Behavior or behaviour is the range of actions and mannerisms made by individuals, organisms, systems or artificial entities in some environment. These systems can include other systems or organisms as well as the inanimate physical environment. It is the computed response of the system or organism to various stimuli or inputs, whether internal or external, conscious or subconscious, overt or covert, and voluntary or involuntary.
Nature versus nurture is a long-standing debate in biology and society about the relative influence on human beings of their genetic inheritance (nature) and the environmental conditions of their development (nurture). The alliterative expression "nature and nurture" in English has been in use since at least the Elizabethan period and goes back to medieval French. The complementary combination of the two concepts is an ancient concept. Nature is what people think of as pre-wiring and is influenced by genetic inheritance and other biological factors. Nurture is generally taken as the influence of external factors after conception e.g. the product of exposure, experience and learning on an individual.
Twin studies are studies conducted on identical or fraternal twins. They aim to reveal the importance of environmental and genetic influences for traits, phenotypes, and disorders. Twin research is considered a key tool in behavioral genetics and in related fields, from biology to psychology. Twin studies are part of the broader methodology used in behavior genetics, which uses all data that are genetically informative – siblings studies, adoption studies, pedigree, etc. These studies have been used to track traits ranging from personal behavior to the presentation of severe mental illnesses such as schizophrenia.
Human genetics is the study of inheritance as it occurs in human beings. Human genetics encompasses a variety of overlapping fields including: classical genetics, cytogenetics, molecular genetics, biochemical genetics, genomics, population genetics, developmental genetics, clinical genetics, and genetic counseling.
The Institute of Psychiatry, Psychology & Neuroscience (IoPPN) is a leading centre for mental health and neuroscience research, education and training in Europe. It is dedicated to understanding, preventing and treating mental illness, neurological conditions, and other conditions that affect the brain. The IoPPN is a faculty of King's College London, England, and was previously known as the Institute of Psychiatry (IoP).
Hereditarianism is the doctrine or school of thought that heredity plays a significant role in determining human nature and character traits, such as intelligence and personality. Hereditarians believe in the power of genetics to explain human character traits and solve human social and political problems. Hereditarians adopt the view that an understanding of human evolution can extend the understanding of human nature.
Glayde D. Whitney was an American behavioral geneticist and psychologist. He was professor at Florida State University. Beyond his work into the genetics of sensory system function in mice, in his later life he supported David Duke as well as research into race and intelligence and eugenics.
Research on the heritability of IQ inquires into the degree of variation in IQ within a population that is due to genetic variation between individuals in that population. There has been significant controversy in the academic community about the heritability of IQ since research on the issue began in the late nineteenth century. Intelligence in the normal range is a polygenic trait, meaning that it is influenced by more than one gene, and in the case of intelligence at least 500 genes. Further, explaining the similarity in IQ of closely related persons requires careful study because environmental factors may be correlated with genetic factors.
Neal Elgar Miller was an American experimental psychologist. Described as an energetic man with a variety of interests, including physics, biology and writing, Miller entered the field of psychology to pursue these. With a background training in the sciences, he was inspired by professors and leading psychologists at the time to work on various areas in behavioral psychology and physiological psychology, specifically, relating visceral responses to behavior.
Peter McGuffin was a Northern Irish psychiatrist and geneticist from Belfast.
Irving Isadore Gottesman was an American professor of psychology who devoted most of his career to the study of the genetics of schizophrenia. He wrote 17 books and more than 290 other publications, mostly on schizophrenia and behavioral genetics, and created the first academic program on behavioral genetics in the United States. He won awards such as the Hofheimer Prize for Research, the highest award from the American Psychiatric Association for psychiatric research. Lastly, Gottesman was a professor in the psychology department at the University of Minnesota, where he received his Ph.D.
