Interview with Jason D. Shepherd, PhD

During the first week of the publication, a Cell paper that I covered a couple of weeks ago has received a lot of attention from media outlets, like The Atlantic, Scicasts and Neuroscience News/University of Utah Press Release. It is not my intention to duplicate here their wonderfully done summaries and interviews; rather to provide answers to some geeky questions arisen from the minds of nerdy scientists like me.

Dr. Shepherd, you are the corresponding author of a paper published on Jan. 11 in Cell about a protein heavily involved in memory formation, called Arc. Your team and another team from University of Massachusetts, who published in the same issue of Cell, simultaneously discovered that Arc looks like and behaves like a virus. The protein “infects” nearby cells, in this case neurons, with instructions of how to make more of itself, i.e. it shuttles its own mRNA from one cell to another.

Neuronicus: Why is this discovery so important?

​Jason D. Shepherd: I think there’s a couple of big implications of this work:

  1. ​The so called “junk” DNA in our genomes that come from viruses and transposable elements actually provide source material for new genes. Arc isn’t the first example, but it’s the first prominent brain gene to have these kinds of origins.

  2. This is the first demonstration that cellular proteins are capable of assembling into capsid-like structures. This is a completely new way of thinking about communication between cells.

  3. We think there may be other genes that can also form capsids, suggesting this method of signaling is fairly common in organisms.

N: 2) When you and your colleagues compared Arc’s genetic sequence across species you concluded Arc comes from a virus that infected four-legged animals some time ago. A little time later the virus infected the flies too. When did these events occur?

​JDS: So we think the origins are from a retrotransposon not a virus. These are DNA sequences or elements that “jump” into the host genome. Think of them as primitive viruses. Indeed, these elements are thought to be the ancestors of retroviruses like HIV. The mammalian Arc gene seems to have originated ~400 million years ago, the fly about 150 million years ago. ​

N: 3) So, if Arc has been so successfully repurposed by the tetrapod and fly ancestors to add memory formation, what does that mean for the animals and insects before the infection? I understand that we move now in the realm of speculation, but who better to speculate on these things than the people who work on Arc? The question is: did these pre-infection creatures have bad and short memories? The alternate view would be that they had similar memory abilities due to a different mechanism that was replaced by Arc. Which one do you think is more likely?

​JDS: Good question. It’s certainly the case that memory capacity improved in tetrapods, but unclear if Arc is the sole reason. I suspect that Arc confers some unique aspects to brains, otherwise it would not have been so conserved after the initial insertion event, but I also think there are probably other Arc-like genes in other organisms that do not have Arc. I will also note that we are not even sure, yet, that the fly Arc is important for fly memory/learning.

N: 4) Remaining in the realm of speculation, if this intercellular mRNA transport proves to be ubiquitous for a variety of mRNAs, what does that say of the transcriptome of a cell at any given time? From a practical point of view, a cell is what is made off, meaning the ensemble of all its enzymes and proteins and so on, collectively termed transcriptome. So if a cell can just alter its neighbor’s transcriptome array, does that mean that it’s possible to alter also its function? Even more outrageously speculative, perhaps even its type? Can we make cancer cells commit suicide by shooting Arc capsules of mRNA at them?

​JDS: Yes! Cool ideas. I think this is quite likely, that these signaling extracellular vesicles can dramatically alter the state of a cell. We are obviously looking into this. ​

N: 5) Finally, in the paper, the Arc capsules containing mRNA are referred to as ACBAR (Arc Capsid Bearing Any RNA). At first I thought it was a reference to “Allahu akbar” which is Arabic for ‘God is greatest’, the allusion being “ACBAR! Our exosome is the greatest!” or “Arc Acbar! Our Arc is the greatest!”. Is this where the naming is coming from?

​JDS: No no. As I said on twitter, my lab came up with this acronym because we are all Star Wars nerds and the classic “It’s a trap!” line from general Ackbar seemed apt for something that was trapping RNA. ​

Below is the Twitter exchange Dr. Shepherd refers to:

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Dr. Shepherd, thank you for your time! And congratulations on a well done paper and a well told story. Your Methods section is absolutely great; anybody can follow the instructions and replicate your data. Somebody in your lab must have kept great records. Congratulations again!

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The ACBAR graphic is from the Cell’s abstract (©2017 Elsevier Inc.) but since it’s for comedic purposes, I’d say is fair use. Same for the Lego Ackbar.

