Once you understand something about how our brains operate and how easily they lead us to see, hear, and feel things that aren’t there, believe in things that don’t exist, and think things that make no sense, you might never again find the courage to walk out of your front door. I have been paying close attention to the work of psychologists and brain scientists for many years, and at times their discoveries have left me reeling. Unfortunately, most people know little or nothing about how the brain operates so they make incorrect assumptions about its reliability. The brutal truth is that human brains do a poor job of separating truth from fiction. This leads to many false beliefs. Therefore, it’s only wise to make at least a minimal effort to understand the brain and be on guard against its deceptive ways.

Many of the weird yet routine processes of the human brain are not only extremely interesting but have direct relevance to the safety and quality of our lives as well. It’s like we are all sharing our bodies with another person, somebody called “Brain” who we barely know. This odd roommate is eccentric, is secretive, and doesn’t ask for our consent when it goes about most of its business. But it does mean well and performs important work that we literally could not live without. So before we address the problems in our heads, let’s make sure we appreciate the human brain for all the good it does.

The brain processes all the tasting, smelling, hearing, seeing, and touching that we do throughout our lives. It regulates breathing and blood circulation. It stands guard over us, ready to alert us to injuries and other problems via a messaging system called pain. And, of course, it’s the place where all our thoughts and memories live. It is the beginning and end of us all. No brain, no you.

Think of what human brains have accomplished to date. They imagined and then made wood and stone tools that allowed our ancestors to rise above challenging environments and overcome stronger, faster predators. They created music, humor, and countless fantastic stories and ideas, some of which reach beyond even the limits of our universe. About 80 to 100 billion cells called neurons make up this amazing three-pound organ. These cells are connected to each other by some 100 trillion little structures called synapses. Electrical and chemical messages fly around in the brain constantly, making it a nonstop hub of action. Even during sleep, the brain keeps working for us.

The problem is that our brains go about many of their duties in very strange ways that most people are unaware of. But you had better clue in fast, because having at least a basic understanding of what that strange thing inside your head is up to is absolutely necessary to being a good skeptic. People who have no idea how human vision and memory work, for example, are far more likely to see an alien spaceship in the sky or a ghost down the hall and then confidently remember the event in great detail and with confidence. Because of their lack of awareness, it may never occur to them that natural processes of the brain present a far more reasonable explanation for what they thought they saw and what they think they remember. Those who understand that our brains don’t play fair when it comes to assessing arguments and evidence are far less likely to spend years of their lives clinging to lies, lame ideas, and bad beliefs. Without some basic knowledge of how stories seduce our brains, you might run right by a pile of solid scientific evidence in order to snuggle up with one tall tale.

I thought I was well informed about cognitive biases, memory flaws, hallucinations, and so on. But while researching my book 50 Popular Beliefs That People Think Are True, I was repeatedly shocked by new things I learned from reviewing scientific research and talking to experts. The inside of a human skull is a far freakier environment than I had ever imagined. That realization helped to inspire this book. I kept thinking: People need to know about this! Science is revealing more and more every day about how our brains work and how they deceive us both in unusual circumstances as well as in routine, everyday life. It can be a rude awakening to realize that you are walking around in a reality that your brain created for you, a “reality” that can never be trusted completely.

REMEMBER NOT TO TRUST YOUR MEMORY

Did you know that you can’t trust even your most precious memories? They may come to you in great detail and feel 100 percent accurate, but it doesn’t matter. They easily could be partial or total lies that your brain is telling you. Really, the personal past that your brain is supposed to be keeping safe for you is not what you think it is. Your memories are pieces and batches of information that your brain cobbles together and serves up to you, not to present the past as accurately as possible, but to provide you with information that you will likely find to be useful in the present. Functional value, not accuracy, is the priority. Your brain is like some power-crazed CIA desk jockey who feeds you memories on a need-to-know basis only. Daniel Schacter, a Harvard memory researcher, says that when the brain remembers, it does so in way that is similar to how an archaeologist reconstructs a past scene relying on an artifact here, an artifact there.1 The end result might be informative and useful, but don’t expect it to be perfect. This is important because those who don’t know anything about how memory works already have one foot in fantasyland. Most people believe that our memory operates in a way that is similar to a video camera. They think that the sights, sounds, and feelings of our experiences are recorded on something like a hard drive in their heads. Totally wrong. When you remember your past, you don’t get to watch an accurately recorded replay.

Even knowing what I know about human memory, however, I continue to live as though my memories are reliable and accurate. One has to in order to function in daily life. Most of the time it all works out fine, which is why the human brain does it this way. But it can be tough sometimes because I’ve peeked behind the curtain. I’ve seen the Wizard. I know what’s really going on in my head. No longer can I be absolutely sure about all the places I’ve been and the things I’ve done. For example, one special day long ago I found the courage to kiss Kimberly, the most beautiful girl in my third-grade class. Or did I?

Did I really start that glorious day as I remember, by giving her the note I had spent an hour crafting the night before, the one that asked her to be my girlfriend? I can see it in my head right now. There was just one line: “Do you love me?” There were three boxes below it for her to check yes, no, or maybe. After the final bell that day, did I really man up, as I recall, and lean in with my little eight year-old body to execute the most romantic kiss on the cheek in the history of all elementary schools? I can see the replay in mind, clear and in great detail. I’m confident that I remember it correctly. But did it really happen that way? Because of the way our brains work, I can’t be sure, no matter how confidently my memories assure me that it did. Who knows? Maybe it did happen, but it was in fourth grade rather than third. Maybe it was Kimberly I dreamed of kissing but it was another girl whom I kissed. Or worse, maybe I missed Kimberly’s cheek and kissed a goat by accident while on a school field trip to a farm. Maybe my classmates ridiculed me for it on the long bus ride back to school. I don’t remember anything like that happening. But perhaps that’s because my brain edited and embellished a bitter memory to help me cope—all without consulting me first, of course. It’s possible because, like it or not, that’s how human brains work when it comes to memory. Was Kimberly a goat? I hope not, but short of photographic evidence of the big kiss, or documentation from an official animal-endangerment investigation, I’ll never know for sure. Don’t laugh at me—for all you know, there may be a goat or two in your past since all human brains operate on a foundation of creative deception when it comes to memory.

