Perceptual illusions are not only great fun, they also remind us of a basic truth: Our perceptions are more than projections of the world into our brain. As our brains assemble sensory inputs they construct our perceptions, based partly on our assumptions. When our brain uses rules that normally give us accurate impressions of the world it can, in some circumstances, fool us. And understanding how we get fooled can teach us how our perceptual system works.   A case in point is the famed Müller-Lyer illusion, for which the Italian visual artist Gianni Sarcone gives us two wonderful new examples. https://www.giannisarcone.com/3-MEDIA_Images/Muller_lyer_star_OR2.gif  https://www.giannisarcone.com/wp/wp-content/uploads/2017/10/Muller_Lyer_waves_S.gif   Many more informative examples can be found amid the 644 pages of the new Oxford Compendium of Visual Illusions. There I discovered a fascinating phenomenon reported by Gettysburg College psychologist Richard Russell.   First (with Professor Russell’s kind permission from his earlier article in Perception) a question: In the pair of Caucasian faces, below, which looks to be the male, and which the female? Do you (as did I) perceive the left face as male, the right face as female?   Many people do, but in actuality, they are the same androgynous face (created by averaging Caucasian male and female faces), but with one subtle difference: the researchers slightly darkened the skin (but not the lips or the eyes) in the left face and lightened the skin in the right face. Why? Because worldwide and across ethnic groups, Russell and others report, women’s skin around the lips and eyes tends to be lighter than men’s. And that means more contrast between their skin and their lips and eyes.   That natural, subtle facial sex difference enabled Russell to recreate what he calls “the illusion of sex” with a second demonstration. This time, he left the skin constant but lightened the lips and eyes of the left face, making it appear male, and he darkened the lips and eyes of the right face, increasing the contrast, making it appear female. Russell suggests that this helps explain why, in some cultures, women use facial cosmetics. Lipstick and eye shadow amplify the perceived sex difference, he notes, “by exaggerating a sexually dimorphic attribute—facial contrast.”   ... View more

Apophenia is seeing patterns in randomness, which may be the mechanism behind conspiracy theory generation. If it feels to me like a set of random events are connected and no one is talking about the connection, then conspiracy must be afoot (Poulsen, 2012). Psychiatrist Klaus Conrad is credited with coining this term in 1958 to describe the descent into psychosis, “Borrowing from ancient Greek, the artificial term ‘apophany’ describes this process of repetitively and monotonously experiencing abnormal meanings in the entire surrounding experiential field, eg, being observed, spoken about, the object of eavesdropping, followed by strangers” (as cited in Mishara, 2010). But this isn’t a post about conspiracy theories or psychosis. While conspiracy theories and psychosis take our ability to see patterns to whole other level, seeing patterns in randomness is just how our brains work. The visual version of apophenia is pareidolia. Have you ever seen a rabbit in a cloud formation? That’s pareidolia. Have you seen a face in a piece of toast? Also pareidolia. After covering the cerebral cortex, tell students that there is an area in the temporal lobe that is especially good at detecting faces: the fusiform face area (FFA). Show students these 20 objects where faces appear. Ask students to guess whether they think that seeing these objects would cause the FFA to be activated. How could that hypothesis be tested? Give students a minute to think about it, a minute to share with a partner, and then ask for volunteers for their suggestions. This would be a nice time to review independent variables and dependent variables. When you’re ready, tell students that researchers compared such face objects with everyday no-face objects, and found that face-objects activated the FFA (Hadjikhani, Kveraga, Naik, & Ahlfors, 2009). If time allows, describe prosopagnosia (pro-soap-ag-nose-ee-ya; face-blindness). Do students think that the FFA would be activated when people with congenital prosopagnosia look at faces? Why or why not? The FFA is activated, but it doesn’t show habituation. When people without prosopagnosia are shown faces a second time, the FFA shows decreased activation; “Not interesting; I’ve seen this before.” For those with prosopagnosia, the activation is just as great the second time around; “Hey, this is new!” (Avidan, Hasson, Malach, & Behrmann, 2005). Again if time allows, do students think the FFA would be activated in people with autism. Why or why not? For the participants in the study, the severity of their autism varied. For those who had impaired face recognition (about half of their sample, 14 out of 27) , the activation of their FFA was weaker.   