Category Archives: Research

Can attention span in infancy predict later executive function? (Best Evidence in Brief)

There is a new Best Evidence in Brief with some interesting studies, such as this one, although I do think it can be regarded in part for an extra argument that executive functions (note the plural) are heavily influenced by nature:

Infant attention skills are significantly related to preschool executive function at age three, according to a new study published in the Yale Journal of Biology and Medicine.

One hundred and fourteen children took part in the study. Jessica H. Kraybill and colleagues measured children’s attention at five months by using parental-report questionnaires and by assessing look duration and shifting rate while the children watched a video clip. Children’s single longest continuous look and the number of shifts of gaze at the video were recorded. Shorter looking durations were taken as an indication of better information processing, and high shift rates typically represent better attention. The performance on four different executive function tasks for these same children was then measured when they were three years old.

Results indicated that higher attention at age five was related to higher executive function at age three (effect size = + 0.05), supporting the notion that attention span in infancy may serve as an early marker of later executive function.

The authors measured character strengths by the Value in Action Inventory of Strengths for Youth (VIA-Youth), and positive classroom behaviors with the Classroom Behavior Rating Scale (CBRS), which cover positive achievement-related behavior and positive social behavior. For primary students, achievement was obtained by teacher ratings; for secondary students, the schools’ administration offices provided their grades. The findings showed that:

  • Perseverance, prudence, hope, social intelligence, and self-regulation were positively related to positive classroom behavior for both primary and secondary students.
  • Perseverance, prudence, hope, love of learning, perspective, zest, and gratitude were positively related to school achievement for both primary and secondary students.
  • Perseverance, prudence, and hope were associated with both positive classroom behavior and school achievement across primary and secondary sectors.
According to the authors, these findings indicate there is a rather distinct set of strengths most relevant in schools. The authors also suggest that further research could explore whether teachers and students value these strengths.

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How many words are sufficient to recognize the author? 12 or less!

Well, if you want to recognize my texts, just count the typo’s ;). No, seriously, I’ve heard about software that was able to write in a certain style of a famous author. This study shows that people are more original than you might have thought. The author’s individuality can already be seen in connections between no more than a dozen of words in English text. In Slavic languages authorship identification would require even fewer words with the results being more certain. I do think it’s important to notice that they did this research on works of famous authors.

From the press release:

Finding out the author of a text is usually not difficult: just read the signature. However, sometimes there is no signature since it has not been preserved or has been deliberately omitted by the author. Often, instead of a first and last name, we see a pseudonym. So, how can we verify who penned a historical text known only from fragments? How can we establish the true creator of an Internet lampoon? How can we really determine if the text of a thesis or doctoral dissertation is not plagiarized? In many cases, traditional stylometric methods fail or do not lead to sufficiently reliable conclusions. In Information Sciences, scientists from the Institute of Nuclear Physics of the Polish Academy of Sciences (IFJ PAN) in Cracow have presented their own statistical tool for stylometric analysis. Constructed with the use of graphs, it makes it possible look at the structure of texts in a qualitatively new way.

“The conclusions of our research are, on the one hand, encouraging. They indicate that the individuality of any person manifests itself clearly in the way they use a surprisingly small number of words. But there is also another, darker side of the coin. Since it turns out we are so original, it will be easier to identify us by our statements,” says Prof. Stanislaw Drozdz (IFJ PAN, Cracow University of Technology).

Stylometry – i.e. the science dealing with the determination of the statistical characteristics of the style of texts – is based on the observation that each of us uses even the same language in a slightly different way. Some have a broader vocabulary, others narrower, some like to use certain phrases and make mistakes, others avoid repetition and are linguistic purists. And when we write, we also differ in the way we use punctuation. In the typical stylometric approach, the basic features of a text are usually examined, e.g. the frequency of occurrence of individual words, whilst punctuation is ignored. Analyses are carried out for the studied text and for texts written by potentially well-known authors. The creator is deemed to be the person whose works have parameters with the values closest to those obtained for the material being identified.

