Implicit stereotype

From Wikipedia, the free encyclopedia

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

In social identity theory, an implicit bias or implicit stereotype, is the pre-reflective attribution of particular qualities by an individual to a member of some social out group.

Implicit stereotypes are thought to be shaped by experience and based on learned associations between particular qualities and social categories, including race and/or gender. Individuals' perceptions and behaviors can be influenced by the implicit stereotypes they hold, even if they are sometimes unaware they hold such stereotypes. Implicit bias is an aspect of implicit social cognition: the phenomenon that perceptions, attitudes, and stereotypes can operate prior to conscious intention or endorsement. The existence of implicit bias is supported by a variety of scientific articles in psychological literature. Implicit stereotype was first defined by psychologists Mahzarin Banaji and Anthony Greenwald in 1995.

Explicit stereotypes, by contrast, are consciously endorsed, intentional, and sometimes controllable thoughts and beliefs.

Implicit biases, however, are thought to be the product of associations learned through past experiences. Implicit biases can be activated by the environment and operate prior to a person's intentional, conscious endorsement. Implicit bias can persist even when an individual rejects the bias explicitly.

Bias, attitude, stereotype and prejudice

Attitudes, stereotypes, prejudices, and bias are all examples of psychological constructs. Psychological constructs are mental associations that can influence a person's behavior and feelings toward an individual or group. If the person is unaware of these mental associations the stereotypes, prejudices, or bias is said to be implicit.

Bias is defined as prejudice in favor of or against one thing, person, or group compared with another, usually in a way considered to be unfair. Bias can be seen as the overarching definition of stereotype and prejudice, because it is how we associate traits (usually negative) to a specific group of people. Our “implicit attitudes reflect constant exposure to stereotypical portrayals of members of, and items in, all kinds of different categories: racial groups, professions, women, nationalities, members of the LGBTQ community, moral and political values, etc.”

An attitude is an evaluative judgment of an object, a person, or a social group. An attitude is held by or characterizes a person. Implicit attitudes are evaluations that occur without conscious awareness towards an attitude object or the self.

A stereotype is the association of a person or a social group with a consistent set of traits. This may include both positive and negative traits, such as African Americans are great at sports or African Americans are more violent than any other race in the United States. There are many types of stereotypes that exists: racial, cultural, gender, group (i.e. college students), all being very explicit in the lives of many people.

Prejudice is defined as unfair negative attitude toward a social group or a member of that group. Prejudices can stem from many of the things that people observe in a different social group that include, but are not limited to, gender, sex, race/ethnicity, or religion. This is pertinent to stereotypes because a stereotype can influence the way people feel toward another group, hence prejudice.

Methods for investigation

There is a clear challenge in measuring the degree to which someone is biased. There are two different forms of bias: implicit and explicit. The two forms of bias are, however, connected. “Explicit bias encompasses our conscious attitudes which can be measured by self-report, but pose the potential of individuals falsely endorsing more socially desirable attitudes. Although implicit biases have been considered unconscious and involuntary attitudes which lie below the surface of consciousness, some people seem to be aware of their influence on their behavior and cognitive processes. The implicit-association test (IAT) is one validated tool used to measure implicit bias. The IAT requires participants to rapidly pair two social groups with either positive or negative attributes.”

Implicit-association test

The implicit-association test (IAT) alleges to predict prejudice an individual has toward different social groups. The test claims to do this by capturing the differences in the time it takes respondent to choose between two unassociated but related topics. Respondents are instructed to click one of two computer keys to categorize stimuli into associated categories. When the categories appear consistent to the respondent, the time taken to categorize the stimuli will be less than when the categories seem inconsistent. An implicit association is said to exist when respondents take longer to respond to a category-inconsistent pairing than a category-consistent pairing. The implicit-association test is used in psychology for a wide array of topics. These fields include gender, race, science, career, weight, sexuality, and disability. While acclaimed and highly influential, the implicit-association test falls short of a strong scientific consensus. Critics of the implicit-association test cite studies that counterintuitively link biased test scores with less discriminatory behavior. Studies have also asserted that the implicit-association test fails to measure unconscious thought.

Go/no-go association task (GNAT)

The GNAT is similar to the implicit-association test. Although the IAT reveals differential associations of two target concepts (e.g. male-female and weak-strong), the GNAT reveals associations within one concept (for example, whether female is associated more strongly with weak or strong).

Participants are presented with word pairs among distractors. Participants are instructed to indicate "go" if the words are target pairs, or "no-go" if they are not. For example, participants may be instructed to indicate "go" if the word pairs are female names and words that are related to strength. Then, participants are instructed to indicate "go" if the word pairs are female names and words that are related to weakness. This method relies on signal detection theory; participants' accuracy rates reveal endorsement of the implicit stereotype. For example, if participants are more accurate for female-weak pairs than for female-strong pairs, this suggests the subject more strongly associates weakness with females than strength.

Semantic priming and lexical decision task

Semantic priming measures the association between two concepts. In a lexical decision task, subjects are presented with pair of words, and asked to indicate whether the pair are words (for example, "butter") or non-words (for example, "tubter"). The theory behind semantic priming is that subjects are quicker to respond to a word if preceded by a word related to it in meaning (e.g. bread-butter vs. bread-dog). In other words, the word "bread" primes other words related in meaning, including butter. Psychologists utilize semantic priming to reveal implicit associations between stereotypic-congruent words. For instance, participants may be asked to indicate whether pronouns are male or female. These pronouns are either preceded by professions that are predominantly female ("secretary, nurse"), or male ("mechanic, doctor"). Reaction times reveal strength of association between professions and gender.

Sentence completion

In a sentence completion task, subjects may be presented with sentences that contain stereotypic black and white names (Jerome, Adam), positive and negative stereotypic black behaviors (easily made the team, blasted loud music in his car) and counter-stereotypic behaviors (got a job at Microsoft, refused to dance). Subjects are asked to add to the end of a sentence in any way that is grammatical, e.g. "Jerome got an A on his test..." could be completed with "because it was easy" (stereotypic-congruent) or "because he studied for months" (stereotypic-incongruent) or "and then he went out to celebrate" (non-explanatory). This task is used to measure stereotypic explanatory bias (SEB): participants have a larger SEB if they give more explanations for stereotype-congruent sentences than stereotype–incongruent sentences, and if they give more stereotypic-congruent explanations.