For 30 years, researchers have debated whether the FFA is face-specific or whether it is for detecting any complex pattern we’re expert in (Kanwisher & Yovel, 2006). Some recent research has found that the FFA is active when expert chess players look at positions of chess pieces, positions taken from actual gameplay, but not a specific chess piece (Bilalic, 2016). And researchers have also compared expert radiologists with beginner medical students. When the experts looked at X-rays, their FFAs were active (Bilalic, Grottenthaler, Nagele, & Lindig, 2016). While the jury is still out on whether the FFA is face-specific or not, this is a wonderful example of science in action. Researchers describe a finding. All researchers start thinking about what might be the cause of that finding, and they start devising experiments to test their hypothesized causes.   References  Avidan, G., Hasson, U., Malach, R., & Behrmann, M. (2005). Detailed exploration of face-related processing in congenital prosopagnosia: 2. Functional neuroimaging findings. Journal of Cognitive Neuroscience, 17(7), 1130–1149. https://doi.org/10.1162/0898929054475154 Bilalic, M. (2016). Revisiting the role of the fusiform face area in expertise. Journal of Cognitive Neuroscience, 28(9), 1345–1357. https://doi.org/10.1162/jocn  Bilalic, M., Grottenthaler, T., Nagele, T., & Lindig, T. (2016). The faces in radiological images: Fusiform face area supports radiological expertise. Cerebral Cortex, 26(3), 1004–1014. https://doi.org/10.1093/cercor/bhu272 Hadjikhani, N., Kveraga, K., Naik, P., & Ahlfors, S. P. (2009). Early (N170) activation of face-specific cortex by face-like objects. Neuroreport, 20(4), 403–407. https://doi.org/10.1097/WNR.0b013e328325a8e1 Kanwisher, N., & Yovel, G. (2006). The fusiform face area: a cortical region specialized for the perception of faces. Philosophical Transactions of the Royal Society B: Biological Sciences, 361(1476), 2109–2128. https://doi.org/10.1098/rstb.2006.1934 Mishara, A. L. (2010). Klaus Conrad (1905-1961): Delusional mood, psychosis, and beginning schizophrenia. Schizophrenia Bulletin, 36(1), 9–13. https://doi.org/10.1093/schbul/sbp144 Poulsen, B. (2012). Being amused by apophenia. Retrieved from https://www.psychologytoday.com/blog/reality-play/201207/being-amused-apophenia ... View more

I didn’t start covering hearing in my Intro Psych course until the earbud-style headphones became popular. When I heard music emanating from a student’s earbuds from the back of the room, I knew it was time for us to have a conversation. In the cochlea, the stereocilia closest to the oval window are the ones responsible for hearing high-pitched sounds. Exposure to loud sounds causes a tsunami to rush over those stereocilia, causing them to bend over farther than they are supposed to resulting in permanent damage (Oghalai, 1997). The Center for Hearing Loss Help has a nice image of a bundle of pristine stereocilia and a bundle of damaged cilia. In fact, this is an interesting article on diplacusis, where one ear hears a pitch that is just above or just below the pitch heard by the other ear (Center for Hearing Loss Help, 2015). In class, after walking students through the structure and workings of the ear, I go to this webpage (Noise Addicts, n.d.) that has 3-second sound files of pitches ranging from 22 kHz down to 8 kHz. I start with the 22 kHz, which none of my students can hear, and then move to lower pitches one by one. I cannot hear them until I get down to about 14 kHz. Fifty years of being exposed to sound, with the last 16 years spent in a noisy urban environment – and more than one rock concert – has likely taken its toll. I have friends in their 70s who have spent their lives in a quiet town who have no problem hearing 17 kHz. Of course exposure to loud sounds is not the only factor that can affect hearing loss for high-pitched sounds, but it is a common factor. Some time ago, I had a student who knew that he had some hearing loss, but he had no idea of the extent of it. When I played the sounds in class, he was stunned to see students reacting to the high-pitched sounds that he couldn’t hear. The first frequency he heard was a mere 8 kHz. He immediately made an appointment with an audiologist. He was (just barely) young enough that he qualified for a special program that got him hearing aids for free. The first time he was in class after getting them, he told me that he was floored by how much he could hear – and how much he hadn’t been hearing. Another student who spent a couple years working as a bouncer at a (very loud) club was 23 years old, and the first frequency he heard was 12 kHz. In Mary Roach’s book Grunt, she writes that the problem with most hearing protection is that not only does it protect against loud sounds, but it also makes it hard to hear softer sounds. This is especially problematic for combat soldiers. They need to protect their hearing in case of a sudden explosion or gunfire, but they need to be able to hear what their fellow soldiers are saying. There are now ear cuffs that protect against loud noises but also amplify quieter sounds. In this 3-minute YouTube video, Roach describes the hearing problem and how these new ear cuffs work. A student of mine, who is in the army, said he got to try out the ear cuffs – although not in combat, and he was very impressed with how well they worked. Video Link : 2162 Knowing how their ears work can help students make informed decisions about how they would like to treat their ears. With that knowledge, students may make better decisions that will affect them for their rest of their lives. References Center for Hearing Loss Help. (2015). Diplacusis -- the strange world of people with double hearing. Retrieved from http://hearinglosshelp.com/blog/diplacusisthe-strange-world-of-people-with-double-hearing/  Noise Addicts. (n.d.). Hearing test -- can you hear this? Retrieved from http://www.noiseaddicts.com/2009/03/can-you-hear-this-hearing-test/  Oghalai, J. S. (1997). Hearing and hair cells. Retrieved November 4, 2017, from http://www.neurophys.wisc.edu/auditory/johc.html  ... View more