By Neuronicus, 28 January 2018

P. S. Since I have obviously managed to annoy the #StarWars universe and twitterverse because I depicted General Ackbar using a Jedi sword when he’s not a Jedi, I thought only fair to annoy the other half of the world, the #trekkies. So here you go:

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Arc: mRNA & protein from one neuron to another

EDIT 1 [Jan 17, 2018]: I promised four days ago that I will post this, while it was still hot, but my Internet was down, thanks to the only behemoth provider in USA. And rated the worst company in the Nation, too. You definitely know by now about whom I’m talking about. Grrrr…  Anyway, here is the paper:

As promised, today’s paper talks about mRNA transfer between neurons.

Pastuzyn et al. (2018) looked at the gene Arc in neurons because they thought its Gag sequence looks suspiciously similar to some retroviruses. Could it be possible that it also behaves like a virus?

Arc is heavily involved in the immune system, is essential for the formation of long-term memories, and is involved in all sorts of diseases, like schizophrenia and Alzheimer’s, among other things.

Pastuzyn et al. (2018) is a relatively long and dense paper, albeit well written. So, I thought that this time, instead of giving you a summary of their research it would be better to give you the authors’ story directly in their own words written as subtitles in the Results section (bold letters – the authors words, normal font – mine). Warning: this is a much more jargon-dense blog post than my previous one on the same topic and, because it is so much material, I will not explain every term.

  • Fly and Tetrapod (us) Arc Genes Independently Originated from Distinct Lineages of Ty3/gypsy Retrotransposons, the phylogenomic analyses tell us, meaning the authors have done a lot of computer-assisted comparisons of similar forms of the gene in hundreds of species.
  • Arc Proteins Self-Assemble into Virus-like Capsids. Arc likes to oligomerize spontaneously (dimers and trimers). The oligomers resemble virus-like capsids, similar to HIV.
  • Arc Binds and Encapsulates RNA. Although it loves its own RNA about 10 times more than other RNAs, it’s a promiscuous protein (doesn’t care which RNA as long as it follows the rules of stoichiometry). Arc capsids encapsulate both the Arc protein (maybe other proteins too?), its mRNA, and whatever mRNA happened to be in the vicinity at the time of encapsulation. Arc capsids are able to protect the mRNA from RNAases.
  • Arc Capsid Assembly Requires RNA. If there is no RNA around, the capsids are few and poorly formed.
  • Arc Protein and Arc mRNA Are Released by Neurons in Extracellular Vesicles. Arc capsid packages Arc protein & Arc mRNA into extracellular vesicles (EV). The size of these EVs is < 100nm, putting them in the exosome category. This exosome, which the authors gave the unfortunate name of ACBAR (Arc Capsid Bearing Any RNA), is being expelled from cortical neurons in an activity-dependent manner. In other words, when neurons are stimulated, they release ACBARs.
  • Arc Mediates Intercellular Transfer of mRNA in Extracellular Vesicles. ACBARs dock to the host cell and then undergo clathrin-dependent endocytosis, meaning they expel their cargo in the host cell. The levels of Arc protein and Arc mRNA peaks in a host hippocampal cell in four hours from incubation. The ACBARs tend to congregate around donor cell’s dendrites.
  • Transferred Arc mRNA Can Undergo Activity-Dependent Translation. Activating the group 1 metabotropic glutamate receptor (mGluR1/5) by application of the agonist DHPG induces a significant increase of the amount of Arc protein in the host neurons.

This is a veritable tour de force paper. The Results section has 7 sub-sections, each with multiple experiments to dot every i and cross every t. I’m eyeballing about 40 experiments. It is true that there are 13 authors on the paper from different institutions – yeay for collaboration! – but c’mon! Is this what you need to get in Cell these days? Apparently so. Don’t get me wrong, this is an outstanding paper. But in the end it is still only one paper, which means only one first author. The rest are there for the ride because for a tenure track application nobody cares about your papers in CNS (Cell, Nature, Science = The Central Nervous System of the scientific community, har, har) if you’re not the first author. It looks like the increasing amount of work you need to be published in top tier journals these days is becoming a pet peeve of mine as I keep mentioning it (for example, here).

My pet peeves aside, Pastuzyn et al. (2018) is an excellent paper that opens interesting practical (drug delivery) and theoretical (biological repurpose of ancient invaders) gates. Kudos!