“We suggested that the characteristic features of the style be sought in a network representation of the text, using graphs,” explains Tomasz Stanisz, PhD student at the IFJ PAN and the first author of the publication, and he specifies: “The graph is a collection of points, or vertices of the graph, connected by lines, i.e. the edges of the graph. In the simplest case – in the so-called unweighted network – the vertices correspond to individual words and are connected by edges if and only if two given words have occurred adjacent to each other at least once in the text. For example, for the sentence ‘Jane is hungry’, the graph would have three vertices, one for each word, but there would only be two edges, one between ‘Jane’ and ‘is’, the other between ‘is’ and ‘hungry’.”

While constructing their stylometric tools, the IFJ PAN researchers tested different types of graphs. The best results were obtained for weighted graphs, that is, those in which each edge carries information about the number of occurrences of its corresponding connection between words. Two parameters turned out to be the most useful in such networks: the node degree and the clustering coefficient. The first describes the number of edges coming from a given node and is directly related to the number of occurrences of a given word in the text. In turn, the clustering coefficient describes the probability that two words connected by an edge with a given word are connected with an edge also between themselves.

Using statistical tools prepared in this way, the Cracow-based physicists looked at 96 books: six novels by eight well-known English authors (Austen, Conrad, Defoe, Dickens, Doyle, Eliot, Orwell and Twain) and eight Polish authors (Korczak, Kraszewski, Lam, Orzeszkowa, Prus, Reymont, Sienkiewicz and Zeromski). The authors included two winners of the Nobel Prize for Literature (Wladyslaw Reymont and Henryk Sienkiewicz). All the texts were downloaded from the internet libraries Project Gutenberg, Wikisource and Wolne Lektury. The group from the IFJ PAN then checked the reliability with which the authorship of 12 randomly selected works in one language could be determined, treating the rest of the pool of works as comparative material.

“In the case of English texts, we identified the authors correctly in almost 90% of cases. In addition, in order to achieve success, it was necessary to trace the connections between only 10-12 words of the examined text. Contrary to naive intuition, a further increase in the number of words studied did not significantly increase the effectiveness of the method,” says Tomasz Stanisz.

In Polish, the determination of authorship turned out to be even simpler: only 5-6 words needed to be traced. What is particularly interesting is that despite the fact that the pool of significant words was half as many as in English, the probability of correct identification was increased by up to 95%! Such high diagnostic accuracy, however, was only achieved when punctuation marks were also treated as separate words. In both languages, omitting punctuation resulted in a significant reduction in the number of correct guesses. The observed role of punctuation is another confirmation of the conclusions from the publication of the group of Prof. Drozdz of 2017, where it was shown that punctuation plays an equally important role in language as the words themselves.

“In comparison with English, Polish seems to give greater possibilities of revealing the style of the author. We think that the other Slavic languages are characterised by similar features. English is a positional language, which means that the order of the words in a sentence is important. This sort of language leaves less room for an individual style of expression than the Slavic languages, in which inflection, or variation, decides about the role of a word or phrase in a sentence. This allows for greater freedom to organize the order of words in a sentence, whilst its meaning remains unchanged,” sums up Prof. Drozdz.

Links to the papers:

“Linguistic data mining with complex networks: A stylometric-oriented approach”
T. Stanisz, J. Kwapien, S. Drozdz
Information Sciences 482 (2019) 301-320
DOI: https://doi.org/10.1016/j.ins.2019.01.040

“In narrative texts punctuation marks obey the same statistics as words”
A. Kulig, J. Kwapien, T. Stanisz, S. Drozdz
Information Sciences 375 (2017) 98-113
DOI: http://dx.doi.org/10.1016/j.ins.2016.09.051

 

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Gender differences in spatial skills probably start in elementary school (meta-analysis)

Is it nature or nurture that men seem to better in spatial skills than women? Well, a new meta-analysis suggests that nurture plays a role and a takeaway idea for parents is that parents it’s a good idea to encourage both their daughters and sons to play with blocks and other construction items that might help in the development of spatial reasoning skills.

From the press release:

It is well-established that, on average, men outperform women on a spatial reasoning task known as mental rotation — imagining multi-dimensional objects from different points of view. Men are not, however, born with this advantage, suggests a major meta-analysis by psychologists at Emory University. Instead, males gain a slight advantage in mental-rotation performance during the first years of formal schooling, and this advantage slowly grows with age, tripling in size by the end of adolescence.

The Psychological Bulletin, a journal of the American Psychological Association, is publishing the findings.

