The Bases of Human Behaviour - Solutions

 CBSE Class 11 Psychology

NCERT Solutions
The Bases of Human Behaviour

1. How does the evolutionary perspective explain the biological basis of behaviour?

Ans. Evolution refers to gradual and orderly biological changes that result in a species from their pre-existing forms in response to the changing adaptation demands of their environment. Physiological as well as behavioural changes that occur due to the evolution process are so slow that they become visible after hundreds of generations.

Three important features of modern human beings differentiate them from their ancestors:

(i) a bigger and developed brain with increased capacity for cognitive behaviours like perception, memory, reasoning, problem solving, and use of language for communication.

(ii) ability to walk upright on two legs.

(iii) a free hand with a workable opposing thumb. These features have been with us for several thousand years.

Our behaviours are highly complex and more developed than those of other species because we have got a large and highly developed brain. Human brain development is evidenced by two facts. Firstly, the weight of the brain is about 2.35 per cent of the total body weight, and it is the highest among all species (in elephant it is 0.2 per cent). Secondly, the human cerebrum is more evolved than other parts of the brain.

These evolutions have resulted due to the influence of environmental demands. Some behaviours play an obvious role in evolution. For example, the ability to find food, avoid predators, and defend one’s young are the objectives related to the survival of the organisms as well as their species. The biological and behavioural qualities, which are helpful in meeting these objectives, increase an organism’s ability to pass it on to the future generation through its genes. The environmental demands lead to biological and behavioural changes over a long period of time.

2. Describe how neurons transmit information.

Ans. Neuron is the basic unit of our nervous system. Neurons are specialised cells, which possess the unique property of converting various forms of stimuli into electrical impulses. They are also specialised for reception, conduction and transmission of information in the form of electrochemical signals. They receive information from sense organs or from other adjacent neurons, carry them to the central nervous system (brain and spinal cord), and bring motor information from the central nervous system to the motor organs (muscles and glands).

Neurons transmit information with the help of dendrites, soma, axon and terminal buttons by converting stimuli into electrical impulses.

The soma or cell body is the main body of the nerve cell. It contains the nucleus of the cell as well as other structures common to living cells of all types. The genetic material of the neuron is stored inside the nucleus and it becomes actively engaged during cell reproduction and protein synthesis. The soma also contains most of the cytoplasm (cell- fluid) of the neuron.

Dendrites are the branch- like specialised structures emanating from the soma. They are the receiving ends of a neuron. Their function is to receive the incoming neural impulses from adjacent neurons or directly from the sense organs. On dendrites are found specialised receptors, which become active when a signal arrives in electrochemical or biochemical form. The received signals are passed on to soma and then to axon so that the information is relayed to another neuron or to muscles.

The axon conducts the information along its length, which can be several feet in the spinal cord and less than a millimetre in the brain. At the terminal point the axon branches into small structures, called terminal buttons. These buttons have the capability for transmitting information to another neuron, gland and muscle. Neurons generally conduct information in one direction, that is, from the dendrites through soma and axon to the terminal buttons.

The conduction of information from one place to another in the nervous system is done through nerves, which are bundles of axons. Nerves are mainly of two types: sensory and motor. Sensory nerves, also called afferent nerves, carry information from sense organs to central nervous system. On the other hand, motor nerves, also called efferent nerves, carry information from central nervous system to muscles or glands. A motor nerve conducts neural commands which direct, control, and regulates our movements and other responses. There are some mixed nerves also, but sensory and motor fibers in these nerves are separate.

3. Name the four lobes of the cerebral cortex. What functions do they perform?

Ans. Cerebral cortex has also been divided into four lobes - Frontal lobe, Parietal lobe, Temporal lobe, and Occipital lobe.

The Frontal lobe is mainly concerned with cognitive functions, such as attention, thinking, memory, learning, and reasoning, but it also exerts inhibitory effects on autonomic and emotional responses.

The Parietal lobe is mainly concerned with cutaneous sensations and their coordination with visual and auditory sensations.

The Temporal lobe is primarily concerned with the processing of auditory information. Memory for symbolic sounds and words resides here. Understanding of speech and written language depends on this lobe.

The Occipital lobe is mainly concerned with visual information. It is believed that interpretation of visual impulses, memory for visual stimuli and colour visual orientation is performed by this lobe.

4. Name the various endocrine glands and the hormones secreted by them. How does the endocrine system affect our behaviour?

