This is the psychological "bait effect". For example, in our daily life, we can often see this effect in commodity pricing. For example, two kinds of packaged candy are displayed at a certain price: large package and small package; The absolute price of large package is high, but the unit price is very low compared with small package.
Then, the price option of that small package is actually a very important psychological reference. This goal allows consumers to find that large packaging is cost-effective through comparison, thus psychologically feeling cheap. In fact, consumers have to pay a higher amount to buy large packages. This is a very typical bait effect in marketing psychology.
This series of advertisements of IKEA is to use very cheap daily necessities, such as cola, coffee and toothpaste, as psychological "bait" to associate them with IKEA household products. Usually, when consumers consume relatively cheap daily necessities, their consumption decisions are often more casual and quick.
When we consume household products, no matter how much money we spend, we may think more seriously. Therefore, when IKEA's series of advertisements integrate IKEA household products with daily necessities, the low price of daily necessities becomes a psychological "bait". It is more conducive to product sales to drive consumers to change their consumption decision-making mode of IKEA household products to that of daily necessities.
Psychology has many applications in advertising. After studying the subject of advertising psychology, I think advertising psychology is really a very interesting part compared with other fields of psychology!