NIOS Class 12 Psychology Chapter 2 Bases of Human Behaviour 

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NIOS Class 12 Psychology Chapter 2 Bases of Human Behaviour 

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Bases of Human Behaviour 

Chapter: 2

PART – I

Module – 1: Foundations of Psychology

Intext Questions 2.1 

Match the following.

Column A	Column B
1. Basic unit of the nervous system	(a) Dendrite
2. Receives messages from other neurons	(b) Myelin sheath
3.Structure on which neurons develop & works	(c) Bipolar
4. Helps in faster conduction of messages	(d) Neuron
5. A type of neuron	(e) Glial Cells

Ans: 

Column A	Column B
1. Basic unit of the nervous system	(d) Neuron
2. Receives messages from other neurons	(a) Dendrite
3.Structure on which neurons develop & works	(e) Glial Cells
4. Helps in faster conduction of messages	(b) Myelin sheath
5. A type of neuron	(c) Bipolar

Intext Questions 2.2 

One Word Answers:

1. Name the part of the neuron that receives messages from adjacent cells.

Ans: Dendrite.

2. The neurons of the motor pathway control ________.

Ans: Voluntary muscles.

3. Name the cell which is responsible for the reproduction of other cells of the body.

Ans: Stem cells.

4. Damage to which brain part may lead to difficulty in heart rate and breathing.

Ans: Medulla.

5. Damage of which part of brain may lead to difficulty in forming new memories.

Ans: Hippocampus.

Intext Questions 2.3

1. Endocrine glands release ______ in blood stream.

Ans: Hormones.

2. Pineal gland is placed near the base of ______.

Ans: Cerebrum.

3. ______ are male gonads.

Ans: Testes.

4. Insulin is secreted in blood stream by ______.

Ans: Pancrease.

5. Metabolism is controlled by ______ (thyroxine / metabolism rate).

Ans: Thyroxin.

Intext Questions 2.4 

Fill in the blanks with suitable answers:

1. At the beginning stage of the new life, Zygote has _______ pairs of chromosomes.

Ans: 23.

2. __________ and _________ interplay determines our physical and psychological makeup.

Ans: Heredity and environment.

3. The Bronfenbrenner’s model focuses on interconnection between the _________ and the environment at various levels.

Ans: Individual.

State whether these statements are True or False:

1. The Bronfenbrenner’s model has been divided into three levels.

Ans: False.

2. The exposure to harmonious, violent, and funny content on television influences a growing child through imitation.

Ans: True.

3. Genes are the codes or commands that are responsible for the physical and psychological development of the offspring.

Ans: True.

TERMINAL EXERCISES

1. Discuss the function of neurons and their structural composition.

Ans: Structural Composition:

(i) Dendrites: These are branch-like structures attached to the soma. Their primary function is to receive incoming chemical messages from other adjacent cells.

(ii) Soma (Cell Body): The soma is the main body of the cell containing the nucleus. It is responsible for carrying out vital biological processes that keep the entire cell alive and functional.

(iii) Axon: An axon is a long, fiber-like structure attached to the soma. Its job is to transmit and carry electrochemical signals away from the soma toward other cells, such as other neurons, muscles, or glands.

(iv) Glial Cells: Glial cells are the supporting cells of the nervous system, accounting for about 90% of the cells in the brain (while neurons represent only 10%). They hold neurons in place, supply them with essential nutrients and oxygen, and form the supportive structural grid of the brain.

(v) Schwann Cells: A specialized type of glial cells, known as Schwann Cells, are responsible for producing the protective fatty sheath (myelin) that wraps around axons. They also clean up metabolic waste products and clear away dead neurons.

(vi) Myelin Sheath: Axons may be wrapped in a myelin sheath, which is interrupted at regular intervals called the Nodes of Ranvier. Myelin acts as insulation, allowing electrical impulses to travel significantly faster than they would along unmyelinated axons.

(vii) Schwann’s Membrane: In the peripheral body, axons are coated with a thin membrane called Schwann’s Membrane. This membrane creates a protective tunnel through which damaged nerve fibers can repair and regenerate themselves. Axons inside the central nervous system (brain and spinal cord) do not have this membrane, making damage to them permanent.