As I draft this on Mother’s Day I think of my mother, who blessed me with nurturing and many other gifts, including, alas, the gift of her hearing loss . . . which she, in turn, had received from her mother. I began my memoir, A Quiet World: Living with Hearing Loss, with this recollection: On one of those treasured visits to my parents' home on Bainbridge Island, Washington, I use a magic pad to communicate with my eighty-year-old mother, who four years previously took the final step from hearing-impaired to deaf as she gave up wearing her by then useless hearing aids. “Do you hear anything?” I write. “No,” she answers, her voice still strong although she cannot hear it. “Last night your Dad came in and found the T.V. blasting. Someone had left the volume way up; I didn't hear a thing.” (Indeed, my father later explained that he recently tested her hearing by sneaking up while she was reading and giving a loud clap just behind her ear. Her eye never wavered from the page.) What is it like, I wonder. “A silent world?” “Yes,” she replies, “it's a silent world.” As with Mother, so, I expect, with me. I have known for many years that I am on a trajectory toward the same deafness. When tested as a teenager, my hearing pattern mimicked Mother's—an unusual “reverse slope” pattern of good hearing for high-pitched sounds and poorer hearing for low-pitched sounds (making soft male voices harder to discern than higher female voices). From upstairs, I can hear the high-pitched microwave oven timer, though my wife, Carol, snuggled beside me in bed, cannot. But I cannot recall ever hearing an owl hoot. Carol touches my leg at each hoot: “There, can you hear it?” I hear nothing.   A quarter century and more later, I continue on that trajectory, unable now (with my hearing aids out) even to hear my wife’s voice from the adjacent pillow, unless she speaks directly into my ear. In daily life I mostly cope well enough, thanks to powerful digital hearing technologies that my mother never knew. Even so, I struggle to hear amid noise—at a party, in a restaurant—or when a questioner is across a room. Like all who suffer this invisible disability, I strain to hear. I move closer. Or, with a smile and a nod, I fake hearing.   On the brighter side, the hearing loss plague has also given me an added life purpose—supporting people with hearing loss by advocating for a “hearing loop” transformation in how America provides listening assistance in public places (through this website, through three dozen articles such as this one, and via nearly 20,000 e-mails). And this advocacy led me to four years representing people with hearing loss on the advisory council of NIH’s National Institute on Deafness and Other Communication Disorders.   There I was privileged to meet and hear from some world class hearing researchers, including the University of Iowa physician-geneticist Richard Smith, who is amassing data on the genes of many thousands of people with hearing loss. When I showed him my audiogram—my profile of hearing loss at various frequencies—he guessed that I carry a mutation on the WSF1 gene, and offered to confirm that.   So I sent in my spit tubes, and last week Smith confirmed: “You have DFNA6/14 hearing loss caused by a mutation in WFS1.”   In psychological science, we teach our students that complex traits, such as intelligence or personality, are the product of “many genes having small effects.” So this is my reminder that some important traits and medical conditions are predisposed by single genes (which my siblings and I each had a 50% chance of inheriting—with my older brother and I, among the four of us, drawing the unlucky cards).   If so, I asked: Is there not some hope that gene editing, such as with the new CRISPR technique, could prevent future hearing loss in children or young adults who carry the gene?  Yes, Smith tells me—this is, indeed, his lab’s exciting aim. Moreover, they plan to conduct the experiment by attempting the gene therapy on but one ear of each volunteer, thus enabling the other ear to serve as what we psychologists call a “within subjects control condition.”   In the meantime, I’m content to be the person Dr. Seuss described in You're Only Old Once!            You'll be told that your hearing's so murky and muddy,            your case calls for special intensified study. They'll test you with noises from far and from near and you'll get a black mark for the ones you can't hear. Then they'll say, "My dear fellow, you're deafer than most. But there's hope, since you're not quite as deaf as a post." ... View more