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REFERENCE: Pastuzyn ED, Day CE, Kearns RB, Kyrke-Smith M, Taibi AV, McCormick J, Yoder N, Belnap DM, Erlendsson S, Morado DR, Briggs JAG, Feschotte C, & Shepherd JD. (11 Jan 2018). The Neuronal Gene Arc Encodes a Repurposed Retrotransposon Gag Protein that Mediates Intercellular RNA Transfer. Cell, 172(1-2):275-288.e18. PMID: 29328916. doi: 10.1016/j.cell.2017.12.024. ARTICLE | FULLTEXT PDF via ResearchGate

P.S. I said that ACBAR is an unfortunate acronym because I don’t know about you but I for one wouldn’t want my discovery to be linked either with a religion or with terrorist cries, even if that link is done only by a small fraction of the population. Although I can totally see the naming-by-committee going: “ACBAR! Our exosome is the greatest! Yeay!” or “Arc Acbar! Our Arc is the greatest. Double yeay!”. On a second thought, it’s kindda nerdy geeky neat. I still wouldn’t have done it though…

By Neuronicus, 14 January 2018

EDIT 2 [Jan 22, 2018]: There is another paper that discovered that Arc forms capsids that encapsulate RNA and then shuttles it across the neuromuscular junction in Drosophila (fly). To their credit, Cell published both these papers back-to-back so no researcher gets scooped of their discovery. From what I can see, the discovery really happened simultaneously, so I modified my infopic to reflect that (both papers were submitted in January 2017, received in revised version on August 15, 2017 and published in the same issue on January 11, 2018). Here is the reference to the other article:

Ashley J, Cordy B, Lucia D, Fradkin LG, Budnik V, & Thomson T (11 Jan 2018). Retrovirus-like Gag Protein Arc1 Binds RNA and Traffics across Synaptic Boutons, Cell. 172(1-2): 262-274.e11. PMID: 29328915. doi: 10.1016/j.cell.2017.12.022. ARTICLE

EDIT 3 [Jan 29, 2018]: Dr. Shepherd, the last author of the paper I featured, was kind enough to answer a few of my questions about the implications of his and his team’s findings, answers which you will find here.

By Neuronicus, 22 January 2018

The FIRSTS: mRNA from one cell can travel to another cell and be translated there (2006)

I’m interrupting the series on cognitive biases (unskilled-and-unaware, superiority illusion, and depressive realism) to tell you that I admit it, I’m old. -Ish. Well, ok, I’m not that old. But this following paper made me feel that old. Because it invalidates some stuff I thought I knew about molecular cell biology. Mind totally blown.

It all started with a paper freshly published two days ago and that I’ll cover tomorrow. It’s about what the title says: mRNA can travel between cells packaged nicely in vesicles and once in a target cell can be made into protein there. I’ll explain – briefly! – why this is such a mind-blowing thing.

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Fig. 1. Illustration of the central dogma of biology: information transfer between DNA, RNA, and protein. Courtesy of Wikipedia, PD

We’ll start with the central dogma of molecular biology (specialists, please bear with me): the DNA is transcribed into RNA and the RNA is translated into protein (see Fig. 1). It is an oversimplification of the complexity of information flow in a biological system, but it’ll do for our purposes.

DNA needs to be transcribed into RNA because RNA is a much more flexible molecule and thus can do many things. So RNA is the traveling mule between DNA and the place where its information becomes protein, i.e. ribosome. Hence the name mRNA. Just kidding; m stands for messenger RNA (not that I will ever be able to call that ever again: muleRNA is stuck in my brain now).

There are many kinds of RNA: some don’t even get out of the nucleus, some are chopped and re-glued (alternative splicing), some decide which bits of DNA (genes) are to be expressed, some are busy housekeepers and so on. Once an RNA has finished its business it is degraded in many inventive ways. It cannot leave the cell because it cannot cross the cell membrane. And that was that. Or so I’ve been taught.

Exceptions from the above were viruses whose ways of going from cell to cell are very clever. A virus is a stretch of nucleic acids (DNA and/or RNA) and some proteins encapsulated in a blob (capsid). Not a cell!

In the ’90s several groups were looking at some blobs (yes, most stuff in biology can be defined by the all-encompassing and enlightening term of ‘blob’) that cells spew out every now and then. These were termed extracellular vesicles (EV) for obvious reasons. Turned out that many kinds of cells were doing it and on a much more regular basis than previously thought. The contents of these EVs varied quite a bit, based on the type of cells studied. Proteins, mostly, and maybe some cytoplasmic debris. In the ’80s it was thought that this was one way for a cell to get rid of trash. But in 1982, Stegmayr & Ronquist showed that prostate cells release some EVs that result in sperm cell motility increase (Raposo & Stoorvogel, 2013) so, clearly, the EVs were more than trash. Soon it became evident that EVs were another way of cell-to-cell communication. (Note to self: the first time intercellular communication by EVs was demonstrated was in 1982, Stegmayr & Ronquist. Maybe I’ll dig out the paper to cover it sometime).

