Both main and interactive AoA effects on plasticity have been attributed to neurological maturation, to neurochemical and hormonal fluctuations, to decrements of cognitive function over time, to decreases in regional brain volume, to the degree of first- language L1 entrenchment at the initial state of L2 acquisition, and to the relative use and maintenance of the L1 vs. AoA may also indirectly condition learner variables such as the extent to which an individual is motivated to acquire an L2 to high levels of proficiency, to engage in the L2 culture, and to identify with L2 speakers e.
A comprehensive synthesis of relevant research is beyond the scope of this article.
1. Introduction
Rather, by use of selected examples, the goal is to expose the essential nature of L2 acquisition and bilingualism from the perspectives of age, plasticity and variability. From these perspectives, we can conceive of linguistic attainment in terms of factors that make L2 learners and bilinguals different from monolinguals, and perhaps get a sense of why these differences are not necessarily deficiencies. After a brief orientation to the developmental neurobiology of age and plasticity in language learning, I consider the evidence for critical periods in L2 acquisition, taking into account the shape of the function that relates AoA to attainment and the im probability of nativelike attainment.
In the next section I examine possible sources of greater heterogeneity of attainment of L2 morphosyntax with increasing AoA. This is followed by consideration of inter-individual differences, first with respect to exceptional L2 learners and polyglots, then in terms of neurogenetically based talent and trainability, then as a function of idiosyncratic construction of categories for representing linguistic form. In the final section I look at several ways in which linguistic dominance instantiates concerns about plasticity and age, and at how the dominance factor can account for variability in pronunciation and language learning among individual bilinguals.
The works reviewed here converge on the conclusion that studying non-uniformity in language learning outcomes is not so much about sifting through noise and scatter in the data, as it is about illuminating an inherent characteristic of both early and late language acquisition.
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To this end, it is important to show how plasticity and age connect with biological and experiential sources of variability, and to orient research questions in ways that expose and exploit variability. A basic motivation of this review is to provide points of reference and theoretical and empirical foundations for readers of the other contributions to the present Frontiers in Psychology Research Topic.
In so doing I hope to give a sense of how plasticity, variability and age conspire to frame fundamental research issues in L2 acquisition and bilingualism. In this review, the relationship between age and L2 attainment will be considered with respect to the time at which learning of the L2 begins, be it from birth or at any time thereafter.
The term AoA refers to the age at which L2 learning begins in earnest and continues with little or no interruption, most often in immersion contexts such as immigration, but not to limited acquaintance with the L2 that takes place in on trips or in the foreign-language classroom. The point at which L2 learning begins is conceptualized as the initial state of L2 acquisition: Since this cluster of features is difficult to quantify, AoA is taken to be a proxy for the L2 acquisition initial state.
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As a predictor variable in statistical analyses, AoA can be applied to both bilingual simultaneous or sequential development in childhood, and to immersion and immigration contexts later in life. In this review, bilingualism is understood to mean routine use of two languages, at whatever level of proficiency in either language. Bilinguals who are immigrants or migrant workers may have acquired their two languages naturalistically only, or they may have had some classroom experience followed by immersion and frequent use. Nevertheless, AoA is commonly employed as a predictive factor for learning outcomes in training studies.
In this contribution critical period is intended as a generic term that subsumes sensitive period. The latter term is sometimes used in contexts of relatively mild maturational effects; at other times it is only meant to suggest heightened receptivity sensitivity to relevant environmental stimuli.
Both terms refer to finite developmental spans, which may range from birth up to adulthood. In some studies, critical period is taken to mean just the peak period of plasticity or receptiveness of the learning system; in other studies including the present one , the critical period begins when plasticity starts to increase above baseline and continues until plasticity has leveled out. Maturational effects are thought to take place within, but not beyond, the critical period. For this reason one distinguishes maturational effects from general age effects over the lifespan and, similarly, from AoA effects.
