Conspicuous consumption

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https://en.wikipedia.org/wiki/Conspicuous_consumption 

 

The sociologist and economist Thorstein Veblen coined the term "conspicuous consumption", and was a pioneer of the institutional economics movement.

In sociology and in economics, the term conspicuous consumption describes and explains the consumer practice of buying and using goods of a higher quality, price, or in greater quantity than practical. In 1899, the sociologist Thorstein Veblen coined the term conspicuous consumption to explain the spending of money on and the acquiring of luxury commodities (goods and services) specifically as a public display of economic power — the income and the accumulated wealth of the buyer. To the conspicuous consumer, the public display of discretionary income is an economic means of either attaining or of maintaining a given social status.

The development of Veblen's sociology of conspicuous consumption also identified and described other economic behaviours such as invidious consumption, which is the ostentatious consumption of goods, an action meant to provoke the envy of other people; and conspicuous compassion, the ostentatious use of charity meant to enhance the reputation and social prestige of the donor; thus the socio-economic practises of consumerism derive from conspicuous consumption.

History and development

In The Theory of the Leisure Class: An Economic Study in the Evolution of Institutions (1899), Thorstein Veblen identified, described, and explained the behavioural characteristics of the nouveau riche (new rich) social class that emerged from capital accumulation during the Second Industrial Revolution (1860–1914). In that 19th-century social and historical context, the term "conspicuous consumption" applied narrowly in association with the men, women, and families of the upper class who applied their great wealth as a means of publicly manifesting their social power and prestige, either real or perceived. The strength of one's reputation is in direct relationship to the amount of money possessed and displayed; that is to say, the basis "of gaining and retaining a good name, are leisure and conspicuous consumption."

In the 1920s, economists such as Paul Nystrom proposed that changes in lifestyle as result of the industrial age led to massive expansion of the "pecuniary emulation." That conspicuous consumption had induced in the mass of society a "philosophy of futility" that would increase the consumption of goods and services as a social fashion; consumption for the sake of consumption.

In 1949, James Duesenberry proposed the "demonstration effect" and the "bandwagon effect", whereby a person's conspicuous consumption psychologically depends upon the actual level of spending, but also depends upon the degree of his or her spending, when compared with and to the spending of other people. That the conspicuous consumer is motivated by the importance, to him or to her, of the opinion of the social and economic reference groups for whom he or she are performed the conspicuous consumption.

Social class and consumption

Veblen said that conspicuous consumption comprised socio-economic behaviours practised by rich people as activities usual and exclusive to people with much disposable income; yet a variation of Veblen's theory is presented in the conspicuous consumption behaviours that are very common to the middle class and to the working class, regardless of the person's race and ethnic group. Such upper-class economic behaviour is especially common in societies with emerging economies in which the conspicuous consumption of goods and services ostentatiously signals that the buyer rose from poverty and has something to prove to society.

In The Millionaire Next Door: The Surprising Secrets of America's Wealthy (1996), Thomas J. Stanley and William D. Danko reported conspicuous frugality, another variation of Veblen's social-class relation to conspicuous consumption. That Americans with a net worth of more than a million dollars usually avoid conspicuous consumption, and tend to practise frugality, such as paying cash for a used car rather using credit, in order to avoid material depreciation and paying interest upon a car loan.

Consumerism theory

Since the 19th century, conspicuous consumption explains the psychology behind the economics of a consumer society, and the increase in the types of goods and services that people consider necessary to and for their lives in a developed economy. Supporting interpretations and explanations of contemporary conspicuous consumption are presented in Consumer Culture (1996) by Celia Lury, Consumer Culture and Modernity (1997) by Don Slater, Symbolic Exchange and Death (1998) by Jean Baudrillard, and Spent: Sex, Evolution, and the Secrets of Consumerism (2009) by Geoffrey Miller.

Moreover, D. Hebdige, in Hiding in the Light (1994), proposes that conspicuous consumption is a form of displaying a personal identity, and a consequent function of advertising, as proposed in Ads, Fads, and Consumer Culture (2000), by A. A. Berger. Each variant interpretation and complementary explanation is derived from Veblen's original sociologic proposition in The Theory of the Leisure Class: that conspicuous consumption is a psychological end in itself, from which the practitioner (man, woman, family) derived the honour of superior social status.

Materialism and gender

In An Examination of Materialism, Conspicuous Consumption and Gender Differences (2013), the researchers Brenda Segal and Jeffrey S. Podoshen reported great differences in the consumerism practised by men and women. The data about materialism and impulse purchases of 1,180 Americans indicate that men have greater scores for materialism and conspicuous consumption; and that women tended to buy goods and services on impulse; and both sexes were equally loyal to a given brand of goods and services.

Distinctions of type

The term conspicuous consumption denotes the act of buying something, especially something expensive, that is not necessary to one's life, in a noticeable way. Scholar Andrew Trigg (2001) defined conspicuous consumption as behaviour by which one can display great wealth, by means of idleness—expending much time in the practice of leisure activities, and spending much money to consume luxury goods and services.

Conspicuous compassion, the practice of publicly donating large sums of money to charity to enhance the social prestige of the donor, is sometimes described as a type of conspicuous consumption. This behaviour has long been recognised and sometimes attacked—for example, the New Testament story Lesson of the widow's mite criticises wealthy people who make large donations ostentatiously, while praising poorer people who make small but comparatively more difficult donations in private.

Possible motivations for conspicuous consumption include:

• Demonstration/bandwagon effect — In the book Income, Saving and the Theory of Consumer Behavior (1949), James Duesenberry proposed that a person's conspicuous consumption psychologically depends not only upon the actual level of spending, but also upon the degree of his or her spending, as compared with the spending of other people. Thus the conspicuous consumer is motivated by the importance, to him or to her, of the opinion of the social and economic reference groups for whom are performed the patterns of conspicuous consumption.
• 'Aggressive ostentation — In a 2006 CBSNews.com article, Dick Meyer said that conspicuous consumption is a form of anger towards society, an "aggressive ostentation" that is an antisocial behaviour, which arose from the social alienation suffered by men, women, and families who feel they have become anonymous in and to their societies. This feeling of alienation is aggravated by the decay of the communitarian ethic essential to a person feeling him or herself part of the whole society.
• Shelter and transport — In the United States, the trend towards building houses that were larger than needed by a nuclear family began in the 1950s. Decades later, in the year 2000, that practice of conspicuous consumption resulted in people buying houses that were double the average size needed to comfortably house a nuclear family. Negative consequences of either buying or building an oversized house might include:
  • the loss of or reduction in the family's domestic recreational space—the backyard and the front yard;
  • the spending of old-age retirement funds to pay for a too-big house;
  • over-long commuting time, from house to job, and vice versa, because the required plot of land was unavailable near a city.