So. In 2005, Baj-Krzyworzeka et al. (2006) looked at some human cancer cells to see what they spew out and for what purpose. They saw that the cancer cells were transferring some of the tumor proteins packaged in EVs to monocytes. For devious purposes, probably. And then they made to what it looks to me like a serious leap in reasoning: since the EVs contain tumor proteins, why wouldn’t they also contain the mRNA for those proteins? My first answer to that would have been: “because it would be rapidly degraded”. And I would have been wrong. To my credit, if the experiment wouldn’t take up too many resources I still would have done it, especially if I would have some random primers lying around the lab. Luckily for the world, I was not in charge with this particular experiment and Baj-Krzyworzeka et al. (2005) proceeded with a real-time PCR (polymerase chain reaction) which showed them that the EVs released by the tumor cells also contained mRNA.

Now the 1 million dollar, stare-in-your-face question was: is this mRNA functional? Meaning, once delivered to the host cell, would it be translated into protein?

Six months later the group answered it. Ratajcza et al. (2006) used embryonic stem cells as the donor cells and hematopoietic progenitor cells as host cells. First, they found out that if you let the donors spit EVs at the hosts, the hosts are faring much better (better survival, upregulated good genes, phosphorylated MAPK to induce proliferation etc.). Next, they looked at the contents of EVs and found out that they contained proteins and mRNA that promote those good things (Wnt-3 protein, mRNA for transcription factors etc.). Next, to make sure that the host cells don’t show this enrichment all of a sudden out of the goodness of their little pluripotent hearts but is instead due to the mRNA from the donor cells, the authors looked at the expression of one of the transcription factors (Oct-4) in the hosts. They used as host a cell line (SKL) that does not express the pluripotent marker Oct-4. So if the hosts express this protein, it must have come only from outside. Lo and behold, they did. This means that the mRNA carried by the EVs is functional (Fig. 2).

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Fig. 2. Cell-to-cell mRNA transfer via extracellular vesicles (EVs). DNA is translated into RNA. A portion of RNA is transcribed into protein and another portion remains untranscribed. Both resultant protein and mRNA can get packaged into a vesicle: either a repackage into a microvesicle (a budding off of the cell membrane that shuttles cargo to and forth, about the size of 100-300nm) or packaged in a newly formed exosome (<100 nm) inside a multivesicular endosome (the yellow circle). The cell releases these vesicles in the intercellular space. The vesicles dock onto the host cell’s membrane and empty their cargo.

What bugs me is that these papers came out in a period where I was doing some heavy reading. How did I miss this?! Probably because they were published in cancer journals, not my field. But this is big enough you’d think others would mention it. (If you’re a recurrent reader of my blog, by now you should be familiarized with my stream-of-consciousness writing and my admittedly sometimes annoying in-parenthesis-meta-cognitions :D). So how did I miss this? How many more great discoveries have I missed? Am I the only one to discover such fundamental gaps in my knowledge? And thus the imposter syndrome takes root.

Just kidding, I don’t have the imposter syndrome. If anything, I got a superiority illusion complex. And I am absolutely sure that many, many scientists read things they consider fundamental to their way of thinking about the world all the time and wonder what other truly great discoveries are out there already that they missed.

Frankly, I should probably be grateful to this blog – and my friend GT who made me do it – because without nosing outside my field in search of material for it I would have probably remained ignorant of this awesome discovery. So, even if this is a decade old discovery for you, for me is one day old and I am a bit giddy about it.

This is a big deal because of the theoretical implications: a cell’s transcriptome (all the mRNA expressed in a cell) varies not only due to its needs, activity, and experiences, but also due to its neighbors’! A cell is, more or less, its transcriptome. Soooo… if we can change that at will, does that means we can change the type or function of the cell too? There are so many questions that such a discovery raises! And possibilities.

This is also a big deal because it opens up not a new therapy, or a new therapy direction, or a new drug class, but a new DELIVERY METHOD, the Holy Grail of Pharmacopeia. You just put your drug in one of these vesicles and let nature take its course. Of course, there are all sorts of roadblocks to overcome, like specificity, toxicity, etc. Looks like some are already conquered as there are several clinical trials out there that take advantage of this mechanism and I bet there will be more.