Ans. The endocrine glands play a crucial role in our development and behaviour. They secrete specific chemical substances, called hormones, which control some of our behaviours.

These glands are called ductless glands or endocrine glands, because they do not have any duct (unlike other glands) to send their secretions to specific places. Hormones are circulated by the bloodstream.

Name and functions of the endocrine glands are following:

(a) The chemical substances secreted from the endocrine are known as HORMONES. These hormones influence the functions of the body and the course of its development and in the growth of personality.

(b) Endocrine glands also control and regulate the individual's behaviour, for instance, when there is extra-supply of sugar in the blood-stream, certain ductless glands secrete insulin which reduces the sugar level in the blood to normal state.

(c) Endocrine glands play role in co-ordinating the body activities. Like in sudden fear or danger, secretion from the endocrine system is mixed with blood which brings widely diverse activities to help us face this situation.

(d) The different endocrine glands work intimately to maintain equilibrium and coordinate body functions. For instance, if one gland is secreting more than optimum, the other gland may secrete a hormone to reduce the excess hormone and maintain equilibrium.

5. How does the autonomic nervous system help us in dealing with an emergency situation?

Ans. The autonomic nervous system governs activities which are normally not under direct control of individuals. It controls such internal functions as breathing, blood circulation, salivation, stomach contraction, and emotional reactions. These activities of the autonomic system are under the control of different structures of the brain.

The autonomic nervous system helps in dealing with emergency situations with the help of its two divisions: Sympathetic division and Parasympathetic division. Although the effect of one division is opposite to the effect of the other, both work together to maintain a state of equilibrium.

The sympathetic division deals with emergencies when the action must be quick and powerful, such as in situations of fight or flight. During this period, the digestion stops, blood flows from internal organs to the muscles, and breathing rate, oxygen supply, heart rate, and blood sugar level increases.

The Parasympathetic division is mainly concerned with conservation of energy. It monitors the routine functions of the internal system of the body. When the emergency is over, the parasympathetic division takes over; it decelerates the sympathetic activation and calms down the individual to a normal condition. As a result all body functions like heart beat, breathing, and blood flow return to their normal levels.

6. Explain the meaning of culture and describe its important features.

Ans. In the simplest terms, culture refers to “the man-made part of the environment”. It comprises diverse products of the behaviour of many people, including ourselves. These products can be material objects (e.g., tools, sculptures), ideas (e.g., categories, norms) or social institutions (e.g., family, school). We find them almost everywhere. They influence behaviour, although we may not always be aware of it.

Some of its essential features are:

  1. Culture includes behavioural products of others who preceded us. It indicates both substantial and abstract particulars that have prior existence in one form or another.
  2. It contains values that will be expressed and a language in which to express them. It contains a way of life that will be followed by most of us who grow up in that context.
  3. Culture provides meaning by creating significant categories like social practices (e.g., marriage) and roles (e.g., bridegroom) as well as values, beliefs and premises.
  4. Culture allows us to categorise and explain many important differences in human behaviour that were previously attributed to biological differences.
  5. Culture involves transmission of learned behaviour from one generation to the other within a community.

7. Do you agree with the statement that 'biology plays an enabling role, while specific aspects of behaviour are related to cultural factors'? Give reasons in support of your answer.

Ans. No doubt those biological factors do play enabling in determinants human behaviour.
Biological factors basically set the limits but our behaviour is more complex then the behaviour of animal.

  • Major reason for the complexity is the role of culture to regulate human behaviour.
  • We can explain the concept with the help of two example hunger is a basic need of human beings as well as of animals but the way this need is gratified by human beings is extremely complex. Different people in different cultures eat different things in a different manner e.g. directly with hand or with the help of spoons, forks and knives.
  • Sexual behaviour can be taken as another example sex is a physiological need. The structure and functioning is determinant by biological mechanism but it expression is different in different culture.
  • At the human level, we find evidence for a dual inheritance theory. Biological inheritance takes place through genes, while cultural inheritance takes place through memes.
  • The former takes place in a "top-down" manner (i.e. from parents to children)., while the latter many also take place in a "bottom-up" manner (i.e. from children to parents). Dual inheritance theory also shows that although biological and cultural forces may involve different processes, they work as parallel forces, and interact with each other in offering explanation of an individuals behaviour.

8. Describe the main agents of socialisation.

Ans. Socialisation is a process of social learning through which a child acquires the norms, attitudes, beliefs and behaviours that are acceptable in his/her culture.

