Statistical significance explained in plain English

A nice refresher

Via BPS research:

Warren Davies, a positive psychology MSc student at UEL, provides the latest in our ongoing series of guest features for students. Warren has just released a Psychology Study Guide, which covers information on statistics, research methods and study skills for psychology students.

Today I’m delighted to discuss an absolutely fascinating topic in psychology – statistical significance. I know you’re as excited about this as I am!

Why is psychology a science? Why bother with complicated research methods and statistical analyses? The answer is that we want to be as sure as possible that our theories about the mind and behaviour are correct. These theories are important – many decisions in areas like psychotherapy, business and social policy depend on what psychologists say.

Despite the myriad rules and procedures of science, some research findings are pure flukes. Perhaps you’re testing a new drug, and by chance alone, a large number of people spontaneously get better. The better your study is conducted, the lower the chance that your result was a fluke – but still, there is always a certain probability that it was.

Statistical significance testing gives you an idea of what this probability is.

In science we’re always testing hypotheses. We never conduct a study to ’see what happens’, because there’s always at least one way to make any useless set of data look important. We take a risk; we put our idea on the line and expose it to potential refutation. Therefore, all statistical tests in psychology test the possibility that the hypothesis is correct, versus the possibility that it isn’t. The latter possibility is called the null hypothesis.

Click Here To Read: Statistical significance explained in plain English

Video: Ted Talk – How we found hundreds of Earth-like planets

About this talk (Via Ted)

Astronomer Dimitar Sasselov and his colleagues search for Earth-like planets that may, someday, help us answer centuries-old questions about the origin and existence of biological life elsewhere (and on Earth). How many such planets have they found already? Several hundreds.

About Dimitar Sasselov (Via Ted)

Dimitar Sasselov works on uniting the physical and life sciences in the hunt for answers to the question of how life began.

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Michael Shermer: When Scientists Sin

Now this book is the kind of book Munger would recommend reading ” On Fact and Fraud: Cautionary Tales from the Front Lines of Science”

Tagline: “Fraud, deception and lies in research reveal how science is (mostly) self-correcting” (via Michael Shermer @ SciAm)

Introduction (via Michael Shermer @ SciAm)

In his 1974 commencement speech at the California Institute of Technology, Nobel laureate physicist Richard P. Feynman articulated the foundation of scientific integrity: “The first principle is that you must not fool yourself—and you are the easiest person to fool…. After you’ve not fooled yourself, it’s easy not to fool other scientists. You just have to be honest in a conventional way after that.”

Unfortunately, says Feynman’s Caltech colleague David Goodstein in his new book On Fact and Fraud: Cautionary Tales from the Front Lines of Science (Princeton University Press, 2010), some scientists do try to fool their colleagues, and believing that everyone is conventionally honest may make a person more likely to be duped by deliberate fraud. Nature may be subtle, but she does not intentionally lie. People do. Why some scientists lie is what Goodstein wants to understand. He begins by debunking myths about science such as: “A scientist should never be motivated to do science for personal gain, advancement or other rewards.” “Scientists should always be objective and impartial when gathering data.” “Scientists must never believe dogmatically in an idea or use rhetorical exaggeration in promoting it.” “Scientists should never permit their judgments to be affected by authority.” These and many other maxims just do not reflect how science works in practice.

Knowing that scientists are highly motivated by status and rewards, that they are no more objective than professionals in other fields, that they can dogmatically defend an idea no less vehemently than ideologues and that they can fall sway to the pull of authority allows us to understand that, in Goodstein’s assessment, “injecting falsehoods into the body of science is rarely, if ever, the purpose of those who perpetrate fraud. They almost always believe that they are injecting a truth into the scientific record.”

Click Here To Read: Michael Shermer: When Scientists Sin

Video:Why Statistics Really Matter!

Introduction (via River Valley TV)

These are strange times. The range and quality of data that exists is richer than ever before, and by some considerable margin. And yet we seem to fail to make good use of much of what is available, and to be frightened in the face of numbers. What kinds of strategies might help?

Click Here To Watch: Video-Why Statistics Really Matter!