Oversized houses facilitated other forms of conspicuous consumption, such as an oversized garage for the family's oversized motor vehicles or buying more clothing to fill larger clothes closets. Conspicuous consumption becomes a self-generating cycle of spending money for the sake of social prestige. Analogous to the consumer trend for oversized houses is the trend towards buying oversized light trucks, specifically the off-road sport utility vehicle type (cf. station wagon/estate car), as a form of psychologically comforting conspicuous consumption, because such large vehicles usually are bought by city-dwellers, an urban nuclear family.

• Prestige – In a 1999 article, Jacqueline Eastman, Ronald Goldsmith, and Leisa Reinecke Flynn said that status consumption is based upon conspicuous consumption; however, the literature of contemporary marketing does not establish definitive meanings for the terms status consumption and conspicuous consumption. Moreover, A. O'Cass and H. Frost (2002) claim that sociologists often incorrectly used the two terms as interchangeable and equivalent terms. In a later study, O'Cass and Frost determined that, as sociological constructs, the terms status consumption and conspicuous consumption denote different sociological behaviours. About the ambiguities of denotation and connotation of the term conspicuous consumption, R. Mason (1984) reported that the classical, general theories of consumer decision-processes do not readily accommodate the construct of "conspicuous consumption," because the nature of said socio-economic behaviours varies according to the social class and the economic group studied.
• Motivations — Paurav Shukla (2010) says that, whilst marketing and sales researchers recognise the importance of the buyer's social and psychological environment, the definition of the term status-directed consumption remains ambiguous, because the development of a comprehensive general theory requires that social scientists accept two fundamental assumptions, which usually do not concord. First, though the "rational" (economic) and the "irrational" (psychologic) elements of consumer decision-making often influence a person's decision to buy particular goods and services, marketing and sales researchers usually consider the rational element dominant in a person's decision to buy the particular goods and services. Second, the consumer perceives the utility of the product (the goods, the services) as a prime consideration in evaluating its usefulness, i.e. the reason to buy the product. These assumptions, required for the development of a general theory of brand selection and brand purchase, are problematic, because the resultant theories tend either to misunderstand or to ignore the "irrational" element in the behaviour of the buyer-as-consumer; and because conspicuous consumption is a behaviour predominantly "psychological" in motivation and expression, Therefore, a comprehensive, general theory of conspicuous consumption would require a separate construct for the psychological (irrational) elements of the socio-economic phenomenon that is conspicuous consumption.

Examples

Conspicuous consumption is exemplified by purchasing goods that are exclusively designed to serve as symbols of wealth, such as luxury-brand clothing, high-tech tools, and vehicles.

Luxury fashion

Materialistic consumers are likely to engage in conspicuous luxury consumption. The global yearly revenue of the luxury fashion industry was €1.64 trillion in 2019. Buying of conspicuous goods is likely to be influenced by the spending habits of others. This view of luxury conspicuous consumption is being incorporated into social media platforms which is impacting consumer behaviour.

Criticism

The journalist H. L. Mencken addressed the sociological and psychological particulars of the socio-economic behaviours that are conspicuous consumption, by asking:

Do I enjoy a decent bath because I know that John Smith cannot afford one — or because I delight in being clean? Do I admire Beethoven's Fifth Symphony because it is incomprehensible to Congressmen and Methodists — or because I genuinely love music? Do I prefer terrapin à la Maryland to fried liver because plowhands must put up with the liver — or because the terrapin is intrinsically a more charming dose? Do I prefer kissing a pretty girl to kissing a charwoman, because even a janitor may kiss a charwoman — or because the pretty girl looks better, smells better, and kisses better?

Inequality and debt

In The Theory of the Leisure Class (1899) Veblen said that “among the motives which lead men to accumulate wealth, the primacy, both in scope and intensity, therefore, continues to belong to this motive of pecuniary emulation of the rich". In the study “Borrowing to Keep Up (with the Joneses): Inequality, Debt, and Conspicuous Consumption” (2020), Sheheryar Banuri and Ha Nguyen reported three findings:

• Consumption tends to increase when the buying and the using of goods and services is conspicuous: Consumption signals status to other people.
• Conspicuous consumption increases the frequency of borrowing money: Poor people take out loans in order to compete at consumption.
• Economic inequality is worsened with access to credit: Poor people borrow money in order to signal status, which becomes a vicious circle.

The findings that Banuri and Nguyen reported indicate that the cyclical effect of borrowing money for conspicuous consumption leads to and perpetuates economic inequality. That poor people imitate, try to match, and emulate the consumption patterns of rich people in order to increase their social status, and perhaps rise in society. That such socio-economic behaviours, facilitated by easy access to credit, generate macroeconomic volatility and support Veblen's concept of pecuniary emulation used to finance a person's social standing.

Other research supports these and similar results. For example income inequality has been found to be associated with reduced savings rates. One hypothesized mechanism for this relationship is 'expenditure cascades' whereby consumption norms are set by the relatively wealthy, who then have more income and consumption relative to others as inequality rises. This emulation of the consumption norms of relatively wealthy peers is supported by a large literature.

One complication found in the macro literature is that the link between inequality and savings may depend on context, in particular on the degree of financialisation. When the degree of financialisation is high, inequality tends to reduce the national savings rate as the emulation effect is more powerful when finance is readily available, but the opposite effect may occur when financialisation is low as the emulation effect is weak, and the rich tend to save at a higher rate than the poor. The effect of inequality on savings is also found to be positive in Asia, where financialization is lower. The relationship is also found to depend on economic policy and institutions. For example inequality appears to lower savings in 'liberal market economies' but to rather reduce aggregate demand in 'coordinated market economies'. 

In the case where inequality lowers savings, and increases leverage and a tendency to run large current account imbalances via the expenditure cascade mechanism, this has been associated with more frequent and/or severe economic crisis.