Stop by tomorrow for a freshly published paper on this mechanism in neurons.

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REFERENCES:

1) Baj-Krzyworzeka M, Szatanek R, Weglarczyk K, Baran J, Urbanowicz B, Brański P, Ratajczak MZ, & Zembala M. (Jul. 2006, Epub 9 Nov 2005). Tumour-derived microvesicles carry several surface determinants and mRNA of tumour cells and transfer some of these determinants to monocytes. Cancer Immunology, Immunotherapy, 55(7):808-818. PMID: 16283305, DOI: 10.1007/s00262-005-0075-9. ARTICLE

2) Ratajczak J, Miekus K, Kucia M, Zhang J, Reca R, Dvorak P, & Ratajczak MZ (May 2006). Embryonic stem cell-derived microvesicles reprogram hematopoietic progenitors: evidence for horizontal transfer of mRNA and protein delivery. Leukemia, 20(5):847-856. PMID: 16453000, DOI: 10.1038/sj.leu.2404132. ARTICLE | FREE FULLTEXT PDF 

Bibliography:

Raposo G & Stoorvogel W. (18 Feb. 2013). Extracellular vesicles: exosomes, microvesicles, and friends. The Journal of Cell Biology, 200(4):373-383. PMID: 23420871, PMCID: PMC3575529, DOI: 10.1083/jcb.201211138. ARTICLE | FREE FULLTEXT PDF

By Neuronicus, 13 January 2018

The FIRSTS: the Dunning–Kruger effect (1999) or the unskilled-and-unaware phenomenon

Much talked about these days in the media, the unskilled-and-unaware phenomenon was mused upon since, as they say, immemorial times, but not actually seriously investigated until the ’80s. The phenomenon refers to the observation that incompetents overestimate their competence whereas the competent tend to underestimate their skill (see Bertrand Russell’s brilliant summary of it).

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Although the phenomenon has gained popularity under the name of the “Dunning–Kruger effect”, it is my understanding that whereas the phenomenon refers to the above-mentioned observation, the effect refers to the cause of the phenomenon, namely that the exact same skills required to make one proficient in a domain are the same skills that allow one to judge proficiency. In the words of Kruger & Dunning (1999),

“those with limited knowledge in a domain suffer a dual burden: Not only do they reach mistaken conclusions and make regrettable errors, but their incompetence robs them of the ability to realize it” (p. 1132).

Today’s paper on the Dunning–Kruger effect is the third in the cognitive biases series (the first was on depressive realism and the second on the superiority illusion).

Kruger & Dunning (1999) took a look at incompetence with the eyes of well-trained psychologists. As usual, let’s start by defining the terms so we are on the same page. The authors tell us, albeit in a footnote on p. 1122, that:

1) incompetence is a “matter of degree and not one of absolutes. There is no categorical bright line that separates ‘competent’ individuals from ‘incompetent’ ones. Thus, when we speak of ‘incompetent’ individuals we mean people who are less competent than their peers”.

and 2) The study is on domain-specific incompetents. “We make no claim that they would be incompetent in any other domains, although many a colleague has pulled us aside to tell us a tale of a person they know who is ‘domain-general’ incompetent. Those people may exist, but they are not the focus of this research”.

That being clarified, the authors chose 3 domains where they believe “knowledge, wisdom, or savvy was crucial: humor, logical reasoning, and English grammar” (p.1122). I know that you, just like me, can hardly wait to see how they assessed humor. Hold your horses, we’ll get there.

The subjects were psychology students, the ubiquitous guinea pigs of most psychology studies since the discipline started to be taught in the universities. Some people in the field even declaim with more or less pathos that most psychological findings do not necessarily apply to the general population; instead, they are restricted to the self-selected group of undergrad psych majors. Just as the biologists know far more about the mouse genome and its maladies than about humans’, so do the psychologists know more about the inner workings of the psychology undergrad’s mind than, say, the average stay-at-home mom. But I digress, as usual.