To try to make it easier for people to understand how memory really works, I describe it like this: Imagine a very tiny old man sitting by a very tiny campfire somewhere inside your head. He’s wearing a worn and raggedy hat and has a long, scruffy, gray beard. He looks a lot like one of those old California gold prospectors from the 1800s. He can be grumpy and uncooperative at times, but he’s the keeper of your memories and you are stuck with him. When you want or need to remember something from your past, you have to go through the old codger. Let’s say you want to recall that time when you scored the winning goal in a middle-school soccer match. You have to tap the old coot on the shoulder and ask him to tell you about it. He usually responds with something. But he doesn’t read from a faithfully recorded transcript, doesn’t review a comprehensive photo archive to create an accurate timeline, and doesn’t double-check his facts before speaking. He definitely doesn’t play a video recording of the game for you. Typically, he just launches into a tale about your glorious goal that won the big game. He throws up some images for you, so it’s kind of like a lecture or slideshow. Nice and useful, perhaps, but definitely not reliable.

Your memories are stories about your past. Without informing you, the old man might take it upon himself to leave out some parts of the story just because he feels they are unimportant. He also might get confused and accidentally toss in a few scenes from that horror film you watched last year. He’s good at that. He can blend the past you are recalling with another past or an entirely made-up event in seamless ways that you probably won’t catch. Also, as with most stories that are told and retold, the key elements, names, and imagery all change over time. With each telling, the facts and people can easily get shuffled or lost entirely. That’s the reality; your memories depend on the whims of an inconsistent and somewhat flakey storyteller. Don’t get me wrong, I’m not condemning the old man. He does all this to try to be helpful to you. And it usually works just fine. It’s the best way most of the time because we don’t want or need to remember everything we see, hear, and experience in life. It’s too much information, and a brain can only store and utilize so much. The key point to keep in mind is that when it comes to remembering very important or unusual things—such as a murder, an alien abduction, or a ghost sighting—the old man might not get it right, so we can’t trust memory alone.

I’LL NEVER FORGET THAT DAY! (YES, YOU WILL)

Contrary to popular belief, even our memories of dramatic and “unforgettable” events are not reliable. This is hard for many of us to believe because we tend to assume that a big, spectacular moment in our lives will be “burned” into our minds forever. Sorry, but that’s just not true. Researchers have shown this repeatedly by doing things like asking people to write down where they were and who they were with when something big went down, such as the 9/11 attacks. They did this shortly after the event. Then, when asked the same questions again years later, many would confidently remember being with people and in places during the event that contradicted their earlier and presumably more accurate memories of the day.2

Perhaps the biggest memory problem that good skeptics need to be aware of is that recollections of real events can be altered or contaminated with false memories and imagination. False memories can even be implanted by other people. This can be done fairly easily, much to the horror of people who care about truth and reality. Memory researchers have shown that doing nothing more than mentioning a name or showing an image of something before asking someone to recall an event can significantly change how he remembers that event. For example, if I was going to test your recall of your first day of high school, I might casually chat with you beforehand and slip in a few comments about cold weather and snow. Then, during questioning about your first day in high school, I would ask: “Was it hot or cold that day?” Chances are, you would answer “cold,” even if it had been hot. Yes, it can be just that easy to change a person’s memory.

Even more strange, it is possible to implant a completely fabricated memory into someone’s brain, not just finesse an existing memory but create an entire event. Again, this is not as difficult to do as you might think. By simply suggesting to someone that she was at a particular family picnic or party years ago, her brain might instantly conjure up a convincing memory of all the fun she had that day—even though she never made it to that particular event. People can end up with partially or totally manufactured memories inspired by films, novels, or stories they hear, too. The cold hard truth is that our memories are highly vulnerable to being altered by suggestions or just plain made up by the brain. You can’t trust them completely. By the way, it’s important to add that this has nothing to do with intelligence or mental-health problems. It’s just how normal, healthy brains work. So, this is your memory and don’t forget it. Now you know that there are very good reasons to be skeptical when people say they remember extraordinarily weird things. They may be remembering accurately, but how can you know for sure? You have to ask for additional evidence. Unfortunately, most people in the world haven’t heard about what scientific research has revealed about human memory, so they are too quick to trust the memories of other people as well as their own memories. Fortunately, you know better now. It doesn’t make sense for us to believe unconditionally when someone claims to have witnessed a paranormal or supernatural event yesterday, last week, or last year. Even if someone happens to be the smartest, most trustworthy person in town, we would still need good evidence to confirm that her memory is an accurate account of what happened.

THE DECEPTIVE BRAIN

Remembering the past accurately is not our only problem. Far from it. We aren’t very good at thinking straight about the present, either. We all have many natural biases that have stealthy ways of distorting our thinking. What we may imagine is a reliable and logical brain is more like a three-ring circus of wacky thinking. For example, did you know that we instinctively notice and remember evidence that supports our beliefs while simultaneously ignoring and forgetting evidence that contradicts our beliefs? It gets worse. We can look at a scene before us, convince ourselves that we are paying close attention to it, and then fail to notice important, unusual, or unexpected things present, even though they are right in front of our open eyes. Yes, just because you may be staring at something doesn’t necessarily mean you see it. Our brains also compulsively “connect dots” in order to create meaningful images out of visual input. This can be a useful ability in some situations, but in others it becomes a mental trap that causes us to see and believe in things that aren’t there. These are only a few of the many problems we face when trying to figure out what’s going on around us. You can go through life never knowing or caring about them, but why would you want to? Don’t you want to give yourself the best chance possible to avoid mistakes in how you think and how you perceive the world around you?

After years of researching skeptic topics and the natural workings of the human brain, I have a lot of empathy for people who believe weird things that almost certainly are not true. It’s so common to the human condition to be snared by irrational beliefs that I feel very fortunate not to be running around somewhere right now searching for fairies, preparing for the mothership to land, or giving away half of my income to some psychic or faith healer. The good news for you is that just being aware of how your brain goes about its business greatly improves your chances of keeping both feet planted in reality. When you realize that your brain is playing its own game by its own rules, then you know better than to trust it unconditionally and you are better prepared to take on the world.