Oxytocin’s Role In Prosocial and Defensive Behavior

And I thought it was the cuddle drug…

Abstract

Humans regulate intergroup conflict through parochial altruism; they self-sacrifice to contribute to in-group welfare and to aggress against competing out-groups. Parochial altruism has distinct survival functions, and the brain may have evolved to sustain and promote in-group cohesion and effectiveness and to ward off threatening out-groups. Here, we have linked oxytocin, a neuropeptide produced in the hypothalamus, to the regulation of intergroup conflict. In three experiments using double-blind placebo-controlled designs, male participants self-administered oxytocin or placebo and made decisions with financial consequences to themselves, their in-group, and a competing out-group. Results showed that oxytocin drives a “tend and defend” response in that it promoted in-group trust and cooperation, and defensive, but not offensive, aggression toward competing out-groups.

Click Here To Read: Oxytocin: Prosocial and Defensive Behavior

Steven Pinker: Free Paper – The cognitive niche: Coevolution of intelligence, sociality, and language

This is the kind of stuff Munger would enjoy. I highly recommend reading this! (As always I have selected bits and pieces to stimulate your curiosity…)

Click Here To Read: Steven Pinker: The cognitive niche: Coevolution of intelligence, sociality, and language

Introduction & Excerpts (via Steven Pinker@ Pnas.org)

Although Darwin insisted that human intelligence could be fully explained by the theory of evolution, the codiscoverer of natural selection, Alfred Russel Wallace, claimed that abstract intelligence was of no use to ancestral humans and could only be explained by intelligent design. Wallace’s apparent paradox can be dissolved with two hypotheses about human cognition. One is that intelligence is an adaptation to a knowledge-using, socially interdependent lifestyle, the “cognitive niche.” This embraces the ability to overcome the evolutionary fixed defenses of plants and animals by applications of reasoning, including weapons, traps, coordinated driving of game, and detoxification of plants. Such reasoning exploits intuitive theories about different aspects of the world, such as objects, forces, paths, places, states, substances, and other people’s beliefs and desires. The theory explains many zoologically unusual traits in Homo sapiens, including our complex toolkit, wide range of habitats and diets, extended childhoods and long lives, hypersociality, complex mating, division into cultures, and language (which multiplies the benefit of knowledge because know-how is useful not only for its practical benefits but as a trade good with others, enhancing the evolution of cooperation). The second hypothesis is that humans possess an ability of metaphorical abstraction, which allows them to coopt faculties that originally evolved for physical problem-solving and social coordination, apply them to abstract subject matter, and combine them productively. These abilities can help explain the emergence of abstract cognition without supernatural or exotic evolutionary forces and are in principle testable by analyses of statistical signs of selection in the human genome.

…..

Few scientists today accept Wallace’s creationism, teleology, or spiritualism. Nonetheless it is appropriate to engage the profound puzzle he raised; namely, why do humans have the ability to pursue abstract intellectual feats such as science, mathematics, philosophy, and law, given that opportunities to exercise these talents did not exist in the foraging lifestyle in which humans evolved and would not have parlayed themselves into advantages in survival and reproduction even if they did?

I suggest that the puzzle can be resolved with two hypotheses. The first is that humans evolved to fill the “cognitive niche,” a mode of survival characterized by manipulating the environment through causal reasoning and social cooperation. The second is that the psychological faculties that evolved to prosper in the cognitive niche can be coopted to abstract domains by processes of metaphorical abstraction and productive combination, both vividly manifested in human language.

….

The theory of the cognitive niche helps explain many zoologically unusual features of H. sapiens: traits that are universal across human cultures (3) but are either unique or hyperdeveloped (especially in combination) with respect to the rest of the animal kingdom. Three in particular make our species stand out.

1. Technological Know-How.

Humans use and depend upon many kinds of tools, which involve multiple parts and complicated methods of fabrication. The tools are deployed in extended sequences of behavior and are acquired both by individual discovery and learning from others. They are deployed to capture and kill animals, to process foods (including cooking, fermenting, soaking, peeling, and crushing them to remove toxins and increase the availability of nutrients), and to generate and administer medicinal drugs (4, 5).

