Can Animals Count? - IELTS Reading Answers & Explanations
From IELTS Trainer 1 Academic Reading Test 4 · Part 1 · Questions 1–13
Reading Passage
You should spend about 20 minutes on Questions 1-13, which are based on Reading Passage 1 below.
Can animals count?
Prime among basic numerical faculties is the ability to distinguish between a larger and a smaller number, says psychologist Elizabeth Brannon. Humans can do this with ease - providing the ratio is big enough - but do other animals share this ability? In one experiment, rhesus monkeys and university students examined two sets of geometrical objects that appeared briefly on a computer monitor. They had to decide which set contained more objects. Both groups performed successfully but, importantly, Brannon's team found that monkeys, like humans, make more errors when two sets of objects are close in number. 'The students' performance ends up looking just like a monkey's. It's practically identical,' she says.
Humans and monkeys are mammals, in the animal family known as primates. These are not the only animals whose numerical capacities rely on ratio, however. The same seems to apply to some amphibians. Psychologist Claudia Uller's team tempted salamanders with two sets of fruit flies held in clear tubes. In a series of trials, the researchers noted which tube the salamanders scampered towards, reasoning that if they had a capacity to recognise number, they would head for the larger number. The salamanders successfully discriminated between tubes containing 8 and 16 flies respectively, but not between 3 and 4, 4 and 6, or 8 and 12. So it seems that for the salamanders to discriminate between two numbers, the larger must be at least twice as big as the smaller. However, they could differentiate between 2 and 3 flies just as well as between 1 and 2 flies, suggesting they recognise small numbers in a different way from larger numbers.
Further support for this theory comes from studies of mosquitofish, which instinctively join the biggest shoal* they can. A team at the University of Padova found that while mosquitofish can tell the difference between a group containing 3 shoal-mates and a group containing 4, they did not show a preference between groups of 4 and 5. The team also found that mosquitofish can discriminate between numbers up to 16, but only if the ratio between the fish in each shoal was greater than 2:1. This indicates that the fish, like salamanders, possess both the approximate and precise number systems found in more intelligent animals such as infant humans and other primates.
While these findings are highly suggestive, some critics argue that the animals might be relying on other factors to complete the tasks, without considering the number itself. 'Any study that's claiming an animal is capable of representing number should also be controlling for other factors,' says Brannon. Experiments have confirmed that primates can indeed perform numerical feats without extra clues, but what about the more primitive animals? To consider this possibility, the mosquitofish tests were repeated, this time using varying geometrical shapes in place of fish. The team arranged these shapes so that they had the same overall surface area and luminance even though they contained a different number of objects. Across hundreds of trials on 14 different fish, the team found they consistently discriminated 2 objects from 3. The team is now testing whether mosquitofish can also distinguish 3 geometric objects from 4.
Even more primitive organisms may share this ability. Entomologist Jurgen Tautz sent a group of bees down a corridor, at the end of which lay two chambers - one which contained sugar water, which they like, while the other was empty. To test the bees' numeracy, the team marked each chamber with a different number of geometrical shapes - between 2 and 6. The bees quickly learned to match the number of shapes with the correct chamber. Like the salamanders and fish, there was a limit to the bees' mathematical prowess - they could differentiate up to 4 shapes, but failed with 5 or 6 shapes.
These studies still do not show whether animals learn to count through training, or whether they are born with the skills already intact. If the latter is true, it would suggest there was a strong evolutionary advantage to a mathematical mind. Proof that this may be the case has emerged from an experiment testing the mathematical ability of three- and four-day-old chicks. Like mosquitofish, chicks prefer to be around as many of their siblings as possible, so they will always head towards a larger number of their kin. If chicks spend their first few days surrounded by certain objects, they become attached to these objects as if they were family. Researchers placed each chick in the middle of a platform and showed it two groups of balls of paper. Next, they hid the two piles behind screens, changed the quantities and revealed them to the chick. This forced the chick to perform simple computations to decide which side now contained the biggest number of its "brothers". Without any prior coaching, the chicks scuttled to the larger quantity at a rate well above chance. They were doing some very simple arithmetic, claim the researchers.