Solutions

In the case of conspicuous consumption, taxes upon luxury goods diminish societal expenditures on high-status goods, by rendering them more expensive than non-positional goods. In this sense, luxury taxes can be seen as a market failure correcting Pigovian tax—with an apparent negative deadweight loss, these taxes are a more efficient mechanism for increasing revenue than 'distorting' labour or capital taxes. A luxury tax applied to goods and services for conspicuous consumption is a type of progressive sales tax that at least partially corrects the negative externality associated with the conspicuous consumption of positional goods. In Utility from Accumulation (2009), Louis Kaplow said that assets exercise an objective social-utility function, i.e. the rich man and the rich woman hoard material assets, because the hoard, itself, functions as status goods that establish his and her socio-economic position within society. When utility is derived directly from accumulation of assets, this lowers the dead weight loss associated with inheritance taxes and raises the optimal rate of inheritance taxation.

In the 19th century, the philosopher John Stuart Mill recommended taxing the practice of conspicuous consumption.

In place of luxury taxes, economist Robert H. Frank proposed the application of a progressive consumption tax; in a 1998 New York Times article, John Tierney said that as a remedy for the social and psychological malaise that is conspicuous consumption, the personal income tax should be replaced with a progressive tax upon the yearly sum of discretionary income spent on the conspicuous consumption of goods and services. Another option is the redistribution of wealth, either by means of an incomes policy – for example the conscious efforts to promote wage compression under variants of social corporatism such as the Rehn–Meidner model and/or by some mix of progressive taxation and transfer policies, and provision of public goods. When individuals are concerned with their relative income or consumption in comparison to their peers, the optimal degree of public good provision and of progression of the tax system is raised. Because the activity of conspicuous consumption, itself, is a form of superior good, diminishing the income inequality of the income distribution by way of an egalitarian policy reduces the conspicuous consumption of positional goods and services. In Wealth and Welfare (1912), the economist A. C. Pigou said that the redistribution of wealth might lead to great gains in social welfare:

Now the part played by comparative, as distinguished from absolute, income is likely to be small for incomes that only suffice to provide the necessaries and primary comforts of life, but to be large with large incomes. In other words, a larger proportion of the satisfaction yielded by the incomes of rich people comes from their relative, rather than from their absolute, amount. This part of it will not be destroyed if the incomes of all rich people are diminished together. The loss of economic welfare suffered by the rich when command over resources is transferred from them to the poor will, therefore, be substantially smaller relatively to the gain of economic welfare to the poor than a consideration of the law of diminishing utility taken by itself suggests.

The economic case for the taxation of positional, luxury goods has a long history; in the mid-19th century, in Principles of Political Economy with some of their Applications to Social Philosophy (1848), John Stuart Mill said:

I disclaim all asceticism, and by no means wish to see discouraged, either by law or opinion, any indulgence which is sought from a genuine inclination for, any enjoyment of, the thing itself; but a great portion of the expenses of the higher and middle classes in most countries ... is not incurred for the sake of the pleasure afforded by the things on which the money is spent, but from regard to opinion, and an idea that certain expenses are expected from them, as an appendage of station; and I cannot but think that expenditure of this sort is a most desirable subject of taxation. If taxation discourages it, some good is done, and if not, no harm; for in so far as taxes are levied on things which are desired and possessed from motives of this description, nobody is the worse for them. When a thing is bought not for its use but for its costliness, cheapness is no recommendation.

In the case where conspicuous consumption mediates a link between inequality and unsustainable borrowing, one suggested policy response is tighter financial regulation.

"Conspicuous non consumption" is a phrase used to describe a conscious choice to opt out of consumption with the intention of sending deliberate social signals.

Terrestrial planet

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https://en.wikipedia.org/wiki/Terrestrial_planet 

 

The terrestrial planets of the Solar System: Mercury, Venus, Earth and Mars, sized to scale

A terrestrial planet, telluric planet, or rocky planet, is a planet that is composed primarily of silicate rocks or metals. Within the Solar System, the terrestrial planets accepted by the IAU are the inner planets closest to the Sun: Mercury, Venus, Earth and Mars. Among astronomers who use the geophysical definition of a planet, two or three planetary-mass satellites – Earth's Moon, Io, and sometimes Europa – may also be considered terrestrial planets; and so may be the rocky protoplanet-asteroids Pallas and Vesta. The terms "terrestrial planet" and "telluric planet" are derived from Latin words for Earth (Terra and Tellus), as these planets are, in terms of structure, Earth-like.

Terrestrial planets have a solid planetary surface, making them substantially different from the larger gaseous planets, which are composed mostly of some combination of hydrogen, helium, and water existing in various physical states.

Structure

All terrestrial planets in the Solar System have the same basic structure, such as a central metallic core (mostly iron) with a surrounding silicate mantle.

The large rocky asteroid 4 Vesta has a similar structure; possibly so does the smaller one 21 Lutetia. Another rocky asteroid 2 Pallas is about the same size as Vesta, but is significantly less dense; it appears to have never differentiated a core and a mantle. The Earth's Moon and Jupiter's moon Io have similar structures to the terrestrial planets, but Earth's Moon has a much smaller iron core. Another Jovian moon Europa has a similar density but has a significant ice layer on the surface: for this reason, it is sometimes considered an icy planet instead.

Terrestrial planets can have surface structures such as canyons, craters, mountains, volcanoes, and others, depending on the presence at any time of an erosive liquid or tectonic activity or both.

Terrestrial planets have secondary atmospheres, generated by volcanic out-gassing or from comet impact debris. This contrasts with the outer, giant planets, whose atmospheres are primary; primary atmospheres were captured directly from the original solar nebula.

Solar System's terrestrial planets

Relative masses of the terrestrial planets of the Solar System, and the Moon (shown here as Luna)

 

The inner planets (sizes to scale). From left to right: Earth, Mars, Venus and Mercury.

The Solar System has four terrestrial planets under the dynamical definition: Mercury, Venus, Earth and Mars. The Earth's Moon as well as Jupiter's moons Io and Europa would also count geophysically. Among these bodies, only the Earth has an active surface hydrosphere. Europa is believed to have an active hydrosphere under its ice layer.

During the formation of the Solar System, there were many terrestrial planetesimals and proto-planets, but most merged with or were ejected by the four terrestrial planets, leaving only Pallas and Vesta to survive more or less intact. These two were likely both dwarf planets in the past, but have been battered out of equilibrium shapes by impacts. Some other protoplanets began to accrete and differentiate, but suffered catastrophic collisions that left only a metallic or rocky core, like 16 Psyche or 8 Flora respectively. Many S-type and M-type asteroids may be such fragments.