For a synopsis of the literature on critical periods for language and other domains, see Birdsong Finally, for the purposes of this paper, learning and acquisition will be used interchangeably. In some studies, the former term is reserved for formal instructional contexts. The notion of plasticity with respect to adult language acquisition is often traced back to Penfield and Roberts , p. Also seminal in this regard are passing remarks by Lenneberg , p. More recent researchers have put forth other neurobiological explanations for plasticity deficits over age.
Another proposed neurobiological culprit is maturationally regulated myelination in the circuitry that underlies language learning. Declines in nigrostriatal dopamine over age are implicated in decrements of cognitive abilities such as attention, sequencing, and suppression of competing information; these domain-general capacities are put to use in online L2 processing Lee, ; Wong et al. To get a fuller sense of the neurobiology of plasticity, and how it might relate to variability in language learning, it is instructive to connect critical-period research in the L1 context with studies in L2 acquisition and bilingualism.
Sequential, overlapping critical periods in infant speech perception development. Solid lines represent typical onsets and offsets; broken lines indicate extensions of periods. Adapted from Werker and Hensch Republished with permission from Annual Reviews. The chronologies of the onset, the duration, and the closure of each of the critical periods are not fixed, but are manipulated by biological and experiential factors. For example, the timing of the closure of critical periods depends on molecular brakes such as myelin and histone deacetylases, and onset timing can be delayed by sensory deprivation and maternal depression.
Thus it is understood that variability and plasticity go hand in hand, as variability within and across overlapping periods of plasticity is a basic feature of the model. Notably, at the level of the individual child the duration of critical periods in speech perception development can be varied through bilingual experience.
As examples, Werker and Hensch cite studies showing that the duration of the critical period for perceptual narrowing — the process by which infants orient their emergent speech perception abilities around just those sounds that occur in their linguistic environment — is longer among simultaneous bilingual children than among monolingual children.
The researchers point to several possibilities for this extension. Relative to monolingual infants, among bilingual infants: At early developmental stages, the two languages of bilingual infants may resemble those of monolingual children. For example, Burns et al. Once simultaneous and early bilinguals reach adulthood, however, their processing and production of speech differs from that of monolinguals in each language see below.
This variability which may reflect asymmetric exposure to or use of the two languages, or exposure to accented speech in one or both languages, along with motivation, context of learning, inter- individual neurobiological and neurocognitive differences over development, etc. For example, Mack looks at early English—French and French—English bilingual adults, all of whom were English dominant.
Similarly, in Sundara et al. It is commonly believed that L2 attainment to nativelike levels among adults is impossible because they have passed a critical period for successful learning. Two general types of evidence are summoned to support this view. The first is the nature of the function that relates AoA to ultimate attainment. The second is evidence for comprehensive nativelike attainment across all aspects of knowledge, production, and processing of the L2.
Theories of the geometry of the function that relates AoA to ultimate asymptotic L2 attainment are reviewed in Birdsong and Birdsong and Vanhove In brief, it is thought that departures from linearity in the function would suggest the effects of developmental events leading to qualitative changes in the neurocognitive mechanisms believed responsible for language learning see Hakuta et al. Some researchers have argued that declines in ultimate L2 attainment should level off after the end of maturation. That is, AoA effects on L2 attainment should be observed among early L2 learners, but AoA should no longer be predictive of L2 asymptote among post-adolescent learners, since maturation would presumably have ceased by this time.
On another view, L2 learning is successful up to a certain age which may vary depending on what language features are being investigated , and learning ability and, consequently, ultimate attainment should decline thereafter. Schematic representations of age of acquisition AoA effects on L2 attainment. A linear decline of L2 attainment over all AoA; B initial decline of L2 attainment followed by leveling off over subsequent AoA; C L2 attainment plateau, followed by decline, followed by leveling off over subsequent AoA; D L2 attainment plateau followed by decline over subsequent AoA.
