TOEFL Listening Part 4: Circadian Rhythms and Medicinal Development (Intermediate)
New TOEFL Listening Part 4 Format
As in the traditional TOEFL, the Listening section remains the most approachable section even after the revision. As long as you have built a solid foundation in vocabulary and grammar through the Reading section, you are unlikely to face major difficulties.
This is particularly true for Parts 1 and 2, which feature listening materials based on everyday situations. For these parts, the main goal of practice is not skill development itself but becoming familiar with the question formats.
Part 4, by contrast, is generally the most challenging area of the Listening section. It closely resembles the academic lectures found in the conventional TOEFL. Because Part 4 is longer and more information-dense than the other listening tasks, careful note-taking is essential when answering the questions that follow.
Structural Patterns of Academic Talks
In Listening Part 4, you will always hear a lecture from a specific academic field. At first, this may seem difficult to manage. However, once you understand the common structural patterns used in lectures, they become much easier to follow.
Most academic lectures in TOEFL Listening can be broadly classified into two types:
- Explanation of a phenomenon
- Discussion of a problem and proposed solutions
Although lectures vary in purpose and content, each type tends to follow a predictable structure.
Explanation of a Phenomenon
Lectures that explain a phenomenon typically follow this sequence:
- Introduction of the phenomenon
- Examples or evidence illustrating the phenomenon
- Applications and concluding remarks
Problems and Suggestion Related to Certain Topic
Lectures that focus on problems related to a topic often follow this structure:
- Introduction of the topic
- Description of the problems
- Suggested solutions or implications
So, quickly identifying which type of lecture you are listening to can significantly reduce the overall difficulty of the task.
Practice Question (Psychology)
1. What is the main focus of the lecture?
A. How internal biological clocks regulate daily physiological functions.
B. How environmental light directly controls all biological processes.
C. Why sleep disorders are increasingly common in modern societies.
D. Why hormone production depends primarily on external conditions.
2. According to the speaker, what role does the suprachiasmatic nucleus play?
A. It responds to hormonal changes produced during sleep cycles.
B. It adjusts metabolic activity during periods of physical exertion.
C. It coordinates internal timing processes within the brain.
D. It controls voluntary behavior related to daily routines.
3. Why does the professor mention shift workers?
A. To explain why night work improves long-term alertness.
B. To compare biological effects across different professions.
C. To show how work schedules permanently alter biological rhythms.
D. To illustrate conflicts between internal clocks and external demands.
4. What can be inferred from the rodent studies described in the lecture?
A. Animal behavior is unaffected by changes in light exposure.
B. Biological cycles function only under natural environmental cues.
C. Circadian rhythms depend entirely on consistent lighting conditions.
D. Internal rhythms can persist without immediate external signals.
5. What does the professor suggest about practical applications of circadian research?
A. Biological clocks can be eliminated through controlled environments.
B. Medical treatments may be influenced by timing considerations.
C. Drug effectiveness is determined mainly by dosage levels.
D. Sleep-related issues can be solved through behavioral training.
Answers, Transcription, and Explanation
Question 1. A
Question 2. C
Question 3. D
Question 4. D
Question 5. B
Transcription
In biology, circadian rhythms refer to internal processes that follow an approximately twenty-four-hour cycle. These rhythms influence a wide range of physiological functions, including sleep patterns, hormone release, and body temperature. Although they are often associated with the daily cycle of light and darkness, circadian rhythms are generated internally rather than directly caused by environmental cues.
Research has shown that a small region in the brain called the suprachiasmatic nucleus plays a central role in regulating these rhythms. Even in constant darkness, individuals tend to maintain regular sleep–wake cycles for several days, suggesting the presence of an internal biological clock. However, external signals such as light can adjust, or reset, this clock through a process known as entrainment.
A well-known example involves shift workers. People who work overnight often experience difficulty sleeping during the day and may suffer from reduced alertness at work. This occurs because their internal rhythms remain synchronized with daylight hours, despite changes in work schedules. Similarly, travelers crossing multiple time zones may experience jet lag, a temporary mismatch between internal rhythms and local time.
Studies using laboratory animals provide further evidence. When rodents are kept under constant lighting conditions, their activity cycles gradually drift, no longer aligning precisely with a twenty-four-hour day. This drift demonstrates that circadian rhythms are self-sustaining but require environmental input to remain accurately synchronized.
Understanding circadian rhythms has practical implications, particularly in medicine, where treatment effectiveness can vary depending on the timing of drug administration.
Question 1: What is the main focus of the lecture?
Correct Answer (A)
Key evidence from the lecture:
- “circadian rhythms refer to internal processes that follow an approximately twenty-four-hour cycle”
- “these rhythms influence sleep patterns, hormone release, and body temperature”
The lecture consistently emphasizes internally generated biological timing systems and how they regulate daily physiological functions. Rather than focusing on sleep disorders or external light alone, the professor explains how internal clocks influence multiple bodily processes. Therefore, choice A best captures the overall focus of the lecture.
Question 2: According to the speaker, what role does the suprachiasmatic nucleus play?
Correct Answer (C)
Key evidence from the lecture:
- “a small region in the brain called the suprachiasmatic nucleus plays a central role”
- “regulating these rhythms”
The speaker identifies the suprachiasmatic nucleus as the central regulator of circadian rhythms. Its function is described as coordinating internal timing processes, not controlling voluntary behavior or responding to hormones. Choice C accurately reflects this role based on the lecture.
Question 3: Why does the professor mention shift workers?
Correct Answer (D)
Key evidence from the lecture:
- “their activity cycles gradually drift, no longer aligning precisely with a twenty-four-hour day.”
- “This drift demonstrates that circadian rhythms are self-sustaining but require environmental input to remain accurately synchronized.”
The rodent studies show that the animals’ activity cycles did not simply stop when lighting conditions were controlled. Instead, the cycles continued, but they slowly moved away from an exact twenty-four-hour pattern. This means internal rhythms can keep operating without immediate external cues, but light or other environmental input is needed to keep them properly aligned.
Question 4:
Correct Answer (D)
Key evidence from the lecture:
- “when rodents are kept under constant lighting conditions their activity cycles gradually drift”
- “circadian rhythms are self-sustaining”
The rodent studies demonstrate that circadian rhythms continue even without immediate environmental cues, although they may drift over time. This supports the inference that internal rhythms can persist independently. So, choice D is the best answer.
Question 5: What does the professor suggest about practical applications of circadian research?
Correct Answer (B)
Key evidence from the lecture:
- “treatment effectiveness can vary depending on the timing of drug administration”
- “understanding circadian rhythms has practical implications, particularly in medicine”
The lecture concludes by applying circadian research to medicine, suggesting that the timing of treatment administration can influence their effectiveness. This directly supports choice B, which focuses on timing as a practical consideration in medical treatment.
2 Comments
The question 4 in the explanation does not match the one on the audio track. Thank you.
Hi,
Thank you very much for pointing that out.
It helped me correct the mistake.
Thank you again!