The other round bodies from the asteroid belt outward are geophysically icy planets. They are similar to terrestrial planets in that they have a solid surface, but are composed of ice and rock rather than of rock and metal. These include the dwarf planets, such as Ceres, Pluto and Eris, which are found today only in the regions beyond the formation snow line where water ice was stable under direct sunlight in the early Solar System. It also includes the other round moons, which are ice-rock (e.g. Ganymede, Callisto, Titan, and Triton) or even primarily ice (e.g. Mimas, Tethys, and Iapetus). Some of these bodies are known to have subsurface hydrospheres (Ganymede, Callisto, Enceladus, and Titan), like Europa, and it is also possible for some others (e.g. Ceres, Dione, Miranda, Ariel, Triton, and Pluto). Titan even has surface bodies of liquid, albeit liquid methane rather than water. Jupiter's Ganymede, though icy, does have a metallic core like the Moon, Io, Europa, and the terrestrial planets.

The name Terran world has been suggested to define all solid worlds (bodies assuming a rounded shape), without regard to their composition. It would thus include both terrestrial and icy planets.

Density trends

The uncompressed density of a terrestrial planet is the average density its materials would have at zero pressure. A greater uncompressed density indicates greater metal content. Uncompressed density differs from the true average density (also often called "bulk" density) because compression within planet cores increases their density; the average density depends on planet size, temperature distribution, and material stiffness as well as composition.

Calculations to estimate uncompressed density inherently require a model of the planet's structure. Where there have been landers or multiple orbiting spacecraft, these models are constrained by seismological data and also moment of inertia data derived from the spacecraft orbits. Where such data is not available, uncertainties are inevitably higher.

The uncompressed density of the rounded terrestrial bodies directly orbiting the Sun trends towards lower values as the distance from the Sun increases, consistent with the temperature gradient that would have existed within the primordial solar nebula. The Galilean satellites show a similar trend going outwards from Jupiter; however, no such trend is observable for the icy satellites of Saturn or Uranus. The icy worlds typically have densities less than 2 g·cm⁻³. Eris is significantly denser (2.43±0.05 g·cm⁻³), and may be mostly rocky with some surface ice, like Europa. It is unknown whether extrasolar terrestrial planets in general will follow such a trend.

The data in the tables below is mostly taken from list of gravitationally rounded objects of the Solar System and planetary-mass moon. All distances from the Sun are averages.

Densities of the terrestrial geophysical planets (including borderline Pallas and Vesta) Object Density (g·cm−3) Distance from Sun (AU) Mean Uncompressed Mercury 5.4 5.3 0.39 Venus 5.2 4.4 0.72 Earth 5.5 4.4 1.0 Moon 3.3 3.3 Mars 3.9 3.8 1.52 Vesta 3.5 3.5 2.36 Pallas 2.9 2.9 2.77 Io 3.5 3.5 5.20 Europa 3.0 3.0

Densities of some icy geophysical planets (other KBO densities are poorly known) Object Density (g·cm−3) Distance from Sun (AU) Ceres 2.2 2.77 Ganymede 1.9 5.20 Callisto 1.8 Mimas 1.2 9.54 Enceladus 1.6 Tethys 1.0 Dione 1.5 Rhea 1.2 Titan 1.9 Iapetus 1.1 Miranda 1.2 19.2 Ariel 1.6 Umbriel 1.5 Titania 1.7 Oberon 1.6 Triton 2.1 30.1 Pluto 1.9 39.5 Charon 1.7 Eris 2.4 67.9

Extrasolar terrestrial planets

See also: Super-Earth, Mega-Earth, and List of nearest terrestrial exoplanet candidates

Most of the planets discovered outside the Solar System are giant planets, because they are more easily detectable. But since 2005, hundreds of potentially terrestrial extrasolar planets have also been found, with several being confirmed as terrestrial. Most of these are super-Earths, i.e. planets with masses between Earth's and Neptune's; super-Earths may be gas planets or terrestrial, depending on their mass and other parameters.

It is likely that most known super-Earths are in fact gas planets similar to Neptune, as examination of the relationship between mass and radius of exoplanets (and thus density trends) shows a transition point at about two Earth masses. This suggests that this is the point at which significant gas envelopes accumulate. In particular, Earth and Venus may already be close to the largest possible size at which a planet can usually remain rocky. Exceptions to this are very close to their stars (and thus would have had their volatile atmospheres boiled away).

During the early 1990s, the first extrasolar planets were discovered orbiting the pulsar PSR B1257+12, with masses of 0.02, 4.3, and 3.9 times that of Earth's, by pulsar timing.

When 51 Pegasi b, the first planet found around a star still undergoing fusion, was discovered, many astronomers assumed it to be a gigantic terrestrial, because it was assumed no gas giant could exist as close to its star (0.052 AU) as 51 Pegasi b did. It was later found to be a gas giant.

In 2005, the first planets orbiting a main-sequence star and which show signs of being terrestrial planets were found: Gliese 876 d and OGLE-2005-BLG-390Lb. Gliese 876 d orbits the red dwarf Gliese 876, 15 light years from Earth, and has a mass seven to nine times that of Earth and an orbital period of just two Earth days. OGLE-2005-BLG-390Lb has about 5.5 times the mass of Earth, orbits a star about 21,000 light years away in the constellation Scorpius. From 2007 to 2010, three (possibly four) potential terrestrial planets were found orbiting within the Gliese 581 planetary system. The smallest, Gliese 581e, is only about 1.9 Earth masses, but orbits very close to the star. Two others, Gliese 581c and Gliese 581d, as well as a disputed planet, Gliese 581g, are more-massive super-Earths orbiting in or close to the habitable zone of the star, so they could potentially be habitable, with Earth-like temperatures.

Another possibly terrestrial planet, HD 85512 b, was discovered in 2011; it has at least 3.6 times the mass of Earth. The radius and composition of all these planets are unknown.

Sizes of Kepler planet candidates based on 2,740 candidates orbiting 2,036 stars as of 4 November 2013 (NASA).

The first confirmed terrestrial exoplanet, Kepler-10b, was found in 2011 by the Kepler Mission, specifically designed to discover Earth-size planets around other stars using the transit method.

In the same year, the Kepler Space Observatory Mission team released a list of 1235 extrasolar planet candidates, including six that are "Earth-size" or "super-Earth-size" (i.e. they have a radius less than 2 Earth radii) and in the habitable zone of their star. Since then, Kepler has discovered hundreds of planets ranging from Moon-sized to super-Earths, with many more candidates in this size range (see image).

