Human DNA is more than 99.9% the same from person to person; the 0.1% that differs comes from variations among about 3 billion DNA “letters.” Human genomes are so similar that any two are about the same, yet enough differences exist that one genome, or even a few, cannot represent everyone. Some variants in DNA change how the body works, while others have no biological effect at all. Even within one family, people can have different blood groups and eye colors, because their DNA differs a little. Fingerprint ridges on every finger of every human being are unique and do not change as a person grows or ages. In 1880, the journal Nature published letters by Henry Faulds and William James Herschel describing the uniqueness and permanence of fingerprints. Each brain has billions of interconnected neurons that form unique pathways, so, like fingerprints, no two brains are alike.
Everyone is different. Different does not mean better or worse. It just means different. Eye color is different from person to person, from very light blue to dark brown. Eye color is directly related to the amount of melanin in the front layers of the iris: brown eyes have a large amount, and blue eyes have much less. Most people are right-handed, but about 1 in 10 people (10.6%) is left-handed. About 9% of people use different hands for different tasks, a share almost as big as the share of left-handers. People differ considerably in the activities for which they prefer a given hand, and in how much better one hand is than the other.
Families come in all different shapes and sizes. Some families have stepparents, one parent, or parents who found their children through adoption. In 2023, 75% of U.S. children under 6 lived with two parents, compared with 68% of children ages 12 to 17, as of November 2023. In 1968, 85% of U.S. children under 18 lived with two parents; by 2020, 70% did, and living with two parents is the most common arrangement, as of April 2021. Living with a mother only is the second most common U.S. children’s living arrangement, at 21% of children (15.3 million) in 2020, as of April 2021. About 3.2 million U.S. children under 18 lived with cohabiting parents in 2023, up from 2.2 million in 2007, as of November 2023.
Braille is a system of raised dots that people who are blind or have low vision read with their fingers. Louis Braille, who was blinded at the age of three, invented the braille system in 1824 as a student at a school for blind children in Paris. The early braille system was based on “night writing,” a dot code that Charles Barbier invented, and Louis Braille cut its 12-dot configuration in half to make a six-dot cell. American Sign Language (ASL) is a complete, natural language with the same linguistic properties as spoken languages, and its grammar differs from English. ASL arose more than 200 years ago from local sign languages mixing with French Sign Language, and no person or committee invented it. In ASL, a question is asked by raising the eyebrows, widening the eyes and tilting the body forward, while English speakers raise the pitch of their voices and change word order.
In 1944 Dr. Ludwig Guttmann opened a spinal injuries centre at Stoke Mandeville Hospital in Great Britain; rehabilitation sport there grew into recreational and then competitive sport. The first competition for wheelchair athletes, the Stoke Mandeville Games, was organized on 29 July 1948 by Dr. Ludwig Guttmann; it included 16 injured servicemen and women in archery. The first Paralympic Games took place in Rome, Italy, in 1960, with 400 athletes from 23 countries. They have been held every four years since. Since the 1988 Summer Games in Seoul and the 1992 Winter Games in Albertville, the Paralympic Games have taken place in the same cities and venues as the Olympics. Special Olympics describes its history as the story of the world’s largest organization dedicated to promoting respect, inclusion and acceptance of people with intellectual disabilities.
In 1975, U.S. public schools accommodated only 1 out of 5 children with disabilities; many states had laws that explicitly excluded some of them, such as children who were deaf or blind. Section 504 of the Rehabilitation Act of 1973 forbade organizations that accepted federal funds from discriminating against people with disabilities. On November 29, 1975, President Gerald Ford signed the Education for All Handicapped Children Act (Public Law 94-142), which requires a “free, appropriate public education” tailored to each child with a disability. The 1975 law aimed to protect the rights of children with disabilities and their parents, and to make sure states and localities educate all children with disabilities. The 1975 law required schools to serve all children with disabilities, write an individualized education program (IEP) for each child, and educate each to the maximum extent appropriate alongside peers without disabilities. In 1990 Congress renamed the 1975 law the Individuals with Disabilities Education Act (IDEA), and it was reauthorized again in 2004. Fourteen years after Public Law 94-142, an amendment introduced by Senator Tom Harkin removed the word “handicapped” from the law’s name, giving the Individuals with Disabilities Education Act.