One of my favorite sources for examples of psychological concepts are comic strips. Some of them get worked into lectures, others show up on exams, and sometimes I’ll offer them for a couple points extra credit, especially for new comics that harken back to content covered earlier in the course. Here are some May 14, 2017 comic strips that may be worth adding to your stable of examples. The Betty comic strip gives us a wonderful example of change blindness. Junior, Betty’s son, is dinking around on his phone while explaining his generation’s amazing ability to multitask. During his explanation, Betty calls in her husband to take her place. When Junior’s attention is returned to his parent, he sees his dad and is completely unaware that he had replaced his mom. In Frank and Ernest Frank has a young person working out on his farm. The young person, upon hearing “crop,” thinks cropping photos instead of crops that are planted. For someone who spends a lot of time in the digital world instead of a farming world, that person would be primed to interpret “crop” as photo manipulation. Frazz gives us commentary on the positive reinforcement provided by smartphones. Pick up your smartphone to get a jolt of pleasure in some form – text messages, phone calls, games, social media updates. Caulfield, the boy in the strip, says that his dad “calls them dopamine pumps.” (If you want to dive deeper into smartphone use, I wrote a post on stress and smartphones a few months ago.) Bonus comic strip. My favorite classical conditioning comic strip comes from Lio (November 14, 2009). A monster replaces Pavlov’s dogs, “Monsta Treats” replace meat powder, and the sound of a ripping bag replaces the tone. Do you have any favorite comic strips that illustrate psychological concepts?   ... View more

After covering sensation and perception, take students back to 2015. In case you missed it, this was the image that blew up social media in February of that year. Viewers were divided into two camps. Some saw the dress as blue/black while others saw it as gold/white. These discussions were not about whether a color was more blue or more purple. People were talking about very different perceptions. Friends and family got into arguments because each camp thought they were being gaslighted by the other. [Side note. The term gaslight, in this context, comes to us from a 1938 play which became a 1944 movie.] What color is the real dress? Blue/black. But before the blue/black perceivers cheer for being right, the image of The Dress that falls on our retinas is more complicated than that. It turns out that both the blue/black and gold/white perceivers are right, that is, in terms of which light waves our eyes pick up. Oh. And if you perceive it as blue/brown, you’re not alone, but there aren’t that many of you. But first, why such different perceptions? Our sensation and perception colleagues identified an assumption that our brains had to make. Some of us assumed that The Dress was lit by artificial, yellow light, the kind of light we get indoors. Others of us assumed that The Dress was lit by natural, blue light, the kind of light we get outdoors. When we assume yellow light, our brains subtract yellow from the light wave data our eyes send to our brains. With the yellow removed, The Dress is perceived as blue/black. When we assume blue light, our brains subtract blue from the light wave data. With blue removed, The Dress is perceived as gold/white. Where does blue/brown come from? Those perceivers are splitting the difference. They’re subtracting a little yellow and a little blue. ASAP Science did a nice 2-minute video on how this – color constancy – works. Video Link : 2015 A closer look at The Dress You can show students exactly what their eyes are seeing, before the brain subtracts a color. On your classroom computer, right-click on the photo of this dress, and select “Copy image address.” Visit the LunaPic website. In the “Open from URL” box, paste the image address. On the far left side of the page you will see a toolbar. Click anywhere over there to enter editing mode. From that toolbar, choose the eyedropper; it’s the ninth icon from the top. Click anywhere on The Dress to see the color of that spot displayed at the top of the page. Click the eyedropper again and choose another spot. When you click on a blue/white band, the color is actually a slate gray. If our brains subtract yellow, we perceive the color as bluer than it is. If our brains subtract blue, we perceive the color as whiter than it is. Use the eyedropper to sample from the black/gold bands. They are a goldish brown. If our brains subtract yellow, we perceive the color as black. If our brains subtract blue, we perceive the color as yellow-gold. Who is more likely to perceive it one way and not another way and why? But none of that answers the question of why some people are more likely to assume yellow light while others are more likely to assume natural light. One hypothesis is that those who spend more of their day inside under artificial lights are more likely to subtract yellow and see a blue/black dress. Those who spend more of their day outside or inside spaces with a lot of natural light – think skylights and large windows – are more likely to subtract blue and see a gold/white dress. Survey research has found that “[o]lder people and women were more likely to report seeing ‘The Dress’ as white and gold, while younger people were more likely to say that it was black and blue” (Cell Press, 2015). Ask your students to work in pairs or small groups to generate some hypotheses as to why this is the case. Ask volunteers to report their hypotheses. For example, is it a cohort effect for age? Did older people spend more of their childhoods outdoors than today’s youth and therefore more likely to assume blue light? Teenagers are also more likely to be “owls.” Psychological scientist Pascal Wallisch reasoned that “owls” – people