Comprehensive Study Guide on Human Development and Language Acquisition

Influences on Human Development

Developmental psychology identifies several factors that influence the progression of a human life, categorized into normative and non-normative influences. Normative influences are those expected occurrences that happen to most individuals. These are further subdivided into age-graded influences and history-graded influences. Age-graded normative influences include biological and social milestones such as dentition, the evolution of speech, and motor difficulties typically associated with old age. History-graded normative influences are structural or environmental shifts affecting a cohort, such as economic crises or significant political changes.

Non-normative influences are unexpected or infrequent events that do not happen to everyone but can produce significant changes in an individual's life and development. Examples of these include suffering an accident, the death of a loved one, or winning the lottery.

Stages of Human Development

The human life cycle is divided into specific chronological stages. The Prenatal stage begins at conception and lasts until birth. First Infancy (Primera infancia) spans from $0$ to $2$ years of age. Early Childhood (Niñez temprana) occurs from $2$ to $6$ years. Intermediate Childhood (Niñez intermedia) covers the period from $6$ to $11$ years. Adolescence is defined as the period between $11$ and $22$ years. Adulthood (Adultez) ranges from $22$ to $70$ years. Finally, Old Age (Vejez) refers to individuals aged $+70$ years.

Psychodynamic and Cognitive Theories

Psychodynamic theories, particularly those of Sigmund Freud and Erik Erikson, focus on internal drives and social crises. Freud's theory of Psychosexual Development posits a personality structure consisting of the Id (Ello), which focuses on instincts and pleasure; the Ego (Yo), which deals with reality; and the Superego (Superyo), which represents norms and morality. Freud proposed five stages of development: Oral ($0$ to $1.5$ years), Anal ($1.5$ to $3$ years), Phallic ($3$ to $6$ years), Latency ($6$ years to puberty), and Genital (from puberty onwards). Erik Erikson expanded on this with his Psychosocial Theory, focusing on evolutionary crises. His stages include Trust vs. Mistrust (confianza vs desconfianza), Autonomy vs. Shame (autonomía vs vergüenza), Initiative vs. Guilt, Industry vs. Inferiority, Identity vs. Confusion, Intimacy vs. Isolation, Generativity vs. Stagnation, and Integrity vs. Despair.

Cognitive theories describe how individuals process information and interact with their environment. Jean Piaget described cognitive development through processes of Assimilation (Asimilación), Accommodation (Acomodación), and Equilibration (Equilibración). His four stages are: Sensorimotor ($0$ to $2$ years), Preoperational ($2$ to $7$ years, characterized by symbolic play), Concrete Operations ($7$ to $11$ years), and Formal Operations ($11$ to $15$ years). Lev Vygotsky proposed a Sociocultural approach, suggesting that development proceeds from the exterior (social interaction) to the interior (individual cognition). Albert Bandura introduced Social Learning Theory, distinguishing between direct learning and vicarious learning (observing the consequences of others' actions).

Ecological and Contextual Models

Urie Bronfenbrenner developed the Bioecological Model to explain how environmental systems influence development. The Microsystem (Microsistema) involves direct interactions with family, school, and friends. The Mesosystem (Mesosistema) represents the relationship between different microsystems. The Exosystem (Exosistema) provides indirect influences on the individual. The Macrosystem (Macrosistema) encompasses broader societal values, culture, and ideologies.

Psychobiological and Motor Development

Motor development follows specific laws: the Cephalocaudal law, where control advances from the head to the feet, and the Proximo-distal law, where control develops from the center of the body toward the midline. At birth, the Apgar Test is administered at $1$ and $5$ minutes to evaluate heart rate (frecuencia cardiaca), respiration, muscle tone, reflexes, and color. A score of $7$-$10$ points is considered normal for a healthy baby; a score of $5$ points indicates developmental difficulties, and a score of less than $3$ points signifies an emergency or vital risk.

Neonatal reflexes are categorized into survival and primitive reflexes. Survival reflexes, such as breathing, swallowing, and blinking, are permanent. Sucking (succión) and rooting (búsqueda) reflexes typically disappear within $3$-$4$ months. Primitive reflexes follow specific timelines: Stepping (Marcha) at $2$ months, Palmar grasp at $3$-$4$ months, Tonic Neck at $4$ months, Moro reflex at $4$-$6$ months, Swimming at $4$-$6$ months, and the Babinski reflex at $8$-$12$ months.

Affective, Emotional, and Social Development

John Bowlby identified four phases of attachment (apego): Indiscriminate ($0$ to $2$ months), Discriminated ($2$ to $7$ months), Defined ($7$ to $14$ months), and Reciprocal attachment (beyond $2$ years). There are four main types of attachment. Type A is Insecure-Avoidant (inseguro huidizo), characterized by indifference. Type B is Secure (seguro), showing a balance between exploration and affection. Type C is Insecure-Ambivalent, characterized by anguish and anger. Type D is Disorganized, involving erratic behaviors often seen in cases of divorce or trauma.