IDEA says students with disabilities should learn in the least restrictive environment, meaning in settings with peers without disabilities as much as possible. Between fall 2012 and fall 2022, the share of students served under IDEA who spent 80 percent or more of their school day in general classes rose from 61 to 67 percent, as of May 2024. By the 2020s, most students served under IDEA with speech or language impairments (89 percent) or specific learning disabilities (76 percent) spent 80 percent or more of the school day in general classes, according to fall 2022 data, as of May 2024. The National Council on Disability wrote in 2015 that IDEA has been the catalyst for most of the progress the nation has achieved in inclusive education since 1975. The National Council on Disability says special education is not a place but a system of services and supports designed to ensure an inclusive, general education for every student.
Universal Design for Learning (UDL) is a framework for designing learning so that it elevates strengths and removes barriers for all learners. Universal Design for Learning is based on the idea that there is no “average” brain and that learner variability is predictable, so schools can plan options for engagement, representation, and action and expression. One school-district study, reported by Malhotra in 2024 and summarized by We Are Teachers, found that including students with disabilities in general classrooms did not hurt the math and reading scores of other students in grades 3 through 8, as of December 2024. The same study found that high school graduation rates rose by nearly 3 percentage points after the district’s inclusion policy was fully implemented, as of December 2024.
The Americans with Disabilities Act (ADA) guarantees that people with disabilities have the same opportunities as everyone else to work, buy goods and services, and take part in state and local government programs. The ADA was signed on July 26, 1990, by President George H.W. Bush; it prohibits disability-based discrimination and required changes to the built environment, including curb cuts. Congress found in the ADA that physical or mental disabilities in no way diminish a person’s right to fully participate in all aspects of society. In 1972 the city of Berkeley, California, installed its first official “curb cut” at an intersection on Telegraph Avenue after disabled activists pressed for it. The “curb-cut effect” is that ramps built for wheelchair users were also used by parents with strollers, workers with carts, travelers with luggage, runners and skateboarders. A study of a Florida shopping mall found that nine out of ten pedestrians without strollers, carts or luggage still went out of their way to use a curb cut.
Conformity means changing beliefs, attitudes, actions or perceptions to match those of groups people belong to or want to belong to. Peer pressure to conform, to do what others are doing, can be powerful and hard to resist. People may feel pressure to conform so they fit in or are accepted, or so they do not feel awkward or uncomfortable. People respond to peer pressure differently: some people are more likely to give in, and others are better able to resist and stand their ground. The classic conformity experiments by Solomon Asch assembled groups of seven to nine people for a study on visual perception. The Asch experiments found that people went along with a clearly wrong majority about one-third of the time, and 27 percent of participants conformed on at least eight trials. In the Asch experiments, 24 percent of participants never conformed, and control participants answering privately made errors less than 1 percent of the time.
Bullying is unwanted, aggressive behavior among school-aged children that involves a real or perceived power imbalance. When teasing becomes hurtful, unkind and constant, it crosses the line into bullying. No single factor puts a child at risk of being bullied. Kids perceived as different, such as for wearing glasses or different clothing or for being new to a school, are more often targeted. Depending on the environment, some groups, such as youth with disabilities and socially isolated youth, may be at increased risk of being bullied. People who act mean and put others down often do so because they lack self-confidence and try to cover it up by staying in control. Bystanders can become upstanders: an upstander sees what is happening and steps in, interrupts or speaks up to stop bullying. Even one person’s support can make a big difference for someone who is being bullied. Bystanders can act as a group: there is strength in numbers when several people show they do not agree with bullying.
Empathy is the ability to sense other people’s emotions and to imagine what someone else might be thinking or feeling. There are two types of empathy: affective empathy is the sensations and feelings we get in response to others’ emotions, and cognitive empathy is the ability to identify and understand other people’s emotions. Empathy has deep roots in our brains and bodies: elementary forms of empathy have been seen in primates, dogs and even rats. Perspective taking is the ability to identify and understand other people's emotions, and it is a skill that keeps developing through adolescence. Contact helps: getting to know people who are different from yourself leads to reduced prejudice and increased understanding. Harvard researcher Richard Weissbourd says almost all kids are kind to somebody, and that the real work is getting kids to be kind to people outside their immediate circle of concern. Playing and working with people who are different from you helps you practice kindness and empathy. A grown-up you trust can help when someone is being unkind or when being different feels hard.
Words to know
- genome: complete DNA set
- braille: raised dot writing
- conformity: matching the group
- empathy: sensing feelings
- upstander: speaks up