Main agents of socialization are:


Parents have most direct and significant impact on children’s development. Parents encourage certain behaviours by rewarding them verbally (e.g.,praising) or in other tangible ways (e.g., buying chocolates or objects of child’s desire). They also discourage certain behaviours through non-approving behaviours. They also arrange to put children in a variety of situations that provide them with a variety of positive experiences, learning opportunities, and challenges.


School is another important socialising agent. Since children spend a long time in schools, which provide them with a fairly organised set up for interaction with teachers and peers, school is today being viewed as a more important agent of child socialisation than parents and family. Children learn not only cognitive skills (e.g., reading, writing, doing mathematics) but also many social skills (e.g., ways of behaving with elders and age mates, accepting roles, fulfilling responsibilities). They also learn and internalise the norms and rules of society. Several other positive qualities, such as self-initiative, self-control, responsibility, and creativity are encouraged in schools.

Peer Groups

One of the chief characteristics of the middle childhood stage is the extension of social network beyond home. Friendship acquires great significance in this respect. It provides children not only with a good opportunity to be in company of others, but also for organising various activities (e.g., play) collectively with the members of their own age. Qualities like sharing, trust, mutual understanding, role acceptance and fulfilment develop in interaction with peers. Children also learn to assert their own point of view and accept and adapt to those of others.

Media Influences

In recent years media has also acquired the property of a socialisation agent. Through television, newspapers, books and cinema the external world has made/is making its way into our home and our lives. While children learn about many things from these sources, adolescents and young adults often derive their models from them, particularly from television and cinema.

9. How can we distinguish between enculturation and socialisation ? Explain.

Ans. Enculturation refers to all learning that occurs in human life because of its availability in our socio-cultural context. The key element of enculturation is learning by observation. Whenever we learn any content of our society by observation, enculturation is in evidence. These contents are culturally shaped by our preceding generations. In this sense, enculturation always refers to learning something that is already available. A major part of our behaviour is the product of enculturation. In Indian families, many complex activities, like cooking, are learned by observation. There is no prescribed curriculum and no textbook for such activities, and there is also no deliberate instruction for cooking.

Socialisation on the other hand is a process by which individuals acquire knowledge, skills and dispositions, which enable them to participate as effective members of groups and society. It is a process that continues over the entire life-span, and through which one learns and develops ways of effective functioning at any stage of development. Socialisation forms the basis of social and cultural transmission from one generation to the next. Its failure in any society may endanger the very existence of that society.

10. What is meant by acculturation? Is acculturation a smooth process? Discuss.

Ans. Acculturation refers to cultural and psychological changes resulting from contact with other cultures. Contact may be direct (e.g., when one moves and settles in a new culture) or indirect (e.g., through media or other means). It may be voluntary (e.g., when one goes abroad for higher studies, training, job, or trade) or involuntary (e.g., through colonial experience, invasion, political refuge). In both cases, people often need to learn (and also they do learn) something new to negotiate life with people of other cultural groups. For example, during the British rule in India many individuals and groups adopted several aspects of British lifestyle. They preferred to go to the English schools, take up salaried jobs, dress in English clothes, speak English language, and change their religion.

  • Changes due to acculturation may be examined at subjective and objective levels.
  • At the subjective level, changes are often reflected in people's attitude towards change. They are referred to as acculturation attitudes.
  • At the subjective level, changes are often reflected in people's day to day behaviours and activities. These are referred to as acculturation strategies.

11. Discuss the acculturative strategies adopted by individuals during the course of acculturation.

Ans. Following are the four acculturative strategies have been adopted by individuals during the course:

Integration : It refers to an attitude in in which there is an interest in both, maintaining one’s original culture and identity, while staying in daily interaction with other cultural groups. In this case, there is some degree of cultural integrity maintained while interacting with other cultural groups.

Assimilation : It refers to an attitude, which people do not wish to maintain their cultural identity, and they move to become an integral part of the other culture. In this case, there is loss of one’s culture and identity.

Separation : It refers to an attitude in which people seem to place a value on holding on to their original culture, and wish to avoid interaction with other cultural groups. In this case, people often tend to glorify their cultural identity.

Marginalisation : It refers to an attitude in which there is little possibility or interest in one’s cultural maintenance, and little interest in having relations with other cultural groups. In this case, people generally remain undecided about what they should do, and continue to stay with a great deal of stress.