THE TRIUNE BRAIN – IELTS Reading Passage 2

THE TRIUNE1 BRAIN

The first of our three brains to evolve is what scientists call the reptilian cortex. This brain sustains the elementary activities of animal survival such as respiration, adequate rest and a beating heart. We are not required to consciously “think” about these activities. The reptilian cortex also houses the “startle centre”, a mechanism that facilitates swift reactions to unexpected occurrences in our surroundings. That panicked lurch you experience when a door slams shut somewhere in the house, or the heightened awareness you feel when a twig cracks in a nearby bush while out on an evening stroll are both examples of the reptilian cortex at work. When it comes to our interaction with others, the reptilian brain offers up only the most basic impulses: aggression, mating, and territorial defence. There is no great difference, in this sense, between a crocodile defending its spot along the river and a turf war between two urban gangs.

Although the lizard may stake a claim to its habitat, it exerts total indifference toward the well-being of its young. Listen to the anguished squeal of a dolphin separated from its pod or witness the sight of elephants mourning their dead, however, and it is clear that a new development is at play. Scientists have identified this as the limbic cortex. Unique to mammals, the limbic cortex impels creatures to nurture their offspring by delivering feelings of tenderness and warmth to the parent when children are nearby. These same sensations also cause mammals to develop various types of social relations and kinship networks. When we are with others of “our kind” – be it at soccer practice, church, school or a nightclub – we experience positive sensations of togetherness, solidarity and comfort. If we spend too long away from these networks, then loneliness sets in and encourages us to seek companionship. 

Only human capabilities extend far beyond the scope of these two cortexes. Humans eat, sleep and play, but we also speak, plot, rationalise and debate finer points of morality. Our unique abilities are the result of an expansive third brain – the neocortex – which engages with logic, reason and ideas. The power of the neocortex comes from its ability to think beyond the present, concrete moment. While other mammals are mainly restricted to impulsive actions (although some, such as apes, can learn and remember simple lessons), humans can think about the “big picture”. We can string together simple lessons (for example, an apple drops downwards from a tree; hurting others causes unhappiness) to develop complex theories of physical or social phenomena (such as the laws of gravity and a concern for human rights).  

The neocortex is also responsible for the process by which we decide on and commit to particular courses of action. Strung together over time, these choices can accumulate into feats of progress unknown to other animals. Anticipating a better grade on the following morning’s exam, a student can ignore the limbic urge to socialise and go to sleep early instead. Over three years, this ongoing sacrifice translates into a first class degree and a scholarship to graduate school; over a lifetime, it can mean ground-breaking contributions to human knowledge and development. The ability to sacrifice our drive for immediate satisfaction in order to benefit later is a product of the neocortex. 

Understanding the triune brain can help us appreciate the different natures of brain damage and psychological disorders. The most devastating form of brain damage, for example, is a condition in which someone is understood to be brain dead. In this state a person appears merely unconscious – sleeping, perhaps – but this is illusory. Here, the reptilian brain is functioning on autopilot despite the permanent loss of other cortexes.   

Disturbances to the limbic cortex are registered in a different manner. Pups with limbic damage can move around and feed themselves well enough but do not register the presence of their littermates. Scientists have observed how, after a limbic lobotomy2, “one impaired monkey stepped on his outraged peers as if treading on a log or a rock”. In our own species, limbic damage is closely related to sociopathic behaviour. Sociopaths in possession of fully-functioning neocortexes are often shrewd and emotionally intelligent people but lack any ability to relate to, empathise with or express concern for others.

One of the neurological wonders of history occurred when a railway worker named Phineas Gage survived an incident during which a metal rod skewered his skull, taking a considerable amount of his neocortex with it. Though Gage continued to live and work as before, his fellow employees observed a shift in the equilibrium of his personality. Gage’s animal propensities were now sharply pronounced while his intellectual abilities suffered; garrulous or obscene jokes replaced his once quick wit. New findings suggest, however, that Gage managed to soften these abrupt changes over time and rediscover an appropriate social manner. This would indicate that reparative therapy has the potential to help patients with advanced brain trauma to gain an improved quality of life.