To clarify, note that these are schematic representations only. Depending on methodological considerations e. Also, the timing of the points along the AoA continuum where changes in slope are said to occur varies considerably from study to study. For further discussion, see Birdsong, ; Meulman et al. The geometry and timing of AoA effects are crucial to the question of age-conditioned plasticity in L2 learning since, in order to be consistent with maturational effects, the inflection points on the function would need to match up with known maturational milestones.
There are two main obstacles to establishing this isomorphism. One is that attained values on accent ratings and knowledge of morphosyntax map onto different functions. Such an account would have to reckon with geometries that are known to vary depending on the pairings of the L1 and the L2, the particular linguistic structures being tested, and exposure, identificational, and motivational factors e. In these ways, considerations of plasticity and variability intersect. Another challenge involves the analytical methods that are employed to generate the AoA- attainment function.
Different statistical methods applied to the same data may result in different shapes of the function, thus introducing an additional dimension of variability in our conceptualization of plasticity. Note that this unsystematic dispersion was interpreted by Johnson and Newport as a flattening of the AoA-L2 attainment function; see below.
In a subsequent reanalysis of the Johnson and Newport data, Elman et al. Importantly, Elman et al. In a re-examination of the Johnson and Newport L2 grammaticality judgment data, Vanhove exposes problems with comparing the correlations for early- vs. Note as well that general performance levels are often predicted by such variables; see e. Vanhove also reanalyzes L2 grammaticality judgment data from DeKeyser et al. For both participant groups, DeKeyser et al. For example, Hartshorne et al. After this plateau, facilitation declines with increasing AoA, with no leveling off. The researchers looked at ERP P signatures for the processing of violations of non-finite verbs and grammatical gender agreement in German by Slavic L1 speakers with advanced proficiency in German L2.
AoA effects were not found for non-finite verb violations, which are similar in Slavic and German.
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As a second type of support for critical period effects in L2 acquisition, some researchers point to the lack of evidence for across-the-board nativelikeness in late L2 acquisition e. The underlying logic is that language learning is biologically destined to be successful if begun in during a critical maturational epoch in early childhood, and that the failure of late learning to attain nativelike competence is the inevitable result of having passed a critical period of neural plasticity.
Close comparisons of monolinguals and late L2 learners typically reveal differences across many dimensions of observation e. This argument is implausible, however, because the nature of bilingualism is such that the languages of an active bilingual are activated simultaneously Dijkstra and Van Heuven, ; Schwartz and Kroll, and influence each other reciprocally Grosjean, ; Cook, , ; Flege et al. Given coactivation and bidirectional effects, neither the first nor the second language of bilinguals can be expected to resemble under scrutiny that of monolinguals in either language.
Returning to the question of plasticity, it is important to keep in mind that the L1 is permeable in bilingualism; thus, considerations of plasticity apply to the L1 as well as the L2. Moreover, the fact that it is not only late L2 learners who exhibit such differences, but early bilinguals and bilinguals-from-birth as well, is plausibly explained under a bilingualism effects account e. Note in this context that no researchers claim that bilingualism effects alone are responsible for all divergences from monolingual-likeness in bilingualism.
Attested non-nativelikeness in both languages of an active bilingual has clear implications for theory. To the extent that an account of L2 acquisition predicts that L2 learners should not attain across-the-board nativelikeness if they have passed a biologically regulated critical period, it should also logically predict that the L1 of a bilingual, which is learned within that critical period, should exemplify monolingual-likeness across the board.
However, this prediction is not borne out in the relevant research. By contrast, the evidence of bilingualism effects supports an account under which neither the L2 irrespective of AoA nor the L1 are completely monolingual-like. Note in this regard that the accuracy figures for bilinguals from birth are significantly lower than those of native monolingual controls in Hartshorne et al.
These observations connect straightforwardly to questions of age, plasticity, and variability.
In their meta-analysis, Liu and Cao cite studies of L1 permeability in bilingualism, which reveal different patterns of neural activation in the L1 after vs. Introducing the AoA factor, several reviewed studies converge on the finding that early bilinguals, relative to late bilinguals — with both sampled populations having the same L1 — showed greater activation in the left fusiform gyrus than late bilinguals when processing the L1.