Why these skills evolved is not hard to imagine, since it would help almost any animal forage for food. Animals on the prowl for sustenance must constantly decide which tree has the most fruit, or which patch of flowers will contain the most nectar. There are also other, less obvious, advantages of numeracy. In one compelling example, researchers in America found that female coots appear to calculate how many eggs they have laid - and add any in the nest laid by an intruder - before making any decisions about adding to them. Exactly how ancient these skills are is difficult to determine, however. Only by studying the numerical abilities of more and more creatures using standardised procedures can we hope to understand the basic preconditions for the evolution of number.
* a group of fish
Questions
Questions 1–7 Table Completion
Complete the table below.
Choose NO MORE THAN THREE WORDS from the passage for each answer.
| Subjects | Experiment | Results |
|---|---|---|
| Mammals and birds | ||
| rhesus monkeys and humans | looked at two sets of geometrical objects on computer screen | performance of two groups is almost 1 |
| chicks | chose between two sets of 2 which are altered | chicks can do calculations in order to choose larger group |
| coots | behaviour of 3 birds was observed | bird seems to have ability to count eggs |
| Amphibians, fish and insects | ||
| salamanders | offered clear tubes containing different quantities of 4 | salamanders distinguish between numbers over four if bigger number is at least two times larger |
| 5 | shown real shoals and later artificial ones of geometrical shapes; these are used to check influence of total 6 and brightness | subjects know difference between two and three and possibly three and four, but not between four and five |
| bees | had to learn where 7 was stored | could soon choose correct place |
Questions 8–13 True / False / Not Given
Do the following statements agree with the information given in Reading Passage 1?
TRUE if the statement agrees with the information
FALSE if the statement contradicts the information
NOT GIVEN if there is no information on this
Answers & Explanations Summary
| # | Answer | Evidence | Explanation |
|---|---|---|---|
| Q1 | identical | 'The students' performance ends up looking just like a monkey's. It's practically identical,' she says | Excerpt/Passage Explanation: The passage explains that when researchers compared the results of human students and monkeys in the counting test, the two groups behaved in the same way. Answer Explanation: The answer means that the test results for the humans and the monkeys were very similar, showing that they performed almost exactly the same way. Reason For Correctness: The correct answer is derived from the first paragraph, which describes an experiment where monkeys and university students looked at shapes on a screen. The researcher, Elizabeth Brannon, notes that the way the humans performed was extremely similar to the monkeys. She uses the word 'identical' to describe this high level of similarity in their performance. Important keywords are 'performance' and 'looking just like'. |
| Q2 | balls of paper | Researchers placed each chick in the middle of a platform and showed it two groups of balls of paper | Excerpt/Passage Explanation: The passage explains that during the study, the scientists showed the baby chickens two different sets of round paper objects to see which one the birds would choose. Answer Explanation: The answer refers to the small, round objects made out of paper that scientists used to test the baby chickens. Reason For Correctness: The correct answer is 'balls of paper' because the passage describes an experiment involving baby birds called chicks. In this test, researchers wanted to see if the chicks could pick the group with more items. The text specifically mentions that the researchers showed the chicks 'two groups of balls of paper' before hiding and changing the numbers of those items. |
| Q3 | female | In one compelling example, researchers in America found that female coots appear to calculate how many eggs they have laid - and add any in the nest laid by an intruder - before making any decisions about adding to them | Excerpt/Passage Explanation: The passage explains that researchers in America saw that girl coots (female coots) seem to count their eggs and any extra eggs they find in their nest. Answer Explanation: The answer means that the researchers specifically looked at the behavior of the girl birds, known as female coots. Reason For Correctness: The correct answer is "female" because the passage mentions a study about coots and their ability to count eggs. The text specifies that "female coots" are the ones that check the number of eggs in their nests before deciding to lay more. The word "female" describes the type of birds mentioned in the table row for coots. |