Differences between measures

The Implicit Association Test (IAT), sequential priming, and other implicit bias tests, are mechanisms for determining how susceptible we are to stereotypes. They are widely used in Social Psychology, although measuring response time to a question as a good measure of implicit biases is still up for debate. “Some theorists do question the interpretation of the scores from tests such as the IAT, but the debate is still going on and responses to the criticisms are certainly widespread.”

Findings

Gender bias

See also: Sexism § Gender stereotypes, and Gender role § Gender stereotypes

Gender biases are the stereotypical attitudes or prejudices that we have towards specific genders. "The concept of gender also refers to the constantly ongoing social construction of what is considered ‘feminine’ and ‘masculine’ and is based on power and sociocultural norms about women and men." Gender biases are the ways in which we judge men and women based on their hegemonically feminine and masculine assigned traits.

The category of male has been found to be associated with traits of strength and achievement. Both male and female subjects associate male category members more strongly than female category members with words like bold, mighty, and power. The strength of this association is not predicted by explicit beliefs, such as responses on a gender stereotype questionnaire (for example, one question asked if subjects endorsed the word feminist). In a test to reveal the false fame effect, non famous male names are more likely to be falsely identified as famous than non famous female names; this is evidence for an implicit stereotype of male achievement. Females are more associated with weakness. This is true for both male and female subjects, but female subjects only show this association when the weak words are positive, such as fine, flower and gentle; female subjects do not show this pattern when the weak words are negative, such as feeble, frail, and scrawny.

Particular professions are implicitly associated with genders. Elementary school teachers are implicitly stereotyped to be female, and engineers are stereotyped to be male.

Gender bias in science and engineering

Implicit-association tests reveal an implicit association for male with science and math, and females with arts and language. Girls as young as nine years old have been found to hold an implicit male-math stereotype and an implicit preference for language over math. Women have stronger negative associations with math than men do, and the stronger females associate with a female gender identity, the more implicit negativity they have towards math. For both men and women, the strength of these implicit stereotypes predicts both implicit and explicit math attitudes, belief in one's math ability, and SAT performance. The strength of these implicit stereotypes in elementary-aged girls predicts academic self-concepts, academic achievement, and enrollment preferences, even more than do explicit measures. Women with a stronger implicit gender-math stereotype were less likely to pursue a math-related career, regardless of their actual math ability or explicit gender-math stereotypes. This may be because women with stronger implicit gender-math stereotypes are more at risk for stereotype threat. Thus, women with strong implicit stereotypes perform much worse on a math test when primed with gender than women who have weak implicit stereotypes.

Though the number of women pursuing and earning degrees in engineering has increased in the last 20 years, women are below men at all degree levels in all fields of engineering. These implicit gender stereotypes are robust; in a study of more than 500,000 respondents from 34 nations, more than 70% of individuals held this implicit stereotype. The national strength of the implicit stereotype is related to national sex differences among 8th graders on the International TIMSS, a worldwide math &science standardized achievement exam. This effect is present even after statistically controlling for gender inequality in general. Additionally, for women across cultures, studies have shown individual differences in strength of this implicit stereotype is associated with interest, participation and performance in sciences. Extending to the professional world, implicit biases and subsequent explicit attitudes toward women can "negatively affect the education, hiring, promotion, and retention of women in STEM".

The effects of such implicit biases can be seen in across multiple studies including:

• Parents rate the math abilities of their daughters lower than parents with sons who perform identically well in school
• College faculty are less likely to respond to inquiries about research opportunities if the email appears to be from a woman as opposed to an identical email from a man
• Science faculty are less likely to hire or mentor students they believe are women as opposed to men

An interagency report from the Office of Science and Technology Policy and Office of Personnel Management has investigated systemic barriers including implicit biases that have traditionally inhibited particularly women and underrepresented minorities in science, technology, engineering, and mathematics (STEM) and makes recommendations for reducing the impact of bias. Research has shown that implicit bias training may improve attitudes towards women in STEM.

Racial bias

Racial bias can be used synonymously with "stereotyping and prejudice" because "it allows for the inclusion of both positive and negative evaluations related to perceptions of race." We begin to create racial biases towards other groups of people starting as young as age 3, creating an ingroup and outgroup view on members of various races, usually starting with skin color.

In lexical decision tasks, after subjects are subliminally primed with the word BLACK, they are quicker to react to words consistent with black stereotypes, such as athletic, musical, poor and promiscuous. When subjects are subliminally primed with WHITE, they are quicker to react to white stereotypes, such as intelligent, ambitious, uptight and greedy. These tendencies are sometimes, but not always, associated with explicit stereotypes.

People may also hold an implicit stereotype that associates black category members as violent. People primed with words like ghetto, slavery and jazz were more likely to interpret a character in a vignette as hostile. However, this finding is controversial; because the character's race was not specified, it is suggested that the procedure primed the race-unspecified concept of hostility, and did not necessarily represent stereotypes.

An implicit stereotype of violent black men may associate black men with weapons. In a video game where subjects were supposed to shoot men with weapons and not shoot men with ordinary objects, subjects were more likely to shoot a black man with an ordinary object than a white man with an ordinary object. This tendency was related to subjects' implicit attitudes toward black people. Similar results were found in a priming task; subjects who saw a black face immediately before either a weapon or an ordinary object more quickly and accurately identified the image as a weapon than when it was preceded by a white face.

Implicit race stereotypes affect behaviors and perceptions. When choosing between pairs of questions to ask a black interviewee, one of which is congruent with racial stereotype, people with a high stereotypic explanatory bias (SEB) are more likely to ask the racially congruent stereotype question. In a related study, subjects with a high SEB rated a black individual more negatively in an unstructured laboratory interaction.