In September 2020, astronomers using microlensing techniques reported the detection, for the first time, of an Earth-mass rogue planet (named OGLE-2016-BLG-1928) unbounded by any star, and free-floating in the Milky Way galaxy.

List of terrestrial exoplanets

See also: List of nearest terrestrial exoplanet candidates

The following exoplanets have a density of at least 5 g/cm³ and a mass below Neptune's and are thus very likely terrestrial:

Kepler-10b, Kepler-20b, Kepler-36b, Kepler-48d, Kepler 68c, Kepler-78b, Kepler-89b, Kepler-93b, Kepler-97b, Kepler-99b, Kepler-100b, Kepler-101c, Kepler-102b, Kepler-102d, Kepler-113b, Kepler-131b, Kepler-131c, Kepler-138c, Kepler-406b, Kepler-406c, Kepler-409b.

Frequency

In 2013, astronomers reported, based on Kepler space mission data, that there could be as many as 40 billion Earth- and super-Earth-sized planets orbiting in the habitable zones of Sun-like stars and red dwarfs within the Milky Way. 11 billion of these estimated planets may be orbiting Sun-like stars. The nearest such planet may be 12 light-years away, according to the scientists. However, this does not give estimates for the number of extrasolar terrestrial planets, because there are planets as small as Earth that have been shown to be gas planets (see Kepler-138d).

Types

Further information: List of planet types

 

Artist's impression of a carbon planet

Several possible classifications for solid planets have been proposed.

Silicate planet

A solid planet like Venus, Earth, or Mars, made primarily of silicon-based rocky mantle with a metallic (iron) core.

Carbon planet (also called "diamond planet")

Main article: Carbon planet

A theoretical class of planets, composed of a metal core surrounded by primarily carbon-based minerals. They may be considered a type of terrestrial planet if the metal content dominates. The Solar System contains no carbon planets but does have carbonaceous asteroids, such as Ceres and 10 Hygiea. It is unknown if Ceres has a rocky or a metallic core.

Iron planet

Main article: Iron planet

A theoretical type of solid planet that consists almost entirely of iron and therefore has a greater density and a smaller radius than other solid planets of comparable mass. Mercury in the Solar System has a metallic core equal to 60–70% of its planetary mass, and is sometimes called an iron planet, though its surface is made of silicates and is iron-poor. Iron planets are thought to form in the high-temperature regions close to a star, like Mercury, and if the protoplanetary disk is rich in iron.

Icy planet

Main article: Ice planet

 

Geysers erupting on Enceladus

A type of solid planet with an icy surface of volatiles. In the Solar System, most planetary-mass moons (such as Titan, Triton, and Enceladus) and many dwarf planets (such as Pluto and Eris) have such a composition. Europa is sometimes considered an icy planet due to its surface ice, but its higher density indicates that its interior is mostly rocky. Such planets can have internal saltwater oceans and cryovolcanoes erupting liquid water (i.e. an internal hydrosphere, like Europa or Enceladus); they can have an atmosphere and hydrosphere made from methane or nitrogen (like Titan). A metallic core is possible, as exists on Ganymede.

Coreless planet

Main article: Coreless planet

A theoretical type of solid planet that consists of silicate rock but has no metallic core, i.e. the opposite of an iron planet. Although the Solar System contains no coreless planets, chondrite asteroids and meteorites are common in the Solar System. Ceres and Pallas have mineral compositions similar to carbonaceous chondrites, though Pallas is significantly less hydrated. Coreless planets are thought to form farther from the star where volatile oxidizing material is more common.

Middle Stone Age

From Wikipedia, the free encyclopedia

https://en.wikipedia.org/wiki/Middle_Stone_Age 

Middle Stone Age tool from Blombos Cave

The Middle Stone Age (or MSA) was a period of African prehistory between the Early Stone Age and the Late Stone Age. It is generally considered to have begun around 280,000 years ago and ended around 50–25,000 years ago. The beginnings of particular MSA stone tools have their origins as far back as 550–500,000 years ago and as such some researchers consider this to be the beginnings of the MSA. The MSA is often mistakenly understood to be synonymous with the Middle Paleolithic of Europe, especially due to their roughly contemporaneous time span, however, the Middle Paleolithic of Europe represents an entirely different hominin population, Homo neanderthalensis, than the MSA of Africa, which did not have Neanderthal populations. Additionally, current archaeological research in Africa has yielded much evidence to suggest that modern human behavior and cognition was beginning to develop much earlier in Africa during the MSA than it was in Europe during the Middle Paleolithic. The MSA is associated with both anatomically modern humans (Homo sapiens) as well as archaic Homo sapiens, sometimes referred to as Homo helmei. Early physical evidence comes from the Gademotta Formation in Ethiopia, the Kapthurin Formation in Kenya and Kathu Pan in South Africa.

Regional development

There are MSA archaeological sites from across the African continent, conventionally divided into five regions: northern Africa, comprising parts of the modern countries of Morocco, Algeria, Tunisia, and Libya; eastern Africa, stretching roughly from the highlands of Ethiopia to the southern part of Kenya; central Africa, stretching from the borders of Tanzania and Kenya to include Angola; southern Africa, which includes the numerous cave sites of South Africa; and western Africa.

In northern and western Africa, the wet-dry cycles of the modern Sahara desert has led to fruitful archaeological sites followed by completely barren soil and vice versa. Preservation in these two regions can vary, yet the sites that have been uncovered document the adaptive nature of early humans to climatically unstable environments.

Eastern Africa represents some of the most reliable dates, due to the use of radiocarbon dating on volcanic ash deposits, as well as some of the earliest MSA sites. Faunal preservation, however, is not spectacular, and standardization in site excavation and lithic classification was, until recently, lacking. Unlike northern Africa, shifts between lithic technologies were not nearly as pronounced, likely due to more favorable climatic conditions that would have allowed for more continuous occupation of sites. Central Africa reflects similar patterning to eastern Africa, yet more archaeological research of the region is certainly required.

Southern Africa consists of many cave sites, most of which show very punctuated starts and stops in stone tool technology. Research in southern Africa has been continuous and quite standardized, allowing for reliable comparisons between sites in the region. Much of the archaeological evidence for the origins of modern human behavior is traced back to sites in this region, including Blombos Cave, Howiesons Poort, Still Bay, and Pinnacle Point.