FORGET EYES—IT’S THE BRAIN THAT SEES

Let’s take a look at vision. Have you heard the old saying, “seeing is believing”? Well, it’s often a case of believing is seeing. It is well known by researchers that what we think we see can be strongly influenced by images and ideas we have been exposed to previously as well as our own thoughts and imagination. This probably explains why it’s the people who already believe in ghosts or UFOs who keep seeing ghosts or UFOs, and why so few nonbelievers do. Seeing things that are not there can happen to anyone because the human brain constructs and interprets the visual reality that is around it. What we see is something the brain has produced for us based on input it received via the eyes. It’s never a 100 percent true and complete reflection of what our eyes are pointed at. For this reason, we can’t always be sure about what we think we see. Yes, that might be an angel that you see up ahead. Or your brain could be showing you an angel that it has mistakenly constructed out of a bush or some other object.

Construct and interpret reality? It sounds crazy when you think about it. We don’t really “see” the things we look at? How can this be? Most people probably assume that the brain simply shows us or somehow faithfully relays whatever images come in through the eyes. But that’s just not how it works. What actually happens is that light patterns enter the eyes and electrical impulses are sent along optic nerves to the brain. Then the brain translates these impulses into visual information that you “see” in your head. Your brain doesn’t reflect or replay the scenery around you like a mirror or a camera and monitor would. It provides you with its own highly edited and customized sketch of the scene. Your brain gives you a version of what you look at. It’s as if your brain comes up with something like a Hollywood movie production that is loosely based on what is really going around you. You are not watching a video feed; you are watching a docudrama. The brain takes the liberty of leaving out what it assumes are unimportant details in the scene before your eyes. Just like memory, this is not necessarily bad most of the time. In fact, it’s necessary in order to avoid information overload. You don’t need to see every leaf in every tree and every blade of grass in full detail when you look around a park. That would be way too much data. It would clutter your thoughts and make you less efficient, if not incapacitate you. What you need in order to walk through a park and function well is to have a general picture of your surroundings, so that’s what your brain gives you. If you need more detail, then your eyes and brain zoom in and focus on a single leaf or an individual blade of grass.

It gets weirder. Not only do our brains leave out a tremendous amount of detail, they also routinely fill in gaps in our vision with images that you can’t possibly “see” or that maybe don’t even exist in reality at all. Your eyes might not be able to track a fast-moving object, for example, so your brain will sometimes conjure it up and show it to you anyway, figuring that it might be useful to you to see a projected version of reality. The brain also fills in missing elements that “should be there” in static scenes because, again, it can help us to navigate our way through the environment. Magicians have known about this for many years. Even if they don’t understand or care about the science behind it, they take full advantage of the way our vision works when they do their sleight-of-hand coin tricks, for example. Again, our brains don’t do any of this for a gag or to make fools of us. They do it because it is the most effective and efficient way to function in life most of the time.

In addition to filling in missing images, our brains also find patterns or connect the dots when we look around. They do this automatically and do it very well. It helps us to see things that otherwise might be difficult or impossible to recognize. It’s probably one of the main reasons you and I are alive right now. Like many other animals, our prehistoric ancestors relied on this ability to eat and to avoid being eaten. When they needed to spot well-camouflaged birds and rabbits hiding in the bushes in order to avoid starvation, this ability to see things through clutter was crucial. It was no less important, of course, for them to identify the vague outline of a predator hiding in ambush in order to avoid becoming dinner in the short term and avoid extinction in the long term.

Although city dwellers rarely, if ever, find themselves in need of locating a predator lurking in the distance, this type of seeing still seems to be deeply ingrained. For example, a friend of mine who does long-distance open-water swims in the Caribbean told me that she does not suffer from shark paranoia, but, regardless of how she feels about it, her brain doesn’t take sharks lightly. When her head is under water during long swims, she says her brain’s visual system seems to be scanning constantly for the outline of sharks in the distance. And it often “sees” shark outlines if something even comes close to the shark template, she explained, although 95 percent of the time it’s nothing, not even a fish.

Michael Shermer, founding publisher of the excellent magazine Skeptic, has studied and written about this skill/habit/obsession of our brain for many years. He calls it patternicity. Defined as “the tendency to find patterns in meaningless noise,” Shermer says our brains do this so often and so well that they ought to be thought of as “pattern-recognition machines.”3 It’s all good, of course, right up until patternicity starts pushing us beyond reality and causing us to see too many things that do not exist. That’s when we get ourselves into trouble.

If I were walking in a forest at sunset and there was by chance a shadow that was vaguely shaped like a bear, my brain might instantly serve up a more complete and convincing image of a dangerous bear lurking in the dark. He’s not there, but I just saw him. I swear, I could even see his sharp teeth and menacing eyes! Now, if a bear really was there, my brain might have saved my life by alerting me. If no bear had been there, however, I was startled briefly and it’s no big deal. But what if I was certain I had seen Bigfoot, a demon, an alien, or a god? That might complicate my life unnecessarily. Shermer explains:

Unfortunately, we did not evolve a Baloney Detection Network in the brain to distinguish between true and false patterns. We have no error-detection governor to modulate the pattern-recognition engine. Thus, the need for science with its self-correcting mechanisms of replication and peer review. But such erroneous cognition is not likely to remove us from the gene pool and would therefore not have been selected against by evolution.4

On one hand, it makes sense for us to see some patterns of things that aren’t really there in order to be very good at seeing real ones that matter. On the other hand, we need to be aware of this phenomenon because it can lead to a confident belief in things that are not real or true. Additionally, patternicity is not limited to vision. It impacts hearing and thinking, too. Good skeptics understand how the brain often creates false patterns, so we know to be very cautious when considering claims of UFO sightings, for example, or anything else that is unusual. It only makes sense to be skeptical and ask for additional evidence when people claim to have seen or heard extraordinary things. Maybe they did, maybe they didn’t. Given what we now know about the brain, however, are you going to believe someone who tells you she saw a flying saucer or Bigfoot last week? She doesn’t have to be lying to be wrong. Anyone with perfect vision can see poorly. Anyone with a bright brain can think and come to the wrong conclusions. Anyone with an excellent memory can have wildly inaccurate memories.