In-group and out-group bias

Group prototypes define social groups through a collection of attributes that define both what representative group members have in common and what distinguishes the ingroup from relevant outgroups. In-group favoritism, sometimes known as in-group–out-group bias, in-group bias, or intergroup bias, is a pattern of favoring members of one's in-group over out-group members. This can be expressed in evaluation of others, in allocation of resources, and in many other ways. Implicit in-group preferences emerge very early in life, even in children as young as six years old. In-group bias wherein people who are ‘one of us’ (i.e., our ingroup) are favored compared to those in the outgroup, meaning those who differ from ourselves. Ingroup favoritism is associated with feelings of trust and positive regard for ingroup members and surfaces often on measures of implicit bias. This categorization (ingroup vs. outgroup) is often automatic and pre-conscious.

The reasons for having in-group and out-group bias could be explained by ethnocentrism, social categorization, oxytocin, etc. A research paper done by Carsten De Dreu reviewed that oxytocin enables the development of trust, specifically towards individuals with similar characteristics - categorized as ‘in-group’ members - promoting cooperation with and favoritism towards such individuals. People who report that they have strong needs for simplifying their environments also show more ingroup favoritism. The tendency to categorize into ingroups and outgroups and resulting ingroup favoritism is likely a universal aspect of human beings.

We generally tend to hold implicit biases that favor our own ingroup, though research has shown that we can still hold implicit biases against our ingroup. The most prominent example of negative affect towards an ingroup was recorded in 1939 by Kenneth and Mamie Clark using their now famous “Dolls Test”. In this test, African American children were asked to pick their favorite doll from a choice of otherwise identical black and white dolls. A high percentage of these African American children indicated a preference for the white dolls. Social identity theory and Freudian theorists explain in-group derogation as the result of a negative self-image, which they believe is then extended to the group.

Other stereotypes

Research on implicit stereotypes primarily focuses on gender and race. However, other topics, such as age, weight, and profession, have been investigated. IATs have revealed implicit stereotypes reflecting explicit stereotypes about adolescents. The results from these tests claim that adolescents are more likely to be associated with words like trendy and defiant than adults. In addition, one IAT study revealed that older adults had a higher preference for younger adults compared to older adults; and younger adults had a lower implicit preference for younger adults compared to older adults. The study also found that women and participants with more education had lower implicit preference for younger adults. IATs have also revealed implicit stereotypes on the relationship between obese individuals and low work performance. Words like lazy and incompetent are more associated with images of obese individuals than images of thin ones. This association is stronger for thin subjects than overweight ones. Like explicit stereotypes, implicit stereotypes may contain both positive and negative traits. This can be seen in examples of occupational implicit stereotypes where people perceive preschool teachers as both warm and incompetent, while lawyers are judged as both cold and competent.

Activation of implicit stereotypes

Implicit stereotypes are activated by environmental and situational factors. These associations develop over the course of a lifetime beginning at a very early age through exposure to direct and indirect messages. In addition to early life experiences, the media and news programming are often-cited origins of implicit associations. In the laboratory, implicit stereotypes are activated by priming. When subjects are primed with dependence by unscrambling words such as dependent, cooperative, and passive, they judge a target female as more dependent. When subjects are primed with aggression with words like aggressive, confident, argumentative, they judge a target male as more aggressive. The fact that females and words such as dependent, cooperative, and passive and males and words like aggressive, confident, argumentative are thought to be associated together suggest an implicit gender stereotype. Stereotypes are also activated by a subliminal prime. To exemplify, white subjects exposed to subliminal words which consist of a black stereotype (ghetto, slavery, jazz) interpret a target male as more hostile, consistent with the implicit stereotype of hostile black man. However, this finding is controversial because the character's race is not specified. Instead, it is suggested that the procedure primed the race-unspecified concept of hostility, and did not necessarily represent stereotypes. By getting to know people who differ from you on a real, personal level, you can begin to build new associations about the groups those individuals represent and break down existing implicit associations.

Malleability of implicit stereotypes

Implicit stereotypes can, at least temporarily, be reduced or increased. Most methods have been found to reduce implicit bias temporarily, and are largely based on context. Some evidence suggests that implicit bias can be reduced long-term, but it may require education and consistent effort. Some implicit bias training techniques designed to counteract implicit bias are stereotype replacement, counter-stereotypic imaging, individuation, perspective taking, and increasing opportunities for contact.

Stereotype replacement is when you replace a stereotypical response with a non-stereotypical response. Counter-stereotypic imagining is when you imagine others in a positive light and replace stereotypes with positive examples. Individuation is when you focus on specific details of a certain member of a group to avoid over-generalizing. Perspective taking is when you take the perspective of a member of a marginalized group. Increasing opportunities for contact is when you actively seek out opportunities to engage in interactions with members of marginalized groups.

Self and social motives

The activation of implicit stereotypes may be decreased when the individual is motivated to promote a positive self-image, either to oneself or to others in a social setting. There are two parts to this: internal and external motivation. Internal motivation is when an individual wants to be careful of what they say, and external motivation is when an individual has a desire to respond in a politically correct way.

Positive feedback from a black person decreases stereotypic sentence completion, while negative feedback from a black person increases it. Subjects also reveal lesser strength of race stereotypes when they feel others disagree with the stereotypes. Motivated self-regulation does not immediately reduce implicit bias. It raises awareness of discrepancies when biases stand in the way of personal beliefs.

Promote counterstereotypes

Implicit stereotypes can be reduced by exposure to counterstereotypes. Reading biographies of females in leadership roles (such as Meg Whitman, the CEO of eBay) increases females’ associations between female names and words like leader, determined, and ambitious in a gender stereotype IAT. Attending a women's college (where students are presumably more often exposed to women in leadership positions) reduces associations between leadership and males after one year of schooling. Merely imagining a strong woman reduces implicit association between females and weakness, and imagining storybook princesses increases the implicit association between females and weakness.

Focus of attention

Diverting a participant's focus of attention can reduce implicit stereotypes. Generally, female primes facilitate reaction time to stereotypical female traits when participants are instructed to indicate whether the prime is animate. When participants instead are instructed to indicate whether a white dot is present on the prime, this diverts their focus of attention from the primes’ feminine features. This successfully weakens the strength of the prime and thus weakening the strength of gender stereotypes.

