This sort of news really scare me. Your brain defines who you are and what capabilities you have, and damaging it can completely change you. The brain is very responsible for a big part of your success and losing it can have a big impact in your life.
Cognitive decline happens whether you like it or not, I'm afraid to say.
I've hit my early 30s and I've started noticing that I'm far more prone to inappropriately replaced words, can't memorise long strings of digits as well as I used to be able to, and so-forth.
>I've hit my early 30s and I've started noticing that I'm far more prone...
That's a really young age to have any sort of marked age-related cognitive decline. It might be explained by something else--even something as "simple" as insufficient quality sleep or stress, both of which can wreak havoc on cognitive ability.
This could be because you're not getting enough sleep (or aren't sleeping well due to e.g. apnea or something). Set up a simple experiment: go to bed 1-1.5 hours earlier than you usually do for a couple of weeks and see if your "cognitive decline" disappears. As you age you might find you need more sleep.
This is very true for me, much to my surprise. I used to get by on 3 to 4 hours every night but that seems to have really caught up with me. If I don't get 8 hours minimum now I'm woozy the rest of the day.
Same here. And "buzzy" when I'm really sleep-deprived. It literally feels like low-level electrical interference running through my head and my thinking and focus are nowhere near as sharp.
It is like some sort of intoxication, which is fitting, because one of the things sleep does for us is clear toxins from our brains.
> And "buzzy" when I'm really sleep-deprived. It literally feels like low-level electrical interference running through my head and my thinking and focus are nowhere near as sharp.
That's eerie, I have that too. Especially when it is totally quiet in the house. At first I thought it was because I heard the refrigerator, but I switched that off to rule it out. Then I powered down the whole house and the low humming remains. I'll have to try this when I'm totally rested to see if it goes away then, I never made the link to lack of sleep.
Ok, now this is really funny. There's the buzzy feeling, which I considered distinct from the low hum (til now), but I absolutely hear that low-hum too and also assumed it was the refrigerator. It is more pronounced at certain times, but I never linked it to my sleep deprivation. I'll have to pay attention to that.
Another thing is that I seem to be "sensitive" to some electronics. For instance, I cannot hold a cell phone to my head for more than a few minutes and I even have to take breaks when listening to music on headphones. The feeling I get bears some similarity to my sleep-deprived state, so I have wondered about a relationship there, if not just a further reduction of my tolerance of electronics.
I think a good part here is that where I live it is very quiet. Last house on a dead end street, nothing but fields around me for miles and miles. So when it's quiet it is really quiet, so quiet that sounds that you'd otherwise never even notice become audible because your brain just keeps cranking up the gain.
I can hear the dear foraging around the house at night, and if a car passes on the nearest highway (a few kilometers away) I can hear that clearly too. But during the day all those sounds vanish, masked by the ever present background noise level which is far higher than it is during the night. And my hearing is actually not nearly as good as it used to be.
One simple solution I've found is to play really low volume white noise, that seems to instantly drown out all of it but strangely enough is very hard to detect by itself.
Interesting. Yeah, it's strange that I never seemed to notice the low hum until, say, 5-6 years ago. I assumed it was the house in which I was living at the time, but we moved and I continued to notice it. In my case, both areas are kind of your "standard" suburb and not too far away from one another. BTW, I've also wondered if it was from some far-off industrial source.
But, I also know we lose our high-frequency hearing as we age. I wonder if that somehow increases our sensitivity to the low frequency range.
In any case, I'll have to try the white noise. Seems like it could help with sleep quality, which might in turn reduce sensitivity to it.
Interesting how much of this I'd already figured out just by experimenting on myself. I definitely did not rule out tinnitus (and I had a pretty bad case of that at some point in the past, which totally ruined listening to violin music for me, but fortunately it has since reduced to the point of not being noticeable, maybe this is some kind of remnant).
Anyway, I think of it as an interesting phenomenon, it doesn't bother me much (except when trying to fall asleep, once I notice it it is impossible to stop noticing it).