| Q4 | fruit flies | Psychologist Claudia Uller's team tempted salamanders with two sets of fruit flies held in clear tubes | Excerpt/Passage Explanation: The passage states that researchers used groups of fruit flies in see-through tubes to attract the salamanders for their study. Answer Explanation: The answer 'fruit flies' refers to the tiny insects that the researchers used to test the salamanders. Reason For Correctness: The correct answer is 'fruit flies' because the passage describes an experiment where researchers put these insects into clear tubes. By watching which tube the salamanders chose, the researchers could tell if the animals were able to recognize and pick the larger number of flies. This matches the table's description of salamanders being offered 'clear tubes containing different quantities' of something. |
| Q5 | mosquitofish | A team at the University of Padova found that while mosquitofish can tell the difference between a group containing 3 shoal-mates and a group containing 4, they did not show a preference between groups of 4 and 5 To consider this possibility, the mosquitofish tests were repeated, this time using varying geometrical shapes in place of fish |
Excerpt/Passage Explanation: The passage explains that these fish were tested to see if they could recognize numbers. It mentions their ability to distinguish between certain group sizes (like 3 and 4) but not others (like 4 and 5). It also says that the researchers used shapes instead of real fish to check if the fish were looking at the number of objects or other clues. Answer Explanation: The answer "mosquitofish" is the name of the small fish that scientists studied to see if they could tell the difference between groups of different sizes. Reason For Correctness: The correct answer is "mosquitofish" because this animal is the subject of the experiment described in that specific row of the table. The passage explains that mosquitofish can tell the difference between groups of three and four fish (shoal-mates) but cannot tell the difference between four and five. Additionally, the table mentions the use of 'geometrical shapes' and controlling for 'brightness' (referred to as luminance in the text), which the passage explicitly links to repeating tests on mosquitofish. |
| Q6 | surface area | The team arranged these shapes so that they had the same overall surface area and luminance even though they contained a different number of objects | Excerpt/Passage Explanation: The passage explains that in the study, scientists made the total size and the light of the shapes equal so that the fish had to rely on the number of objects rather than other visual clues. Answer Explanation: The answer "surface area" is the total amount of space that the outside or flat part of an object covers. Reason For Correctness: The correct answer is "surface area" because the passage describes how researchers tested mosquitofish to see if they could count. To make sure the fish were not just looking at how big or bright the objects were, they used shapes with the same total "surface area" and "luminance" (which means brightness). The table asks for the factor related to the total size that researchers checked along with brightness. |
| Q7 | sugar water | one which contained sugar water, which they like, while the other was empty | Excerpt/Passage Explanation: The passage explains that in the experiment, one of the two rooms had sugar water inside it for the bees, and the other room did not have anything. Answer Explanation: The answer is sugar water, which is a liquid made of water and sugar that bees enjoy eating. Reason For Correctness: The correct answer is found in the section about bees and their ability to count. In the experiment, bees were sent down a hallway toward two rooms. One room held sugar water as a reward, and the other room was empty. The bees had to learn to identify which room contained the food by looking at the number of shapes on the door. Therefore, they had to learn the location where the sugar water was kept. |
| Q8 | TRUE | Humans can do this with ease - providing the ratio is big enough monkeys, like humans, make more errors when two sets of objects are close in number Humans and monkeys are mammals, in the animal family known as primates |
Excerpt/Passage Explanation: The passage states that humans find it easy to tell which number is bigger if the difference is large. It also shows that monkeys perform like humans and make more mistakes when numbers are almost the same. Finally, it confirms that humans and monkeys are both part of the group called primates. Answer Explanation: The answer means that primates (which include humans and monkeys) are more accurate when they have to pick the bigger number, as long as there is a large difference between the two numbers. Reason For Correctness: The correct answer is TRUE because the passage says humans can identify the larger number with 'ease' if the 'ratio is big enough' (meaning there is a large difference). It also notes that monkeys and humans make 'more errors' (mistakes) when the numbers are 'close'. Since the passage also defines humans and monkeys as 'primates', we can conclude that these animals are better at identifying the larger number when the difference between the two is big. |