THE APE THAT WASN’T THERE

As if all this weren’t enough, we also have to be on guard against something called inattentional blindness. This fancy phrase is what scientists call it when people look right at something and think they are paying close attention, but really aren’t seeing as well as they imagine. Inattentional blindness is the reason it’s not safe to drive while talking on a phone. You can be staring wide-eyed at the road ahead of you, but as your brain devotes itself to the phone conversation, you fail to notice the truck that brakes in front of you or the motorcycle rider who pulls out in front of you.

Scientists Christopher Chabris and Daniel Simons constructed a funny and effective experiment that shows just how easily inattentional blindness cripples our awareness. If you would like to take the test yourself, visit their website and view the brief video before reading the rest of this paragraph (www.theinvisiblegorilla.com/videos.html). What Simons and Chabris have revealed about us would be difficult to believe if they hadn’t repeated the experiment so many times with similar results. Their video shows two teams of people dribbling and passing basketballs. One team is dressed in white shirts, the other in black. Test subjects viewing the video are instructed to count the number of times players in white shirts pass the ball as they move around on the court. That’s it, nothing more. But while test subjects are concentrating and trying their best to keep an accurate count of the passes, a woman in a full-body gorilla suit walks into the middle of the scene, beats her chest, and then casually walks off. To be clear, it’s not some brief, subliminal flash of an image. The gorilla is on screen for a total of about nine seconds. After researchers ask for pass counts, they ask test subjects if they happened to have noticed anything unusual or out of place during the video. Surprisingly, about half of the people who take this test don’t see the gorilla. They fail to notice a hairy gorilla strolling around right in front of their eyes for nine seconds! They are so focused on the ball that their brains fail to recognize and remember the gorilla, even though the ball they are intently tracking with their eyes passes directly in front of the gorilla.

This is inattentional blindness, and it’s a normal, useful feature of our brains. We can’t pay attention to everything all the time, so our brains zoom in on some things while sacrificing broader awareness. The implications ought to be obvious to aspiring skeptics. Not understanding inattentional blindness can lead us to be overconfident in our ability to take in everything around us and not let important things slip by. The truth is, however, we do miss important and unusual details—such as gorillas!

We can’t always be sure that we see everything we need to see in order to make sense of a scene or a situation before us. If someone observes what she thinks is a ghost, for example, the “ghost sighting” might hinge on key details in the scene being left out by her hyper-focused brain. For example, maybe the brain was so locked in on what she thought was a ghost that she failed to notice the lawn lights a few feet away that were shining on the bushes at an angle that formed a light image similar to what popular culture had taught her a ghost is supposed to look like. Inattentional blindness is yet another reason to be skeptical of eyewitness accounts and to always ask for better evidence.

CONFIRMATION BIAS

Anyone who hopes to be a good skeptic has to understand “confirmation bias” and consciously resist it. You will never defeat it totally, but knowing it’s there can prevent you from becoming a slave to it and turning your head into a haven for false beliefs. Confirmation bias is the problem we all have—even good skeptics—when it comes to thinking about our beliefs. Without being aware of it, we tend to protect our beliefs. Confirmation bias draws us toward evidence and arguments that support our beliefs while simultaneously turning us off to evidence and arguments that go against our beliefs. It might seem obvious that people gravitate toward the things they already agree with and like the arguments they already agree with, but it’s not obvious when it’s happening to you. This bias makes believing in weird, unproven claims much easier than it would be otherwise. It can make recognizing that a belief is wrong and abandoning it extremely difficult. Someone who believes in psychics, for example, has a brain that will naturally perk up and go into overdrive when someone comes on TV to talk about “the confirmed science of psychic readings.” The stories and “facts” presented by the person on TV might be marked “high priority” by the brain and stored for future retrieval. But if a skeptic like me comes on TV and begins explaining how psychic readings really only seem to work and why it doesn’t make sense to believe in them, the believer’s brain is likely to instinctively go into siege mode. The drawbridge is raised, crocodiles are released into the moat, and defenders man the walls. Little or nothing the skeptic on TV says gets in. Anything that does somehow manage to penetrate is likely to be promptly forgotten forever. The worst part of all this is that the believer usually doesn’t recognize how biased and close-minded he is being. He likely feels that he is completely rational and fair. It doesn’t happen just with fans of psychics. We are all vulnerable to this distorted way of thinking.

A good skeptic seeks to keep an open mind and knows that it’s always wise to second-guess her conclusions and beliefs, no matter how sensible they seem or how beloved they may be. We have to do this both because we aren’t perfect in our thinking and because things change. If you think you will never make a single mistake in your life, then, by all means, never reconsider your conclusions. But if you are like the rest of us, then you want to constantly check yourself. Remember, nothing is static. New information and new discoveries often mean some things were in error and need revision or rejection. Nothing should be thought of as written in stone. Sure, some conclusions are very likely to be true for all time—but which ones? We can’t possibly know for sure in every case. The best we can do is accept conclusions that are backed up by the best evidence we have today and agree to change our minds if better evidence ever comes along that says something different tomorrow. You never want to be too loyal to a claim, a belief, or an conclusion about something. I think the claims of astrology are untrue, but I’m not chained to that position until my final breath. If the scientific process ever shows that Libras are the best lovers and Capricorns make better gardeners because of star and planet locations, then I’ll adjust my view of astrology immediately. Changing your mind is okay. It shows wisdom and maturity. Never wavering from a belief no matter what is a mistake. What matters is trying to be as closely aligned with truth and reality as you can be at all times. And that requires many navigational adjustments over a lifetime.