Good point on the apnea, which tends to come with age, especially if overweight. There are different forms and degrees that don't involve waking and gasping for air, but that could easily impair quality sleep. One sign is consistently feeling unrefreshed after a full night's sleep.
Also a good point about giving it a couple weeks. Chronic sleep deprivation can't be fixed with a night or two of "catching up".
Very important point. When I sleep well for a couple of week my memory and cognition are very sharp, but when I don't sleep well I'm having all kinds of cognitive problems. At 30 years old you're likely to have developed something like a sleep apnea, or caffeine metabolism slowdown, or some of the many other problems affecting sleep.
Having said that, simply going to be earlier is not likely to help weed out most of these disorders. Go to a sleep doctor and see what they say. Also, are you getting more irate? For many people it's a lot easier to get angry when they lack sleep.
Not the guy you're asking, but I recently said "portico" when I meant to say "patio." I mixed up the two words because they both start with a P and have something to do with architecture. I think this is the kind of thing he meant by "replacement," and it's been happening to me (55) more frequently in recent years.
Yup, precisely this. I'm inclined to think it may be more sleep deprivation driven than anything else, as I find myself doing it intermittently - and the odd thing is I'll proof what I've written thrice and I'll still mis-read incorrect words as what I had intended rather than what I wrote.
Definitely didn't do this in the past, I find it disquieting, but it's hardly insurmountable!
That's way too early in life for signs of cognitive decline. Are you challenging yourself enough? Do you get adequate and deep rest? Are you preoccupied or depressed? Are you keeping yourself healthy? I know, these are personal (and maybe somewhat condescending-sounding) questions - but they're just examples for things that can impact your mental performance.
Generally, the body's ability to take punishment starts to decline in the thirties which can manifest in mental impairment, but someone who's taking good care of themselves should actually enjoy a pretty well-tuned brain. Biologically speaking there should not be enough damage to justify capability deterioration for a long time to come.
All things being equal, I'd say it comes down to the use-it-or-lose it mantra: your brain gets better in areas where it's being used, and atrophies in others where it isn't.
Mental competence is not a hallmark of youth. In fact, problem-solving performance in many fields should go up with experience, and only degrade very late in life when things like ischemic attacks, prions, cellular garbage, and the natural neuronal die-off rate all come into play as significant factors.
I have noticed the same symptoms as the parent. And I can't be blamed by not challenging my brain enough - I am learning Haskell, doing a side project and there's the day job.
If I had to measure myself, I'd guess that I'm working at 40% of what I was in my 20's (I'm 34). However, I probably have sleep apnea (I say probably because my doctor asked me to get a bunch of exams and I'm not through with all of them yet, only thing I know for certain is that the blood pressure is higher than it should be). I self medicate with copious amounts of caffeine and yet I'm always feeling sleepy and hazy, as if I were not fully out in the real world.
So yeah, the other poster likely has some underlying health condition. Which could be as simple as not getting enough sleep. I can't function at all with less than 8 hours, while I could in my youth.
Adult acne? Itchy ears? Intermittent neck cramps? Progressive hair loss? Sleep better with a fan blowing over you? Acid reflux?
If so, possibly try getting into a tub, drawing a moderate layer of water, and then performing breathing exercises into the water. In/out with force. Nose/nose, Mouth/mouth, Nose/mouth, yatta. Note: I did not relish the outcome, ymmv.
Also, if the hair one is true, regularly brush your hair w/ a soft end comb. (I almost guarantee loss will stop)
Also, if the adult acne is true, try the opposite of common sense, and apply a thick skin cream (Aveno's decent) or a gellified salt like deodorant if it's not sensitive skin. Make sure to apply well to areas near openings to ears/nose/mouth/eyes. (You should do this anyhow as it slows your apparent age)
Also, if reflux, try high acidic/bitter/basic/spicy/salty foods and see whether they trigger/solve reflux and whether you sleep better/worse.
Also, possibly try sleeping fully enclosed within a sheet.