Gender consciousness develops in stages: Gender Identity at $3$ years, Gender Stability at $4$ years, and Gender Consistency at $5$ years. Parenting styles defined by Becker include Democratic (acceptance and control), Authoritarian (rejection and high control), Permissive (acceptance and permissiveness), Indifferent (rejection and permissiveness), and Overprotective (acceptance and excessive control).

Emotionally, crying is the first and most important communication tool. The smile evolves from being reflexive in the first month to being social between $8$ and $12$ months. Basic emotions such as anger, surprise, sadness, joy, and fear appear between $3$ and $7$ months. Secondary emotions like empathy, shyness, envy, and jealousy appear at $2$ years, followed by shame, guilt, and pride at $2.5$ years.

Language, Communication, and Components

Basic terminology defines Speech (Habla) as the neuromuscular motor process of producing sounds and combining words. Language (Lenguaje) is a structured, arbitrary system of shared symbols with social rules. Communication (Comunicación) is the active process of encoding, transmitting, and decoding messages. The five components of language include Syntax (word order and grammar), Morphology (internal word organization and morphemes), Phonology (rules for sound sequencing where the phoneme is the minimum sound unit), Semantics (meaning and conceptual vocabulary), and Pragmatics (social language use).

Theoretical models of language acquisition include Skinner's Behaviorist theory (verbal behavior learned through imitation and reinforcement), Chomsky's Innatist theory (Language Acquisition Device or LAD), the Semantic-Cognitive model (language depends on previous cognitive development), and the Interactionist model by Bruner and Vygotsky (language arises from social interaction and speech acts).

Chronology of Initial Language and Phonological Development

The pre-linguistic period occurs from $0$ to $12$ months. From $0$ to $6$ months, babies produce spontaneous vocalizations, cries, and reflexes. Between $6$ and $9$ months, babbling (balbuceo) involves repetitive consonant-vowel combinations. From $9$ to $12$ months, pseudo-conversations begin with adult-like intonation. The linguistic period starts with the first isolated words from $12$ to $18$ months. Phonological development emerges around $10$-$11$ months, while grammatical and structural lexical development occurs from $12$ to $36$ months. Semantic development flourishes after $30$ months. A "Lexical Explosion" typically occurs at $1.5$ years ($18$ months).

Phonological acquisition follows a timeline: by $3$ years, phonemes like $m$, $n$, $p$, $k$, and $f$ are acquired; by $4$ years, $b$, $g$, and $r$ are added; by $5$ years, groups like $fl$, $kl$, and $br$; and by $6$ years, complex clusters like $mr$, $s$, $x$, and $dr$. Productive phonological processes include Substitution (e.g., changing a fricative to an occlusive), Omission (suppressing segments like final consonants or weak syllables), and Assimilation (substituting a segment due to the influence of a nearby sound, such as "kata" for "vaca"). Cluster reduction is the most frequent process in children under $30$ months.

The Holophrastic Stage and Lexical Development

The holophrastic stage begins around $10$ months, where a single word (word-phrase) conveys the meaning of a complex sentence. Substages include the constitution of the oral linguistic sign ($10$-$12$ months) and the evolution toward adult-like speech ($13$-$14$ months). Conceptual deviations include Underextensions (using a word too restrictively, like "cup" only for one specific cup) and Overextensions (using a word too broadly, like calling all men "papa").

Lexical development involves taxonomic knowledge (hierarchical categories) and event-based knowledge (mental scripts for habitual sequences). Learning strategies include receptive strategies ($14$-$19$ months), expressive strategies, and Bootstrapping (using known information to learn the unknown). Slobin's principles suggest children tend to pay attention to word endings, learn word order, avoid exceptions, and use semantic markers.

Syntactic, Pragmatic, and Bilingual Development

Syntactic development is measured via Mean Length of Utterance (MLU or Longitud Media de Emisión) in morphemes. Between $18$ months and $5$ years, MLU increases by approximately $1.2$ morphemes per year. Brown's stages of development are Stage I ($12$-$26$ months: linear semantic relations), Stage II ($27$-$30$ months: morphological development), Stage III ($31$-$34$ months: sentence forms), Stage IV ($35$-$40$ months: embedding), and Stage V ($41$-$46$ months: joining clauses).

Pragmatic development tracks conversational skills. By $2$ years, children respond to interlocutors and take turns. By $24$-$30$ months, verbal responses and attention improve. By $3$ years, dialogues are longer, and by $4$ years, they can discuss emotions. Pragmatic capacities include elliptical responses (omitting shared information) and contingent queries for clarification. Conversational categories include representation (declarations), control (desires/requests), expression, social, and tutorial.

Bilingual acquisition is classified as Simultaneous (before $3$ years) or Successive (after $3$ years). Code-switching (intercambio de códigos) occurs when speakers share similar linguistic structures and serves a stylistic function to emphasize or clarify points.