There are many subjective factors determining consumption function.

1. The subjective motives such as motive of precaution, motive of foresight, motive of calculation, motive of improvement, motive of independence, motive of enterprise, motive of pride, motive of avarice, etc. affects consumption function. 

2. For example, high motive of enterprise and high motive of Independence results in decrease in the consumption and increase in savings and vice versa. 

3. Thus, there are many subjective factors determining consumption function.