Autonomous investment is investment spending that does not depend directly on current national income or output.
The macroeconomic idea
In simple Keynesian models, some investment is treated as “autonomous” because it reflects business expectations, technology, interest rates, or public policy rather than current income. This makes it an important independent driver of aggregate demand.
Why it matters
Because autonomous investment is not mechanically tied to current income, shifts in it can start broader multiplier effects. A rise in planned investment increases income, which can then induce additional consumption and output growth.
A simple expression
In a stripped-down spending model:
$$
I = I_0
$$
where (I_0) represents the autonomous component of investment. Richer models then allow interest rates, expectations, or capacity utilization to influence it.
Knowledge Check
### Autonomous investment is called "autonomous" because it:
- [x] is treated as independent of current income in simple macro models
- [ ] can never change
- [ ] always comes from the government
- [ ] is unrelated to expectations
> **Explanation:** The term means it is not driven directly by current output in the model.
### Why can autonomous investment have a multiplier effect?
- [x] Because an initial rise in investment raises income and can induce further spending
- [ ] Because investment has no link to demand
- [ ] Because it automatically lowers all taxes
- [ ] Because it eliminates interest rates
> **Explanation:** In Keynesian frameworks, one source of spending can propagate through the wider economy.
### Which factor can influence autonomous investment in richer models?
- [x] business expectations
- [ ] only current GDP by accounting identity
- [ ] only household grocery spending
- [ ] nothing at all
> **Explanation:** Even though it is autonomous relative to current income, it can still depend on expectations, rates, and policy.