THE TALE OF LITTLE GRETCHEN GREENGUMS

The following short story is presented to help you remember some of the weird ways our brains can cause us to believe in things that aren’t real. It’s about a good girl who was not a good skeptic and suffered a most grisly fate as a result: brain rot and a derailed life. Please remember this tragic tale whenever you find yourself on the brink of accepting an extraordinary claim that lacks overwhelming evidence. Maybe it’s true, but do make the effort to think before you believe. Recall what happened to little Gretchen Greengums whenever you are tempted to believe in something unusual for no good reason.

NO DOUBT about it, young Gretchen Greengums was a winner. Hands down, she was the smartest and most popular kid in the tiny town of Rottbridge, population 7,495. Greengums was special, and everybody knew it. Cute as a button, too. Nobody cared that she had a wicked overbite and a frightening set of eyebrow ridges that might have looked a tad thick on a Neanderthal boxer. There was just something special about the girl, and the whole town loved her for it. Gretchen was so beloved and respected that no one bothered to oppose her when she ran for president of the fifth grade class. She was the rare overachiever no one resented. Many adults predicted that she was sharp enough and motivated enough to make it all the way to the top. More than a few openly talked about her having the potential to one day run the town’s most prestigious and successful business, a factory that recycles used kitty litter to make dentures and decorative tobacco pipes. But Gretchen had even bigger plans than that.

Her goal was to head off to college after high school and earn a degree in astronomy. She wasn’t shy about telling anyone that she was going to either prove or disprove string theory and crack the mysteries of both dark matter and dark energy once and for all. Nobody in town had the slightest clue what she was talking about, but they knew enough to respect her ambition and not to doubt her.

GRETCHEN WAS NO SPAZ. In addition to her lofty academic goals, she also dreamed of being the best baton twirler in the world. She already had won the annual Pro-Am Rottbridge Baton-Twirling Championship three years straight. Everyone just knew she would go pro one day. All she needed was a little more seasoning, a bit more height on her back throws, and she would be ready for the big leagues. Yep, she was the real deal, the total package, the golden child of Rottbridge. Gretchen Greengums was going places. But, out of the blue, everything changed one strange autumn day.

During a twirling practice session all by herself out on the YWCA field, Gretchen tossed her baton high in the air like she had done a million times before. But this time, while looking up, something odd caught her attention. Up in the sky, something was hovering in the air. It was strange. Definitely no plane, she thought. As the baton fell to earth beside her, she just kept staring up. “Cripes! What in heckfire is that thing?”

Alternating jolts of fear, curiosity, and excitement surged through her little body as she began to figure out what it was. “Wait, I know! It’s a UFO! Just like the one I saw in that show on the Pseudohistory Channel last week! Holy moley! It’s even shaped kinda like one of the spaceships they showed! It must be aliens! What else it could be?”

Gretchen analyzed the object carefully. Her mind raced. She placed her hands on top of her head and said out loud that this was the most important day of her life. No longer hovering, the object began moving away toward the distant horizon. “It’s gigantic,” she said aloud to herself, “Maybe 1,000 feet wide! No way is this a balloon or a blimp. It’s gotta be a spaceship. Gotta be!” She began to imagine what the occupants might look like. Questions flooded her mind: What is their planet like? How smart are they? Are they friendly? Will they share their knowledge with us? What if they’re mean? What if they wanna eat us or something like that?

GRETCHEN WAS NO IDIOT. She remembered something her third-grade teacher once said to the class about being skeptical of UFO sightings. She blinked hard and slow twice, took a deep breath, and tried to look at the scene before her with fresh eyes. She clenched her teeth in total concentration and stared at the UFO with all the mental focus and intensity she could muster.

But it was still there. “No!” she said, “This really is real. I’m not imagining it and there is no way that big thing is a plane or a helicopter or anything else like that! I can’t figure out what it is. It has to be an alien spaceship!”

Gretchen continued to watch the object for another few minutes. But as the Sun set behind her, the UFO vanished. Stunned by what she had just experienced, she took a deep breath. “Whoa! I just saw a UFO, a spaceship from outer space!” Her hands trembled, but she wasn’t scared anymore. Now she was excited. This is fantastic, she thought. Now I know for sure. Aliens are real! We are not alone!

Gretchen took off for home, running as fast as she could.

When she arrived at home, Gretchen told her family about the UFO. The next day, she told everybody at school about it. Because of Gretchen’s reputation for being smart and honest, everyone was inclined to believe her. “Wow,” said her teacher, Mrs. Flurston. “I guess this means alien are real. How exciting! Hey, students, what do you say we do a special lesson on UFOs this week?”

“Yay!” yelled the students. Mrs. Flurston then told the class that she would bring in a few “excellent and educational” Pseudohistory Channel DVDs she had at home. She said one shows how Hitler had used alien spaceships to nearly win World War II. The kids cheered again, even louder this time. “Another one of the DVDs explains how aliens visited us thousands of years ago and left a few pets behind by mistake,” said Mrs. Flurston. “Those pets, it turns out, were our distant ancestors!” This time the students all stood up and clapped wildly.

Little Kevin Handfurt, the cute class clown with a weak bladder, raised his hand enthusiastically and blurted out that he could bring in his daddy’s “science books” about the UFO crash at Roswell. “It’s even got real pictures of the alien bodies!” he said. Mrs. Flurston nodded approvingly. The boys in the front row high-fived each other. Some of the kids punched the sky in celebration. Even Todd McSfinster, the grumpiest kid in class, got in the spirit. “Finally!” he said, “We get to learn some real science. It’s about time!”

One classroom couldn’t contain this much energy for long. By the end of the week, the whole school was buzzing about Gretchen’s UFO, and soon after that, the whole town was. When Gretchen got home from school one day, she was greeted in the living room by a reporter from the local newspaper who had been waiting to interview her. The very next day, an article about her was on the front page of the town paper. It included a sketch of the spaceship, based on Gretchen’s description. The illustration included several details that Gretchen didn’t actually say that she saw, but the artist thought it would make it more interesting for people so he added them. She never saw any strange markings on the side, missile things attached to it, or an alien waving from a window like the newspaper sketch showed, but the general shape of the object was about right, so Gretchen didn’t say anything.