Behavioural genetics, also referred to as behaviour genetics, is a field of scientific research that uses genetic methods to investigate the nature and origins of individual differences in behaviour. While the name "behavioural genetics" connotes a focus on genetic influences, the field broadly investigates the extent to which genetic and environmental factors influence individual differences, and the development of research designs that can remove the confounding of genes and environment. Behavioural genetics was founded as a scientific discipline by Francis Galton in the late 19th century, only to be discredited through association with eugenics movements before and during World War II. In the latter half of the 20th century, the field saw renewed prominence with research on inheritance of behaviour and mental illness in humans, as well as research on genetically informative model organisms through selective breeding and crosses. In the late 20th and early 21st centuries, technological advances in molecular genetics made it possible to measure and modify the genome directly. This led to major advances in model organism research and in human studies, leading to new scientific discoveries.
John C. DeFries is one of the world's leading behavior geneticists. His achievements include being President of the Behavior Genetics Association (1982–1983) and cofounder of the journal Behavior Genetics, as well as its co-editor (1970–1978). His awards include The Dobzhansky Award for Outstanding Research in Behavior Genetics, Consulting Editor of the Journal of Learning Disabilities (1987–2002), Fellowships in the International Academy for Research in Learning Disabilities, Association for Psychological Science, and the American Association for the Advancement of Science, Section J (Psychology).
There are a variety of disabilities affecting cognitive ability. This is a broad concept encompassing various intellectual or cognitive deficits, including intellectual disability, deficits too mild to properly qualify as intellectual disability, various specific conditions, and problems acquired later in life through acquired brain injuries or neurodegenerative diseases like dementia.
Gerald Paul Koocher is an American psychologist and past president of the American Psychological Association (APA). His interests include ethics, clinical child psychology and the study of scientific misconduct. He is Dean Emeritus Simmons University and also holds an academic appointment at Harvard Medical School. Koocher has over 350 publications including 18 books and has edited three scholarly journals including Ethics & Behavior which he founded.
Gerald "Jerry" McClearn was an American behavior geneticist and professor emeritus of health and human development and biobehavioral health at the Pennsylvania State University.
In behavioural genetics, DeFries–Fulker (DF) regression, also sometimes called DeFries–Fulker extremes analysis, is a type of multiple regression analysis designed for estimating the magnitude of genetic and environmental effects in twin studies. It is named after John C. DeFries and David Fulker, who first proposed it in 1985. It was originally developed to assess heritability of reading disability in twin studies, but it has since been used to assess the heritability of other cognitive traits, and has also been applied to non-twin methodologies.
Jenae M. Neiderhiser is an American behavior geneticist who is a Distinguished Professor of Psychology and Human Development and Family Studies at Pennsylvania State University, where she is also co-director of the Gene Environment Research Initiative.
Nancy L. Pedersen is an American genetic epidemiologist. She is Professor of Genetic Epidemiology and the leader of the Swedish Adoption/Twin Study of Aging (SATSA) at the Karolinska Institutet in Stockholm, Sweden. She is known for her research on human twins, much of which is based on the Swedish Twin Registry. This has included research on the genetic basis of Alzheimer's disease and self-confidence.
In adoption studies, selective placement refers to the practice by which adoption agencies tend to deliberately match certain characteristics of an adopted child's adopted parents with those of his or her biological parents. When this occurs, it results in a correlation between environments between biological relatives raised in different homes. It has the potential to bias the conclusions of such studies, because twins who were reared in separate environments may in fact have been reared in much more similar environments than assumed. This can result in an inflated estimate of heritability. There is evidence that selective placement was a major confound in many early studies of twins reared apart. Some adoption studies report little or no evidence of selective placement. For example, a 1979 study by Ho et al. reported a generally low level of selective placement in adopted children for either physical or behavioral traits. The authors concluded that to the extent that selective placement occurred for such traits, "our data suggest that it is based largely on characteristics of the birth father," rather than those of the adoptee. Carey (2003) concluded that selective placement was "moderate" for physical characteristics and typically "small or nonexistent" for behavioral characteristics.