Not a doctor, your own risk, other standard medical disclaimers by non-pro.
Oh, my overall cognition is fine, as far as I can internally assess, and no, I get nowhere near as much sleep as I should, which probably accounts for more than I grant. As to challenge - plenty of it.
It's really rather more associative fuckups, as someone else in the thread describes - even if I have the right word in my head, my hands may type something utterly different, which usually starts with the same letter and relates to what I was after, but differs.
As to memorisation - I'm talking having gone from being able to indefinitely retain 20+ digit strings on first sight to maybe half that, and often finding I've switched a digit.
As you say, sleep is probably a major component in this, and I can't recall sleeping more than a few consecutive hours in years - usually manage six hours of restless sleep before throwing the towel in and getting back to doing whatever it was I was doing when I nodded off. Can't bear to spend time just lying there. There's too much to do.
It's possible to push oneself "harder" and regain function ("neuroplasticity"), as evidenced by stroke rehab.
This is why it's vital to do challenging mental exercises like crosswords puzzles, etc. ("use it or lose it.)
Generally though, the article makes sense because the common cell machinery of nerves (which don't divide as much as say intenstine or dermis cells) can be hampered by underlying issues affecting organelles within nerve cells, which then manifests as functional, quantitative deficit at the macro level.
I'm in my late 40s. Definitely I'm not the same person, cognitively, that I was in my 20s. It's not all bad, though. I'm sure I would score lower in an IQ test, but I'm actually more capable than I was back then. Experience counts for a lot. I can deal with emotional stress much better, or perhaps I can avoid the situations which cause it (more likely). I can see other people's point of view a lot easier now. I can see gradations in judgement, where before everything was black and white.
It sucks to lose the horse power, but I more than make up for it by driving the car in the right direction. I suspect the decline will continue, but in many ways I look forward to what I will be able to accomplish when I'm older.
Anecdotally: I'm a week away from turning 39 and I don't feel I've lost any "raw" mental ability, but actual performance has gotten more challenging because I'm pulled in many more directions at once.
Very few people face the same level of obligations at 20 as they will at 30 or 40.
There's also the Dunning-Kruger effect: the better you get at something, the worse you feel you are at it... presumably, all of us have made strides towards mastering our craft in the last 10 or 20 years....
I've noticed a decline in memorization capability in my 30s too, and it sometimes takes a little while to remember small details like what I just ate. It's offset by an increase in my ability to make connections between different topics and ideas.
On balance, I'd choose the connection-making brain over the raw-power brain.
I can definitely relate to this comment. The synaptic composition of your brain is essentially your identity, your merits and demerits. I'm definitely a hypochondriac when it comes to brain health, given how high the stakes are. It's crazy that even a minor concussion can cause lasting brain damage: http://www.npr.org/2013/03/15/174409382/can-just-one-concuss...
The brain is also quite resilient. I got shot in the head a few decades ago (.22, luckily) with skull fracture and moderate brain damage – mainly a large hole in my visual field, with occasional visual migraines. Intellectually, I seem to have mainly lost a few steps as far as 3d visualizations are concerned, otherwise still about +3 sd IQ.
Glad to hear you are doing so well! Yes, I completely agree with you the power of the brain to heal itself is amazing. I'm also quite excited by what things are coming in the next ten or twenty years. A good diet probably does wonders, too.
I've been suffering from health issues for the past four years. That's why I'm interested in the brain (I suffer from extreme brain fog, and by extreme I really mean extreme; I can't have a conversation with anyone face to face, and I even have some issues when chatting with people. It takes a long time to really think about what I need to say. I still cannot understand how I'm managing to go through college).
Interesting study, but as the authors concede, one can't quite rule out that the causal flow is in the opposite direction to that which they propose - that is, people with lower cognitive ability are more likely to end up with infections, and people with much lower cognitive ability are more likely to end up with severe infections.