The humor was assessed thusly: students were asked to rate on a scale from 1 to 11 the funniness of 30 jokes. Said jokes were previously rated by 8 professional comedians and that provided the reference scale. “Afterward, participants compared their ‘ability to recognize what’s funny’ with that of the average Cornell student by providing a percentile ranking. In this and in all subsequent studies, we explained that percentile rankings could range from 0 (I’m at the very bottom) to 50 (I’m exactly average) to 99 (I’m at the very top)” (p. 1123). Since the social ability to identify humor may be less rigorously amenable to quantification (despite comedians’ input, which did not achieve a high interrater reliability anyway) the authors chose a task that requires more intellectual muscles. Like logical reasoning, whose test consisted of 20 logical problems taken from a Law School Admission Test. Afterward the students estimated their general logical ability compared to their classmates and their test performance. Finally, another batch of students answered 20 grammar questions taken from the National Teacher Examination preparation guide.

In all three tasks,

  • Everybody thought they were above average, showing the superiority illusion.
  • But the people in the bottom quartile (the lowest 25%) dubbed incompetents (or unskilled), overestimated their abilities the most, by approx. 50%. They were also unaware that, in fact, they scored the lowest.
  • In contrast, people in the top quartile underestimated their competence, but not by the same degree as the bottom quartile, by about 10%-15% (see Fig. 1).

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I wish the paper showed scatter-plots with a fitted regression line instead of the quartile graphs without error bars. So I can judge the data for myself. I mean everybody thought they are above average? Not a single one out of more than three hundred students thought they are kindda… meah? The authors did not find any gender differences in any experiments.

Next, the authors tested the hypothesis about the unskilled that “the same incompetence that leads them to make wrong choices also deprives them of the savvy necessary to recognize competence, be it their own or anyone else’s” (p. 1126). And they did that by having both the competents and the incompetents see the answers that their peers gave at the tests. Indeed, the incompetents not only failed to recognize competence, but they continued to believe they performed very well in the face of contrary evidence. In contrast, the competents adjusted their ratings after seeing their peer’s performance, so they did not underestimate themselves anymore. In other words, the competents learned from seeing other’s mistakes, but the incompetents did not.

Based on this data, Kruger & Dunning (1999) argue that the incompetents are so because they lack the skills to recognize competence and error in them or others (jargon: lack of metacognitive skills). Whereas the competents overestimate themselves because they assume everybody does as well as they did, but when shown the evidence that other people performed poorly, they become accurate in their self-evaluations (jargon: the false consensus effect, a.k.a the social-projection error).

So, the obvious implication is: if incompetents learn to recognize competence, does that also translate into them becoming more competent? The last experiment in the paper attempted to answer just that. The authors got 70 students to complete a short (10 min) logical reasoning improving session and 70 students did something unrelated for 10 min. The data showed that the trained students not only improved their self-assessments (still showing superiority illusion though), but they also improved their performance. Yeays all around, all is not lost, there is hope left in the world!

This is an extremely easy read. I totally recommend it to non-specialists. Compare Kruger & Dunning (1999) with Pennycook et al. (2017): they both talk about the same subject and they both are redoubtable personages in their fields. But while the former is a pleasant leisurely read, the latter lacks mundane operationalizations and requires serious familiarization with the literature and its jargon.

Since Kruger & Dunning (1999) is under the paywall of the infamous APA website (infamous because they don’t even let you see the abstract and even with institutional access is difficult to extract the papers out of them, as if they own the darn things!), write to me at scientiaportal@gmail.com specifying that you need it for educational purposes and promise not to distribute it for financial gain, and thou shalt have its .pdf. As always. Do not, under any circumstance, use a sci-hub server to obtain this paper illegally! Actually, follow me on Twitter @Neuronicus to find out exactly which servers to avoid.

REFERENCES:

1) Kruger J, & Dunning D. (Dec. 1999). Unskilled and unaware of it: how difficulties in recognizing one’s own incompetence lead to inflated self-assessments. Journal of Personality and Social Psychology, 77(6):1121-1134. PMID: 10626367. ARTICLE

2) Russell, B. (1931-1935). “The Triumph of Stupidity” (10 May 1933), p. 28, in Mortals and Others: American Essays, vol. 2, published in 1998 by Routledge, London and New York, ISBN 0415178665. FREE FULLTEXT By GoogleBooks | FREE FULLTEXT of ‘The Triumph of Stupidity”

P.S. I personally liked this example from the paper for illustrating what lack of metacognitive skills means:

“The skills that enable one to construct a grammatical sentence are the same skills necessary to recognize a grammatical sentence, and thus are the same skills necessary to determine if a grammatical mistake has been made. In short, the same knowledge that underlies the ability to produce correct judgment is also the knowledge that underlies the ability to recognize correct judgment. To lack the former is to be deficient in the latter” (p. 1121-1122).

By Neuronicus, 10 January 2018