who get up late and go to bed late – would experience more yellow light and, thus, would be more likely to perceive The Dress as blue/black. Conversely, he expected “larks” – people who get up early and go to bed early – would experience more blue light and, thus, would be more likely to perceive The Dress as gold/white. He found a statistically significant difference between the owls and larks in their perceptions of The Dress, but the differences weren’t huge. In other words, it appears that this is one factor, but not the only factor, that influences our assumptions about the lighting (Wallisch, 2017). Recap Remind students that color does not exist outside of our brains. Outside, it’s light waves. Our eyes convert those light waves into neural signals. Our brain takes those neural signals and uses them in combination with other factors, like the surrounding colors and assumptions about the environment, to create the color that we see.   ... View more

When I cover monocular cues in the perception section of Intro Psych, I like to show students a few photos and have them identify the monocular cues in the photos. This also works as a small group activity – put a photo up on the screen, ask students to huddle up and identify as many monocular cues as they can, then ask volunteers to identify the cues they found. This is a nice way to show travel photos and give students who haven’t traveled much a different view of the world. The Association for Psychological Science held their 2017 International Conference on Psychological Science in Vienna, Austria. As we’ve been out and about, I’ve been looking for good monocular cue photo opportunities. In the photo above we see the entrance to the Hofburg Palace. The buildings and the cobblestones provide linear perspective. The streetlight on the right and the streetlight farther down on the left, as do the people, illustrate relative size. Relative height -- the bottom of the image is closer to us and the middle of the image is farther away. Interposition (overlap) can be seen with the people, the streetlights, the wires hanging across the walkway. In the cobblestones, you can see every nook and cranny in the ones up close, but as texture gradient tells us, the cobblestones that appear smoother are farther away.   In this photo, the building at the end of the street on the right is the biggest synagogue in Vienna. It survived WWII by looking like any other apartment building. Linear perspective: cobblestones, buildings Relative size: windows Relative height: cobblestones (the closer ones are lower in the field of vision) Interposition: the person overlaps the building Texture gradient: cobblestones (closer ones are more distinct)   This photo is part of the Vienna State Opera. The building was completed in 1869. Linear perspective: columns become narrower Relative size: tables and chairs, lights Relative height: cobblestones (the closer ones are lower in the field of vision) Interposition: the chairs overlap each other Texture gradient: cobblestones (closer ones are more distinct) While you are certainly welcome to use my photos to illustrate monocular cues, consider working in a few shots on your next trip. ... View more

My friend and psychology colleague, Sue Frantz, alerted me to the pride the University of Kansas athletic department took this week in setting a Guinness World Record—with a 130.4 decibel crowd roar during their men’s basketball team’s come-from-behind win over West Virginia. That took my mind to my hometown Seattle Seahawks’ pride on having the loudest outdoor sports stadium, thanks to its “12th Man” crowd noise—which has hit a record 137.6 decibels . . . much louder than a jackhammer, noted hearing blogger Katherine Bouton.  As I mentioned in earlier blog post, with three hours of 100+ decibel game sound, “many fans surely experience temporary tinnitus—ringing in the ears—afterwards . . . which is nature warning us that we have been baaad to our ears. Hair cells have been likened to carpet fibers. Leave furniture on them for a long time and they may never rebound. A rule of thumb: If we cannot talk over a prolonged noise, it is potentially harmful.” Coincidentally, Sue Frantz’s Highline College is just 17 miles from Seahawks stadium, where, she tells me “my former postal carrier ruptured his eardrum. He said he felt the sound wave move from one end of the stadium to the other, and when it bounced back, he felt a sharp pain in his ear that faced that end of the stadium. His eardrum never recovered; his hearing loss was permanent.” The hearing aid industry may welcome the future customers whose hearing decline is hastened by such toxic noise. But for the University of Kansas and my Seahawks, these disability-enhancing Guinness Records are matters for concern, not boasting. ... View more

Open your discussion of sensation and perception by showing students this image. Note the white on the clear bulb where the light is reflecting. Our eyes detect white, but our brains know that those white spots aren’t really white. Based on past experience, our brain perceives the white as merely reflections of light. Image source: https://www.pexels.com/photo/clear-glass-light-bulb-75427 Next, show students this photo. Image source: http://cheezburger.com/8985651968/shiny-legs-optical-illusion-paint-whats-making-these-legs-look-so-shiny     It’s not quite The Dress, but this is still pretty cool. Like many people, what you see are shiny legs. Do they look like they are covered in a hard, clear plastic? But what if I told you that there is no plastic. It’s just strategically placed white paint? If you saw shiny legs, you were perceiving the white as reflected light, as you rightly did with the light bulb. Once you’re told the white is paint, the shininess disappears, and you are just left with, well, white paint. ... View more