Transition from Acheulean

The Awash Valley

The term "Middle Stone Age" (MSA) was proposed to the African Archaeological Congress by Goodwin and Van Riet Lowe in 1929. The use of these terms was officially abandoned in 1965. although the term remains in use in the context of sub-Saharan Africa, beginning with a transitional late Acheulean period known as the Fauresmith industry. The Fauresmith industry is poorly dated, according to Herries (2011) beginning around 511–435 kya. This time, rather than the actual end of the Achaeulean around 130 kya is taken as the beginning of the MSA. The MSA so defined is associated with the gradual replacement of archaic humans by anatomically modern humans.

In a different convention, MSA refers to sites characterized by the use of Levallois methods for flake production, to the exclusion of Acheulean sites with large cleavers or handaxes. Following McBrearty and Tryon (2006), the term "early MSA" (EMSA) refers to sites predating the 126 kya interglacial, and "later MSA" (LMSA) refers to site younger than 126 kya. In this convention, Fauresmith sites of 500 to 300 kya are within the ESA, and the MSA begins after about 280 kya and is largely associated with H. sapiens, the earliest reliably dated MSA site in East Africa being Gademotta in Ethiopia, at 276 kya. The Middle Awash valley of Ethiopia and the Central Rift Valley of Kenya constituted a major center for behavioural innovation. It is likely that the large terrestrial mammal biomass of these regions supported substantial human populations with subsistence and manufacturing patterns similar to those of ethnographically known foragers.

Archaeological evidence from eastern Africa extending from the Rift Valley from Ethiopia to northern Tanzania represents the largest archaeological evidence of the shift from the Late Acheulian to the Middle Stone Age tool technologies. This transition is characterized by stratigraphic layering of Acheulian stone tools, a bifacial handaxe technology, underneath and even contemporaneous with MSA technologies, such as Levallois tools, flakes, flaked tools, pointed flakes, smaller bifaces that are projectile in form, and, on rare occasions, hafted tools. Evidence of the gradual displacement of Acheulian by MSA technologies is further supported by this layering and contemporaneous placement, as well as by the earliest appearance of MSA technologies at Gademotta and the latest Acheulian technologies at the Bouri Formation of Ethiopia, dated to 154 to 160 kya. This suggests a possible overlap of 100–150 thousand years.

Late Acheulean artefacts associated with Homo sapiens have been found in South African cave sites. The Cave of Hearths and Montague Cave in South Africa contain evidence of Acheulian technologies, as well as later MSA technologies, however there is no evidence of crossover in this region.

ESA Acheulean sites are well documented across West Africa (except from the most tropical regions) but mostly remain undated. A few late Acheulean sites ("MSA" in the sense of late Acheulean, not Levallois) have been dated. Middle Pleistocene (pre 126 kya) sites are known form the northern Sahelian zones, while Late Pleistocene (post 126 kya) sites are known both from northern and southern West Africa. Unlike elsewhere in Africa, MSA sites appear to persist until very late, down to the Holocene boundary (12 kya), pointing to the possibility of late survival of archaic humans, and late hybridization with H. sapiens in West Africa. Furthermore, such results highlight significant spatiotemporal cultural variability and suggest that long inter-group cultural differences played a major role in later stages of human evolution in Africa.

Lithic technology

2009 excavations at the Diepkloof Rock Shelter

Early blades have been documented as far back as 550–500,000 years in the Kapthurin Formation in Kenya and Kathu Pan in South Africa. Backed pieces from the Twin Rivers and Kalambo Falls sites in Zambia, dated at sometime between 300 and 140,000 years, likewise indicate a suite of new behaviors. A high level of technical competence is also indicated for the c. 280 ka blades recovered from the Kapthurin Formation, Kenya.

The stone tool technology in use during the Middle Stone Age shows a mosaic of techniques. Beginning approximately 300 kya, the large cutting tools of the Achuelian are gradually displaced by Levallois prepared core technologies, also widely used by Neanderthals during the European Middle Palaeolithic. As the MSA progresses, highly varied technocomplexes become common throughout Africa and include pointed artifacts, blades, retouched flakes, end and side scrapers, grinding stones, and even bone tools. However, the use of blades (associated mainly with the Upper Palaeolithic in Europe) is seen at many sites as well. In Africa, blades may have been used during the transition from the Early Stone Age to the Middle Stone Age onwards. Finally, during the later part of the Middle Stone Age, microlithic technologies aimed at producing replaceable components of composite hafted tools are seen from at least 70 ka at sites such as Pinnacle Point and Diepkloof Rock Shelter in South Africa.

Artifact technology during the Middle Stone Age shows a pattern of innovation followed by disappearance. This occurs with technology such as the manufacture of shell beads, arrows and hide working tools including needles, and gluing technology. These pieces of evidence provide a counterpoint to the classic "Out of Africa" scenario in which increasing complexity accumulated during the Middle Stone Age. Instead, it has been argued that such technological innovations "appear, disappear and re-appear in a way that best fits a scenario in which historical contingencies and environmental rather than cognitive changes are seen as main drivers".

Hominin evolution and migration

Homo erectus skull, Museum of Natural History, Ann Arbor

 

See also: Human evolution

There have been two migration events out of Africa. The first was the expansion of H. erectus into Eurasia approximately 1.9 to 1.7 million years ago, and the second, by H. sapiens began during the MSA by 80 – 50 ka MSA out of Africa to Asia, Australia and Europe. Perhaps only in small numbers initially, but by 30 ka they had replaced Neanderthals and H. erectus. Each of these migrations represent the increased flexibility of the genus Homo to survive in widely varied climates. Based on the measurement of a large number of human skulls a recent study supports a central/southern African origin for Homo sapiens as this region shows the highest intra-population diversity in phenotypic measurements. Genetic data supports this conclusion. However, there is genetic evidence to suggest that dispersal out of Africa began in eastern Africa. Sites such as the Omo Kibish Formation, the Herto Member of the Bouri Formation, and Mumba Cave contain fossil evidence to support this conclusion as well.

Evidence for modern human behavior

See also: Behavioral modernity

There have been a number of theories proposed regarding the development of modern human behavior, but in recent years the mosaic approach has been the most favored perspective in regards to the MSA, especially when taken in consideration with the archaeological evidence. Some scholars including Klein have argued for discontinuity, while others including McBrearty and Brooks have argued that cognitive advances can be detected in the MSA and that the origin of our species is linked with the appearance of Middle Stone Age technology at 250–300 ka. The earliest remains of Homo sapiens date back to approximately 300 thousand years ago in Africa. the continent was mainly populated by groups of hunter-gatherers. In the archaeological record of both eastern Africa and southern Africa, there is immense variability associated with Homo sapiens sites, and it is during this time that we see evidence of the origins of modern human behavior. According to McBrearty and Brooks, there are four features that are characteristic of modern human behavior: abstract thinking, the ability to plan and strategize, "behavioral, economic and technological innovativeness," and symbolic behavior. Many of these aspects of modern human behavior can be broken down into more specific categories, including art, personal adornment, technological advancement, yet these four overarching categories allow for a thorough, albeit significantly overlapping, discussion of behavioral modernity.