I mean, consider people with dementia, sat in their own faeces (at the severely diminished/severe infection end of the scale), or people with lower intellect lower on the socio-economic scale engaging with jobs where they're more likely to end up with infections - construction, handling hazardous waste, etc. etc.
>this reverse association could not account for the observed temporal correlations or the correlations with the severity of infection. Moreover, the correlation between infections and cognitive ability retained significance even after adjustment for other parameters known to influence general cognitive ability...which are also associated with socio-economic gradients.
I'm sympathetic to your point of view; in some cases it seems nearly impossible to rigorously exclude reverse-associations when there are so many complexities.
The authors respond to this objection as follows:
The finding that infections are associated with decreased general cognitive ability after a latency period might be an epiphenomenon and not a biologically-mediated relationship. For instance, a reverse association could have existed so that lower cognitive ability may be a risk factor for acquiring infections. Furthermore, studies have indicated that immune related genes might be implicated in cognition [34], and individuals with genetic liability towards a lower general cognitive ability might also be more genetically vulnerable towards infections. However, although a genetic or reverse association could have partly explained some of the observed associations, this probably does not account for the observed temporal associations or the associations with severity of the infection.
The association between infections and cognitive ability remained significant after adjusting for other factors known to influence a decrease of general cognitive ability, such as gestational age, birth weight [35], and having more older siblings (i.e. being later in a sibship), which often correlate with socio-economic gradients [36]. ..Nevertheless, the findings remained significant also after adjustment for an individual or family history of psychiatric disorders and substance abuse which could be associated with several of these unmeasured risk factors as well as socio-economic factors. Furthermore, the possible effect of maternal smoking during pregnancy should to some degree be captured by the included birth weight and gestational age in the adjustments. Moreover, there may be diseases that are associated with both increased susceptibility to infections and somewhat lower cognition (either the disease itself or its treatment).
How do the authors manage to just wave away all the genetic effects with just "this probably does not account for the observed temporal association"? Either the authors have some evidence or else it is not a hypothesis that they can rule out. All their correction factors are non-genetic factors.
"temporal association" is the point that shortly after infections, there is a stronger effect on intelligence. So you're saying "maybe people who get hit in the head with 2x4s are just dumber" and they're saying "that doesn't explain why they do so bad on cognitive tests right after they got hit". It's much stronger evidence that way.
The p-value (a function used for testing a statistical hypothesis) corresponding to these results was less than 0.001, indicating that the probability that the findings were due to chance alone (or that the null hypothesis is true) is less than 0.1%.
Actually, I think it means that IF the null hypothesis is true, there is only a 0.1% chance that we would get this much deviation (or more) from it due to chance. Which isn't the same thing. Still, seems like a significant result of course, but let's be correct about these things.
The whole science industry should follow the lead of those scientific journals who've banned p-values from their publications. P-values just lead to so much confusion and nonsense.
And that's without even considering the scientists who cheat the p-values, which is actually just a tiny part of the problem with p-values.
I think that the outright banning of p-values is not the right way to go. The researchers that misuse them and the reviewers that apparently don't understand them are a much bigger problem than the p-value metric itself.
What's needed is a better understanding of empirical conditional statistics and the application of that understanding to the degign of experiments and the analysis of the results produced therefrom.
And the best way to do that is to eliminate the crutch.
Many of the more data-centric fields did away with p-values long ago in favor of far more robust approaches to establishing the value of a paper. Look at papers in the data science field. Using p-values in a paper there would get you laughed out of the industry fast.
Only problem that p-values ever solved was allowing journal reviewers to be lazier, helping scientists to be lazier, and making writing more sensational press releases easier.
I left a comment on OP several days ago pointing that out; still hasn't appeared nor has it been fixed. Apparently they don't care about being correct.
Interesting study. Intelligence and the immune system share a common property in that they are have a very large number of genes influencing them (several thousand). I would not be surprised if there is quite a bit of overlap in the genes that contibute to both intelligence and immunity. What we might be seeing here is the effect of null mutations in genes that effect both immunity and intellegence.
