to? By what mechanism might a human mind move an object at a distance? Do these energies and mechanisms fit in with the standard model ( http://en.wikipedia.org/wiki/Standard_Model )? If not, why have physicists been denied evidence of the existence of these energies and mechanisms?

Before the parapsychologists get carried away with the intricacies of this theory, I would suggest that first of all they provide any reliable evidence that the mind can physically affect an object at a distance. Perhaps when devising their experiments it would be prudent to seek the advice of James Randi?

Summing up

Jerome, if you are to convince me that there is anything more to poltergeist activity than trickery (by self delusion or by pranksters) you are going to have to bring something more substantial to the table. As has been seen, uncritical acceptance of anecdote has led to pseudoscientific hypothesizing (e.g. ‘PKE’). I look forward to your next post in which, no doubt, you will bring the scientific peer reviewed evidence required. ;)

To finish I would like to quote your German proverb; ‘when the ghosthunter arrives, the ghost flies out of the window.’ and ask you to meditate on the question; Why should this be?

:cheers: