Category Archives: Review

May 4, 2013 · 3:33 pm

Are many of the neurological studies possible examples of false positives? (research)

People who often read this blog know that one of the reasons I write posts is to debunk myths, mostly in education. Quite often these are neuromyths, because neurology is getting quite popular in education.

This study published in Nature by Button et al. is a whole different story. The analysis doesn’t attack neuromyths, but the neurological research itself and the team that has done this consists of neuroscientists, psychologists, geneticists and statisticians. They analysed meta-analyses of neuroscience research to determine the statistical power of the papers contained within and found that there is something wrong with the power. But what is power?

From Wikipedia:

The power of a statistical test is the probability that the test will reject the null hypothesis when the null hypothesis is false (i.e. the probability of not committing a Type II error, hence the probability of confirming the alternative hypothesis when the alternative hypothesis is true). The power is in general a function of the possible distributions, often determined by a parameter, under the alternative hypothesis. As the power increases, the chances of a Type II error occurring decrease. The probability of a Type II error occurring is referred to as the false negative rate (β). Therefore power is equal to 1 − β, which is also known as the sensitivity.

Power analysis can be used to calculate the minimum sample size required so that one can be reasonably likely to detect an effect of a given size. Power analysis can also be used to calculate the minimum effect size that is likely to be detected in a study using a given sample size. In addition, the concept of power is used to make comparisons between different statistical testing procedures: for example, between a parametric and a nonparametric test of the same hypothesis.

What happens if research is underpowered? Well, with too few samples there is a big risk for false positives, something that might be happening in neuroscience.

Read here an interview on the research @ Neurobonkers.

Abstract of the research:

A study with low statistical power has a reduced chance of detecting a true effect, but it is less well appreciated that low power also reduces the likelihood that a statistically significant result reflects a true effect. Here, we show that the average statistical power of studies in the neurosciences is very low. The consequences of this include overestimates of effect size and low reproducibility of results. There are also ethical dimensions to this problem, as unreliable research is inefficient and wasteful. Improving reproducibility in neuroscience is a key priority and requires attention to well-established but often ignored methodological principles.

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April 26, 2013 · 3:18 pm

“Fighting bullying should start before school”, the influence of parenting on bullying (research)

I was having doubts if I would blog about this research by Dieter Wolke, Dr Suzet Lereya and Dr Muthanna Samara because the last thing that I would want to is make good parents feel unsure  or even worse guilty. In their meta-analysis they examined the influence of the parenting style on being bullied at school, and their conclusion is harsch, but clear: Poor parenting -including overprotection – increases bullying risk.

From the press release:

Children who are exposed to negative parenting – including abuse, neglect but also overprotection – are more likely to experience childhood bullying by their peers, according to a meta-analysis of 70 studies of more than 200,000 children.

The research, led by the University of Warwick and published in the journal Child Abuse & Neglect, found the effects of poor parenting were stronger for children who are both a victim and perpetrator of bulling (bully-victims) than children who were solely victims.

It found that negative or harsh parenting was linked to a moderate increase in the risk of being a ‘bully-victim’ and a small increase in the risk of being a victim of bullying. In contrast, warm but firm parenting reduced the risk of being bullied by peers.

The study authors, Professor Dieter Wolke, Dr Suzet Lereya and Dr Muthanna Samara, called for anti-bullying intervention programmes to extend their focus beyond schools to focus on positive parenting within families and to start before children enter school.

Professor Wolke said: “The long shadow of bullying falls well beyond the school playground – it has lasting and profound effects into adulthood. We know that victims and bully-victims are more likely to develop physical health problems, suffer from anxiety and depression and are also at increased risk of self-harm and suicide. It is vital we understand more about the factors linked to bullying in order to reduce the burden it places on the affected children and society.
People often assume bullying is a problem for schools alone but it’s clear from this study that parents also have a very important role to play. We should therefore target intervention programmes not just in schools but also in families to encourage positive parenting practices such as warmth, affection, communication and support. The study categorised behaviours such as abuse/neglect, maladaptive parenting and overprotection as negative parenting behaviour. It categorised authoritative parenting, parent-child communication, parental involvement and support, supervision and warmth and affection as positive parenting behaviours.”
Professor Wolke highlighted the finding that overprotection was linked to an increased risk of bullying. Although parental involvement, support and high supervision decrease the chances of children being involved in bullying, for victims overprotection increased this risk. Children need support but some parents try to buffer their children from all negative experiences.
In the process, they prevent their children from learning ways of dealing with bullies and make them more vulnerable. It could be that children with overprotective parents may not develop qualities such as autonomy and assertion and therefore may be easy targets for bullies. But it could also be that parents of victims become overprotective of their children. In either case, parents cannot sit on the school bench with their children. Parenting that includes clear rules about behaviour while being supportive and emotionally warm is most likely to prevent victimisation. These parents allow children to have some conflicts with peers to learn how to solve them rather than intervene at the smallest argument.”