> Cognitive ability score (Børge Prien’s Prøve Test) has here been converted to parallel conventional IQ scaling, with a mean of 100 and an SD of 15, to give a more familiar metric of effect size.
I have no idea what 6 points mean in this setting.
It's probably not the infection itself, but the fluoroquinolones or other bacteriocidal antibiotics that they give people, that are causing mitochondrial dysfunction in the brain. -_-
Never thought bout this, but it's clear that it's possible to have an "antibiotic" that target the mitochondria but leave the rest of the cell alive (for a while). That will be a poison, and be not useful as a actual antibiotic. I there a well know substance like this?
This is a premature conclusion. There was no measurement of IQ before and after infection, so no such conclusion can be made.
There could be other, unknown, factors that happen to affect BOTH: a person's IQ and their likelihood to be infected, along with severity of infection. For example some genetic, environmental, or other variable that affects your IQ as well as infection-resistance.
It very well might be true, that infection does have the ability to lower IQ. But this study does not prove it.
I wish scientists would be more straightforward about conclusions. The title of the article should read: "Study finds that individuals who have suffered infection have a lower IQ than the general population" or something along those lines. Much different than saying that "infection lowers IQ".
This is beginner-level confusion of causation and correlation.
The title of the article is, in fact "The Association between Infections and General Cognitive Ability in Young Men - A Nationwide Study." And as others have pointed out elsewhere, the authors controlled for some (though not every) conceivable common causes of infection and reduced IQ.
Though, as a criticism of the author of the blog post, I would agree with your comment.
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I've hit my early 30s and I've started noticing that I'm far more prone to inappropriately replaced words, can't memorise long strings of digits as well as I used to be able to, and so-forth.
That's a really young age to have any sort of marked age-related cognitive decline. It might be explained by something else--even something as "simple" as insufficient quality sleep or stress, both of which can wreak havoc on cognitive ability.
This is very true for me, much to my surprise. I used to get by on 3 to 4 hours every night but that seems to have really caught up with me. If I don't get 8 hours minimum now I'm woozy the rest of the day.
It is like some sort of intoxication, which is fitting, because one of the things sleep does for us is clear toxins from our brains.
That's eerie, I have that too. Especially when it is totally quiet in the house. At first I thought it was because I heard the refrigerator, but I switched that off to rule it out. Then I powered down the whole house and the low humming remains. I'll have to try this when I'm totally rested to see if it goes away then, I never made the link to lack of sleep.
Another thing is that I seem to be "sensitive" to some electronics. For instance, I cannot hold a cell phone to my head for more than a few minutes and I even have to take breaks when listening to music on headphones. The feeling I get bears some similarity to my sleep-deprived state, so I have wondered about a relationship there, if not just a further reduction of my tolerance of electronics.
I can hear the dear foraging around the house at night, and if a car passes on the nearest highway (a few kilometers away) I can hear that clearly too. But during the day all those sounds vanish, masked by the ever present background noise level which is far higher than it is during the night. And my hearing is actually not nearly as good as it used to be.
One simple solution I've found is to play really low volume white noise, that seems to instantly drown out all of it but strangely enough is very hard to detect by itself.
I never noticed any 'sensitivity to electronics'.
But, I also know we lose our high-frequency hearing as we age. I wonder if that somehow increases our sensitivity to the low frequency range.
In any case, I'll have to try the white noise. Seems like it could help with sleep quality, which might in turn reduce sensitivity to it.
Read that a while back, look at the possible explanations, especially tinnitus might be a possibility.
Anyway, I think of it as an interesting phenomenon, it doesn't bother me much (except when trying to fall asleep, once I notice it it is impossible to stop noticing it).
Also a good point about giving it a couple weeks. Chronic sleep deprivation can't be fixed with a night or two of "catching up".
Having said that, simply going to be earlier is not likely to help weed out most of these disorders. Go to a sleep doctor and see what they say. Also, are you getting more irate? For many people it's a lot easier to get angry when they lack sleep.
