childhood obesity: In a child, having a BMI (body mass index) above the 95th percentile, according to the U.S. Centers for Disease Control’s 1980 standards for children of a given age.

concrete operational thought: Piaget’s term for the ability to reason logically about direct experiences and perceptions.

asthma: A chronic disease of the respiratory system in which inflammation narrows the airways from the nose and mouth to the lungs, causing difficulty in breathing. Signs and symptoms include wheezing, shortness of breath, chest tightness, and coughing.

middle childhood: The period between early childhood and early adolescence, approximately from ages 6 to 11.

classification: The logical principle that things can be organized into groups (or categories or classes) according to some characteristic they have in common.

control processes: The part of the information-processing system that regulates the analysis and flow of information. Memory and retrieval strategies, selective attention, and rules or strategies for problem solving are all control processes.

reaction time: The time it takes to respond to a stimulus, either physically (with a reflexive movement such as an eyeblink) or cognitively (with a thought).

metacognition: “Thinking about thinking,” or the ability to evaluate a cognitive task in order to determine how best to accomplish it and then to monitor and adjust one’s performance on that task.

selective attention: The ability to concentrate on some stimuli while ignoring others.

working memory: The component of the information-processing system in which current conscious mental activity occurs. (Formerly called short-term memory.)

seriation: The concept that things can be arranged in a logical series, such as the number series or the alphabet.

knowledge base: A body of knowledge in a particular area that makes it easier to master new information in that area.

childhood overweight: In a child, having a BMI (body mass index) above the 85th percentile, according to the U.S. Centers for Disease Control’s 1980 standards for children of a given age.

long-term memory: The component of the information-processing system in which virtually limitless amounts of information can be stored indefinitely.

sensory memory: The component of the information-processing system in which incoming stimulus information is stored for a split second to allow it to be processed. (Also called the sensory register.)

charter schools: Public schools with their own set of standards funded and licensed by the state or local district in which they are located.

vouchers: A monetary commitment by the government to pay for the education of a child. Vouchers vary a great deal from place to place, not only in amount and availability, but in who gets them and what schools accept them.

home schooling: Education in which children are taught at home, usually by their parents, instead of attending any school, public or private.

hidden curriculum: The unofficial, unstated, or implicit rules and priorities that influence the academic curriculum and every other aspect of learning in a school.

private schools: Schools funded by parents and sponsoring institutions. Such schools have control over admissions, hiring, and specifics of curriculum, although some regulations apply.

No Child Left Behind Act (NCLB): A U.S. law enacted in 2001 that was intended to increase accountability in education by requiring states to qualify for federal educational funding by administering standardized tests to measure school achievement.

automatization: A process in which repetition of a sequence of thoughts and actions makes the sequence routine, so it no longer requires conscious thought.

National Assessment of Educational Progress (NAEP): An ongoing and nationally representative measure of U.S. children’s achievement in reading, mathematics, and other subjects over time; nicknamed “the Nation’s Report Card.”

immersion: A strategy in which instruction in all school subjects occurs in the second (usually the majority) language that a child is learning.

Trends in Math and Science Study (TIMSS): An international assessment of the math and science skills of fourth- and eighth-graders. Although very useful, different countries´ scores are not always comparable because sample selection, test administration, and content validity are hard to keep uniform.

bilingual education: A strategy in which school subjects are taught in both the learner’s original language and the second (majority) language.

Progress in International Reading Literacy Study (PIRLS): Inaugurated in 2001, a planned five-year cycle of international trend studies in the reading ability.

ELLs (English Language Learners): Children in the United States whose proficiency in English is low—usually below a cutoff score on an oral or written test. Many children who speak a non-English language at home are also capable in English; they are not ELLs.

ESL (English as a second language): An approach to teaching English in which all children who do not speak English are placed together in an intensive course to learn basic English so that they can be educated with native English speakers.

developmental psychopathology: The field that uses insights into typical development to understand and remediate developmental disorders.

response to intervention (RTI): An educational strategy that uses early intervention to help children who demonstrate below-average achievement. Only children who are not helped are designated for more intense measures.

autism spectrum disorder (ASD): Any of several conditions characterized by inadequate social skills, impaired communication, and unusual play.

neurodiversity: The idea that people have diverse brain structures, with each person having neurological strengths and weaknesses that should be appreciated, in much the same way diverse cultures and ethnicities are welcomed.

aptitude: The potential to master a specific skill or to learn a certain body of knowledge.

attention-deficit/hyperactivity disorder (ADHD): A condition in which a person not only has difficulty concentrating but also is inattentive, impulsive, and overactive.

equifinality: A basic principle of developmental psychopathology that holds that one symptom can have many causes.

specific learning disorder: A marked deficit in a particular area of learning that is not caused by an apparent physical disability, or by an unusually stressful home environment.

multiple intelligences: The idea that human intelligence is comprised of a varied set of abilities rather than a single, all-encompassing one.

dyslexia: Unusual difficulty with reading; thought to be the result of some neurological underdevelopment.

dyscalculia: Unusual difficulty with math, probably originating from a distinct part of the brain.

individual education plan (IEP): A document that specifies educational goals and plans for a child with special needs.

achievement test: A measure of mastery or proficiency in reading, mathematics, writing, science, or some other subject.

Flynn effect: The rise in average IQ scores that has occurred over the decades in many nations.

multifinality: A basic principle of developmental psychopathology which holds that one cause can have many (multiple) final manifestations.