“Some researchers have argued that there is an intrinsic gender difference in spatial reasoning — that boys are naturally better at it than girls,” says lead author Jillian Lauer, who is set to graduate from Emory in May with a PhD in psychology. “While our results don’t exclude any possibility that biological influences contribute to the gender gap, they suggest that other factors may be more important in driving the gender difference in spatial skills during childhood.”

Co-authors of the paper include Stella Lourenco, associate professor of psychology at Emory, whose lab specializes in the development of spatial and numerical cognition. Co-author Eukyung Yhang worked on the paper as an Emory undergraduate, funded by the university’s Institute for Quantitative Theory and Methods. Yhang graduated in 2018 and is now at Yale University School of Medicine.

The meta-analysis included 128 studies of gender differences in spatial reasoning, combining statistics on more than 30,000 children and adolescents aged three to 18 years. The authors found no gender difference in mental-rotation skills among preschoolers, but a small male advantage emerged in children between the ages of six and eight.

While differences in verbal and mathematical abilities between men and women tend to be small or non-existent, twice as many men as women are top performers in mental rotation, making it one of the largest gender differences in cognition.

Mental rotation is considered one of the hallmarks of spatial reasoning. “If you’re packing your suitcase and trying to figure out how each item can fit within that space, or you’re building furniture based on a diagram, you’re likely engaged in mental rotation, imagining how different objects can rotate to fit together,” Lauer explains.

Prior research has also shown that superior spatial skills predict success in male-dominated science, technology engineering and math (STEM) fields, and that the gender difference in spatial reasoning may contribute to the gender disparity in these STEM fields.

“We’re interested in the origins of gender differences in spatial skills because of their potential role in the gender gap we see in math and science fields,” Lauer says. “By determining when the gender difference can first be detected in childhood and how it changes with age, we may be able to develop ways to make educational systems more equitable.”

It takes most of childhood and adolescence for the gender gap in spatial skills to reach the size of the difference seen in adulthood, Lauer says. She adds that the meta-analysis did not address causes for why the gender gap for mental rotation emerges and grows.

Lauer notes that previous research has shown that parents use more spatial language when they talk to preschool sons than daughters. Studies have also found that girls report more anxiety about having to perform spatial tasks than do boys by first grade, and that children are aware of gender stereotypes about spatial intelligence during elementary school.

“Now that we’ve characterized how gender differences in spatial reasoning skills develop in children over time we can start to hone in on the reasons for those differences,” Lauer says.

Meanwhile, she adds, parents may want to be aware to encourage both their daughters and sons to play with blocks and other construction items that might help in the development of spatial reasoning skills, since evidence shows that these skills can be improved with training.

“Giving both girls and boys more opportunities to develop their spatial skills is something that parents and educators have the power to do,” Lauer says.

Abstract of the meta-analysis:

Gender differences in spatial aptitude are well established by adulthood, particularly when measured by tasks that require the mental rotation of objects (Linn & Petersen, 1985; Voyer, Voyer, & Bryden, 1995). Although the male advantage in mental rotation performance represents one of the most robust gender differences in adult cognition, the developmental trajectory of this male advantage remains a topic of considerable debate. To address this debate, we meta-analyzed 303 effect sizes pertaining to gender differences in mental rotation performance among 30,613 children and adolescents. We found significant developmental change in the magnitude of the gender difference: A small male advantage in mental rotation performance first emerged during childhood and then subsequently increased with age, reaching a moderate effect size during adolescence. Procedural factors, including task and stimulus characteristics, also accounted for variability in reported gender differences, even when controlling for the effect of age. These results demonstrate that both age and procedural characteristics moderate the magnitude of the gender difference in mental rotation throughout development.

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Inspiring: it’s storytime at the Laundromat

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What a difference reading to children make: a ‘million word gap’

We’ve known the importance of reading to your children for ages now, but this new study stresses again what the difference can be.

From the press release:

Young children whose parents read them five books a day enter kindergarten having heard about 1.4 million more words than kids who were never read to, a new study found.

This “million word gap” could be one key in explaining differences in vocabulary and reading development, said Jessica Logan, lead author of the study and assistant professor of educational studies at The Ohio State University.

Even kids who are read only one book a day will hear about 290,000 more words by age 5 than those who don’t regularly read books with a parent or caregiver.

