I read 100 marketing papers and these are the 5 I found most interesting
Disclaimer: Many of these summaries are an oversimplified version of the paper. It’s hard to put everything into a few sentences. You can access most of these papers for free on Google Scholar.

1. People travel through grocery stores in unusual ways

A study from the University of Pennsylvania discovered that grocery store shoppers tend to travel along the outer racetrack of the store's layout, while periodically making short excursions part way into the aisles for specific items, and then back out the same way they came.

This is different from the common belief that shoppers travel up and down many isles during their visit. This increases the importance of product placements at aisle end caps and suggests that products in the middle of aisles receive less face time.

Source: Larson, J. S., Bradlow, E. T., & Fader, P. S. (2005). An exploratory look at supermarket shopping paths. International Journal of research in Marketing, 22(4), 395-414.

2. People are more likely to buy “organic” foods when it can be used as a justification for chocolate, cookies, etc.

Foods labeled as "organic" do not always create a higher willingness to buy among consumers. Most people agree that organic food is healthier, but they are not more likely to buy it for that reason. But they will be more likely to buy it if they believe it is a higher quality product, especially if it's a so-called "vice food" such as cheese, chocolate, cookies or biscuits to name a few.

What this means is consumers will use the fact that chocolate is "organic" as a guilt-reducing mechanism or justification for buying the product - but won't do the same for so called "virtue organic products" such as veggies or fruit.

Source: Van Doorn, J., & Verhoef, P. C. (2011). Willingness to pay for organic products: Differences between virtue and vice foods. International Journal of Research in Marketing, 28(3), 167-180.

3. Online consumers are motivated to share online advertisements based on the need for self-enhancement

In other words, when a person believes an ad is consistent with the person they want to become, they are more likely to share it with others. As a marketer, you can use this to your advantage by creating ads that feed into the ego of your audience.

Source: Taylor, D. G., Strutton, D., & Thompson, K. (2012). Self-enhancement as a motivation for sharing online advertising. Journal of Interactive Advertising, 12(2), 13-28.

4. A pricing discount is not likely to encourage many consumers to switch brands if the perceived quality of the discounted product is lower

In other words, people are not willing to sacrifice quality for a slightly less expensive product (loss aversion). Also, first movers into a market act as a reference point for comparing quality.

The lesson: Do not simply offer a lower priced version of the incumbent product if your company is entering a new market. Position your product as a premium alternative or introduce a new product attribute that will establish your product as the new market reference point.

Source: Hardie, B. G., Johnson, E. J., & Fader, P. S. (1993). Modeling loss aversion and reference dependence effects on brand choice. Marketing science, 12(4), 378-394.

5. Losses loom larger than gains

Customers that have a negative experience with a service provider are less likely to stay with that service provider in the future, which is not surprising. But what's interesting is that customers who had a great experience stay with a service provider for as long as those who had a neutral experience. So it’s more important to focus on minimizing bad experiences over anything else.

Source: Bolton, R. N. (1998). A dynamic model of the duration of the customer's relationship with a continuous service provider: The role of satisfaction. Marketing science, 17(1), 45-65.

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