The last sentence of the article read as follows: “The town of Rottbridge can only applaud Gretchen Greengums’s extraordinary courage for sharing this story of her close encounter. While there are many questions still left to be answered, we now know, thanks to this one special little girl, that we are not alone in the universe.”

Even better than the article, Rottbridge’s mayor, the Honorable Earl Wayne Chipply, publicly and officially praised Gretchen at a special town-hall ceremony. He even presented her with a fancy plaque suitable for hanging. During the event, the mayor called her a hero. He also said that he too was a believer and encouraged everyone to keep watching the skies because “they are definitely up there.”

TIME FLIES FOR HEROES. Fifteen years after seeing the UFO, Gretchen was still smart and still cute. But she was not quite as popular as she used to be. Things were never the same for her after that day. She became convinced that the spaceship would come back, so she spent more and more of her time looking up and waiting. Over the years, the townspeople, then her friends, and finally her own family grew bored with the story. They still liked her well enough, and most people thought Gretchen meant well, but after years of UFO hunting with nothing to show for it and all the constant talking about aliens, the whole thing grew stale and a bit embarrassing. There was just something about a young woman in the prime of her life, with so much potential, constantly staring up at the sky and doing nothing else that some people didn’t feel comfortable with. But she didn’t care. Day after day, night after night, Gretchen stood with her head facing up, scanning the sky, looking for that UFO.

“Look down, once in while!” her father screamed at her one day. “For Pete’s sake, you’re wasting your life staring at clouds all day!” But Gretchen kept looking up and hoping the aliens would return. Sadly, all that looking up made her lose sight of her dreams down here on Earth.

Gretchen never did go to college. Never took over as boss at the kitty-litter recycling factory. As soon as she graduated from high school, she devoted herself full-time to “alienology.” She devoured every book, magazine, and website she could find that promoted belief in UFOs and aliens. She read about alien abductions, the famous crash at Roswell, secret activities at Area 51, and people who were in communication with aliens. She attended lectures by people who said they had been aboard UFOs and taken trips in space. She partied with Raelians one wild weekend in Vegas. She played her Close Encounters of the Third Kind DVD so many times that one day her DVD player just up and died.

Gretchen’s greatest moment of glory probably came when she appeared for twenty-seven seconds in a primetime Pseudohistory Channel documentary titled Nostradamus: Human Savant or Alien Astrologer? She told them her UFO story on camera, but it didn’t make the final cut. They only used her comments about aliens probably having the ability to predict the future and her statement that therefore there’s a good chance that Nostradamus was one of them or at least consulted with them.

Gretchen had no interest in reading books that were skeptical of UFO claims and refused to listen to the perspectives of professional astronomers, Search for Extraterrestrial Intelligence (SETI) researchers, astrobiologists, and National Aeronautics and Space Administration (NASA) officials on this subject. She felt she knew better than all of them. After all, she had seen a spaceship with her own eyes—not them. To her, it made no sense to waste time considering possible alternate explanations, so she devoted herself to researching stories and mining data only from those who believed. Her older brother was skeptical and often tried to argue with her about UFOs, but she wouldn’t have it. “He didn’t see, so he doesn’t know,” she said to herself. “Besides, it’s not like he can disprove my story.”

That big UFO day was a long, long time ago. Gretchen’s gone gray now. She is winding down a life that certainly no one would have predicted for her half a century ago. She never did leave Rottbridge. Never did take a stab at string theory. Despite all that potential, she never competed in another baton-twirling event after fifth grade. To this day, she still walks around town with her face angled upward. When she talks to people on the street, she rarely makes eye contact. Too busy looking up. It wasn’t only her social life and career that suffered. Gretchen paid a physical price as well. Today her legs are gnarly sticks of scarred flesh. All that staring up at the sky doesn’t make for safe walking down on the ground. Over the years, she’s slammed into so many fire hydrants and park benches and collided with so many skateboarders that it’s a wonder she’s still alive. If you didn’t know better, after one look at those mangled and dented shins, you might assume she’s a retired Muay Thai fighter who had spent a long career battling in Bangkok. Yeah, that day Gretchen saw her UFO changed everything about her.

Gretchen spends most of her time these days alone in a small apartment, writing and posting her UFO newsletter on the web. She’ll play that DVD of her twenty-seven-second Pseudohistory Channel sound bite for anyone willing to watch. A couple of times a year, she gives a lecture on “UFO Science” at the Rottbridge public library. Pretty much the same small audience shows up every time. There are the diehard believers, the homeless people, and a few who get lost looking for the romance-novel section. But Gretchen never fails to deliver. When it’s show time, she glows with enthusiasm. “I know intelligent extraterrestrials are visiting us,” she says. “I saw them with my own eyes. They are here.”

HER UNBLINKING STARE IS CREEPY TO SOME. But others seem inspired to believe. “I can remember that day so clearly, all those years ago,” she says. “The spaceship hovered right above my head. It was silver with flashing lights. It had strange markings on the hull. There were missiles or some kind of auxiliary rockets on the sides, too. I could even see a window, and I could see an alien with a large head inside. He was very pale, either gray or white. I’ll never forget his eyes, large, black eyes. And then he waved at me. Yes, it was a moment I’ll never forget.”

Gretchen checked out at the age of eighty-seven. Right up to her death, she clung to her belief that she saw a spaceship long ago. It never occurred to her that she could have reacted to that event differently. She never imagined that her UFO was nothing more than a flock of birds, the setting Sun, and her own brain conspiring to fool her. She had never heard of confirmation bias or inattentional bias. She never learned that memories are fallible fabrications of the brain. No one ever advised her that it is better to live with an unanswered question than to pretend to know something you don’t. No one had ever suggested to that bright little girl that it was important for her to think before she believed.

The loss goes two ways. It wasn’t only Gretchen who paid a price for not being skeptical enough. Everyone else lost too. Gretchen’s family lost the joy and reward of watching a daughter strive for big things. The town was robbed of one of its brightest lights. In real life, it works this way, too. Our entire world is diminished when minds, filled with potential, are sacrificed on the many altars of irrational belief. Sadly, it happens every minute of every day. Millions of people who are much like the fictional Gretchen have their wonderful and powerful brains smothered and dimmed as their skulls are packed with the cheap sawdust of unproven and unlikely claims. Given the many very serious problems humankind currently faces and will face, I’m not sure that we can afford to keep losing so much intellectual wealth each generation. It seems to me that we need all the brainpower we can muster, including yours.