“Kids who hear more vocabulary words are going to be better prepared to see those words in print when they enter school,” said Logan, a member of Ohio State’s Crane Center for Early Childhood Research and Policy.

“They are likely to pick up reading skills more quickly and easily.”

The study appears online in the Journal of Developmental and Behavioral Pediatrics and will be published in a future print edition.

Logan said the idea for this research came from one of her earlier studies, which found that about one-fourth of children in a national sample were never read to and another fourth were seldom read to (once or twice weekly).

“The fact that we had so many parents who said they never or seldom read to their kids was pretty shocking to us. We wanted to figure out what that might mean for their kids,” Logan said.

The researchers collaborated with the Columbus Metropolitan Library, which identified the 100 most circulated books for both board books (targeting infants and toddlers) and picture books (targeting preschoolers).

Logan and her colleagues randomly selected 30 books from both lists and counted how many words were in each book. They found that board books contained an average of 140 words, while picture books contained an average of 228 words.

With that information, the researchers calculated how many words a child would hear from birth through his or her 5th birthday at different levels of reading. They assumed that kids would be read board books through their 3rd birthday and picture books the next two years, and that every reading session (except for one category) would include one book.

They also assumed that parents who reported never reading to their kids actually read one book to their children every other month.

Based on these calculations, here’s how many words kids would have heard by the time they were 5 years old: Never read to, 4,662 words; 1-2 times per week, 63,570 words; 3-5 times per week, 169,520 words; daily, 296,660 words; and five books a day, 1,483,300 words.

“The word gap of more than 1 million words between children raised in a literacy-rich environment and those who were never read to is striking,” Logan said.

The word gap examined in this research isn’t the only type kids may face.

A controversial 1992 study suggested that children growing up in poverty hear about 30 million fewer words in conversation by age 3 than those from more privileged backgrounds. Other studies since then suggest this 30 million word gap may be much smaller or even non-existent, Logan said.

The vocabulary word gap in this study is different from the conversational word gap and may have different implications for children, she said.

“This isn’t about everyday communication. The words kids hear in books are going to be much more complex, difficult words than they hear just talking to their parents and others in the home,” she said.

For instance, a children’s book may be about penguins in Antarctica – introducing words and concepts that are unlikely to come up in everyday conversation.

“The words kids hear from books may have special importance in learning to read,” she said.

Logan said the million word gap found in this study is likely to be conservative. Parents will often talk about the book they’re reading with their children or add elements if they have read the story many times.

This “extra-textual” talk will reinforce new vocabulary words that kids are hearing and may introduce even more words.

The results of this study highlight the importance of reading to children.

“Exposure to vocabulary is good for all kids. Parents can get access to books that are appropriate for their children at the local library,” Logan said.

Abstract of the study:

Objective: In the United States, there are numerous ongoing efforts to remedy the Word Gap: massive differences in heardvocabulary for poor versus advantaged children during the first 5 years of life. One potentially important resource for vocabulary exposure is children’s book reading sessions, which are more lexically diverse than standard caregiver-child conversations and have demonstrated significant correlational and causal influences on children’s vocabulary development. Yet, nationally representative data suggest that around 25% of caregivers never read with their children.
Method: This study uses data from 60 commonly read children’s books to estimate the number of words that children are exposed to during book reading sessions. We estimated the total cumulative word exposure for children who are read to at varying frequencies corresponding to nationally representative benchmarks across the first 5 years of life.
Results: Parents who read 1 picture book with their children every day provide their children with exposure to an estimated 78,000 words each a year. Cumulatively, over the 5 years before kindergarten entry, we estimate that children from literacy-rich homes hear a cumulative 1.4 million more words during storybook reading than children who are never read to.
Conclusion: Home-based shared book reading represents an important resource for closing the Word Gap.