Is this an example of that? Did you mean 'placed' or do I mis-understand you?
Definitely didn't do this in the past, I find it disquieting, but it's hardly insurmountable!
Generally, the body's ability to take punishment starts to decline in the thirties which can manifest in mental impairment, but someone who's taking good care of themselves should actually enjoy a pretty well-tuned brain. Biologically speaking there should not be enough damage to justify capability deterioration for a long time to come.
All things being equal, I'd say it comes down to the use-it-or-lose it mantra: your brain gets better in areas where it's being used, and atrophies in others where it isn't.
Mental competence is not a hallmark of youth. In fact, problem-solving performance in many fields should go up with experience, and only degrade very late in life when things like ischemic attacks, prions, cellular garbage, and the natural neuronal die-off rate all come into play as significant factors.
This is key.
I have noticed the same symptoms as the parent. And I can't be blamed by not challenging my brain enough - I am learning Haskell, doing a side project and there's the day job.
If I had to measure myself, I'd guess that I'm working at 40% of what I was in my 20's (I'm 34). However, I probably have sleep apnea (I say probably because my doctor asked me to get a bunch of exams and I'm not through with all of them yet, only thing I know for certain is that the blood pressure is higher than it should be). I self medicate with copious amounts of caffeine and yet I'm always feeling sleepy and hazy, as if I were not fully out in the real world.
So yeah, the other poster likely has some underlying health condition. Which could be as simple as not getting enough sleep. I can't function at all with less than 8 hours, while I could in my youth.
Have you tried stopping? I mean, too much caffeine makes me sleepy too (not over the same say, but after a while).
Adult acne? Itchy ears? Intermittent neck cramps? Progressive hair loss? Sleep better with a fan blowing over you? Acid reflux?
If so, possibly try getting into a tub, drawing a moderate layer of water, and then performing breathing exercises into the water. In/out with force. Nose/nose, Mouth/mouth, Nose/mouth, yatta. Note: I did not relish the outcome, ymmv.
Repeat after: twisting torso, xing/unxing arms, alternating closed nostrils, plugging nostrils and pressurizing breathing tract + ears, vigorous activity (jogging)
Also, if the hair one is true, regularly brush your hair w/ a soft end comb. (I almost guarantee loss will stop)
Also, if the adult acne is true, try the opposite of common sense, and apply a thick skin cream (Aveno's decent) or a gellified salt like deodorant if it's not sensitive skin. Make sure to apply well to areas near openings to ears/nose/mouth/eyes. (You should do this anyhow as it slows your apparent age)
Also, if reflux, try high acidic/bitter/basic/spicy/salty foods and see whether they trigger/solve reflux and whether you sleep better/worse.
Also, possibly try sleeping fully enclosed within a sheet.
Not a doctor, your own risk, other standard medical disclaimers by non-pro.
It's really rather more associative fuckups, as someone else in the thread describes - even if I have the right word in my head, my hands may type something utterly different, which usually starts with the same letter and relates to what I was after, but differs.
As to memorisation - I'm talking having gone from being able to indefinitely retain 20+ digit strings on first sight to maybe half that, and often finding I've switched a digit.
As you say, sleep is probably a major component in this, and I can't recall sleeping more than a few consecutive hours in years - usually manage six hours of restless sleep before throwing the towel in and getting back to doing whatever it was I was doing when I nodded off. Can't bear to spend time just lying there. There's too much to do.
This is why it's vital to do challenging mental exercises like crosswords puzzles, etc. ("use it or lose it.)
Generally though, the article makes sense because the common cell machinery of nerves (which don't divide as much as say intenstine or dermis cells) can be hampered by underlying issues affecting organelles within nerve cells, which then manifests as functional, quantitative deficit at the macro level.
It sucks to lose the horse power, but I more than make up for it by driving the car in the right direction. I suspect the decline will continue, but in many ways I look forward to what I will be able to accomplish when I'm older.
Very few people face the same level of obligations at 20 as they will at 30 or 40.
