If there is a high level of PERCEIVED RISK, then consumers will take more time and effort in making a decision.
Think for example buying a house versus buying a soda.
There is not much thought needed when you are buying a soda. Choose which brand and what size, you are done.
When buying a house, because it is both more complex and more expensive, there is a greater perceived risk of losing money. When buying a home, it is a large investment and carries much risk, therefore the consumer will take more time and effort evaluating the purchase decision.