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Understanding math anxiety (Best Evidence in Brief)

There is a new Best Evidence in Brief with this time many interesting studies, such as this one:

While mathematics is often considered a hard subject, not all difficulties with the subject result from cognitive difficulties. Many children and adults experience feelings of anxiety, apprehension, tension or discomfort when confronted by a math problem. Research conducted by the Centre for Neuroscience in Education at the University of Cambridge examined the math performance of more than 2,700 primary and secondary students in the UK and Italy who were screened for math anxiety and general anxiety. Researchers then worked one-to-one with the children in order to gain deeper understanding of their cognitive abilities and feelings towards math using a series of cognitive tasks, questionnaires, and interviews.
Emma Carey and colleagues found that a general feeling that math was more difficult than other subjects often contributed to feelings of anxiety about the subject, and that teachers and parents may inadvertently play a role. Girls in both primary and secondary school were found to have higher levels of both math anxiety and general anxiety.
Students indicated poor test results, or negative comparisons to peers or siblings, as reasons for feeling anxious. Secondary school students also indicated that the transition from primary to secondary school was a cause of math anxiety, as the work seemed harder and there was greater pressure on tests and increased homework.
The report sets out a series of recommendations, including:
  • Teachers should be aware that math anxiety can affect students’ math performance.
  • Teachers and parents need to be aware that their own math anxiety might influence students’ math anxiety.
  • Teachers and parents also need to be aware that gendered stereotypes about math ability might contribute to the gender gap in math performance.
  • Reducing classroom pressure and using methods like free writing about emotions before a test could help to alleviate math anxiety.

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The ‘Ambassador Model’ in science communication

I’m taking a bit of leap here, as my colleagues in Leiden are much bigger experts on science communication than I am. I mean they do research on science communication while I just communicate about science. Still I thought this study to be pretty interesting and relevant. The study shows that building relationships between scientists and communities that are founded on shared values, does work.

An excerpt from the press release:

Bring science to people where they are. That’s the driving philosophy that propels U biology professor Nalini Nadkarni to stretch the possibilities of science communication and bring the beauty of science to people and places that others have overlooked.

Building public trust in science is about more than just providing information and improving science literacy, she says. It’s about building relationships between scientists and communities that are founded on shared values. It’s called the “Ambassador Model”, and Nadkarni now has the data to say that the approach works, at relatively low cost and with high effectiveness.

In two recent studies, one published today in BioScience and another published in 2018 in Science CommunicationNadkarni and her colleagues present evidence-based conclusions about the effectiveness of science engagement in two programs: The INSPIRE program, which brings science lectures to prisons, and the STEM Ambassador Program, which trains scientists to engage members of the public in discussions about science.

“Our goal is to help people realize that all citizens are interested in, capable of understanding and full of wonder at science, if it is presented in places and ways that are accessible to them,” Nadkarni says.

*DO NOTE: I was only able to read the 2018 study as the 2019 isn’t accessible yet.

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Learning a native language? That’s 1.5 MB… (But still robots won’t be able to do it that good fast)

This study has more to it than the fun fact in the title of this post. But it does seem to be something you’d share in a conversation, that

…from infancy to young adulthood, learners absorb approximately 12.5 million bits of information about language — about two bits per minute — to fully acquire linguistic knowledge. If converted into binary code, the data would fill a 1.5 MB floppy disk.

For the people who don’t know what a floppy disk was, it’s the icon in Word to save something and it’s a predecessor of the cloud, but than stored locally. And small, well the storage room on the disk.

And now the more important insight from the study taken from the press release:

The findings, published today in the Royal Society Open Science journal, challenge assumptions that human language acquisition happens effortlessly, and that robots would have an easy time mastering it.

“Ours is the first study to put a number on the amount you have to learn to acquire language,” said study senior author Steven Piantadosi, an assistant professor of psychology at UC Berkeley. “It highlights that children and teens are remarkable learners, absorbing upwards of 1,000 bits of information each day.”

For example, when presented with the word “turkey,” a young learner typically gathers bits of information by asking, “Is a turkey a bird? Yes, or no? Does a turkey fly? Yes, or no?” and so on, until grasping the full meaning of the word “turkey.”

A bit, or binary digit, is a basic unit of data in computing, and computers store information and calculate using only zeroes and ones. The study uses the standard definition of eight bits to a byte.

“When you think about a child having to remember millions of zeroes and ones (in language), that says they must have really pretty impressive learning mechanisms.”

Piantadosi and study lead author Frank Mollica, a Ph.D. candidate in cognitive science at the University of Rochester, sought to gauge the amounts and different kinds of information that English speakers need to learn their native language.

They arrived at their results by running various calculations about language semantics and syntax through computational models. Notably, the study found that linguistic knowledge focuses mostly on the meaning of words, as opposed to the grammar of language.