Originally posted on September 15, 2016. With thanks to Christopher Platt (NIDCD Director of Hearing and Balance programs), here’s a simple demonstration of our super-speedy vestibular system. As you have surely noticed, if you slip, your vestibular sensors automatically, in a microsecond, direct your skeletal response—well before you have consciously decided how to right yourself. Our vestibular sense is even faster than our visual sense. Try this, suggests Platt: Hold one of your thumbs in front of your face, then move it rapidly right to left and back. Notice how your thumb blurs. (Your vision isn’t fast enough to track it.) Now hold your thumb still and swivel your head from left to right. Voila! Your thumb stays in focus, because your vestibular system, which is monitoring your head position, speedily moves the eyes. Head moves right, eyes move left. Vision is fast, but the vestibular sense is faster. ... View more

This extinction illusion (Hermann grid variation) has been making the rounds on social media courtesy of a Facebook post by psychological scientist Akiyoshi Kitaoka. There are 12 black dots in this grid. Most people cannot see them all at once. The illusion itself first made an appearance in a 2000 journal article by Ninio & Stevens. Check out their paper for other illusions. The larger lesson for your students: Our senses, including vision, allow our brains to create a representation of the world around us. Our senses do not allow our brains to generate a perfect replication of the world. For students who want to know why the illusion works, well, that’s a little more challenging. The short answer is that our retinas are hard-wired to send the clearest, sharpest signals to the brain. Receptor cells that get the strongest signal block out the weaker signals. Those dots in the periphery get blocked by the grey that surround them thanks to the sparser rods in the periphery. For the longer answer, read up on lateral inhibition. Wikipedia provides a nice summary. (Yes, lateral inhibition is also used to explain Mach bands.) If you want to wade into this even deeper with your students, Wesley Jordan (St. Mary’s College of Maryland) has created a class activity that should help students understand lateral inhibition.   References Ninio, J. & Stevens, K.A. (2000). Variations on the Hermann grid: An extinction illusion. Perception, 29, 1209-1217. ... View more

What makes synesthesia such a powerful lecture topic in the Intro Psych sensation and perception chapter is that it’s a beautiful illustration of how our experience is merely a representation, and just one representation, of the world around us. The neuroscientist David Eagleman provides a nice introduction to synesthesia in this two and a half minute video. Video Link : 1751 Years ago in class, after I concluded my lecture on synesthesia, a young woman in the back of the room raised her hand. She said she didn’t know her experience of the world was different from everyone else’s until a friend of hers took my class a year earlier. She said a group of them were standing around when he started talking about this cool thing called synesthesia that he learned about that day in his Intro Psych course. He explained that the most common form is seeing sounds where sounds produce color, like a filter has been applied to vision. My current student said to her friends, “Doesn’t everybody experience that?” They all stopped and looked at her. At the age of 18, she learned that she was a synesthete. I made the same error once in class. After talking about synesthesia, I said it’s like when you’re drifting off to sleep and a sudden noise causes a black and white pattern to flash in your vision – sound produces a visual sensation. My students looked at me blankly. Apparently I was the only one with such an experience. My visual experience used to happen pretty regularly, probably a few times a week, but now it’s a rare occurrence, probably once every few months. In any case, I learned that it’s non-existent in many, at least amongst my students that term. I suppose this assumption is a kind of extension of the false consensus effect. We not only assume that others share our beliefs and attitudes, but that others share our sensory experiences. There is research evidence that suggests we are all born synesthetes (see for example Wagner and Dobkins, 2011), and as we mature through infancy and childhood our senses begin to specialize, much like how infants can produce sounds used in all languages only to become specialists in their native language or languages as they develop.   