RESEARCH BASE

Search 3,721 documents across 34 fields — every claim tier-rated by evidence

3,721 documents 34 sections 43,623 citations 34,854 keywords indexed 4 evidence tiers

3,633 are the core, quality-scored corpus (34 lettered sections — see How We Work); the remaining 88 are cross-corpus synthesis documents (68 InterDocs, 12 Connections, 8 Theories) also indexed here.

1,606 results for "tit for tat" — page 56 of 81

L_2_02 Genetics & Origins

L_2_02 — Population Genetics and Hardy-Weinberg Equilibrium

Population genetics — the mathematical study of allele frequency change in populations — provides the quantitative framework underlying evolutionary biology. The Hardy-Weinberg principle (1908), independently derived by

population genetics Hardy-Weinberg equilibrium allele frequency genetic drift natural selection migration
L_2_16 Verified Genetics & Origins

L_2_16 — Genetic Diversity and Inbreeding: Population Health Across History

Genetic diversity — the total amount of genetic variation within a population — is a fundamental determinant of population health, adaptive potential, and long-term survival. The loss of diversity through inbreeding (mat

genetic diversity inbreeding consanguinity runs of homozygosity ROH inbreeding depression
L_2_07 Genetics & Origins

L_2_07 — European Genetics and Three Ancestral Populations

The genetic history of Europe has been revolutionized by ancient DNA, revealing that most present-day Europeans can be modeled at a broad level as mixtures of three major ancestral components assembled over the past ~10,

European genetics ancient DNA three ancestral populations Western Hunter-Gatherers Early European Farmers Steppe pastoralists
L_2_04 Genetics & Origins

L_2_04 — Oceanian Genetics and Pacific Migration

The human settlement of Oceania represents the last major expansion of Homo sapiens across the globe, and the most remarkable feat of maritime exploration in human history. It occurred in two major phases separated by ~4

Oceanian genetics Pacific migration Lapita Austronesian expansion Polynesia Melanesia
L_3_06 Genetics & Origins

L_3_06 — Genetics of Intelligence and Cognition

The genetics of intelligence — one of the most studied yet contentious areas in behavioral genetics — has established that cognitive ability, as measured by standardized tests, has a substantial heritable component (~50–

intelligence genetics cognitive ability IQ heritability GWAS intelligence polygenic score educational attainment
L_3_17 Verified Genetics & Origins

L_3_17 — Endogenous Retroviruses (HERVs) in the Human Genome

Human endogenous retroviruses (HERVs) — remnants of ancient retroviral infections that integrated into the germline DNA of human ancestors and have been vertically transmitted through the host genome for millions of year

endogenous retroviruses HERVs HERV-K HERV-W syncytin retroviral integration
L_3_09 Verified Genetics & Origins

L_3_09 — HLA Diversity and Immune System Evolution

The Human Leukocyte Antigen (HLA) system — the human version of the Major Histocompatibility Complex (MHC) found in all jawed vertebrates — is the most polymorphic gene region in the entire human genome. Located on chrom

HLA MHC major histocompatibility complex immune diversity balancing selection antigen presentation
L_3_05 Genetics & Origins

L_3_05 — Blood Type Genetics and the ABO System

Blood group genetics represents one of the earliest and most clinically important applications of Mendelian inheritance in human biology. Karl Landsteiner's discovery of the ABO blood group system (1900–1901) — which ear

blood type ABO system Rh factor Karl Landsteiner blood transfusion blood group antigens
L_3_11 Verified Genetics & Origins

L_3_11 — Genetics of Taste and Dietary Adaptation

Taste perception — the ability to detect sweet, salty, sour, bitter, and umami (savory) stimuli — is mediated by genetically encoded receptor proteins whose variation across individuals and populations reflects evolution

taste genetics TAS2R_4_05 PTC PROP bitter taste umami
L_5_10 Verified Genetics & Origins