Functions of Neurons:

(i) Information Conduction: Neurons act as the baseline communication network of the body, facilitating the rapid flow of sensory and motor information required for behavior.

(ii) All-or-None Law: Neurons function on an “All-or-None” basis. If a stimulus is weak and does not reach a critical trigger point (threshold level), the neuron will not fire at all. However, if the stimulus reaches or exceeds that threshold, the neuron fires with its total, maximum strength.

(iii) Electrical Nerve Impulse: During rest (resting potential), the inside of the cell membrane maintains a negative electrical charge. When excited by a threshold stimulus, special membrane channels open, allowing positive sodium ions from the outside to rush into the cell. This sudden change in electrical charge generates a nerve impulse that moves rapidly along the axon.

2. Describe the process involved in information transmission between neurons.

Ans: Because neurons do not have direct physical contact, communication across the microscopic gap separating them, known as the synaptic cleft (or synaptic gap), occurs chemically through a process called synaptic transmission. 

This process follows several coordinated steps:

(i) Impulse Arrival: The electrical nerve impulse travels down the axon of the presynaptic neuron until it reaches the axon terminal.

(ii) Neurotransmitter Release: The arrival of the impulse triggers voltage-gated calcium (Ca2+) channels in the terminal membrane to open. The influx of calcium ions causes tiny storage sacs called synaptic vesicles to fuse with the presynaptic membrane and release chemical messengers called neurotransmitters into the synaptic cleft.

(iii) Receptor Binding: The released neurotransmitters diffuse across the synaptic gap and bind to highly specific receptors located on the dendrite of the postsynaptic neuron in a lock-and-key fashion.

(iv) Postsynaptic Effect: This binding alters the postsynaptic density. Depending on the type of neurotransmitter and receptor involved, this will either excite the receiving neuron (promoting a new electrical impulse) or inhibit it (making it less likely to fire).

(v) Reuptake/Cleanup: To clear the synaptic cleft for the next signal, neurotransmitter transporters in the presynaptic terminal retrieve leftover neurotransmitter molecules from the gap in a recycling process called reuptake.

3. Why are psychologists concerned with the role of heredity and environment while studying human behavior?

Ans: Psychologists study the Nature vs. Nurture (heredity vs. environment) relationship because human behavior is a complex, integrated product of both biological inheritance and life experiences.

The Role of Heredity (Nature): Every individual begins life as a single-celled zygote, inheriting exactly 23 pairs of chromosomes (half from the mother and half from the father). Chromosomes house genes, which are the fundamental units of heredity containing the structural codes that direct our physical and psychological development. Characteristics such as eye/hair color, physical traits, and foundational psychological traits like temperament and emotional expression are strongly influenced by genetics.

The Role of Environment (Nurture): The environment includes physical, psychological, socio-cultural, and ecological systems. While biology provides a baseline biological need (such as hunger), our actual choices, habits, food preferences, languages, and learned social behaviors are heavily shaped by our environmental upbringing, situation, and cultural context.

Interplay and Adaptation: Heredity and environment do not act independently; they exist in a state of continuous interplay to determine our overall physical and psychological makeup. Genes gather information from the environment and adapt to situational demands to promote overall survival and betterment.

Twin Studies: Psychologists study identical (monozygotic) and fraternal (dizygotic) twins to scientifically isolate the relative impacts of genetic makeup versus environmental factors.

4. Discuss the functioning of human behavior.

Ans: Human behavior functions through a dynamic, continuous loop of internal biological processing and socio-cultural interactions:

(i) Internal Biological Origins: Sensory and motor pathways in the nervous system, combined with hormonal secretions from the endocrine glands, serve as the internal engines of human behavior, driving actions and reactions.

(ii) Nervous System Integration: Sensory receptors capture external stimuli (such as heat, light, or sound) and transmit them inward to the central nervous system via sensory fibers. The brain integrates this information, evaluates it through cognitive appraisal, and sends appropriate commands outward to muscles and glands via motor fibers.

(iii) Autonomic vs. Voluntary Control: Simple and highly rapid survival responses, such as instantly withdrawing your hand from a hot iron or blinking in response to a sudden bright light, are coordinated automatically by the brain and spinal cord. More complex behaviors, such as logical thinking, planning, and language, are managed by higher-order cerebral structures.