Exploring vision in non-human animals helps students appreciate that their own sensory experiences may be very different from others. For example, dogs have two kinds of cones in their retinas; they detect yellow and blue. That may make them roughly equivalent to humans who have red-green color blindness (Wolchover, 2012). And birds? They have four kinds of cones, the fourth allows them to see ultraviolet light. It’s been posited that the ability to see UV light allows some songbirds to better see each other as their plumage glows with UV light and that raptors can better track prey that leave a urine trail that also glows with UV light. There’s reason to believe that the jury is still out on both of those hypotheses (see for example, Lind, et.al., 2013). Both are given though in this rapid-fire 4-minute SciShow on what birds see. Video Link : 1752 And what about infrared light? While the human eye can’t see it, our digital cameras can. Turn on your cellphone camera and direct it at the end of your TV remote, the end you point toward your TV. Press and hold the "on" button on your remote. You’ll see the light through your phone’s camera even though your naked eye can't see it. This is also the easiest way to determine whether you need to change the batteries in your remote or whether it's just your dog standing in front of the TV’s receiver. For a short in-class next-day assignment – or same-day assignment, if your students have in-class internet access – or for an online discussion board assignment, invite students to research other individual differences in human sensation or differences in sensory experiences between humans and other animals. In class, students can share in small groups, and then invite volunteers to share the most interesting things they found. Ask students to identify the site where they found the information and why they believe the site is a reputable source.   References Lind, O., Mitkus, M., Olsson, P., & Kelber, A. (2013). Ultraviolet sensitivity and colour vision in raptor foraging. Journal of Experimental Biology, 216(19), 3764-3764. doi:10.1242/jeb.096123 Wagner, K., & Dobkins, K. R. (2011). Synaesthetic associations decrease during infancy. Psychological Science, 22(8), 1067-1072. doi:10.1177/0956797611416250 Wolchover, N. (2012, June 26). How do dogs see the world? Retrieved from http://www.livescience.com/34029-dog-color-vision.html ... View more

Originally posted on April 25, 2014. We’ve all experienced it. You’re some place where screaming isn’t tolerated, some kids starts wailing, and the parents rush to quiet them down. What happens next is the twist: “They’re the best behaved kids we know,” the parents say, as their child continues to bellow. We nod our heads, feign a smile, and go back to what we’re doing. Before you pounce on me for being impatient and inexperienced, I’m here to share some good news. The more positively we view our close relationship partners, the stronger relationship we have. The best part is that the positivity doesn’t have to exist. If you ask many people, they’ll tell you their close friends are above average on nearly every positive trait. They’re funnier, smarter, and kinder than their peers. We might have positive illusions, but that doesn’t hurt anything. Or does it? Let’s return to how we see our kids. Seeing them as above average might have certain benefits. It might boost your parenting commitment and satisfaction. Who wants to devote the time and energy it takes to parent if you see your kid as a dud? A recent study suggests a potential drawback: many parents perceive their children as healthier than they actually are. The study, which drew on several investigations involving over 15,000 children, found that half of parents who have overweight or obese children rate their child as slimmer than their weight suggests. Just as people villainize parents of screaming children, it’s easy to attack parents who don’t know their children are overweight or obese. But let’s show parents some empathy. Parenting is hard. I don’t have kids, but I can’t tell you how much respect I have for people who do. Parents might not want to hurt their children’s feelings by calling them overweight or obese. They also might not know what it means to be overweight or obese. Is it simply if your son fits into his clothes? If your daughter comes home crying because a school bully called her fat? But there’s a third possibility: when we love someone, we see them in the best possible light. Instead of seeing an obese child, we see our daughter who jumps down the stairs to welcome us home from work. We see our son who loves to get dirty in the mud. When I read about the study, I tucked it away in my files. The next morning my wife and I took our two golden retrievers, Finnegan and Atticus, to the veterinarian. They’re both of our dogs, but Finnegan is mine and Atticus is my wife’s. They weighed Finnegan, who came in at a beefy 85 pounds. Then it was Atticus’s turn. “He’s much skinnier than Finnegan,” my wife, Alice, said. “Just look at him.” I looked and realized we weren’t seeing the same dog. “He looks the same to me. We feed him the same amount and give him the same amount of exercise.” “Nah, I bet he’s 70 pounds,” she said. They took Atticus away, weighed him, and returned with the results. He was exactly the same as Finnegan: 85 pounds. So, this finding might apply to dog owners, too. ... View more