Configuration of stimulus cues

Whether stereotypes are activated depends on the context. When presented with an image of a Chinese woman, Chinese stereotypes were stronger after seeing her use chopsticks, and female stereotypes were stronger after seeing her put on makeup.

Characteristics of individual category members

Stereotype activation may be stronger for some category members than for others. People express weaker gender stereotypes with unfamiliar than familiar names. Judgments and gut reactions that go along with implicit biases are based on how familiar something is.

Criticism

Some social psychology research has indicated that individuating information (giving someone any information about an individual group member other than category information) may eliminate the effects of stereotype bias.

Meta-analyses

Researchers from the University of Wisconsin at Madison, Harvard, and the University of Virginia examined 426 studies over 20 years involving 72,063 participants that used the IAT and other similar tests. They concluded two things:

1. The correlation between implicit bias and discriminatory behavior appears weaker than previously thought.
2. There is little evidence that changes in implicit bias correlate with changes in a person’s behavior.

In a 2013 meta-analysis of papers, Hart Blanton, et al. declared that, despite its frequent misrepresentation as a proxy for the unconscious, "the IAT provides little insight into who will discriminate against whom, and provides no more insight than explicit measures of bias."

News outlets

Heather Mac Donald, writing in the Wall Street Journal, noted that:

Few academic ideas have been as eagerly absorbed into public discourse lately as “implicit bias.” Embraced by Barack Obama, Hillary Clinton and most of the press, implicit bias has spawned a multimillion-dollar consulting industry, along with a movement to remove the concept of individual agency from the law. Yet its scientific basis is crumbling.

Mac Donald suggests there is still a political and economic drive to use the implicit bias paradigm as a political lever and to profit off entities which want to avoid litigation.

Psychometric Concerns

Edouard Machery has argued that “the use of [indirect measures like the implicit association test] is deeply problematic” because the tests do not exhibit the psychometric properties we would expect from measures of "attitudes". However, many have already admitted that these indirect tests "assess behavior" rather than attitudes. This is an example of how the debate about implicit bias can involve "talking past one another" based on "different expectations of indirect measures", views of (what) implicit bias (is), assumptions about which evidence is relevant, threshholds for scientific significance, psychometric standards, and even norms of science communication. So evaluating debates about tests of implicit bias requires one to pay careful attention to debators' background assumptions and whether (or how well) debators' justify those assumptions.

Statement by original authors

Where previously Greenwald and Banaji asserted in their book BlindSpot (2013).

Given the relatively small proportion of people who are overtly prejudiced and how clearly it is established that automatic race preference predicts discrimination, it is reasonable to conclude not only that implicit bias is a cause of Black disadvantage but also that it plausibly plays a greater role than does explicit bias.

The evidence presented by their peer researchers led them to concede in correspondence that:

1. The IAT does not predict biased behaviour(in laboratory settings)
2. It is "problematic to use [the IAT] to classify persons as likely to engage in discrimination".

However, they also stated, "Regardless of inclusion policy, both meta-analyses estimated aggregate correlational effect sizes that were large enough to explain discriminatory impacts that are societally significant either because they can affect many people simultaneously or because they can repeatedly affect single persons."

Summary

Implicit bias is thought to be the product of positive or negative mental associations about persons, things, or groups that are formed and activated pre-consciously or subconsciously. In 1995, researchers Banaji and Greenwald noted that someone’s social learning experiences, such as observing parents, friends, or others, could create this type of association and, therefore, trigger this type of bias. Many studies have found that culture is able to stimulate biases as well, both in a negative and positive way regardless someone’s personal experience with other cultures. As far as many people are concerned, implicit bias knows no age restriction and it can be held by anyone regardless of their age. In fact, implicit biases can be found in a person as young as six years old. Even though implicates bias may be difficult to catch, especially compared to explicit bias, it can be measured through a number of mechanisms, such as sequential priming, response competition, EDA, EMG, fMRI, ERP and ITA. Thus, once a person becomes aware of their own bias, they can take action to change it, if they wish.

The existence of implicitly biased behavior is supported by several articles in psychological literature. Adults- and even children- may hold implicit stereotypes of social categories, categories to which they may themselves belong to. Without intention, or even awareness, implicit stereotypes affect human behavior and judgments. This has wide-ranging implications for society, from discrimination and personal career choices to understanding others in social interactions each day.

Group 3 element

From Wikipedia, the free encyclopedia

https://en.wikipedia.org/wiki/Group_3_element 

Group 3 in the periodic table
Hydrogen Helium Lithium Beryllium Boron Carbon Nitrogen Oxygen Fluorine Neon Sodium Magnesium Aluminium Silicon Phosphorus Sulfur Chlorine Argon Potassium Calcium Scandium Titanium Vanadium Chromium Manganese Iron Cobalt Nickel Copper Zinc Gallium Germanium Arsenic Selenium Bromine Krypton Rubidium Strontium Yttrium Zirconium Niobium Molybdenum Technetium Ruthenium Rhodium Palladium Silver Cadmium Indium Tin Antimony Tellurium Iodine Xenon Caesium Barium Lanthanum Cerium Praseodymium Neodymium Promethium Samarium Europium Gadolinium Terbium Dysprosium Holmium Erbium Thulium Ytterbium Lutetium Hafnium Tantalum Tungsten Rhenium Osmium Iridium Platinum Gold Mercury (element) Thallium Lead Bismuth Polonium Astatine Radon Francium Radium Actinium Thorium Protactinium Uranium Neptunium Plutonium Americium Curium Berkelium Californium Einsteinium Fermium Mendelevium Nobelium Lawrencium Rutherfordium Dubnium Seaborgium Bohrium Hassium Meitnerium Darmstadtium Roentgenium Copernicium Nihonium Flerovium Moscovium Livermorium Tennessine Oganesson alkaline earth metals ←    → group 4
IUPAC group number 3 Name by element scandium group CAS group number (US, pattern A-B-A) IIIB old IUPAC number (Europe, pattern A-B) IIIA
↓ Period
4	Scandium (Sc) 21 Transition metal
5	Yttrium (Y) 39 Transition metal
6	Lutetium (Lu) 71 Lanthanide
7	Lawrencium (Lr) 103 Actinide
Legend primordial element synthetic element Atomic number color: black=solid

Group 3 is the first group of transition metals in the periodic table. This group is closely related to the rare-earth elements. Although some controversy exists regarding the composition and placement of this group, it is generally agreed among those who study the matter that this group contains the four elements scandium (Sc), yttrium (Y), lutetium (Lu), and lawrencium (Lr). The group is also called the scandium group or scandium family after its lightest member.