Possible cultural complexes

Aterian stone tool

As early Homo sapiens began to diversify the ecological zones that they inhabited during the MSA, the archaeological record associated with these zones begins to show evidence for regional continuities. These continuities are significant for a number of reasons. The expansion of Homo sapiens into various ecological zones demonstrates an ability to adapt to a variety of environmental contexts including marine environments, savanna grasslands, relatively arid deserts, and forests. This adaptability is reflected in MSA artifacts found in these zones. These artifacts display stylistic variability depending on zone. During the Acheulian, which spanned from 1.5 million years ago to 300 thousand years ago, lithic technology displayed incredible homogeneity throughout all ecological niches. MSA technologies, with their evidence for regional variability and continuity, represent a remarkable advance. These data have been used to support theories of social and stylistic development throughout the MSA.

In southern Africa, we see the technocomplexes of Howiesons Poort and Stillbay, named after the sites at which they were first discovered. Several others have not been dated or have been dated unreliably; these include the Lupemban technocomplex of central Africa, the Bambatan in southeast Africa, 70–80ka, and the Aterian technocomplex of northern Africa, 160–90ka.

Abstract thinking

Evidence of abstract thinking can be seen in the archaeological record as early as the Acheulean–Middle Stone Age transition, approximately 300,000–250,000 years ago. This transition involves a shift in stone tool technology from Mode 2, Acheulean tools, to Mode 3 and 4, which include blades and microliths. The manufacture of these tools requires planning and the understanding of how striking a stone will produce different flaking patterns. This requires abstract thought, one of the hallmarks of modern human behavior. The shift from large cutting tools in the Acheulian to smaller and more diversified toolkits in the MSA represents a better cognitive and conceptual understanding of flintknapping, as well as the potential functional effects of distinct tool types.

Planning depth

The ability to plan and strategize, much like abstract thinking, can be seen in the more diversified toolkit of the Middle Stone Age, as well as in the subsistence patterns of the period. As MSA hominins began to migrate into a range of different ecological zones, it became necessary to base hunting strategies around seasonally available resources. Awareness of seasonality is evident in the faunal remains found at temporary sites. In less forgiving ecological zones, this awareness would have been essential for survival and the ability to plan subsistence strategies based on this awareness demonstrates an ability to think beyond the present tense and act upon this knowledge.

This planning depth is also seen in the presence of exotic raw materials at a variety of sites throughout the MSA. Procurement of local raw materials would have been a simple task to accomplish, yet MSA sites regularly contain raw materials that were obtained from sources over 100 km away, and sometimes farther than 300 km. Obtaining raw materials from this distance would require an awareness of the resources, a perceived value in the resources, whether it be functional or symbolic, and, possibly, the ability to organize an exchange network in order to obtain the materials.

Innovation

The ability to expand into new environments throughout Africa and, ultimately, the world, displays a level of adaptability and, consequently, innovativeness that is often seen as characteristic of behavioral modernity.^[1] Middle Stone Age sites are found in a wide range of environments, including coastal and inland areas of southern and eastern Africa, and in at least one case MSA foragers were exploiting high-altitude glaciated environments, at Fincha Habera in Ethiopia. This, however, is not the only evidence of innovativeness that can be seen in early Homo sapiens. The development of new, regionally relevant tools, such as those used for the collection of marine resources seen at Abdur, Ethiopia, Pinnacle Point Cave, South Africa, and Blombos Cave, South Africa. The use of fire demonstrates another innovative aspect of human behavior when it is used in order to create stronger tools, such as the heated silcrete at Blombos, Howiesons Poort and Still Bay, and the heat treated bone tools from Still Bay.

Hafted tools are further representative of human innovation. The large cutting tools of the Acheulian technocomplex become smaller, as more complex tools are better suited towards the needs of highly diversified environments. Composite tools represent a new level of innovation in their increased efficacy and more complex manufacturing process. The ability to conceptualize beyond the mere reduction of stone cores demonstrates cognitive flexibility, and the use of glue, which was often processed with ochre, to attach flakes to hafts demonstrates an understanding of chemical changes that can be utilized beyond the simple use of color. Adhesives were used to construct hafted tools by 70ka at Sibudu Cave in South Africa.

Other technological innovations of the period include specialized projectile weapons found at various sites in Middle Stone Age Africa such as: bone and stone arrowheads at South African sites such as Sibudu Cave (along with an early bone needle also found at Sibudu) dating approximately 60,000–70,000 years ago, and bone harpoons at the Central African site of Katanda dating to about 90,000 years ago. Evidence also exists for the systematic heat treating of silcrete stone to increase its flake-ability for the purpose of toolmaking, beginning approximately 164,000 years ago at the South African site of Pinnacle Point and becoming common there for the creation of microlithic tools at about 72,000 years ago.

Characteristically modern human behaviors, such as the making of shell beads, bone tools and arrows, and the use of ochre pigment, are evident at Panga ya Saidi in Kenya by 78,000–67,000 years ago. Evidence of early stone-tipped projectile weapons (a characteristic tool of Homo sapiens), the stone tips of javelins or throwing spears, were discovered in 2013 at the Ethiopian site of Gademotta, and date to around 279,000 years ago.

Evidence was found in 2018, dating to about 320,000 years ago, at the Kenyan site of Olorgesailie, of the early emergence of innovations and behaviors including: long-distance trade networks (involving goods such as obsidian), the use of pigments, and the possible making of projectile points. It is observed by the authors of three 2018 studies on the site, that the evidence of these behaviors is approximately contemporary to the earliest known Homo sapiens fossil remains from Africa (such as at Jebel Irhoud and Florisbad), and they suggest that complex and modern behaviors had already begun in Africa around the time of the emergence of Homo sapiens.