YOUR BIZARRE AND BIASED BRAIN

The following is a list of some natural mental biases and common thinking errors that can lead any one of us to accept wrong or dubious claims and beliefs. To become a good skeptic, you don’t need to earn a degree in psychology, but you should have some level of awareness about how your own thinking can trick you. You can never be immune, but the more you know, the safer you will be from self-deception. It can also help you to understand how others may have gone wrong in their thinking when they are trying to convince you of something they believe. Billions of smart, sane, and sincere people fall for nonsense every day because of these weird thought processes.

It may startle some to realize it, but a very small portion of our brain’s activity is what you might describe as conscious, or things we are aware of. Probably more than 90 percent of what is going on in our brains every day is subconscious, meaning we are mostly clueless about it. Think of it like this: Our brain is like a house that has twenty rooms on four floors. But we are allowed to enter only one room in the entire house. The doors to the other nineteen rooms are locked. The house is always busy. A lot of activity is going on in those other nineteen rooms and it all directly impacts us. But we don’t get to peek in.

Basic brain-awareness information should be taught to everyone and taught early. Sadly, however, the vast majority of the world’s people go their entire lives without ever learning about it. This is one of the reasons why so many brains end up in all the wrong places. But not yours, right?

 

Anchoring. This bias leads us to rely so much on one past experience or one piece of information that we ignore or reject new, more, and better information that contradicts it. Don’t drop anchor in the muck of a past error when you could set sail for more sensible lands.

Argument from authority. We are social creatures who devote a lot of our time to thinking about social ranking. A by-product of this obsession is a tendency to blindly trust the claims and ideas of people who rank above us. Whether or not we realize it, perceptions of authority and superiority impress us and influence us whether they are valid or not. A good skeptic knows to assess the merits of a claim independent of who presents it. Just remember that truth can come from below us and lies can come from above us. Pay less attention to the messenger and more attention to the message.

Argument from ignorance. When you don’t know, you don’t know! Too often, many people think that the absence of a normal, sensible answer must therefore mean that the answer is something special, magical, or supernatural. No, unknown means unknown. When weak skeptics say, “You can’t explain exactly how it happened, so it must me a miracle,” a fair reply is: “You can’t explain exactly how the miracle happened, so it must be a natural event.”

Availability cascade. When you say something repeatedly, you are likely to believe it with increasing confidence, even if it’s not true. It turns out that we actually listen to ourselves when we speak—and trust what we hear. So be careful about what you go around saying. Make sure it’s valid, because your brain is always listening.

Availability heuristic. This is a big one. We tend to be influenced far more by one or two “real-life” examples in our head than we are by more abstract facts and statistics. So if you were to show a person a few studies done by credible researchers that showed ear candling failed to deliver health benefits, a weak skeptic might not be impressed because she’s too busy thinking about a family member who swears ear candling cleared his sinuses and fixed his vertigo problem.

Backfire effect. I observe this one in action all the time, and it drives me nuts. It turns out that there is a natural bias that can make us believe something with greater confidence when we are confronted with evidence or strong arguments that oppose it. Because of this bias toward digging in your heels, more and stronger evidence often results in strengthened irrational belief. Be aware of it and resist it or you may end up defending nonsense.

Base-rate fallacy. This one derails us with ease. We can readily find ourselves focusing on one tiny speck of information (a single story, for example) or on bad data that supports a claim while simultaneously ignoring more credible information or a larger body of data that goes against it.

Bias blind spot. This bias can trip anyone, of course, but I always stress to skeptics that they pay particular attention to it. We can more easily see biases and illogical reasoning in others than we can in ourselves. It seems natural to think you are less likely to be fooled than everyone else around you is. That is the kind of arrogance that will lead you straight into the spider’s web.

Confabulation. This is the scary weakness we all have for remembering things incorrectly yet feeling like the memory is totally accurate. As I’ve described earlier, it’s very easy for the brain to jumble the timeline of events or combine different events to create one believable memory. Good skeptics have to keep this one in mind because very intelligent, confident, respectable, and sincere people can be completely wrong when they describe something that they experienced in the past.

Confirmation bias. As explained previously, this wicked mental filtering process will have you noticing, emphasizing, and remembering information and experiences that support your beliefs while ignoring and tossing out data that contradict your beliefs. Make the effort to pay attention to this tendency and always consider evidence and arguments that go against the grain of your brain. A good skeptic keeps an open mind.

Conformity, also known as the bandwagon effect. You probably think you are an individual who thinks independently and doesn’t care too much about what everybody else thinks or does. The truth is, however, we all feel the lure and often succumb to social pressures when it comes to how we eat, dress, talk, buy things, entertain ourselves, and think. A good skeptic remembers this when doing an inventory of his or her beliefs and conclusions. Did I really think this through, or am I just following the herd? Nothing to be ashamed of here. We all want and need the herd to some degree. Just don’t allow yourself to be blinded by this powerful and constant pull on your brain.

Emotional bias. This one is so simple but can cause many problems. Our emotions can easily dominate our attention to the point where we don’t see or consider relevant information right in front of our faces. Emotions are great, the spice of life, but don’t let them rule your decision-making process. Don’t just feel, think!

False-consensus effect. This is the tendency we have to overestimate how many people agree with us about the things we believe. This can cause people to have more confidence in their beliefs. If everyone believes in ghosts, then they must be real.

False memory. This is a common problem in which imagination is mistaken for the memory of something that actually happened. This one has obvious implications for everything from angel sightings and near-death experiences to alien abductions.

Forer effect, also known as the Barnum effect. This bias helps explain the popularity of things like psychic readings and astrology. When given a general personality description, for example, many people naturally think it describes them in a unique and special way, even though it is vague and could apply to many people or even to all people.