The chemistry of the group 3 elements is typical for early transition metals: they all essentially have only the group oxidation state of +3 as a major one, and like the preceding main-group metals are quite electropositive and have a less rich coordination chemistry. Due to the effects of the lanthanide contraction, yttrium and lutetium are very similar in properties. Yttrium and lutetium have essentially the chemistry of the heavy lanthanides, but scandium shows several differences due to its small size. This is a similar pattern to those of the early transition metal groups, where the lightest element is distinct from the very similar next two.

All the group 3 elements are rather soft, silvery-white metals, although their hardness increases with atomic number. They quickly tarnish in air and react with water, though their reactivity is masked by the formation of an oxide layer. The first three of them occur naturally, and especially yttrium and lutetium are almost invariably associated with the lanthanides due to their similar chemistry. Lawrencium is strongly radioactive: it does not occur naturally and must be produced by artificial synthesis, but its observed and theoretically predicted properties are consistent with it being a heavier homologue of lutetium. None of them have any biological role.

Historically, sometimes lanthanum (La) and actinium (Ac) were included in the group instead of lutetium and lawrencium, and this option is still commonly found in textbooks. Some compromises between the two major options have been proposed and used, involving either the shrinking of the group to scandium and yttrium only, or the inclusion of all 30 lanthanides and actinides in the group as well.

History

Discoveries of the elements

The discovery of the group 3 elements is inextricably tied to that of the rare earths, with which they are universally associated in nature. In 1787, Swedish part-time chemist Carl Axel Arrhenius found a heavy black rock near the Swedish village of Ytterby, Sweden (part of the Stockholm Archipelago). Thinking that it was an unknown mineral containing the newly discovered element tungsten, he named it ytterbite. Finnish scientist Johan Gadolin identified a new oxide or "earth" in Arrhenius' sample in 1789, and published his completed analysis in 1794; in 1797, the new oxide was named yttria. In the decades after French scientist Antoine Lavoisier developed the first modern definition of chemical elements, it was believed that earths could be reduced to their elements, meaning that the discovery of a new earth was equivalent to the discovery of the element within, which in this case would have been yttrium. Until the early 1920s, the chemical symbol "Yt" was used for the element, after which "Y" came into common use. Yttrium metal, albeit impure, was first prepared in 1828 when Friedrich Wöhler heated anhydrous yttrium(III) chloride with potassium to form metallic yttrium and potassium chloride. In fact, Gadolin's yttria proved to be a mixture of many metal oxides, that started the history of the discovery of the rare earths.

In 1869, Russian chemist Dmitri Mendeleev published his periodic table, which had an empty space for an element above yttrium. Mendeleev made several predictions on this hypothetical element, which he called eka-boron. By then, Gadolin's yttria had already been split several times; first by Swedish chemist Carl Gustaf Mosander, who in 1843 had split out two more earths which he called terbia and erbia (splitting the name of Ytterby just as yttria had been split); and then in 1878 when Swiss chemist Jean Charles Galissard de Marignac split terbia and erbia themselves into more earths. Among these was ytterbia (a component of the old erbia), which Swedish chemist Lars Fredrik Nilson successfully split in 1879 to reveal yet another new element. He named it scandium, from the Latin Scandia meaning "Scandinavia". Nilson was apparently unaware of Mendeleev's prediction, but Per Teodor Cleve recognized the correspondence and notified Mendeleev. Chemical experiments on scandium proved that Mendeleev's suggestions were correct; along with discovery and characterization of gallium and germanium this proved the correctness of the whole periodic table and periodic law. Metallic scandium was produced for the first time in 1937 by electrolysis of a eutectic mixture, at 700–800 °C, of potassium, lithium, and scandium chlorides. Scandium exists in the same ores that yttrium had been discovered from, but is much rarer and probably for that reason had eluded discovery.

The remaining component of Marignac's ytterbia also proved to be a composite. In 1907, French scientist Georges Urbain, Austrian mineralogist Baron Carl Auer von Welsbach, and American chemist Charles James all independently discovered a new element within ytterbia. Welsbach proposed the name cassiopeium for his new element (after Cassiopeia), whereas Urbain chose the name lutecium (from Latin Lutetia, for Paris). The dispute on the priority of the discovery is documented in two articles in which Urbain and von Welsbach accuse each other of publishing results influenced by the published research of the other. In 1909, the Commission on Atomic Mass, which was responsible for the attribution of the names for the new elements, granted priority to Urbain and adopting his names as official ones. An obvious problem with this decision was that Urbain was one of the four members of the commission. In 1949, the spelling of element 71 was changed to lutetium. Later work connected with Urbain's attempts to further split his lutecium however revealed that it had only contained traces of the new element 71, and that it was only von Welsbach's cassiopeium that was pure element 71. For this reason many German scientists continued to use the name cassiopeium for the element until the 1950s. Ironically, Charles James, who had modestly stayed out of the argument as to priority, worked on a much larger scale than the others, and undoubtedly possessed the largest supply of lutetium at the time. Lutetium was the last of the stable rare earths to be discovered. Over a century of research had split the original yttrium of Gadolin into yttrium, scandium, lutetium, and seven other new elements.