Originally posted on February 5, 2015. Even though the smartphone has only been around for the past seven or eight years, it’s sometimes difficult to remember what life was like before we had so much information at our fingertips. You could argue with a friend about what year “Back to the Future, Part 2” came out, or in what year the “future” was set. (It was released in 1989. The future, filled with flying cars and floating skateboards, was set in 2015.) Back then, you couldn’t resolve discussions by swiping a screen and touching a button. Siri wasn’t even a twinkle in Steve Jobs’s eye. If you got lost, you had to consult a map or stop and ask for directions, and if you got bored while waiting in line, you couldn’t pass the time by playing Candy Crush or perusing Instagram. Luddites argue that life was better before the smart phone, whereas others tout the benefits of instant communication and information. But one thing is certain: The smartphone has changed our lives. And our thumbs. Yes, when we spend time on smartphones using a touchscreen, it changes the way our thumbs and brains work together, according to a new study by researchers from the University of Zurich and ETH Zurich in Switzerland. Our obsession with smartphones presented the perfect opportunity to explore the everyday plasticity of our brains. With smartphones, we are using our fingertips—especially our thumbs—in a new way, and we do it a lot. And because our phones keep track of how we use them, they carry a wealth of information that can be studied. In the study, the research team used electroencephalography (EEG) to record brain response to the touch of the thumb, index finger, and middle fingerprints of touchscreen phone users compared to people who still use flip phones or other old-school devices. They found that the electrical activity in the brains of smartphone users was enhanced when all three fingertips were touched. The amount of activity in the brain’s cortex associated with the thumb and index fingertips was directly proportional to the amount of phone use. Repetitive movements over the touchscreen surface might reshape sensory processing from the hand. Cortical sensory processing in our brains is constantly shaped by personal digital technology. So, the next time you use your thumbs to tweet, answer email, or jot yourself a note, remember that you’re training your brain. Keep in mind, too, that excessive phone usage is linked with motor dysfunction and pain. Remember the so-called “BlackBerry thumb”? ... View more

Originally posted on April 24, 2014. “39-Year-Old Deaf Woman Hears for First Time” headlined Yahoo, in one of the many gone-viral Deaf-can-now-hear videos.  Each depicts the compelling emotions of someone who, thanks to the activation of a new cochlear implant (CI), is said to be hearing sound for the first time—and (in this case) conversing in English!  Was this woman (Joanne) completely congenitally deaf as a result of Ushers Syndrome?  And did she immediately gain, as some media implied, the ability to understand speech on first hearing it? As my brother said in forwarding this, it’s “an amazing story.” The power of CIs to restore hearing is, indeed, amazing, as I can attest from meeting many people with CIs at hearing loss meetings.  As one who is tracking toward the complete deafness that marked the last dozen years of my mother’s life, I anticipate someday benefitting from CIs. Moreover, I appreciate the power of a compelling example, such as the video example I offer (here) of a child’s first experience of a home TV room hearing loop.  And who can suppress a smile when watching this boy’s first experience of a CI? Without disrespecting the Deaf culture (which regards deafness and Sign language as not defects needing fixing), and without diminishing Joanne’s powerful experience, what shall we make of her ability to understand and to speak? Does this video overturn what psychological science has taught us about the critical period for language development during life’s early years?  Is it not important that children receive CIs before language develops?  Haven’t experiments that removed cataracts and “restored vision” to natively blind people taught us that, for normal perceptual experience, the brain must be sculpted by sensory input in life’s early years? I posed these questions to Dr. Debara Tucci, a Duke Medical Center cochlear implant surgeon with whom I serve on the advisory council of the National Institute on Deafness and Other Communication Disorders.  Our shared questions:      1. Was Joanne completely deaf from birth?  Has she heard no sound until the moment of this recording?  As I will explain in a future entry, in popular use “deaf” often conflates true and complete deafness with substantial hearing loss.  Some Usher’s Syndrome patients sometimes are born completely deaf, but others experience progressive hearing loss.  With hearing aids, they acquire language early in life.  Joanne’s use of spoken language suggests that she is not hearing speech for the first time in her life.      2. A person who has been completely deaf from birth could potentially lip read.  When testing such patients with newly activated CIs, it would be interesting to know if they can “hear” speech when the speaker’s face is obscured. As a CI provider, Dr. Tucci nevertheless welcomes such videos:  “Even though the history accompanying the video may not be entirely correct, and a little misleading, it is basically a positive thing.  I would rather have 10 people come in and be told they are not a candidate than miss one person who is.  Also, we are implanting long deafened people who don't have speech/language ability not with the thought that they will develop or understand speech, but to increase connectedness and for safety concerns.” ... View more