Framing effect. This bias scares me as an author. We can be swayed to judge information and ideas based on who delivers them to us and how they are presented. So, if you don’t like me, you may not be inclined to accept my message that skepticism is good for you. I hope you like me. But even if you do like me, don’t let that be the reason you embrace skeptical thinking. Do it because you thought it think it through and it makes sense.

Hallucinations. It is well established that human beings are capable of seeing things that aren’t there. What is really weird is that hallucinations can occur in the same parts of the brain that see and hear real things, so hallucinations can feel totally authentic. The obvious question is, why do so many people who go on and on about paranormal/supernatural sightings fail to consider hallucinations first? If someone says, “It was too real to be a hallucination,” she or he has done nothing more than reveal that she or he doesn’t understand hallucinations.

Hindsight bias. Never underestimate how effective our brains can be at keeping us feeling good about ourselves. This bias is the routine lie we tell ourselves and then believe when we learn that we were dead wrong about something. “I knew it all along,” is an ego-soothing, natural reaction. But you probably already knew that, right?

Illusion-of-truth effect. When we hear a claim that is familiar to us, we are more likely to believe it than we would if we had never heard it before. This means simply being exposed to statements about “X” makes you prone to trust and believe in “X” further down the line when told about it. It can work with ESP and conspiracy theories the same way it works with car commercials and laundry-detergent ads.

Illusory correlation. This is very common. Remember how we love to connect those dots? Well, our brains are so eager to do this that many of us often connect two or more unrelated events and then wrongly conclude that one caused the others or that they are somehow linked in a meaningful way when they are not.

Inattentional blindness. We are capable of staring at something, thinking that we are paying very close attention to the scene, but still missing important or unusual things that are there right in front of our eyes. Remember the gorilla that pounded its chest in the middle of a basketball game.

In-group bias. Everybody knows about this one, but how many make an effort to recognize and resist it when confronted with an extraordinary claim? We tend to respect, admire, and listen to people who are in our groups (nations, religions, schools, clubs, etc.). This can lead us to trust them about a belief or claim over someone who is outside the group, even if the outsider makes more sense.

Irrational escalation. This one can be uncomfortable to deal with, but fight it if the situation demands. This bias can leave us feeling too invested in a decision or a belief to let go and reverse course, even when logic and evidence make it clear that we should. Please don’t spend years or an entire lifetime saddled with a bad belief. If you figure out that it’s wrong, cut your losses and move on.

Observational-selection bias. I notice this one going on in my own head all the time. Whenever I buy a new laptop, MP3 player, or some other gadget, I suddenly see that specific model everywhere. Of course, it’s because I have a heightened awareness of it because I just purchased one. This selective perception can fool us into thinking special or weird things are happening when they aren’t. Oh my gosh, so many people at school today are wearing a crucifix necklace just like mine. It must be a sign.

Pareidolia. This one helps to explain many claims people make about seeing strange things. When we see or hear something that is nothing meaningful, our brains might decide to go ahead and give it meaning anyway. Our brains can create a recognizable picture in a cloud or on a slice of toast. We can also hear words in meaningless noise where none exist.

Priming. Never underestimate how easy it is to manipulate a human being. For example, just by hearing or reading a word, you are likely to think of it and to be influenced by it later in unrelated thoughts and activities—even if you forget all about originally hearing or reading that word.

Status-quo bias. We are creatures of habit. I don’t know about you, but I haven’t changed my hairstyle since first grade. A general reluctance to change can derail us when we try to sort out truth from fiction. If we have a few bad beliefs in our heads, we may hold onto them for no other reason than we like familiarity and don’t like change.

Got all those memorized? I hope you remember them, because there will be a test—it’s called the rest of your life. No, you don’t need to memorize them. But it helps to familiarize yourself with them, and you should at least be vaguely aware of what your subconscious brain is up to every day. Accept that we need these strange biases and weird mental processes. If not for the kooky minefield of tricks, shortcuts, and deceptions inside our heads, we would not function as well as we do in our daily lives. It’s an interesting twist: If our brains were not so nutty, we’d all go nuts. In most cases, the mysterious workings of the brain are necessary for efficient thinking and living. So don’t hate your brain for its deceptive ways in setting you up to make mistakes in reasoning and perception. Thank it for doing the best it can to get you through one more day safely. Just be sure to understand that you can never trust it completely when trying to separate truth from fiction.

ARM YOURSELF IN THE WAR AGAINST REALITY

Now that we know something about why it’s important to be skeptical and we looked at some of the ways our brains can trick us into believing unlikely things, let’s turn our attention to some specific challenges in the next chapter. It helps if a good skeptic is familiar with key problems associated with some of the more popular beliefs out there. For example, you would be right to ask, “Where’s the evidence?” if someone tried to convince you that the lost continent of Atlantis was real and was inhabited by an advanced race of superhumans or extraterrestrials. But it would be much better if you had enough background information to be able to ask the Atlantis believer a few good questions that both expose the weakness of the claim and encourage the believer to think more deeply about it. Sure, it’s correct that no one has proved the story of an alien spaceship crashing near Roswell, New Mexico, in 1947. But it’s much better if you can share the real story of what happened there. When someone attempts to get you to buy into the latest magical end-of-the-world prediction, you can deflate his sales pitch faster and more effectively if you know something about the long history of these baseless beliefs. The next chapter is going to be a wild ride around, over, and through tall tales and wild claims, so strap on your helmet and brace yourself. We’re going in.

GOOD THINKING!

Don’t forget this about your memory: You can’t trust it! Human memory is a fragile and fallible thing. Our memories are constructed in our head, like stories based on bits of information. They are not reliable playbacks of “recordings.”

Your brain constructs and interprets what you look at. You don’t have a camera in your head that faithfully captures reality. What we see is something the brain has produced for us, based loosely on what comes in through our eyes. It’s never 100 percent true and complete. For this reason, we can’t always be sure about what we think we see.

Learn about some of the many cognitive biases that come with every human brain. If you are not careful, these weird thinking processes will trip you up, leading you to make errors in reasoning and embrace bad beliefs.