The dating of phenomena in the past, such as the existence of a specific species of animal or the presence of humans, is always based upon the earliest and latest evidence discovered so far. When you think about it, it is obviously very unlikely that we will have discovered the absolute earliest or latest occurrence of anything in the past.
It it therefore very common for new discoveries of fossils or archaeological evidence to increase the range of a phenomenon. Date ranges are always tentative and changing, although new discoveries still often lead to headlines emphasizing how surprised scientists were at the find.
For example, when did humans first live in the Arctic circle? There are essentially three types of evidence for a human presence. The first is direct evidence – human fossils found in the location and dated to a specific time. The second is human artifacts, stone tools being the most common because they preserve well and are unambiguous human artifacts. The third is human activity, such as fire pits or butchered animals.
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Continued from Part I
5) How to Analyze a Scientific Study
I don’t expect a non-scientist, or even a scientist far outside their area of expertise, to be able to do a detailed analysis of the strengths and weaknesses of a study. That is what peer-review is for. However, there are some basic rules of thumb that could give even a lay person a rough idea how seriously they should take a study. Always ask at least the following questions:
Is the study controlled in some way? Was the treatment group compared to a control group, or was the alleged effect compared to some baseline?
Is the study blinded? Were the primary measurements or assessments performed by someone who was blinded to whether or not the alleged effect is supposed to be present?
Are the outcomes being measured subjective or objective? How are they being measured? What do they really mean?
How large is the study? Studies with small numbers of subjects or measurements (less than 50 per group is a good rule of thumb) are considered small and unreliable.
Is the study an observation or an experiment? Are they just looking for some correlation (in which it is difficult to make statements about cause and effect), or are they controlling for variables and isolating the one factor of interest?
What is the reaction of the scientific community to the study? Are experts generally critical or excited about the results? Continue Reading »
What does it mean to be scientifically literate? There is no completely objective answer to this question, it can be defined in multiple ways and the bar can be set anywhere along a spectrum.
Many tests of scientific literacy essentially ask a series of scientific facts – they are tests of factual knowledge, but not scientific thinking. This glaring deficit has been pointed out many times before, and was so again in a recent editorial by Danielle Teller. She writes:
There are a number of problems with teaching science as a collection of facts. First, facts change. Before oxygen was discovered, the theoretical existence of phlogiston made sense. For a brief, heady moment in 1989, it looked like cold fusion (paywall) was going to change the world.
I agree. A true measure of scientific literacy should be a combination of facts, concepts, and process. Facts are still important. Concepts without facts are hollow, and facts without concepts are meaningless. Both need to be understood in the context of the process that led us to our current conclusions.
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Campbell Soup has just announced that they are switching sides in the GMO labeling debate – they are now in favor of federal mandatory labeling for all products that contain genetically modified organisms. This has perhaps opened up a new chapter in the debate.
In response Mark Lynas, a journalist who, after researching the topic, is staunchly pro-GMO, has responded with an interesting essay agreeing with this move by Campbell.
Let me state up front that I think the answer to mandatory labeling is no, but let me also walk you through my thinking on this complex issue.
The Scientific Case Continue Reading »
I have written a little about Bayes Theorem, mainly on Science-Based Medicine, which is a statistical method for analyzing data. A recent Scientific American column has some interesting things to say about it as well. I thought a brief overview would be helpful for those who are not sure what it is.
This statistical method is named for Thomas Bayes who first formulated the basic process, which is this: begin with an estimate of the probability that any claim, belief, hypothesis is true, then look at any new data and update the probability given the new data.
If this sounds simple and intuitive, it’s because it is. Psychologists have found that people innately take a Bayesian approach to knowledge. We tend to increment our beliefs, updating them as new information comes in.
Of course, this is only true when we do not have an emotional investment in one conclusion or narrative, in which case we jealously defend our beliefs even in the face of overwhelming new evidence. Absent a significant bias, we are natural Bayesians.
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It can be difficult to know what the optimal attitude is to have toward rare or unlikely events that would be catastrophic. How much should we worry about a large asteroid striking the earth? It could happen any time, but statistically is unlikely anytime soon (although is almost inevitable over the long term, meaning millions of years).
There are other rare but devastating natural phenomena. Phil Plait wrote about all the things that can bring Death from the Skies, including asteroids but also gamma ray bursts and other astronomical phenomena.
Today, however, we’re talking about death from below, specifically volcanic eruptions, more specifically supervolcanoes, and even more specifically the Yellowstone supervolcano. Recent news reports are breathlessly stating that scientists warn Yellowstone could blow in the next 70 years. Well, not so fast. Continue Reading »
This is old news, but attention is being freshly paid to the issue of creationists using academic freedom as an excuse to teach creationism in public schools, in violation of the First Amendment. This attention is due to an anonymous whistle-blower from the Discovery Institute confirming what everyone already knew.
According to reports:
“Critical thinking, critical analysis, teach the controversy, academic freedom—these are words that stand for legitimate pedagogical approaches and doctrines in the fields of public education and public education policy,” said the former Discovery Institute employee. “That is why DI co-opts them. DI hollows these words out and fills them with their own purposes; it then passes them off to the public and to government as secular, pedagogically appropriate, and religiously neutral.”
Whether or not you believe this anonymous source, the DiscoTute has objectively caused a lot of mischief. They authored model anti-evolution laws that have been used in various states, including successfully in Louisiana.
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I am a technophile, so I follow new and emerging technologies pretty closely. I am also an occasional early adopter, as much as my finances allow, which is not anywhere close to what I would like. Often I must wait for a new technology to come down in price to the consumer level, or at least the “prosumer” level.
Over the last couple of years I have had my eye on 3-D printers. This is an extremely promising technology, often referred to as additive manufacturing. Traditional manufacturing methods start with a block of material and then take away material to create the shape, or they use some kind of mold, or they hammer, pull, bend, or press material into shape. Continue Reading »
Yesterday I wrote about types of misinformation online. I left one out – skeptics or scientists creating false information to show how easy it is for people (or specifically the press or journal editors) to be fooled.
I have never personally done this for several reasons (as tempting as it may be): I think it’s important to protect my integrity as an honest broker of information and opinion, and that would be sullied by a deliberate hoax, no matter what my intentions. I also worry about adding to the pile of misinformation out there, while the lesson would be largely lost. Also, it can be a lose-lose situation. If you pull it off well, it can backfire. If you don’t pull it off well, you look silly.
Case in point – in 2012 a Portugese-language blog created the false conspiracy theory that Avril Lavigne killed herself after her first album, and was replace by a doppleganger who took over her career. However, the replacement dropped subtle clues in lyrics and elsewhere, revealing the conspiracy.
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Diana Rusk writing for BBC news has a good article about fake photos and videos that were spread in 2015. It is a sobering reminder of how much fake, misleading, and deliberately fraudulent information there is out there.
As I have often pointed out, the internet is a fantastic tool for communication, but is also a double-edge sword. If even a tiny percentage of the online public are generating false information, for whatever reason, that will create a steady stream of misinformation. We will never be rid of it.
Think about this, estimates are that about 1% of the population are psychopaths. That is 3 million psychopaths in the US alone. Some are in prison, but many are in the general population and have access to the internet. Online they can wreak havoc with impunity. In fact there is some preliminary information that there is a huge overlap between being an internet troll and a psychopath. Continue Reading »