Lawrencium is the only element of the group that does not occur naturally. It was first synthesized by Albert Ghiorso and his team on February 14, 1961, at the Lawrence Radiation Laboratory (now called the Lawrence Berkeley National Laboratory) at the University of California in Berkeley, California, United States. The first atoms of lawrencium were produced by bombarding a three-milligram target consisting of three isotopes of the element californium with boron-10 and boron-11 nuclei from the Heavy Ion Linear Accelerator (HILAC). The nuclide ²⁵⁷103 was originally reported, but then this was reassigned to ²⁵⁸103. The team at the University of California suggested the name lawrencium (after Ernest O. Lawrence, the inventor of cyclotron particle accelerator) and the symbol "Lw", for the new element, but "Lw" was not adopted, and "Lr" was officially accepted instead. Nuclear-physics researchers in Dubna, Soviet Union (now Russia), reported in 1967 that they were not able to confirm American scientists' data on ²⁵⁷103. Two years earlier, the Dubna team reported ²⁵⁶103. In 1992, the IUPAC Trans-fermium Working Group officially recognized element 103, confirmed its naming as lawrencium, with symbol "Lr", and named the nuclear physics teams at Dubna and Berkeley as the co-discoverers of lawrencium.

Dispute on composition

For a reference to the electron configurations of the elements involved, see Periodic table (electron configurations).

The rare-earth elements historically gave very many problems for the periodic table. In 1871, Russian chemist Dmitri Mendeleev (inventor of the periodic table) attempted to put them in the same groups as other elements, but further investigation of the rare earths made it clear that they did not show the necessary valences for those placements to make sense. In 1902, Czech chemist Bohuslav Brauner suggested that the rare earths all belonged in one place on the periodic table: he called this the "asteroid hypothesis", since just as between Mars and Jupiter there is an asteroid belt instead of a planet, so below yttrium there would be all the lanthanides instead of a single element.

With the measurements of the ground-state gas-phase electron configurations of the elements, and their adoption as a basis for periodic table placement, the older form of group 3 containing scandium, yttrium, lanthanum, and actinium gained prominence in the 1940s. The ground-state configurations of caesium, barium and lanthanum are [Xe]6s¹, [Xe]6s² and [Xe]5d¹6s². Lanthanum thus emerges with a 5d differentiating electron and on these grounds it was considered to be "in group 3 as the first member of the d-block for period 6". A superficially consistent set of electron configurations was then seen in group 3: scandium [Ar]3d¹4s², yttrium [Kr]4d¹5s², lanthanum [Xe]5d¹6s² and actinium [Rn]6d¹7s². Still in period 6, ytterbium was erroneously assigned an electron configuration of [Xe]4f¹³5d¹6s² and lutetium [Xe]4f¹⁴5d¹6s², which suggested that lutetium was the last element of the f-block. This format thus results in the f-block coming between and splitting apart groups 3 and 4 of the d-block.

However, later spectroscopic work found that the correct electron configuration of ytterbium was in fact [Xe]4f¹⁴6s². This meant that ytterbium and lutetium—the latter with [Xe]4f¹⁴5d¹6s²—both had 14 f-electrons, "resulting in a d- rather than an f- differentiating electron" for lutetium and making it an "equally valid candidate" with [Xe]5d¹6s² lanthanum, for the group 3 periodic table position below yttrium. This would result in a group 3 with scandium, yttrium, lutetium, and lawrencium. The first to point out these implications were the Russian physicists Lev Landau and Evgeny Lifshitz in 1948: their textbook Course of Theoretical Physics stated "In books on chemistry, lutetium is also placed with the rare-earth elements. This, however is incorrect, since the 4f shell is complete in lutetium." After Landau and Lifshitz made their statement, many physicists likewise supported the change in the 1960s and 1970s, focusing on many properties such as the crystal structure, melting points, conduction band structure, and superconductivity in which lutetium matches the behaviour of scandium and yttrium, but lanthanum is distinct. This form requires no split blocks.

Some authors had also arrived at this conclusion via other means. In 1905, before lutetium had been discovered, Swiss chemist Alfred Werner already placed lanthanum in a different column from scandium and yttrium because of its distinct chemical behaviour. French engineer Charles Janet had also placed lutetium under yttrium in 1928. The Soviet chemist Chistyakov noted in 1968 that secondary periodicity was fulfilled in group 3 only if lutetium was included in it rather than lanthanum. However, the chemical community largely ignored these conclusions. The philosopher of science Eric Scerri suggests that a factor may have been that several authors who proposed this change were physicists.

The American chemist William B. Jensen collected many of the above arguments in a concerted 1982 plea to chemists to change their periodic tables and put lutetium and lawrencium in group 3. Besides those physical and chemical arguments, he also pointed out that the configurations of lanthanum and actinium are better considered as irregular, similar to how thorium was even then universally treated. Thorium has no f-electrons in its ground state (being [Rn]6d²7s²), but was and is universally placed as an f-block element with an irregular ground-state gas-phase configuration replacing the ideal [Rn]5f²7s². Lanthanum and actinium could then be considered similar cases where an ideal f¹s² configuration is replaced by a d¹s² configuration in the ground state. Since most of the f-block elements in fact have an fⁿs² configuration, and not an fⁿ⁻¹d¹s² configuration, the former is strongly suggested as the ideal general configuration for the f-block elements. This reassignment similarly creates a homologous series of configurations in group 3: in particular, the addition of a filled f-shell to the core passing from yttrium to lutetium is exactly analogous to what happens down every other d-block group.

In any case, ground-state gas-phase configurations consider only isolated atoms as opposed to bonding atoms in compounds (the latter being more relevant for chemistry), which often show different configurations. The idea of irregular configurations is supported by low-lying excited states: despite not having an f-electron in its ground state, lanthanum nevertheless has f-orbitals of low enough energy that they may be used for chemistry, and this affects the physical properties that had been adduced as evidence for the proposed reassignment. (Scandium, yttrium, and lutetium have no such low-lying available f-orbitals.) The irregular configuration of lawrencium ([Rn]5f¹⁴7s²7p¹ rather than [Rn]5f¹⁴6d¹7s²) can similarly be rationalised as another (albeit unique) anomaly due to relativistic effects that become important for the heaviest elements. These irregular configurations in the 4f elements are the result of strong interelectronic repulsion in the compact 4f shell, with the result that when the ionic charge is low, a lower energy state is obtained by moving some electrons to the 5d and 6s orbitals which do not suffer such large interelectronic repulsion, even though the 4f energy level is normally lower than the 5d or the 6s one: a similar effect happens early in the 5f series.