1. Triune = three-in-one

2. Lobotomy = surgical cutting of brain nerves

Questions

Questions 14-22

Classify the following as typical of

AThe reptilian cortexB. The limbic cortexC. The neocortex
THE TRIUNE BRAIN

Write the correct letter, A, B or C, in boxes 14-22 on your answer sheet

14 ……………. Giving up short-term happiness for future gains

15 ……………. Maintaining the bodily functions necessary for life

16 ……………. Experiencing the pain of losing another

17 ……………. Forming communities and social groups

18 ……………. Making a decision and carrying it out

19 ……………. Guarding areas of land

20 ……………. Developing explanations for things

21 ……………. Looking after one’s young

22 ……………. Responding quickly to sudden movement and noise

Questions 23-26

Complete the sentences below

Write NO MORE THAN TWO WORDS from the passage for each answer

Write your answers in boxes 23-26 on your answer sheet

  • A person with only a functioning reptilian cortex is known as 23 ……………..
  • 24 …………….  in humans is associated with limbic disruption.
  • An industrial accident caused Phineas Gage to lose part of his 25 ……………. .
  • After his accident, co-workers noticed an imbalance between Gage’s 26 ……………. and higher-order thinking.

Answers

Questions 14-22

14. Answer: C 

Giving up short-term happiness for future gains

  • Keywords: Giving up, short-term happiness, future gains
  • Look for synonyms of the keywords in the text and you will find this sentence at the end of paragraph 4: “The ability to sacrifice our drive for immediate satisfaction in order to benefit later is a product of the neocortex”. 
  • This means the neocortex is the part of the brain that enables us to give up present satisfaction so as to gain benefits later in the future.

give up = sacrifice

short-term happiness = immediate satisfaction

future gains = benefit later

=> The answer is C

15. Answer: A 

Maintaining the bodily functions necessary for life

  • Key words: maintaining, bodily functions, necessary for life
  • The evidence can be found in paragraph 1: “The first of our three brains to evolve is what scientists call the reptilian cortex. This brain sustains the elementary activities of animal survival such as respiration, adequate rest and a beating heart.”. 
  • This means the reptilian cortex is in charge of basic functions of survival including breathing, resting and keeping the heart beating.

maintains = sustains

bodily functions necessary for life = elementary activities of animal survival

=> The answer is A

16. Answer: B 

Experiencing the pain of losing another

  • Key words: pain of losing
  • In paragraph 2, it is stated that: “Listen to the anguished squeal of a dolphin separated from its pod or witness the sight of elephants mourning their dead, however, and it is clear that a new development is at play. Scientists have identified this as the limbic cortex”. 
  • This means the limbic cortex allows animals (mammals) to feel the pain of losing their family members.

pain of losing another = mourning their dead

=>The answer is B

17. Answer: B 

Forming communities and social groups

  • Key word: Forming communities, social groups
  • Also stated in paragraph 2: “Unique to mammals, the limbic cortex impels creatures to nurture their offspring by delivering feelings of tenderness and warmth to the parent when children are nearby. These same sensations also cause mammals to develop various types of social relations and kinship networks”. 
  • This means the limbic cortex is the reason for mammals to etablish different kinds of relationships within their family or their society and to form groups.

forming communities and social groups = develop various types of social relations and kinship networks

=> The answer is B

18. Answer: C 

Making a decision and carrying it out

  • Key words: decision, carry out
  • Paragraph 4 mentions: “The neocortex is also responsible for the process by which we decide on and commit to particular courses of action”. 
  • This means the neocortex enables humans to make decisions and act accordingly.

make a decision = decide

carry out = commit to (a course of action)

=>The answer is C

19. Answer: A 

Guarding areas of land

  • Key words: Guarding, land
  • It is mentioned in paragraph 1 that: “When it comes to our interaction with others, the reptilian brain offers up only the most basic impulses: aggression, mating, and territorial defence. There is no great difference, in this sense, between a crococile defending its spot along the river and a turf war between two urban gangs”.  
  • This means that the reptilian cortex is in charge of the most basic reactions, including territorial defence, which means protecting the areas of land that reptilians think is their territory.

guarding land = territorial defence

=>The answer is A

20. Answer: C 

Developing explanations for things

  • Keywords: developing, explanations
  • As can be seen in paragraph 3: “Our unique abilities are the result of an expansive third brain – the neocortex – which engages with logic, reason and ideas. […] We can string together simple lessons (for example, an apple drops downwards from a tree; hurting others causes unhappiness) to develop complex theories of physical or social phenomena (such as the lawsof gravity and a concern for human rights).”  
  • This means the neocortex allows humans to come up with explanations for complicated theories of physical or social phenomena.