| Q9 | FALSE | the team marked each chamber with a different number of geometrical shapes — between 2 and 6 | Excerpt/Passage Explanation: The passage explains that the researchers used a specific amount of geometric pictures (like several circles or squares) to label the rooms, not the actual written characters of numbers. Answer Explanation: The answer is false because Jurgen Tautz did not teach the bees to recognize symbols for numbers (like 1, 2, or 3). Reason For Correctness: The correct answer is false because the experiment did not involve teaching the bees to recognize the written shapes of numbers (the digits themselves). Instead, the researchers used a "number of geometrical shapes" (like a group of dots or squares). The bees had to look at how many shapes were there, not what shape a written number makes. Therefore, the statement in the question is wrong because it says they recognized "shapes of individual numbers" rather than a quantity of geometric items. |
| Q10 | NOT GIVEN | Proof that this may be the case has emerged from an experiment testing the mathematical ability of three- and four-day-old chicks | Excerpt/Passage Explanation: The passage says that the chicks used in the test were three and four days old, but it never mentions how many days the scientists spent doing the research. Answer Explanation: The answer is NOT GIVEN because the passage does not provide information about how many days the research lasted. Reason For Correctness: The correct answer is NOT GIVEN because the passage mentions the age of the chicks (three and four days old) rather than the length of the experiment itself. Just because the chicks were three and four days old does not mean the researchers only worked for two days. Since the text does not say how much time the study took, we cannot confirm if the statement is true or false. |
| Q11 | TRUE | Proof that this may be the case has emerged from an experiment testing the mathematical ability of three- and four-day-old chicks Without any prior coaching, the chicks scuttled to the larger quantity at a rate well above chance |
Excerpt/Passage Explanation: The passage explains that very young baby birds, which are basically newborns, could do math. It also says they were not taught this skill, meaning they were born with it already. Answer Explanation: The answer means that the study showed baby birds (chicks) have a natural ability to understand numbers right after being born. Reason For Correctness: The correct answer is TRUE because the text describes a study where chicks that were only three or four days old could identify which group had more objects. Because they did this "without any prior coaching" (meaning they were never taught), it shows that they were born with this math skill. Keywords to look for include "three- and four-day-old" (referring to newborn animals) and "mathematical ability" or "arithmetic" (referring to numerical ability). |
| Q12 | NOT GIVEN | Animals on the prowl for sustenance must constantly decide which tree has the most fruit, or which patch of flowers will contain the most nectar | Excerpt/Passage Explanation: The passage explains that animals need to find the best places to eat, but it does not mention that researchers changed the amount of food in any experiments. Answer Explanation: The answer is NOT GIVEN because the passage does not say whether scientists did tests where they changed the amount of fruit or nectar for animals in the wild. Reason For Correctness: The correct answer is NOT GIVEN because the text only mentions fruit and nectar as examples of why counting is a useful skill for animals looking for food. While it says animals need to choose the tree with the most fruit or the flowers with the most nectar, it never describes a specific study or experiment where researchers actually changed these food amounts to test wild animals. The experiments that are described in the text used things like geometric shapes, paper balls, or flies in tubes instead of actual fruit or nectar in a natural setting. |
| Q13 | TRUE | In one compelling example, researchers in America found that female coots appear to calculate how many eggs they have laid - and add any in the nest laid by an intruder - before making any decisions about adding to them | Excerpt/Passage Explanation: The passage explains that female coots count the eggs they laid themselves and also count any eggs put in their nest by a different bird before他们 decided whether to lay more eggs. Answer Explanation: The answer means that coots include the eggs from other birds when they are counting how many eggs are in their nest. Reason For Correctness: The correct answer is TRUE because the text specifically mentions that female coots count their own eggs and also include any eggs left in their nest by an 'intruder'. In this context, an intruder is another bird. This shows that they do take the eggs of other birds into account when looking at their nest. |