Genes, Evolution and Intelligence

Abstract

I argue that the g factor meets the fundamental criteria of a scientific construct more fully than any other conception of intelligence. I briefly discuss the evidence regarding the relationship of brain size to intelligence. A review of a large body of evidence demonstrates that there is a g factor in a wide range of species and that, in the species studied, it relates to brain size and is heritable. These findings suggest that many species have evolved a general-purpose mechanism (a general biological intelligence) for dealing with the environments in which they evolved. In spite of numerous studies with considerable statistical power, we know of very few genes that influence g and the effects are very small. Nevertheless, g appears to be highly polygenic. Given the complexity of the human brain, it is not surprising that that one of its primary faculties-intelligence-is best explained by the near infinitesimal model of quantitative genetics.

Bonobo personality traits are heritable and associated with vasopressin receptor gene 1a variation

“…Despite differences in the number of bonobos for which we had codings and ratings, the heritability estimates were comparable, and in line with estimates ranging from 0 to 0.6 found in animal personality studies1112131415161718. Adding mother ID and group as random effects to the model significantly improved the heritability models for all of the personality dimensions except Conscientiousness R .…”

“…Personality traits typically have heritabilities ranging from 0 to 60% in species, such as dumpling squid ( Euprymna tasmanica )11, yellow-bellied marmots ( Marmota flaviventris )12, American red squirrels ( Tamiasciurus hudsonicus )13, rhesus macaques ( Macaca mulatta )14, chimpanzees ( Pan troglodytes )1516 and humans ( Homo sapiens )17 (for review see18). Further completing the picture of how genes and environment interact to produce behavioral phenotypes is difficult, but candidate genes with large behavioral effects have been identified19.…”

Human high intelligence is involved in spectral redshift of biophotonic activities in the brain

“…Then donation program coordinators would arrange the transport of donated body to an approved autopsy center, where the brain was carefully removed according to a standard procedure and collected by CBBC. (5) 646.9 ± 1.53*** 591.1 ± 2.78*** 711.8 ± 0.0** Chicken (5) 667.3 ± 2.00*** 607.4 ± 2.97* 739.2 ± 1.96*** Pig (34) 682.3 ± 0.68*** 604.9 ± 1.29 777.7 ± 0.75*** Monkey (11) 696.9 ± 0.85*** 609.8 ± 1.76 806.1 ± 1.49*** Human (31) 714.6 ± 1.59*** 595.6 ± 2.13*** 865.3 ± 2.74*** F value; P value F = 399; P < 0.0001 F = 82; P < 0.0001 F = 569; P < 0.0001 λ ave , λ min , and λ max are the average, minimum, and maximum wavelength, respectively; N, the number of brain slices. Asterisks indicate a significant difference between the neighboring two groups: *P < 0.01; **P < 0.001; ***P < 0.0001.…”

“…Early studies have proposed that brain size and the degree of encephalization [encephalization quotient (EQ)] might be related to the evolution of animal intelligence, including that of human beings (2-4), but, so far, the relationship between relative brain size and intelligence is inconclusive, and EQ is also not the best predictor of intelligence (1,(5)(6)(7). Communications and information-processing capacity between neurons in neural circuits play an important role in the realization of various neural functions, such as sensorimotor control, learning and memory, consciousness, and cognition.…”

Effect of tryptophan hydroxylase-2 gene polymorphism G-703 T on personality in a population representative sample

“…Subjects with higher scores in certain personality traits, such as Neuroticism and Harm Avoidance (HA), are at higher risk for affective disorders (Clark et al, 1994;Fava and Kendler, 2000). Evidence from twin studies indicates that personality traits are to a great extent genetically determined (Bouchard and Loehlin, 2001;Jang et al, 1996) and a wide range of studies have tried to identify specific genetic markers for anxiety-related personality traits. Indeed, some polymorphisms in genes encoding the key proteins of the 5-HT system have been associated with negative emotionality.…”