The neutral theory of molecular evolution holds that most evolutionary changes occur at the molecular level, and most of the variation within and between species are due to random genetic drift of mutant alleles that are selectively neutral. The theory applies only for evolution at the molecular level, and is compatible with phenotypic evolution being shaped by natural selection as postulated by Charles Darwin. The neutral theory allows for the possibility that most mutations are deleterious, but holds that because these are rapidly removed by natural selection, they do not make significant contributions to variation within and between species at the molecular level. A neutral mutation is one that does not affect an organism's ability to survive and reproduce. The neutral theory assumes that most mutations that are not deleterious are neutral rather than beneficial. Because only a fraction of gametes are sampled in each generation of a species, the neutral theory suggests that a mutant allele can arise within a population and reach fixation by chance, rather than by selective advantage.
Population genetics is a subfield of genetics that deals with genetic differences within and among populations, and is a part of evolutionary biology. Studies in this branch of biology examine such phenomena as adaptation, speciation, and population structure.
Michael A. Persinger was an American-Canadian professor of psychology at Laurentian University, a position he had held from 1971 until his death in 2018. His most well-known hypotheses include the temporal lobes of the human brain as the central correlate for mystical experiences, subtle changes in geomagnetic activity as mediators of parapsychological phenomena, the tectonic strain within the Earth's crust as the source of luminous phenomena attributed to unidentified aerial objects, and the importance of specific quantifications for energy, photon flux density, and small shifts in magnetic field intensities for integrating cellular activity as well as human thought with universal phenomena.
Expressive language disorder is one of the "specific developmental disorders of speech and language" recognised by the tenth edition of the International Classification of Diseases (ICD-10). As of the eleventh edition, it is considered to be covered by the various categories of developmental language disorder. Transition to the ICD-11 will take place at a different time in different countries.
The Lüscher color test is a psychological test invented by Max Lüscher in Basel, Switzerland. Lüscher believed that sensory perception of color is objective and universally shared by all, but that color preferences are subjective, and that this distinction allows subjective states to be objectively measured by using test colors. Lüscher believed that because the color selections are guided in an unconscious manner, they reveal the person as they really are, not as they perceive themselves or would like to be perceived.
Irlen syndrome, also referred to as scotopic sensitivity syndrome (SSS), visual stress, or Meares–Irlen syndrome, is a light-based visual processing disorder. Many mainstream professionals are skeptical of the concept; however, current neuroscience research has successfully documented differences in brain function among this population versus those without the condition. Early research on Irlen syndrome produced mixed results; however, the overwhelming majority of studies conducted over the last 40 years have documented the benefits of using precision-tinted colored lenses to address a variety of related symptomology, including: reduction in physical symptoms that include headaches, migraines, eye strain, fatigue, and light sensitivity; and improved functioning and success in both academia and the workplace.
The God helmet is an experimental apparatus originally called the Koren helmet after its inventor Stanley Koren. It was developed by Koren and neuroscientist Michael Persinger to study creativity, religious experience and the effects of subtle stimulation of the temporal lobes. Reports by participants of a "sensed presence" while wearing the God helmet brought public attention and resulted in several TV documentaries. The device has been used in Persinger's research in the field of neurotheology, the study of the purported neural correlations of religion and spirituality. The apparatus, placed on the head of an experimental subject, generates very weak magnetic fields, that Persinger refers to as "complex". Like other neural stimulation with low-intensity magnetic fields, these fields are approximately as strong as those generated by a land line telephone handset or an ordinary hair dryer, but far weaker than that of an ordinary refrigerator magnet and approximately a million times weaker than transcranial magnetic stimulation.
The name-letter effect is the tendency of people to prefer the letters in their name over other letters in the alphabet. Whether subjects are asked to rank all letters of the alphabet, rate each of the letters, choose the letter they prefer out of a set of two, or pick a small set of letters they most prefer, on average people consistently like the letters in their own name the most. Crucially, subjects are not aware that they are choosing letters from their name.
Researchers have suggested a link between handedness and ability with mathematics. This link has been proposed by Geschwind, Galaburda, Annett, and Kilshaw. The suggested link is that a brain without extreme bias towards locating language in the left hemisphere would have an advantage in mathematical ability.
The Gollin figures test is a psychological test used to assess someone's visual perception. Subjects are shown pictures of common objects: namely five consecutive incomplete line drawings for each picture, from least to most complete, that the subjects need to mentally complete to identify the object drawn. On a retention test sometime later, however, subjects identify the image sooner than they did on the first test, indicating some form of memory for the image. Amnesiac subjects also show improvement on this test, even though they do not recall taking the test before.
A Navon figure is made of a larger recognisable shape, such as a letter, composed of copies of a smaller different shape. Navon figures are used in tests of visual neglect. David Navon's research demonstrated that global features are perceived more quickly than local features. Jules Davidoff also performed research, but in a remote culture, finding opposite results; the participants more readily identified the local features. Patients with simultanagnosia have difficulty identifying global features, and when presented with a Navon figure will identify only the local features. A 2010 study comparing global-local processing in different races, found that East Asians demonstrated significantly stronger global processing than Caucasians.
The four boxes test is a computer-based test used to measure reaction times. In the test, a black circle appears in one of four boxes on the screen, and the patient presses the corresponding key on the keyboard as quickly as possible. The next circle appears after 500 ms, until 52 circles have been exposed. The computer measures the time the subject takes to complete the test and the number of errors they make.
Anton K. Formann was an Austrian research psychologist, statistician, and psychometrician. He is renowned for his contributions to item response theory, latent class analysis, the measurement of change, mixture models, categorical data analysis, and quantitative methods for research synthesis (meta-analysis).
Bizarreness effect is the tendency of bizarre material to be better remembered than common material. The scientific evidence for its existence is contested. Some research suggests it does exist, some suggests it doesn't exist and some suggests it leads to worse remembering.
"The Unsuccessful Self-Treatment of a Case of 'Writer's Block'" is a humorous academic article by psychologist Dennis Upper about writer's block. It contains no content except for a title, journal formatting elements, and a humorous footnote.
The Vineland Social Maturity Scale is a psychometric assessment instrument designed to help in the assessment of social competence. It was developed by the American psychologist Edgar Arnold Doll and published in 1940. He published a manual for it in 1953. Doll named it after the Vineland Training School for the Mentally Retarded, where he developed it.
The birthday-number effect is the subconscious tendency of people to prefer the numbers in the date of their birthday over other numbers. First reported in 1997 by Japanese psychologists Shinobu Kitayama and Mayumi Karasawa, the birthday-number effect has been replicated in various countries. It holds across age and gender. The effect is most prominent for numbers over 12.
Martin S. Fiebert, is an emeritus professor at California State University, Long Beach in the Department of Psychology. He has published more than 70 articles in peer-reviewed journals.
Franziska Baumgarten-Tramèr was an industrial psychologist, professor, and researcher. She is known for her work on the effects of war and trauma, aptitude testing, and gifted schoolchildren.
A dream character, sometimes abbreviated as DC, is an interactable human-like entity in the person's dream, especially while the person is REM-sleeping. The topic has been profoundly addressed in the lucid dreaming community, since while experiencing a lucid dream, the person can consciously interact with dream characters.
