Final answer:
The mere ownership effect is a psychological phenomenon where individuals value an object more just because they own it, regardless of their wealth or how long they have owned the object.
Step-by-step explanation:
An accurate statement about the mere ownership effect is: It occurs almost immediately when an individual obtains an object and it increases with time of ownership. This psychological effect suggests that people tend to value objects more highly simply because they own them. This valuation is not limited to wealthy individuals or those who own a large number of objects. Rather, it can affect anyone, regardless of their socio-economic status, and relates to how ownership can alter an individual's perception and emotional attachment to an object over time.