There's also the Dunning-Kruger effect: the better you get at something, the worse you feel you are at it... presumably, all of us have made strides towards mastering our craft in the last 10 or 20 years....
On balance, I'd choose the connection-making brain over the raw-power brain.
I've been suffering from health issues for the past four years. That's why I'm interested in the brain (I suffer from extreme brain fog, and by extreme I really mean extreme; I can't have a conversation with anyone face to face, and I even have some issues when chatting with people. It takes a long time to really think about what I need to say. I still cannot understand how I'm managing to go through college).
I mean, consider people with dementia, sat in their own faeces (at the severely diminished/severe infection end of the scale), or people with lower intellect lower on the socio-economic scale engaging with jobs where they're more likely to end up with infections - construction, handling hazardous waste, etc. etc.
Could possibly be both.
The authors respond to this objection as follows:
The finding that infections are associated with decreased general cognitive ability after a latency period might be an epiphenomenon and not a biologically-mediated relationship. For instance, a reverse association could have existed so that lower cognitive ability may be a risk factor for acquiring infections. Furthermore, studies have indicated that immune related genes might be implicated in cognition [34], and individuals with genetic liability towards a lower general cognitive ability might also be more genetically vulnerable towards infections. However, although a genetic or reverse association could have partly explained some of the observed associations, this probably does not account for the observed temporal associations or the associations with severity of the infection.
The association between infections and cognitive ability remained significant after adjusting for other factors known to influence a decrease of general cognitive ability, such as gestational age, birth weight [35], and having more older siblings (i.e. being later in a sibship), which often correlate with socio-economic gradients [36]. ..Nevertheless, the findings remained significant also after adjustment for an individual or family history of psychiatric disorders and substance abuse which could be associated with several of these unmeasured risk factors as well as socio-economic factors. Furthermore, the possible effect of maternal smoking during pregnancy should to some degree be captured by the included birth weight and gestational age in the adjustments. Moreover, there may be diseases that are associated with both increased susceptibility to infections and somewhat lower cognition (either the disease itself or its treatment).
Actually, I think it means that IF the null hypothesis is true, there is only a 0.1% chance that we would get this much deviation (or more) from it due to chance. Which isn't the same thing. Still, seems like a significant result of course, but let's be correct about these things.
And that's without even considering the scientists who cheat the p-values, which is actually just a tiny part of the problem with p-values.
What's needed is a better understanding of empirical conditional statistics and the application of that understanding to the degign of experiments and the analysis of the results produced therefrom.
Many of the more data-centric fields did away with p-values long ago in favor of far more robust approaches to establishing the value of a paper. Look at papers in the data science field. Using p-values in a paper there would get you laughed out of the industry fast.
Only problem that p-values ever solved was allowing journal reviewers to be lazier, helping scientists to be lazier, and making writing more sensational press releases easier.
P.S.: Why do most articles about the 'brain' try to dumb down people?
People with 10 hospitalizations scored lower by .37 SD = 6 iq points.
I have no idea what 6 points mean in this setting.
Nearly 16% of people would lie between 97 and 103. [1]
It's 40% of a full letter grade[2]
[0]http://en.wikipedia.org/wiki/Standard_deviation [1]http://www.wolframalpha.com/input/?i=area+e%5E%28-1%2F450+%2... [2]http://en.wikipedia.org/wiki/Academic_grading_in_the_United_...
There could be other, unknown, factors that happen to affect BOTH: a person's IQ and their likelihood to be infected, along with severity of infection. For example some genetic, environmental, or other variable that affects your IQ as well as infection-resistance.
It very well might be true, that infection does have the ability to lower IQ. But this study does not prove it.
I wish scientists would be more straightforward about conclusions. The title of the article should read: "Study finds that individuals who have suffered infection have a lower IQ than the general population" or something along those lines. Much different than saying that "infection lowers IQ".
This is beginner-level confusion of causation and correlation.
Though, as a criticism of the author of the blog post, I would agree with your comment.