Final answer:
Altruism is intrinsically rewarding and is based on voluntary actions meant to help others, and it is often driven by empathy. While these actions can boost personal happiness, they are distinct from the just-world hypothesis, which relates to the belief that people get what they deserve, and from the 'invisible hand' metaphor about self-interest inadvertently leading to social good.
Step-by-step explanation:
The idea that employees who spend their windfall bonuses on others experience greater happiness aligns with the concept of altruism being intrinsically rewarding. Altruism refers to the voluntary behavior intended to benefit another, even when the costs to the individual are high. This concept is distinct from the just-world hypothesis, which suggests that people get what they deserve in life, and where empathy is less of a guiding principle.
Altruistic actions are often driven by empathy, the ability to understand and share the feelings of others, which may lead to the desire to help and support them. Despite the ongoing debate on whether altruism is truly selfless or tinged with self-interest due to the personal satisfaction it brings, the experience of helping others does generally contribute to an individual's happiness.
The concept that good deeds may sometimes lead to personal happiness does not necessarily align with the 'invisible hand' metaphor, which deals with self-interest leading to broader social good, as altruistic actions may not be motivated by self-gain.