This relationship is attested as well in behavioral studies. The basic notion that L2 ultimate attainment is conditioned by the age of initial immersion or significant exposure is examined by Qureshi in a meta-analysis of 26 studies of morphosyntactic knowledge. The materials reviewed largely substantiated the general idea of AoA effects as opposed to maturational effects, which were not explicitly examined.
At the same time, experiential and methodological factors were found to introduce considerable variability in outcomes. It is important to emphasize that, despite bilingualism effects, there are late L2 learners who resemble native monolinguals with respect to targeted aspects of the L2 as opposed to bilinguals being indistinguishable from monolinguals in every measurable respect. Behavioral evidence ranges from acquisition of fine-grained phonetic features such as VOT to global pronunciation Bongaerts, ; Flege et al.
In online tasks such as self-paced reading, late bilinguals show monolingual-like sensitivity to subtle and unique aspects of the L2 such as order of clitic pronouns Rossi et al. In brain-based studies, high-proficient late L2 learners exhibit convergence with native participants Green, in the processing of information structure Reichle and Birdsong, and across a variety of syntactic and morpho- syntactic features: The incidence of nativelikeness among late L2 learners can vary as a function of the particular structural characteristics that are investigated and as a function of the experimental procedures that are employed.
For example, in a series of experiments that involved both ERP and eye-tracking methodologies, Foucart and Frenck-Mestre find that violations of noun-adjective gender agreement in French trigger nativelike P signatures among English-speaking late learners of L2 French when the adjectives follow the nouns, but elicit non-nativelike Ns when the adjectives are preposed. When the stimuli involve agreement violations in predicative structures where the noun and the adjective are separated by a copula , natives and learners diverge in terms of ERP, but show similar patterns in eye tracking.
Birdsong and Gertken point out that the incidence of nativelikeness may depend on which native speakers the learners are being compared to. For example, Indefrey , reviewing studies involving the processing of complex syntax, discerns that natives with high memory spans attend to structural features for correct interpretation in online tasks whereas natives with low memory spans rely on lexico-semantic information — as do many L2 speakers. Indefrey , p. In some of these and related studies, the findings of nativelikeness have been interpreted as counter-evidence to critical-period predictions with respect to the attainment of nativelikeness in late L2 acquisition articulated.
Recall, however, that proponents of the critical period hypothesis in the L2 context advance the criterion of across-the-board nativelikeness as necessary evidence for rejection of the hypothesis. As stated above, however, the position regarding falsification of the hypothesis by impeccable nativelikeness does not take into account the natural effects of bilingualism, which make it impossible for both early and late bilinguals to be exactly like monolinguals in either the L1 or the L2.
It was also noted that, by the logic of this position, for rejection of the nature-of-bilingualism account and for support of the critical period account one would need evidence of across-the-board monolingual-likeness in the first-learned language of late bilinguals, or in either language of simultaneous bilinguals Birdsong and Vanhove, As seen in the plateau at ceiling, participants with early AoA up to about 7 years of age perform relatively homogeneously and within or close to the range of native controls.
Results of a test of English morphosyntax, as a function of age of arrival in the United States. A Shows overall percent correct for Korean native speakers filled circles and native English controls open circles ; B breaks out test results by grammatical items top and ungrammatical items bottom ; C depicts different functions for ungrammatical rule-based items vs. Adapted from Flege et al. Republished with permission from Elsevier.
Second-language learning and changes in the brain
Both the top and bottom images reveal increased variability over AoA; however, the degree of variability depends on the grammatical status of the items analyzed, with the cone-shaped scatter of results more pronounced for responses to ungrammatical items than to grammatical items. As a second illustration of sources of variability, Ettlinger et al. In an artificial language based on Shimakonde, a Bantu language of Mozambique, university student participants were trained on noun stems, plurals, diminutives, and diminutive plurals representing animals.