(iv) Socio-Cultural Regulation: How we analyze, perceive, and react to our environment is fundamentally guided by social agents (like parents, school, and peers) and the cultural values of the society we are raised in.

5. Elaborate the role of endocrine system in human behavior.

Ans: The endocrine system is a network of ductless glands that secretes chemical messengers called hormones directly into the bloodstream. Working alongside the nervous system as the Neuro-endocrine System, it plays a critical role in regulating emotional reactions, metabolic speed, and overall physical development.

The major endocrine glands and their behavioral impacts include:

Pituitary Gland: Located in the brain, it is known as the “master gland” because its secretions directly control the activity of other endocrine glands. It also secretes hormones responsible for human growth.

Pineal Gland: Located near the base of the cerebrum, it secretes the hormone melatonin, which regulates the body’s sleep-wake cycle.

Thyroid Gland: Found in the neck region, it releases thyroxine, which controls the metabolic rate of the body. Imbalances can cause sluggishness (hypothyroidism) or hyperactive anxiety (hyperthyroidism).

Pancreas: Positioned in the abdomen, it secretes insulin, which regulates blood sugar levels. Inadequate insulin affects energy levels, physical comfort, and general mood.

Gonads: These are the primary sex organs (testes in males, ovaries in females). They secrete sex hormones that drive sexual development, reproduction, and gender-related behaviors.

Adrenal Gland: Located atop the kidneys, its medulla secretes epinephrine (adrenaline) and norepinephrine, which trigger the sympathetic nervous system to increase heart rate and breathing during stress, preparing the body for fight-or-flight reactions. Its cortex secretes corticoids, which help manage physical and emotional stress.

6. What are the major social agents that guide human behavior?

Ans: A child’s socialization process is actively directed by several crucial social environments and figures, known as social agents:

(i) Parents: As a child’s first social contact, parents heavily shape early behavior. Through daily interactions, language modeling, meal habits, guidance, rewarding positive behavior, and punishing negative behavior, parents establish a child’s foundational behavioral habits.

(ii) Siblings: Since siblings spend extensive time together, they strongly influence each other’s social development. Sibling interactions teach children important peer-to-peer life skills like adjustment, sharing, respecting personal boundaries, and managing interpersonal conflicts.

(iii) School: School is a child’s first exposure to a structured, formal social system. It helps children learn social rules and regulations, provides a platform for self-initiative, and helps them form relationships outside of their immediate family, particularly with teachers and peers.

(iv) Peers: Peers are individuals of a similar age, making them highly relatable social agents. Through peer interactions, children learn to assert their viewpoints, build mutual trust, develop deep empathy, and practice healthy sharing and cooperation.

(v) Media: Digital media (such as television, video games, and the internet) serves as a powerful agent of observational learning. Children frequently learn and mimic funny, cooperative, or aggressive behaviors via imitation of media models.

7. Explain different levels of Bronfenbrenner’s model that focuses on interconnection between the individual and the environment.

Ans: Urie Bronfenbrenner’s Bioecological Model describes how an individual’s development is influenced by five interconnected environmental layers:

(i) Microsystem: The immediate setting in which the child directly lives and has face-to-face contact. This includes family, school, peer groups, and neighborhood. Warm, supportive interactions within this system foster healthy psychological development.

(ii) Mesosystem: This layer consists of the linkages or connections between a child’s different microsystems. For example, the interaction between a child’s parents and their school teachers, or parents and peers, represents a mesosystemic influence.

(iii) Exosystem: Environmental settings that indirectly affect a child’s development, even though the child does not directly participate in them. A key example is a parent’s workplace; if a parent experiences extreme stress or frustration at work, they may bring that tension home, which indirectly impacts the child’s emotional well-being.

(iv) Macrosystem: The cultural and societal framework in which an individual is raised, encompassing cultural values, societal laws, and general belief systems. For example, children raised in individualistic Western societies develop different behavioral independence compared to those raised in collectivistic Eastern cultures.

(v) Chronosystem: The temporal dimension of development, which tracks life changes and environmental shifts over time. Examples include the birth of a sibling, moving to a new city, parental divorce, or major historical events.