2. Cooperation Among Nonkin.

Humans cooperate with other humans: they trade goods, favors, know-how, and loyalty, and act collectively in child-rearing, gathering, hunting, and defense. This cooperation extends to other humans who are not related to them, in shifting partnerships, coalitions, and trading relationships, and thus must be explained not by kin selection but by mutualism or reciprocity (11).

3. Grammatical Language.

…… Although every language must be learned, humans have an ability to coin, pool, and learn new words and rules and thus are not dependent on some other species as teachers (as is the case with apes), or even on a longstanding linguistic community, to develop and use language (26).

Click Here To Read: Steven Pinker: The cognitive niche: Coevolution of intelligence, sociality, and language

Video: Science & Skepticism

Introduction (Via Fora.tv)

How are science and skepticism related? Is skepticism a part of science, or is science a tool of skepticism? Dr. Eugenie C. Scott, Executive Director of the National Center for Science Education, discusses these questions, and explores the importance of teaching both science and skepticism.

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When Will We Be Able to Build Brains Like Ours?

Introduction (Via Terry Sejnowski @ Sci Am)

When physicists puzzle out the workings of some new part of nature, that knowledge can be used to build devices that do amazing things — airplanes that fly, radios that reach millions of listeners.  When we come to understand how brains function, we should become able to build amazing devices with cognitive abilities — such as cognitive cars that are better at driving than we are because they communicate with other cars and share knowledge on road conditions.  In 2008, the National Academy of Engineering chose as one of its grand challenges to reverse-engineer the human brain.  When will this happen? Some are predicting that the first wave of results will arrive within the decade, propelled by rapid advances in both brain science and computer science. This sounds astonishing, but it’s becoming increasingly plausible. So plausible, in fact, that the great race to reverse-engineer the brain is already triggering a dispute over historic “firsts.”

The backdrop for the debate is one of dramatic progress. Neuroscientists are disassembling brains into their component parts, down to the last molecule, and trying to understand how they work from the bottom up.  Researchers are racing to work out the wiring diagrams of big brains, starting with mice, cats and eventually humans, a new field called connectomics.  New techniques are making it possible to record from many neurons simultaneously, and to selectively stimulate or silence specific neurons. There is an excitement in the air and a sense that we are beginning to understand how the brain works at the circuit level.  Brain modelers have so far been limited to modeling small networks with only a few thousand neurons, but this is rapidly changing.

Click Here To Read: When Will We Be Able to Build Brains Like Ours?

Video: Ted Talk- Toward a science of simplicity

About this talk (via Ted)

Simplicity: We know it when we see it — but what is it, exactly? In this funny, philosophical talk, George Whitesides chisels out an answer.

About George Whitesides (Via Ted)

In his legendary career in chemistry, George Whitesides has been a pioneer in microfabrication and nanoscale self-assembly. Now, he’s fabbing a diagnostic lab on a chip.

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How Our Brains Make Memories

H/T Vaughn Bell @ Mind Hacks

*note “Brizendine has received a great deal of scrutiny for some of her claims” – h/t Eric Barker for bringing this to my attention.

Subtitle : Surprising new research about the act of remembering may help people with post-traumatic stress disorder

Introduction (Via Greg Miller @ Smithosian)

Like millions of people, Nader has vivid and emotional memories of the September 11, 2001, attacks and their aftermath. But as an expert on memory, and, in particular, on the malleability of memory, he knows better than to fully trust his recollections.

Most people have so-called flashbulb memories of where they were and what they were doing when something momentous happened: the assassination of President John F. Kennedy, say, or the explosion of the space shuttle Challenger. (Unfortunately, staggeringly terrible news seems to come out of the blue more often than staggeringly good news.) But as clear and detailed as these memories feel, psychologists find they are surprisingly inaccurate.

Nader, now a neuroscientist at McGill University in Montreal, says his memory of the World Trade Center attack has played a few tricks on him. He recalled seeing television footage on September 11 of the first plane hitting the north tower of the World Trade Center. But he was surprised to learn that such footage aired for the first time the following day. Apparently he wasn’t alone: a 2003 study of 569 college students found that 73 percent shared this misperception.

Nader believes he may have an explanation for such quirks of memory. His ideas are unconventional within neuroscience, and they have caused researchers to reconsider some of their most basic assumptions about how memory works. In short, Nader believes that the very act of remembering can change our memories.