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About the How to Spot a Liar Reading Passage
This passage draws on psychology and behavioural science research to examine whether humans can reliably detect deception. It covers topics including the myth of Pinocchio-style tells, the science of microexpressions, baseline behaviour analysis, and the limited success of professional lie detection training.
The Cambridge source is a practice passage (exact Cambridge book number not confirmed).
You should spend about 20 minutes on Questions 1–14, which are based on the passage below.
The passage contains three question types: Matching Headings (Questions 1–6), True/False/Not Given (Questions 7–10), and Summary Completion (Questions 11–14).
How to Spot a Liar — Full Reading Passage
Paragraph A
Most people believe they can tell when someone is lying. They look for the classic signs: avoiding eye contact, touching the face, hesitating before speaking, and shifting in the seat. Research, however, shows that these popular beliefs are largely myths. Studies conducted across several countries found that people perform little better than chance when trying to identify liars, even when they are highly motivated to do so. Police officers, judges, and customs officials, people whose jobs require detecting deception, perform only marginally better than the general public.
Paragraph B
One reason for this poor performance is that there is no single reliable cue to deception. Unlike Pinocchio's nose, which grew unmistakably when he lied, real liars do not display one clear signal. The behaviours people associate with lying, gaze aversion, fidgeting, and speech errors occur in honest people too, particularly when they are nervous, tired, or under pressure. The absence of a universal tell makes deception detection extremely difficult. Research confirms that even trained investigators rely on the same unreliable cues as everyone else.
Paragraph C
A more promising line of research involves microexpressions, brief, involuntary facial expressions that flash across a person's face for a fraction of a second before the person regains composure. First identified by psychologist Paul Ekman, microexpressions are thought to reveal genuine emotions that a person is trying to conceal. Because they are so fast, lasting between 1/25 and 1/5 of a second, they are invisible to most untrained observers. Ekman argues that learning to spot microexpressions offers a more reliable window into deception than the traditional cues most people rely on.
Paragraph D
A different approach focuses not on what liars do, but on what changes in their behaviour when they lie. Researchers advocate establishing a "baseline" for each individual, observing how that person behaves normally so that deviations become detectable. A person who is generally relaxed and direct may arouse suspicion if they suddenly become evasive. However, critics point out that establishing a reliable baseline is time-consuming and impractical in most real-world situations, such as customs screening or police interviews, where officers must evaluate strangers quickly. The belief that liars always avoid eye contact, for example, is false: some practised liars maintain steady eye contact precisely to appear truthful.
Paragraph E
Physiological measures offer another path. The polygraph machine, commonly called a lie detector, records changes in blood pressure, respiration, and skin conductance that arise from the physiological stress of lying. Polygraph use is widespread in the United States, where it is used in criminal investigations and pre-employment screening. However, the scientific consensus is that the polygraph is unreliable. It measures stress, not deception, and innocent people under pressure can produce results indistinguishable from those of guilty individuals. Several major scientific bodies have concluded that polygraph evidence should not be admissible in court.
Paragraph F
Given the failure of common techniques, researchers have turned to training as a potential solution. Specialist programmes teach investigators to look for clusters of behaviour rather than single cues, to establish baselines systematically, and to use strategic questioning to increase the cognitive load on a potential liar. When liars must maintain a false story under repeated, unpredictable questioning, their accounts are more likely to become internally inconsistent. Some studies show that investigators trained in these methods improve their detection rates modestly, though the improvements are smaller than training advocates claim.
Paragraph G
Despite decades of research, no foolproof method of lie detection exists. Emerging technologies such as brain-scanning and thermal imaging are being explored, but none have achieved the level of reliability needed for real-world use. Researchers broadly agree that the problem lies not in a lack of technology but in the complexity of human behaviour itself. Lying is deeply embedded in human social life. People lie to protect themselves, to spare others' feelings, and to maintain social relationships. Any method that treats deception as a simple, detectable biological event is likely to oversimplify what is, in reality, a profoundly social act.
How to Spot a Liar Reading Questions and Answers
Questions 1–6: Matching Headings
The reading passage has seven sections, A–G. Choose the correct heading for sections A–F from the list of headings below. Write the correct number, i–vii, in boxes 1–6 on your answer sheet.
List of Headings i. Why a single behavioural signal does not exist ii. Watching for changes from normal behaviour iii. Can investigators be taught to do better? iv. A machine that measures the wrong thing v. The difficulty of observing fast facial signals vi. Popular beliefs that research has disproved vii. Detecting emotions hidden beneath the surface
1. Section A
2. Section B
3. Section C
4. Section D
5. Section E
6. Section F
Questions 7–10: True/False/Not Given
Do the following statements agree with the information given in the reading passage?
In boxes 7–10 on your answer sheet,
write:
- TRUE if the statement agrees with the information
- FALSE if the statement contradicts the information
- NOT GIVEN if there is no information on this
7. Research shows that professional lie detectors perform only slightly better than ordinary people.
8. Establishing a baseline is described in the passage as a quick and practical technique.
9. Paul Ekman conducted his microexpression research primarily in Asian countries.
10. Researchers agree that no reliable method of lie detection currently exists.
Questions 11–14: Summary Completion
Complete the summary below. Choose NO MORE THAN ONE WORD from the passage for each answer. Write your answers in boxes 11–14 on your answer sheet.
Approaches to Detecting Deception
Paul Ekman's work on 11 _____ shows that hidden emotions can surface briefly on a person's face. A contrasting approach involves studying a person's 12 _____ behaviour so that any change becomes noticeable. The polygraph records signs of physiological 13 _____, but this does not prove that someone is lying. Specialist 14 _____ programmes can improve detection rates, though the gains are limited.