Symbolic behavior

Zoomorphic pictogram on stone slab from the MSA of Apollo 11 Cave, Namibia

Symbolic behavior is, perhaps, one of the most difficult aspects of modern human behavior to distinguish archaeologically. When searching for evidence of symbolic behavior in the MSA, there are three lines of evidence that can be considered: direct evidence reflecting concrete examples of symbols; indirect evidence reflecting behaviors that would have been used to convey symbolic thought; and technological evidence reflecting the tools and skills that would have been used to produce art. Direct evidence is difficult to find beyond 40ka, and indirect evidence is essentially intangible, thus technological evidence is the most fruitful of the three.

Today there is widespread agreement among archaeologists that the world's first art and symbolic culture dates to the African Middle Stone Age. Some of the most striking artifacts, including engraved pieces of red ochre, were manufactured at Blombos Cave in South Africa 75,000 years ago. Pierced and ochred Nassarius shell beads were also recovered from Blombos, with even earlier examples (Middle Stone Age, Aterian) from the Taforalt Caves. In addition, ostrich egg shell containers engraved with geometric designs dating to 60,000 years ago were found at Diepkloof, South Africa, beads and other personal ornamentation have been found from Morocco which might be as much as 130,000 years old, and the Cave of Hearths in South Africa has yielded a number of beads dating from significantly prior to 50,000 years ago. At Panga ya Saidi in Kenya, marine shell beads appear perhaps as early as 67,000 years ago and certainly by 33,000 years ago, and engraved ochre by 48,500 years ago. Arrows and hide working tools (including a needle-like tool) have been found at Sibudu Cave dating between about 70–60,000 years ago. as evidence of making weapons with compound heat treated gluing technology. Evidence for the making of paints by a complex process also exists dating to 100,000 years ago in South Africa, and for the use of pigments in Kenya dating to about 320,000 years ago.

Complex cognition

A series of innovations have been documented by 170–160,000 years ago at the site of Pinnacle Point 13B on the southern Cape coast of South Africa. This includes the oldest confirmed evidence for the utilization of ochre and marine resources in the form of shellfish exploitation for food. Based on his analysis of the MSA bovid assemblage at Klasies, Milo reports MSA people were formidable hunters and that their social behavior patterns approached those of modern humans. Deacon maintains that the management of plant food resources through deliberate burning of the veld to encourage the growth of plants with corms or tubers in the southern Cape during the Howiesons Poort (c. 70–55 ka) is indicative of modern human behavior. A family basis to foraging groups, color symbolism and the reciprocal exchange of artifacts and the formal organization of living space are, he suggests, further evidence for modernity in the MSA.

Lyn Wadley et al. have argued that the complexity of the skill needed to process the heat-treated compound glue (gum and red ochre) used to haft spears would seem to argue for continuity between modern human cognition and that of humans 70,000 BP at Sibudu Cave.

In 2008, an ochre processing workshop likely for the production of paints was uncovered dating to ca. 100,000 years ago at Blombos Cave, South Africa. Analysis shows that a liquefied pigment-rich mixture was produced and stored in the two abalone shells, and that ochre, bone, charcoal, grindstones and hammer-stones also formed a composite part of the toolkits. Evidence for the complexity of the task includes procuring and combining raw materials from various sources (implying they had a mental template of the process they would follow), possibly using pyrotechnology to facilitate fat extraction from bone, using a probable recipe to produce the compound, and the use of shell containers for mixing and storage for later use.

Evidence for language

Ochre is reported from some early MSA sites, for example at Kapthurin and Twin Rivers, and is common after c. 100 ka. Barham argues that even if some of this ochre was used in a symbolic, color-related role then this abstraction could not have worked without language. Ochre, he suggests, could be one proxy for trying to find the emergence of language.

Formal bone tools are frequently associated with modern behaviour by archaeologists. Sophisticated bone harpoons manufactured at Katanda, West Africa at c. 90 ka^[61][62] and bone tools from Blombos Cave dated at c. 77 ka may then also serve as examples of material culture associated with modern language.

Language has been suggested to be necessary to maintain exchange networks. Evidence of some form of exchange networks during the Middle Stone Age is presented in Marwick (2003) in which the distance between the source of raw material and location in which a stone artifact was found was compared throughout sites containing early stone artifacts. Five Middle Stone Age sites contained distances between 140–340 km and have been interpreted, when compared with ethnographic data, that these distances were made possible through exchange networks. Barham also views syntactic language as one aspect of behavior that in fact allowed MSA people to settle in the tropical forest environments of what is now the Democratic Republic of the Congo.

Many authors have speculated that at the core of this symbolic explosion, and in tandem, was the development of syntactic language that evolved through a highly specialized social learning system providing the means for semantically unbounded discourse. Syntax would have played a key role in this process and its full adoption could have been a crucial element of the symbolic behavioral package in the MSA.

Brain change

Although the advent of anatomical physical modernity cannot confidently be linked with palaeoneurological change, it does seem probable that hominid brains evolved through the same selection processes as other body parts. Genes that promoted a capacity for symbolism may have been selected for, suggesting that the foundations for symbolic culture may well be grounded in biology. However, behavior that was mediated by symbolism may have only come later, even though this physical capacity was already in place much earlier. Skoyles and Sagan, for example, argue that human brain expansion by increasing the prefrontal cortex would have created a brain capable of symbolizing its previously non-symbolic cognition, and that this process, slow to begin with, increasingly accelerated during the last 100,000 years. Symbolically mediated behavior may then feed back upon this process by creating a greater ability to manufacture symbolic artifacts and social networks. According to the research team in Jebel Irhoud, the discovery means that Homo sapiens—not members of a rival or ancestor species (Homo heidelbergensis, Homo naledi)—were the ones who left behind Middle Stone Age hand tools that have since been unearthed all over Africa.

Sites

Excavations at Pinnacle Point, South Africa

Numerous sites in southern Africa reflect the four characteristics of behavioral modernity. Blombos Cave, South Africa contains personal ornaments and what are presumed to be the tools used for the production of artistic imagery, as well as bone tools. Still Bay and Howieson's Poort contain variable tool technologies. These different types of assemblages allow researchers to extrapolate behaviors that would likely be associated with such technologies, such as shifts in foraging behaviors, which are further supported by faunal data at these sites.

• Blombos Cave, South Africa
• Klasies River Caves, South Africa
• Sibudu Cave, South Africa
• Diepkloof Rock Shelter, South Africa
• Pinnacle Point, South Africa
• Border Cave, South Africa
• Bambata Cave, South Africa
• Mossel Bay, South Africa
• Mumba Cave, Tanzania
• Mumbwa Caves, Zambia
• Laminia and Saxomununya, Senegal