In 1988, a IUPAC report was published that touched on the matter. While it wrote that electron configurations were in favour of the new assignment of group 3 with lutetium and lawrencium, it instead decided on a compromise where the lower spots in group 3 were instead left blank, because the traditional form with lanthanum and actinium remained popular. This could be interpreted either as shrinking group 3 to scandium and yttrium only, or as including all lanthanides and actinides in group 3; the latter interpretation is in effect a return to Brauner's asteroid hypothesis. In either case, the f-block appears with 15 elements, despite quantum mechanics dictating that it should have 14. Such a table appears in many IUPAC publications; despite being commonly labelled "IUPAC periodic table", it is not actually officially supported by IUPAC. The following IUPAC Red Book (a collection of nomenclature rules for inorganic chemistry) of 1990 displayed the periodic table in three formats, 8-column (based on Mendeleev's original), 18-column, and 32-column; the first two showed the compromise with all lanthanides and actinides in group 3, but the third showed lutetium and lawrencium alone under yttrium in group 3. In 2005, the 8-column and 32-column forms were dropped from the IUPAC Red Book, leaving only the compromise version in 18-column format.

This compromise did not stop the debate. Although some chemists were convinced by the arguments to reassign lutetium to group 3, many continued to show lanthanum in group 3, either because they did not know of the arguments or were unconvinced by them. Most research on the matter tended to support the proposed reassignment of lutetium to group 3. However, in chemistry textbooks, the traditional form continued being the most popular up to the 2010s, although it gradually lost some ground to both the new form with lutetium and the compromise form. Some textbooks even inconsistently showed different forms in different places. Laurence Lavelle went further, defending the traditional form with lanthanum in group 3 on the grounds of neither lanthanum nor actinium having valence f-electrons in the ground state, giving rise to heated debate. Jensen later rebutted this by pointing out the inconsistency of Lavelle's arguments (since the same was true of thorium and lutetium, which Lavelle placed in the f-block) and the evidence for irregular configurations. Scerri, who has published widely on this issue, has noted that Jensen's case based on physical and chemical properties is not conclusive because of its selectivity, pointing to other choices of properties that seem to support lanthanum in group 3 instead of lutetium. Nonetheless, he has also consistently supported lutetium in group 3 on the basis of avoiding a split in the d-block, and has also referred to the fact that electron configurations are approximations and the problem of thorium.

In December 2015 an IUPAC project, chaired by Scerri and including (among others) Jensen and Lavelle, was established to make a recommendation on the matter. Its preliminary report was published in January 2021. It concluded that none of the criteria previously invoked in the debate gave a clear-cut resolution of the question and that ultimately the question rested on convention rather than being something that was objectively scientifically decidable. As such, it suggested "a degree of convention" to be used for "selecting a periodic table that can be presented as the best compromise table that combines objective factors as well as interest dependence", for presentation to "the widest possible audience of chemists, chemical educators and chemistry students". Three desiderata were given: (1) all elements should be displayed in order of increasing atomic number, (2) the d-block should not be split into "two highly uneven portions", and (3) the blocks should have the widths 2, 6, 10, and 14 in accordance with the quantum mechanical basis of the periodic table. The block assignment was admitted to be approximate, just like the assignment of electron configurations: the case of thorium was specifically remarked on. These three desiderata are only fulfilled by the table with lutetium and lawrencium in group 3; the traditional form of group 3 with lanthanum violates (2), and the compromise form of group 3 with all lanthanides and actinides violates (3). As such, the form with lutetium in group 3 was suggested as a compromise.

The project ended in December 2021. Currently, IUPAC's website on the periodic table still shows the 1988 compromise, but mentions the group 3 problem and project to resolve it, and writes "Stay tune[d]".

Characteristics

Chemical

Electron configurations of the group 3 elements
Z	Element	Electron configuration
21	Sc, scandium	2, 8,  9,  2	[Ar]      3d1 4s2
39	Y, yttrium	2, 8, 18,  9,  2	[Kr]      4d1 5s2
71	Lu, lutetium	2, 8, 18, 32,  9, 2	[Xe] 4f14 5d1 6s2
103	Lr, lawrencium	2, 8, 18, 32, 32, 8, 3	[Rn] 5f14 6d0 7s2 7p1

Like other groups, the members of this family show patterns in their electron configurations, especially the outermost shells, resulting in trends in chemical behavior. Due to relativistic effects that become important for high atomic numbers, lawrencium's configuration has an irregular 7p occupancy instead of the expected 6d, but the regular [Rn]5f¹⁴6d¹7s² configuration turns out to be low enough in energy that no significant difference from the rest of the group is observed or expected.

Most of the chemistry has been observed only for the first three members of the group; chemical properties of lawrencium are not well-characterized, but what is known and predicted matches its position as a heavier homolog of lutetium. The remaining elements of the group (scandium, yttrium, lutetium) are quite electropositive. They are reactive metals, although this is not obvious due to the formation of a stable oxide layer which prevents further reactions. The metals burn easily to give the oxides, which are white high-melting solids. They are usually oxidized to the +3 oxidation state, in which they form mostly ionic compounds and have a mostly cationic aqueous chemistry. In this way they are similar to the lanthanides, although they lack the involvement of f orbitals that characterises the chemistry of the 4f elements lanthanum through ytterbium. The stable group 3 elements are thus often grouped with the 4f elements as the so-called rare earths.