explanations for things = theories of physical or social phenomena

=> The answer is C

21. Answer: B 

Looking after one’s young

  • Key words: Looking after, young
  • It is stated in paragraph 2 that: “Unique to mammals, the limbic cortex impels creatures to nurture their offspring by delivering feelings of tenderness and warmth to the parent when children are nearby”.
  • This means that the limbic cortex causes mammals to have feelings for their children and hence, raise their children.

looking after = nurture

one’s young = their offspring

=> The answer is B

22. Answer: A

Responding quickly to sudden movement and noise

  • Paragraph 1 stated that: “The reptilian cortex also houses the “startle centre”, a mechanism that facilitates swift reactions to unexpected occurrences in our surroundings”. 
  • This means that the reptilian cortex is the reason for natural reflexes to react quickly to anything startling or unexpected in our surroundings. 

responding quickly = swift reactions

sudden movement and noise = unexpected occurrences

=> The answer is A

Questions 23-26

23. Answer: brain dead 

A person with only a functioning reptilian cortex is known as ………………….

  • Keywords: only, functioning reptilian cortex
  • The information is found in paragraph 5: “The most devastating form of brain damage, for example, is a condition in which someone is understood to be brain dead. In this state a person appears merely unconscious –sleeping, perhaps – but this is illusory. Here, the reptilian brain is functioning on autopilot despite the permanent loss of other cortexes.”
  • Brain dead is a kind of brain damage where the victim’s limbic cortex and neocortex do not function anymore (=permanent loss of other cortexes), only the reptilian cortex does (= reptilian brain functioning on autopilot).

A person with only a functioning reptilian cortex is known as ………………….

  • Keywords: only, functioning reptilian cortex
  • The information is found in paragraph 5: “The most devastating form of brain damage, for example, is a condition in which someone is understood to be brain dead. In this state a person appears merely unconscious –sleeping, perhaps – but this is illusory. Here, the reptilian brain is functioning on autopilot despite the permanent loss of other cortexes.”
  • Brain dead is a kind of brain damage where the victim’s limbic cortex and neocortex do not function anymore (=permanent loss of other cortexes), only the reptilian cortex does (= reptilian brain functioning on autopilot).

A person with only a functioning reptilian cortex is known as ………………….

  • Keywords: only, functioning reptilian cortex
  • The information is found in paragraph 5: “The most devastating form of brain damage, for example, is a condition in which someone is understood to be brain dead. In this state a person appears merely unconscious –sleeping, perhaps – but this is illusory. Here, the reptilian brain is functioning on autopilot despite the permanent loss of other cortexes.”
  • Brain dead is a kind of brain damage where the victim’s limbic cortex and neocortex do not function anymore (=permanent loss of other cortexes), only the reptilian cortex does (= reptilian brain functioning on autopilot).

=>The answer is “brain dead”

24. Answer: sociopathic behaviour 

…………………in humans is associated with limbic disruption.

  • Key words: in humans, limbic disruption
  • Stated in pargraph 6: “In our own species, limbic damage is closely related to sociopathic behaviour.”
  • This sentence means that, in humans, disruptions in the functions of the limbic cortex is linked with sociopathic behaviour.

in humans= in our own species

associated with = closely related to

limbic disruption = limbic damage

=> The answer is “sociopathic behaviour”

25. Answer: neocortex 

An industrial accident caused Phineas Gage to lose part of his ………………….

  • Key words: industrial accident, Phineas Gage, lose part of
  • It is mentioned in paragraph 7 that: “One of the neurological wonders of history occurred when a railway worker named Phineas Gage survived an incident during which a metal rod skewered his skull, taking a considerable amount of his neocortex with it”.

industrial accident = a metal rod skewered a railway worker’s skull

(Phineas) lose part of = (the accident) taking a considerable amount of

=> The answer is “neocortex”

26. Answer: animal propensities 

After his accident, co-workers noticed an imbalance between Gage’s …………………and higher-order thinking.

  • Key words: imbalance between, higher-order thinking
  • The information can be found in paragraph 7: “… his fellow employees observed a shift in the equilibrium of his personality. Gage’s animal propensities were now sharply pronounced while his intellectual abilities suffered; garrulous or obscene jokes replaced his once quick wit”. 
  • This suggests that after the accident, Gage’s animal propensities were much more evident than his intellectual abilities. 

co-workers = fellow employees

imbalance = a shift in the equilibrium

higher-order thinking = intellectual abilities

=>The answer is “animal propensities”

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