“A lot of research on language learning focuses on syntax, like word order,” Piantadosi said. “But our study shows that syntax represents just a tiny piece of language learning, and that the main difficulty has got to be in learning what so many words mean.”

That focus on semantics versus syntax distinguishes humans from robots, including voice-controlled digital helpers such as Alexa, Siri and Google Assistant.

“This really highlights a difference between machine learners and human learners,” Piantadosi said. “Machines know what words go together and where they go in sentences, but know very little about the meaning of words.”

As for the question of whether bilingual people must store twice as many bits of information, Piantadosi said this is unlikely in the case of word meanings, many of which are shared across languages.

“The meanings of many common nouns like ‘mother’ will be similar across languages, and so you won’t need to learn all of the bits of information about their meanings twice,” he said.

Abstract of the study:

We introduce theory-neutral estimates of the amount of information learners possess about how language works. We provide estimates at several levels of linguistic analysis: phonemes, wordforms, lexical semantics, word frequency and syntax. Our best guess is that the average English-speaking adult has learned 12.5 million bits of information, the majority of which is lexical semantics. Interestingly, very little of this information is syntactic, even in our upper bound analyses. Generally, our results suggest that learners possess remarkable inferential mechanisms capable of extracting, on average, nearly 2000 bits of information about how language works each day for 18 years.

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Nerd alert: maybe we’re a bit closer to a real holodeck…

Both Casper and myself are a bit of trekkies, we have to admit. So this study is a bit different than the typical research I discuss on this blog. But do forgive me, there is a relation with education: elementary mathematics brings Star Trek’s Holodeck closer to reality

From the press release:

For many years we have been hearing that holographic technology is one step closer to realizing Star Trek’s famous Holodeck, a virtual reality stage that simulates any object in 3D as if they are real. Sadly, 3D holographic projection has never been realized. A team of scientists from Bilkent University, Turkey, again raised our hopes on Holodeck realization by showing the first realistic 3D holograms that can be viewed from any angle. Dr. Ghaith Makey, the lead author of the paper appearing in the April 2019 issue of Nature Photonics today, says “Our technique can work in realtime, and will surely pave the way to dynamic 3D video holography. Soon, it may be possible to create a simple version of a Holodeck”.

3D holographic projection relies on back-to-back stacking of a large number of 2D images. The problem is, they cross-talk! Interference between the images makes the 3D projection fuzzy and far from realistic looking. The expectations have always been placed on the development of optical technology. Prof. F. Ömer Ilday, the co-leader of the project, disagrees: “The reason of this cross-talk is the mathematics, not shortcomings of the physical components. Any pair of high-dimensional mutually random vectors tend to be orthogonal. This basic result is a consequence of the Central Limit Theorem and the Law of Large Numbers. We use this property, together with a neat, but straightforward wavefront engineering trick to add random phase to each image, to eliminate cross-talk without using any additional optics”. Prof. Onur Tokel, the other co-leader, adds “It was not possible to simultaneously project a 3D object’s back, middle and front parts. We solve this issue through a simple connection between the equations developed by Jean-Baptiste Joseph Fourier and Augustin-Jean Fresnel in the early days of the field. Using this math property, we advance the state-of-the-art from the projection of 3-4 images to 1000 simultaneous projections!”

“The best part is that 3D projection performance will become better and better with increasing hologram resolution because the orthogonality result becomes exact for infinite dimensions — as display technologies continue to improve and support higher-resolution, they enable ever more realistic looking holograms using our technique,” says Dr. Makey. The team believes that the full potential of holography may be unleashed if such a 3D capability is at hand. “Our holograms already surpass all previous digitally synthesized 3D holograms in every quality metric. Our method is universally applicable to all types of holographic media, be they static or dynamic holograms. Therefore, opportunities are vast. Immediate applications may be in 3D displays for medical visualization or air traffic control, but also laser-material interactions and microscopy” says Prof. Serim Ilday of the Bilkent team.

“The most important concept associated with holography has always been the third dimension. This is even more clear with our new 3D projection capability. Many challenges remain, but we are one step closer to the visions defined by Holodeck in Star Trek; or Holovision of Isaac Asimov in the Foundation novels. Even Jules Verne touched upon the idea, in his book Carpathian Castle published in 1892,” adds Dr. Tokel.