The stereotypical transition-metal properties are mostly absent from this group, as they are for the heavier elements of groups 4 and 5: there is only one typical oxidation state and the coordination chemistry is not very rich (though high coordination numbers are common due to the large size of the M³⁺ ions). This said, low-oxidation state compounds may be prepared and some cyclopentadienyl chemistry is known. The chemistries of group 3 elements are thus mostly distinguished by their atomic radii: yttrium and lutetium are very similar, but scandium stands out as the least basic and the best complexing agent, approaching aluminium in some properties. They naturally take their places together with the rare earths in a series of trivalent elements: yttrium acts as a rare earth intermediate between dysprosium and holmium in basicity; lutetium as less basic than the 4f elements and the least basic of the lanthanides; and scandium as a rare earth less basic than even lutetium. Scandium oxide is amphoteric; lutetium oxide is more basic (although it can with difficulty be made to display some acidic properties), and yttrium oxide is more basic still. Salts with strong acids of these metals are soluble, whereas those with weak acids (e.g. fluorides, phosphates, oxalates) are sparingly soluble or insoluble.

Physical

The trends in group 3 follow those of the other early d-block groups and reflect the addition of a filled f-shell into the core in passing from the fifth to the sixth period. For example, scandium and yttrium are both soft metals. But because of the lanthanide contraction, the expected increase in atomic radius from yttrium to lutetium is in fact more than cancelled out; lutetium atoms are slightly smaller than yttrium atoms, but are heavier and have a higher nuclear charge. This makes the metal more dense, and also harder because the extraction of the electrons from the atom to form metallic bonding becomes more difficult. All three metals have similar melting and boiling points. Very little is known about lawrencium, but calculations suggest it continues the trend of its lighter congeners toward increasing density.

Scandium, yttrium, and lutetium all crystallize in the hexagonal close-packed structure at room temperature, and lawrencium is expected to do the same. The stable members of the group are known to change structure at high temperature. In comparison with most metals, they are not very good conductors of heat and electricity because of the low number of electrons available for metallic bonding.

Properties of the group 3 elements

Name	Sc, scandium	Y, yttrium	Lu, lutetium	Lr, lawrencium
Melting point	1814 K, 1541 °C	1799 K, 1526 °C	1925 K, 1652 °C	1900 K, 1627 °C
Boiling point	3109 K, 2836 °C	3609 K, 3336 °C	3675 K, 3402 °C	?
Density	2.99 g·cm−3	4.47 g·cm−3	9.84 g·cm−3	? 14.4 g·cm−3
Appearance	silver metallic	silver white	silver gray	?
Atomic radius	162 pm	180 pm	174 pm	?

Occurrence

Scandium, yttrium, and lutetium tend to occur together with the other lanthanides (except short-lived promethium) in the Earth's crust, and are often harder to extract from their ores. The abundance of elements in Earth's crust for group 3 is quite low—all the elements in the group are uncommon, the most abundant being yttrium with abundance of approximately 30 parts per million (ppm); the abundance of scandium is 16 ppm, while that of lutetium is about 0.5 ppm. For comparison, the abundance of copper is 50 ppm, that of chromium is 160 ppm, and that of molybdenum is 1.5 ppm.

Scandium is distributed sparsely and occurs in trace amounts in many minerals. Rare minerals from Scandinavia and Madagascar such as gadolinite, euxenite, and thortveitite are the only known concentrated sources of this element, the latter containing up to 45% of scandium in the form of scandium(III) oxide. Yttrium has the same trend in occurrence places; it is found in lunar rock samples collected during the American Apollo Project in a relatively high content as well.

Monazite, the most important lutetium ore

The principal commercially viable ore of lutetium is the rare-earth phosphate mineral monazite, (Ce,La,etc.)PO₄, which contains 0.003% of the element. The main mining areas are China, United States, Brazil, India, Sri Lanka and Australia. Pure lutetium metal is one of the rarest and most expensive of the rare-earth metals with the price about US$10,000/kg, or about one-fourth that of gold.

Production

The most available element in group 3 is yttrium, with annual production of 8,900 tonnes in 2010. Yttrium is mostly produced as oxide, by a single country, China (99%). Lutetium and scandium are also mostly obtained as oxides, and their annual production by 2001 was about 10 and 2 tonnes, respectively.

Group 3 elements are mined only as a byproduct from the extraction of other elements. They are not often produced as the pure metals; the production of metallic yttrium is about a few tonnes, and that of scandium is in the order of 10 kg per year; production of lutetium is not calculated, but it is certainly small. The elements, after purification from other rare-earth metals, are isolated as oxides; the oxides are converted to fluorides during reactions with hydrofluoric acid. The resulting fluorides are reduced with alkaline earth metals or alloys of the metals; metallic calcium is used most frequently. For example:

Sc₂O₃ + 3 HF → 2 ScF₃ + 3 H₂O

2 ScF₃ + 3 Ca → 3 CaF₂ + 2 Sc

Biological chemistry

Group 3 metals have low availability to the biosphere. Scandium, yttrium, and lutetium have no documented biological role in living organisms. The high radioactivity of lawrencium would make it highly toxic to living cells, causing radiation poisoning.

Scandium concentrates in the liver and is a threat to it; some of its compounds are possibly carcinogenic, even through in general scandium is not toxic. Scandium is known to have reached the food chain, but in trace amounts only; a typical human takes in less than 0.1 micrograms per day. Once released into the environment, scandium gradually accumulates in soils, which leads to increased concentrations in soil particles, animals and humans. Scandium is mostly dangerous in the working environment, due to the fact that damps and gases can be inhaled with air. This can cause lung embolisms, especially during long-term exposure. The element is known to damage cell membranes of water animals, causing several negative influences on reproduction and on the functions of the nervous system.

Yttrium tends to concentrate in the liver, kidney, spleen, lungs, and bones of humans. There is normally as little as 0.5 milligrams found within the entire human body; human breast milk contains 4 ppm. Yttrium can be found in edible plants in concentrations between 20 ppm and 100 ppm (fresh weight), with cabbage having the largest amount. With up to 700 ppm, the seeds of woody plants have the highest known concentrations.

Lutetium concentrates in bones, and to a lesser extent in the liver and kidneys. Lutetium salts are known to cause metabolism and they occur together with other lanthanide salts in nature; the element is the least abundant in the human body of all lanthanides. Human diets have not been monitored for lutetium content, so it is not known how much the average human takes in, but estimations show the amount is only about several micrograms per year, all coming from tiny amounts taken by plants. Soluble lutetium salts are mildly toxic, but insoluble ones are not.