For two types of diminutive plurals in the language, the diminutive and the plural morphemes are simply affixed on the singular stem. A third type of diminutive plurals is more complex, as the vowels in the stem and the plural affix require rephonologization. Some learners termed Simplifiers tended to apply the simple pattern in instances of both complex and simple diminutive plurals; others Learners successfully learned both the complex and simple diminutive plurals; others Non-learners performed poorly overall.
On a prior test of working memory, Learners, Simplifiers and Non-learners performed similarly. However, the groups varied on prior tests of procedural memory and declarative memory. Those participants who were Learners generally scored high on both procedural and declarative memory tests. Those with high procedural memory scores, but lower declarative memory scores, tended to be Simplifiers. Those with poor procedural memory, irrespective of declarative memory scores, were Non-learners. Adapted from Ettlinger et al. Republished with permission from Cambridge University Press.
In some studies, as AoA increases, the outcome of learning of L2 morphosyntax appears to become more variable see, e. Candidate sources for such wide dispersions can be inferred from an increase over age of the range of values that are associated with relevant experiential variables. For example, in a random participant sample, the range of lengths of residence in the L2 environment, along with the range of years and types of education will increase correspondingly with AoA. Along with such scaling effects on demographic variables, it is also possible that, with increasing AoA, motivation to attain accuracy in lexico-grammatical knowledge in L2 will become more heterogeneous across participants, particularly so as goals for L2 learning become more diverse.
Cognitive aging may also figure in the mix of candidate reasons for age-related variability in L2 attainment. For example, Buczylowska and Petermann summarize age-related differences in six executive function tests administered to participants ranging in age from 18 to 99 years. Declines in mean scores over age were accompanied by increased age-dependent heterogeneity in scores.
Connecting this finding to the cone-shaped dispersion of L2 morphosyntax scores over AoA is not a straightforward matter, however, as the heterogeneity observed by Buczylowska and Petermann is most notable in the later age ranges, whereas most individuals undertaking L2 do not begin so late in life. Further, the degree of dispersion varied greatly by task in this study. Similarly, Mella et al. Relatedly, Hartshorne and Germine find that the peaks in cognitive skill are not synchronized over skill types, with some occurring earlier than others.
A strong case can be made for both general effects and inter-individual effects of progressive cognitive decline, as well as for effects of dopamine declines see above , progressive L1 entrenchment Marchman, ; Elman et al. At the same time, it is fair to say that further study is needed to establish a direct link between heterogeneity in cognitive function over age and AoA-related patterns of dispersion of results on tests of L2 attainment.
It is axiomatic that people vary widely in the effectiveness and efficiency with which they learn an L2. Often the study of individual differences in L2 learning focuses on exceptionally successful learners. Although researchers do not all agree on terminological distinctions between the notions of ability, aptitude, talent, and giftedness in the context of L2 learning, the cognitive and conative attributes of high achievers in this domain are well understood; for a recent review, including the question of the mutability of aptitude with experience, see Singleton Individuals who attain near-nativelikeness in multiple languages tend to be endowed with high working memory capacity, are highly motivated to learn, and strategically apply metalinguistic knowledge and analysis across their learned languages.
Polyglots — defined by Hyltenstam as those who reach high proficiency in six or more languages after puberty — and hyper- polyglots — for Erard those who proficiently speak, read, or write in at least 11 languages — share the same traits as gifted multilinguals, while also possessing extraordinary verbal memory. They apply their superior analytic skills to recognize patterns in phonology and morphosyntax, and with remarkable executive control are able to switch between languages with little interference.
The linguistic savant Christopher Smith et al. Pring notes that autistic savants also differ behaviorally from non-autistic experts by their obsession with memorization and practice, which appears to be more about the pleasure of obsessiveness than about achievement. According to Pring, it is typical of high achievers, but not of savants, to strategically set goals and to use feedback when learning. As suggested above, it is more apposite to point out that there are no exceptions to the effects of bilingualism, even among the most talented learners of languages.
