The effect of mental fatigue are :
(a) Decreased attention
(b) Decreased motivation
(c) Increased mental performance
(d) Impaired thinking
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Question

Accepted Answer

Option 2, which includes (a) Decreased attention, (b) Decreased motivation, and (d) Impaired thinking, is the correct answer for the effects of mental fatigue. Here's a detailed explanation supporting this choice:

1. **Decreased Attention (a):** Mental fatigue often results in a reduced ability to focus and maintain attention on tasks. This is because the brain's resources are depleted, making it harder to concentrate and process information efficiently. Studies have shown that individuals experiencing mental fatigue have slower reaction times and are more prone to distractions.

2. **Decreased Motivation (b):** When a person is mentally fatigued, their drive to engage in activities or complete tasks diminishes. This is due to the exhaustion of mental energy, which makes it challenging to initiate or sustain effort in activities that require cognitive engagement. Decreased motivation is a common symptom of mental fatigue, as the brain seeks to conserve energy.

3. **Impaired Thinking (d):** Mental fatigue can lead to impaired cognitive functions, such as problem-solving, decision-making, and critical thinking. The brain's ability to process information and generate solutions is compromised, leading to errors and slower cognitive processing. This impairment is a direct consequence of the brain's reduced capacity to function optimally when fatigued.

**Why Other Options Are Incorrect:**

- **Option 1 (a), (b), (c):** This option includes (c) Increased mental performance, which is incorrect. Mental fatigue does not enhance mental performance; rather, it diminishes it. Increased mental performance is contrary to the effects of fatigue, which typically involve a decline in cognitive abilities.

- **Option 3 (a), (b), (c), (d):** This option includes all four effects, including (c) Increased mental performance, which is incorrect for the reasons mentioned above. Mental fatigue does not lead to increased mental performance, making this option incorrect.

- **Option 4 (b), (c), (d):** This option also includes (c) Increased mental performance, which is incorrect. While it correctly identifies decreased motivation and impaired thinking, the inclusion of increased mental performance makes this option incorrect.

In conclusion, Option 2 is the correct answer as it accurately identifies the effects of mental fatigue without including any incorrect effects like increased mental performance.