Abstract of the paper, published in Nature photonics:

Holography is the most promising route to true-to-life three-dimensional (3D) projections, but the incorporation of complex images with full depth control remains elusive. Digitally synthesized holograms, which do not require real objects to create a hologram, offer the possibility of dynamic projection of 3D video. Despite extensive efforts aimed at 3D holographic projection, however, the available methods remain limited to creating images on a few planes, over a narrow depth of field or with low resolution. Truly 3D holography also requires full depth control and dynamic projection capabilities, which are hampered by high crosstalk. The fundamental difficulty is in storing all the information necessary to depict a complex 3D image in the 2D form of a hologram without letting projections at different depths contaminate each other. Here, we solve this problem by pre-shaping the wavefronts to locally reduce Fresnel diffraction to Fourier holography, which allows the inclusion of random phase for each depth without altering the image projection at that particular depth, but eliminates crosstalk due to the near-orthogonality of large-dimensional random vectors. We demonstrate Fresnel holograms that form on-axis with full depth control without any crosstalk, producing large-volume, high-density, dynamic 3D projections with 1,000 image planes simultaneously, improving the state of the art for the number of simultaneously created planes by two orders of magnitude. Although our proof-of-principle experiments use spatial light modulators, our solution is applicable to all types of holographic media.

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So just you know: Trials testing new educational methods in schools ‘often fail to produce useful evidence’

Doing research in education is difficult, very difficult. Trust me. So while this review may come as a shock, I’m not that shocked.
I’m performing a RCT myself at the moment and doing it in real life situations is proving to be very hard.

From the press release:

Educational trials aimed at boosting academic achievement in schools are often uninformative, new research suggests.

The new study, published in the journal Educational Researcher, found that 40% of large-scale randomised controlled trials (RCTs) in the UK and the US failed to produce any evidence as to whether an educational intervention helped to boost academic attainment or not.

The researchers evaluated 141 trials involving more than one million students, which tested schemes ranging from whether providing free school breakfasts raises grades in Maths and English, to whether playing chess improves numeracy skills.

The trials, which were carried out by the charitable organisation the Education Endowment Foundation (EEF) in the UK and the National Center for Education Evaluation and Regional Assistance (NCEE) in the US, are expensive – with costs often exceeding £500,000.

The authors of the study argue that more research is urgently needed to understand why RCTs in education are so often uninformative.

Lead author of the research, Dr Hugues Lortie-Forgues, from the Department of Education at the University of York, UK, said: “Just like in medicine, trials of educational interventions are an important way to allow policy makers and teachers to make informed decisions about how to improve education. However, many of these trials are currently not fulfilling their main aim of demonstrating which interventions are effective and which are not.”

“Further research to investigate the reasons for this should be a priority. These organisations are trying to achieve something positive and reform is urgently needed to help them to do so.”

In recent years there have been a growing number of RCTs conducted in education. For example, in the UK, the Education Endowment Foundation (EEF) has commissioned more than 191 trials since 2012.

The researchers cite possible reasons why current trials may be ineffective, including:

  • The interventions being tested may not be suitable for trial in the first place.
  • Interventions may not be being correctly implemented during trials – for example due to inadequate training of teachers in the methods being tested.
  • The trials themselves may be poorly designed

The authors suggest a series of changes that could make the trials more informative, including higher-standards when considering which new initiatives are trialled.

Rigorous Large-Scale Educational RCTs are Often Uninformative: Should We Be Concerned? Is published in the journal Educational Researcher. The study was carried out in collaboration with researchers at Loughborough University.

Abstract of the review:

There are a growing number of large-scale educational randomized controlled trials (RCTs). Considering their expense, it is important to reflect on the effectiveness of this approach. We assessed the magnitude and precision of effects found in those large-scale RCTs commissioned by the UK-based Education Endowment Foundation and the U.S.-based National Center for Educational Evaluation and Regional Assistance, which evaluated interventions aimed at improving academic achievement in K–12 (141 RCTs; 1,222,024 students). The mean effect size was 0.06 standard deviations. These sat within relatively large confidence intervals (mean width = 0.30 SDs), which meant that the results were often uninformative (the median Bayes factor was 0.56). We argue that our field needs, as a priority, to understand why educational RCTs often find small and uninformative effects.

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