Turning to less exceptional cases, Della Rosa et al. Their longitudinal study of children living in the South Tyrol region of Italy, where German, Italian, Ladin and English are routinely used, showed specific multilingualism-induced gray matter volume increases in the LIPL. The researchers suggest that such structural adaptations result from the necessity to apply general memory and attentional functions to the processing of more than one language.
A neurogenetic approach to individual differences in L2 learning is advanced by Wong et al. Procedural learning is associated with concatenation of constituents in syntax and with abstract relations between phonology and morphology, and is localized in the prefrontal cortex and basal ganglia. These differences extend to inhibitory function and executive control, which in L2 processing enable suppression of competing information such as knowledge and intrusion of the L1 Lee, Under the DA account, a mediating role of AoA can be postulated as well, as dopamine receptor and binding declines over age are well documented e.
Taking this approach to variation a step farther, Wong et al. Drawing parallels with personalized medicine in the pharmacological field, the authors suggest that understanding individual differences will lead to customization and optimization of language instruction. For other studies of individual differences in cognitive abilities in particular, differences in procedural, declarative and working memory , and how these play out in second language acquisition, see Morgan-Short et al.
A dual-systems learning model developed by Chandrasekaran et al. The reflective system explicitly develops and tests categorization rules; in contrast, the nature of the reflexive system is procedural and implicit. In experiments involving novel linguistic tone category learning, adult participants initially display a bias toward using the reflective system, which turns out to be ill-adapted to the task. Those individuals who succeed in tone learning are able to shift to the reflexive system, using cortico-striatal connections whose plasticity is regulated by DA reinforcement signals.
Relative to younger participants, older adults appear to be less likely to be able to shift from reflective learning to reflexive learning. Birdsong examines native-language literacy and education as sources of variability across participants in L2 attainment studies. These factors may interact with task type e. Birdsong also notes that both native speakers and L2 learners exhibit grammatical idiosyncrasies and other types of variability in representations of linguistic structure Dabrowska, ; therefore variability per se whatever the type or source is not necessarily evidence of learning deficiencies.
For an overview of individual variation in L2 processing as opposed to attainment , see Van Hell and Abdollahi A feature of bilingualism that conspicuously connects age, plasticity and variability is linguistic dominance. Regarding plasticity and age, it is not always the case that language learned in infancy is the dominant language of a bilingual: Among international adoptees and heritage speakers, dominance shifts involve attrition of the L1, a representational and functional loss which likewise reflects neural plasticity see below.
As concerns variability, inter-individual differences in dominance relationships are natural consequences of idiosyncratic experiences with, skills in, and use of the two languages. No two bilinguals are identical in terms of dominance. Linguistic dominance in bilingualism is understood in terms of dimensions — relative performance in a language skill such as speech rate, picture naming or grammatical accuracy — and in terms of domains — typically, the comparative frequency of use of each language at work, with family members, or at school.
Dominance is not uniquely equatable with relative proficiency as defined in terms of grammatical and lexical accuracy, speech fluency, etc. As with many other features of bilingualism, linguistic dominance is not inherently categorical. Accordingly, in order to faithfully capture the construct, dominance, like AoA, is properly operationalized and analyzed as a continuous subject factor. As with any other continuous variable, participant assignment to dominance categories may mask intra-group variability and result in loss of statistical power e. Some instruments for assessing dominance take into account both domains and dimensions of dominance.
Birdsong reviews methods of calculating dominance indices, along with problems of incommensurability in comparing individual bilinguals who may have the same composite dominance indices, but who vary with respect to the underlying dimensions and domains measured by the instrument. The term is sometimes used or assumed to denote very high or near- nativelike proficiency in both languages. However, degree of proficiency is independent from degree of dominance.
