Lesson 7 of 7 / Nutrition in humans
Alcohol, the brain and the liver
How can a slower response become a wider social risk?
In this lesson: Connect alcohol's effects on the brain and liver to immediate, long-term and social consequences.
About 5 min
The key ideaAlcohol can slow responses and reduce self-control. Repeated excessive consumption can damage the liver and brain, with consequences for the person and others.
Reaction time is the time between a stimulus and the response to it. A longer reaction time means responding more slowly, not more quickly.
Explore the idea
Connect a body effect to a consequence
In this original example, a 0.5 s extra delay at 10 m/s adds 5 m travelled before a response begins. This is not an alcohol-dose prediction.
Original cause-and-effect model. It separates an immediate biological effect from a possible consequence; it does not predict an individual's response or specify an alcohol dose.
Explanation
Alcohol affects brain function. It can increase reaction time, so a person takes longer to respond to a signal or hazard. It can also reduce self-control and impair judgement and coordination. Feeling more confident does not mean that responses have become more accurate.
Slower responses and poorer decisions can increase the risk of injury, including road accidents. A delay between seeing a hazard and beginning to react lets a moving vehicle travel further before braking starts. This is a consequence of response delay, not a change in the vehicle's brakes.
The liver breaks down alcohol, but this capacity is limited. Long-term excessive consumption can cause liver disease, including scarring that interferes with liver function, and can damage the brain. Acute effects on decisions and coordination are different from damage that develops over time.
The effects can extend to other people. Injuries may affect passengers or pedestrians; impaired decisions can strain relationships, study or work; dependence and illness can create financial and care burdens. Explain these links without assuming that every individual experiences the same outcome.
Step by step
- 1
Name the biological effect
For example, increased reaction time, reduced self-control or liver damage after excessive long-term consumption.
- 2
Explain the consequence
A slower response to a hazard can increase injury risk. Reduced self-control can affect decisions.
- 3
Connect to others
Show how a particular consequence can affect family, other road users, work or health services.
Worked example
Extra distance before a response
In an illustrative example, a vehicle travels at 10 m/s. A driver's reaction time increases from 0.3 s to 0.8 s. How much further does it travel before the driver begins to respond?
One way to explain it
The extra delay is 0.5 s. At 10 m/s the vehicle travels an additional 10 x 0.5 = 5 m before the response begins. This illustrates why an increased reaction time can increase risk; it is not a measurement of any particular alcohol dose.
Why this answer works
- Subtract the two reaction times.
- Multiply speed by the extra delay.
- Distinguish distance before responding from braking distance.
Is this true? "Increased reaction time means a person reacts faster."
Reaction time is a duration. An increase means the response starts later, which can leave less time to avoid a hazard.