L_5_10 — Neandertal Introgression: Which Genes and Why They Persisted

When modern humans (Homo sapiens) migrated out of Africa ~60,000-70,000 years ago and encountered Neanderthals (Homo neanderthalensis) in western Asia and Europe, the two species interbred — and the genetic legacy of tha

Neandertal introgression admixture adaptive introgression purifying selection immune genes
L_5_09 Verified Genetics & Origins

L_5_09 — Human Microbiome Co-Evolution: Ancient Gut Companions

The human microbiome — the trillions of bacteria, archaea, fungi, and viruses that inhabit our bodies, particularly the gastrointestinal tract — is not merely a passive inhabitant but a co-evolved partner that has shaped

microbiome gut bacteria co-evolution Helicobacter pylori human migration paleomicrobiology
L_5_14 Verified Genetics & Origins

L_5_14 — Amino Acid Racemization Dating Method

Amino acid racemization (AAR) — a geochronological dating technique based on the chemical conversion of L-amino acids (the biologically predominant enantiomer in living organisms) to D-amino acids (the mirror-image confi

amino acid racemization AAR dating method D/L ratio enantiomers isoleucine epimerization
Y_4_02 Altered States

Y_4_02 — Savant Syndrome and Acquired Genius

Savant syndrome — extraordinary ability coexisting with significant cognitive disability — affects roughly 1 in 10 people with autism and ~1 in 2,000 people with other developmental disabilities or brain injuries. What m

savant syndrome acquired savant traumatic brain injury autistic savant Kim Peek Daniel Tammet
Y_4_04 Altered States

Y_4_04 — Entoptic Phenomena and Phosphene Patterns

This document examines Entoptic Phenomena and Phosphene Patterns, a topic within the Consciousness research area. Key areas of investigation include Defining Entoptic Phenomena, Phosphenes: Light from Within, Heinrich Kl

entoptic phenomena phosphene form constants Heinrich Klüver mescaline Lewis-Williams
Y_4_01 Altered States

Y_4_01 — Lucid Dreaming Research

Lucid dreaming — being consciously aware that you are dreaming WHILE dreaming, and potentially controlling dream content — was scientifically verified in 1975-1981 through a breakthrough protocol: pre-arranged EYE SIGNAL

lucid dreaming dream consciousness REM sleep sleeping brain metacognition prefrontal cortex
Y_4_22 Credible Altered States

Y_4_22 — Hypnagogic & Hypnopompic States

Hypnagogia (the transitional state between wakefulness and sleep onset) and hypnopompia (the transition from sleep to waking) are naturally occurring altered states of consciousness experienced universally by humans. Cha

hypnagogia hypnopompia sleep onset phosphenes tetris effect sleep paralysis
Y_4_20 Credible Altered States

Y_4_20 — Drumming & Trance Neuroscience

Shamanic drumming — typically monotonous percussive rhythms at approximately 4–4.5 beats per second — has been used across virtually every indigenous culture as a primary technology for inducing trance states, and modern

drumming trance theta rhythm auditory driving EEG entrainment
Y_4_13 Verified Altered States

Y_4_13 — Collective Effervescence and Group Altered States

Collective effervescence — Émile Durkheim's term (The Elementary Forms of Religious Life, 1912) for the heightened emotional energy generated when people gather and act together in coordinated ritual — describes a group

collective effervescence Durkheim group ritual emotional contagion synchrony entrainment
Y_4_19 Credible Altered States

Y_4_19 — Ritual-Induced Ecstasy

Ritual-induced ecstasy — altered states of consciousness produced through collective ceremonial practices including dance, chanting, drumming, fasting, pain ordeal, and rhythmic movement — is one of the oldest and most u

ritual ecstasy trance collective effervescence Durkheim sacred dance
Y_4_09 Altered States

Y_4_09 — Sensory Deprivation — Float Tanks, Dark Retreats, and Consciousness Isolation

Sensory deprivation research — the systematic reduction or elimination of sensory input to study consciousness — began with John C. Lilly's invention of the isolation/flotation tank in 1954 at the National Institute of M

sensory deprivation float tank isolation tank REST John Lilly Epsom salt