An individual who is at an equally low proficiency level in two languages, and an individual who is highly and equally proficient in two languages, are both by definition balanced bilinguals. Bilinguals who are not balanced that is, who are dominant in either Language A or Language B are situated to one side or the other of the diagonal. Adapted from Goto Butler and Hakuta Republished with permission from John Wiley and Sons. Amygdala is one of the brain centres that controls emotions and stimulations from aggression to sexuality.
Due to its function of control, it takes part in forming long term memory which is very important in second language learning. Losing function of amygdala in human brain might lead to some distortions as depression and anxiety.
I enjoy learning English very much. Studying French can be important to me because it will allow me to..
The Neurobiological Factors in Second Language Learning and Acquisition
Being able to speak English will add to my social status. Schumann and Wood provided further explanation of the neurobiological bases of motivation as Sustained Deep Learning SDL , the kind of learning that requires an extended period of time to achieve. Deep learning is an approach and an attitude to learning, where the learner uses higher-order cognitive skills such as the ability to analyse, synthesize, solve problems, and thinks meta-cognitively in order to construct long-term understanding.
It involves the critical analysis of new ideas, linking them to already known concepts, and principles so that this understanding can be used for problem solving in new, unfamiliar contexts. Deep learning entails a sustained, substantial, and positive influence on the way students act, think, or feel. Learning by integrating new knowledge with existing knowledge. Knowledge is transmitted from the teacher to the student. Focus on what the student does.
Focus on what the teacher does. The Myers-Briggs typology model regards personality type as similar to left or right handedness: The MBTI sorts some of these psychological differences into four opposite pairs, or dichotomies , with a resulting 16 possible psychological types. None of these types are "better" or "worse"; however, Briggs and Myers theorized that individuals naturally prefer one overall combination of type differences.
In the same way that writing with the left hand is hard work for a right-hander, so people tend to find using their opposite psychological preferences more difficult, even if they can become more proficient with practice and development. The 16 types are typically referred to by an abbreviation of four letters—the initial letters of each of their four type preferences except in the case of iNtuition , which uses the abbreviation N to distinguish it from Introversion. The four pairs of preferences or dichotomies are shown in the table to the below.
ISTJ Quiet, serious, earn success by thoroughness and dependability. Practical, matter-of-fact, realistic, and responsible. Decide logically what should be done and work toward it steadily, regardless of distractions. Take pleasure in making everything orderly and organized — their work, their home, their life. Value traditions and loyalty. ISFJ Quiet, friendly, responsible, and conscientious.
Committed and steady in meeting their obligations. Thorough, painstaking, and accurate. Loyal, considerate, notice and remember specifics about people who are important to them, concerned with how others feel. Strive to create an orderly and harmonious environment at work and at home. INFJ Seek meaning and connection in ideas, relationships, and material possessions.
Want to understand what motivates people and are insightful about others. Conscientious and committed to their firm values. Develop a clear vision about how best to serve the common good. Organized and decisive in implementing their vision. INTJ Have original minds and great drive for implementing their ideas and achieving their goals. Quickly see patterns in external events and develop long-range explanatory perspectives. When committed, organize a job and carry it through. Skeptical and independent, have high standards of competence and performance — for themselves and others.
ISTP Tolerant and flexible, quiet observers until a problem appears, then act quickly to find workable solutions. Analyze what makes things work and readily get through large amounts of data to isolate the core of practical problems. Interested in cause and effect, organize facts using logical principles, value efficiency. ISFP Quiet, friendly, sensitive, and kind.
Like to have their own space and to work within their own time frame. Loyal and committed to their values and to people who are important to them. Dislike disagreements and conflicts, do not force their opinions or values on others. INFP Idealistic, loyal to their values and to people who are important to them.
Want an external life that is congruent with their values. Curious, quick to see possibilities, can be catalysts for implementing ideas. Seek to understand people and to help them fulfill their potential. Adaptable, flexible, and accepting unless a value is threatened. INTP Seek to develop logical explanations for everything that interests them. Theoretical and abstract, interested more in ideas than in social interaction.