Abstract of the meta-analysis:

Objective: Being bullied has adverse effects on children’s health. Children’s family experiences and parenting behavior before entering school help shape their capacity to adapt and cope at school and have an impact on children’s peer relationship, hence it is important to identify how parenting styles and parent–child relationship are related to victimization in order to develop intervention programs to prevent or mitigate victimization in childhood and adolescence.

Methods: We conducted a systematic review of the published literature on parenting behavior and peer victimization using MEDLINE, PsychINFO, Eric and EMBASE from 1970 through the end of December 2012. We included prospective cohort studies and cross-sectional studies that investigated the association between parenting behavior and peer victimization.

Results: Both victims and those who both bully and are victims (bully/victims) were more likely to be exposed to negative parenting behavior including abuse and neglect and maladaptive parenting. The effects were generally small to moderate for victims (Hedge’s g range: 0.10–0.31) but moderate for bully/victims (0.13–0.68). Positive parenting behavior including good communication of parents with the child, warm and affectionate relationship, parental involvement and support, and parental supervision were protective against peer victimization. The protective effects were generally small to moderate for both victims (Hedge’s g: range: −0.12 to −0.22) and bully/victims (−0.17 to −0.42).

Conclusions: Negative parenting behavior is related to a moderate increase of risk for becoming a bully/victim and small to moderate effects on victim status at school. Intervention programs against bullying should extend their focus beyond schools to include families and start before children enter school.

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October 4, 2012 · 7:28 pm

My review of ‘Brain Gain’, the new book by Marc Prenzky + his response!

I was asked by Louis Hilgers to write a review on this new book. It was first published on ictnieuws.nl together with a response of Marc Prenzky to my comments, do check it beneath the Dutch version of this review. The response is in English.

Brain Gain - Marc PrenskySome people may think it is strange for me to review the new book by Marc Prensky, because for the past years I have been quite critical about one of the main concepts he coined the digital natives.

But it is not because a concept is refuted, it wasn’t interesting by conception. Don’t expect a ‘rotten tomatoes’-review, en contraire, I have read the book in a benevolent way, despite the title ‘Brain gain’.

Actually the title sets you off on the wrong foot, the book has little or nothing to do with neurology, in the contrary.  Prensky duly notes that we have seen many new discoveries in this field of science, but any neurologist will tell you that we only have touched the surface. He warns us also for going too fast to conclusions and stays away from neurology.

The brain gain Prensky wants to talk about is how technology can facilitate our life and how it can be a natural extension of our thinking and abilities. The central question for the author is how can we optimally combine humans and technology.

The book wants to be an antidote for the negative press technology received during the past years, example given Nicholas Carr telling us how internet is dumbing us down or Sherry Turkle who describes how internet is making us lonelier.

The central concept in the book is ‘digital wisdom’. It would be a mistake to see this word as synonym for media literacy. To wisely handle media is a part of digital wisdom, but now we are developing bionic eyes and ears, Prensky wants to take things further than dealing with Internet or social media.

Digital wisdom has in his vision always 2 components: both how to use technology in a smart way and how to get smarter through technology.

Like in many of his earlier works, Prensky devotes a lot of attention to education and asks a question I also think crucial: he gives a plea for a renewed discussion on the ‘what’ in education. While we often concentrate on the question how technology can change or improve our education, we seldom discuss the influence on the content of the curriculum.

The suggestions Prensky gives will probably provoke a lot of people, such as do children still have to learn how to write or do we still need those old math theorems in an age in which we rather should learn how to code.

I think he takes it too far and is forgetting the task of conserving education still has. To stand on the shoulders of giants, we still need to know those giants. I read in an interview that Presnsky is now working on a book or article on a zero based curriculum. What do we need to learn, when everything can be found on the Internet? By doing this he seems to ignore everything we now know about learning and digital skills, namely that, maybe ironically, need more knowledge for those 21st century skills. In this chapter Prensky shows himself as an anti-Furedi. Still they both think the teacher as most important with technology in a supporting role.

An often-read complaint about Prensky is that he sometimes simplify things to much. Actually, I discovered many nuances in his story, although I sometimes had the feeling he did some cherry picking in his sources. A point of criticism I have is that that Prensky becomes a bit too insistent in the first, more theoretical part through the plenty examples and repetitions.

The questions he raises about the future deliver an excellent starting point for further thinking. Too me, this is an important merit.

Oh, btw, just one more thing. In this book Prensky abandons the metaphor of the digital natives himself. He acknowledges the many research and criticism the concept received and thinks of this concept less useful in present day. I also agree with him on this point ;) .

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