Ask yourself this question the next time you are deciding what clothes to buy, where to eat, or which television show to watch: How much do other people’s behaviors influence your choices?

In the book Invisible Influence, author Jonah Berger argues that the decisions we make are influenced a great deal by other people. Not only that, but we are often unaware of this influence, hence its "invisible" nature.

The book explains the various forces that dictate when we want to be like others and when we strive to be different. In addition to outlining the fascinating underpinnings of why these phenomena occur, the author delves into how social factors influence all kinds of behavior, including consumer behavior.

The central tenets of Invisible Influence are broken down across five chapters, each one delving deeper into how social influence operates in our daily lives.

Chapter 1 begins with the classic Solomon Asch line study which showed how a unanimous majority can persuade people to give answers that are objectively false. This highlights how the social pressure to conform can be a powerful motivator of behavior. Such pressure is often magnified in novel or ambiguous situations where we rely on others to help us make a better decision.

If chapter 1 showed why we want to mimic others' behavior, chapter 2 explains scenarios when we strive to be different. Berger highlights how, at least in the United States, individualism is a central part of our identity and as a result, people often strive to be unique. The "snob effect" in retail explains how an individual's demand for a product can be negatively correlated with market demand. Likewise, even products designed for mass consumption are often customizable (think Starbucks) and have slogans highlighting this fact (e.g., "Have it your way").

Chapter 3 discusses how brand identity can influence purchasing behavior and, therefore, why many companies work diligently to keep their brand identity pure. If, for example, I like a particular athlete and they wear a certain brand of apparel, I will be more likely to use that brand. But the inverse can also be true, as explained by an amusing anecdote in this chapter regarding some companies paying celebrities to not use their brands. They want to avoid misidentification of the brand and do not want the brand identity signal to become too diffuse. Ultimately, this underlying psychology allows companies to target their ideal consumer through brand association.

In chapter 4, certain themes begin to converge as the author discusses "the value of moderate similarity." This is described as "The Goldilocks Effect" because marketers and product developers need to get their strategy just right. If something is too novel, we find it hard to incorporate into what we already know, but if it's too familiar, we find it boring and uninspiring. So, while we often value uniqueness and novelty, we gravitate toward things that feel familiar because it takes less effort to process what they are and are not. The key takeaway from this chapter is that the degree to which the consumer perceives a product to be "optimally distinct" will determine the success of that product.

Chapter 5 focuses on the many ways social influence motivates us to action. One in particular, the social norms approach to persuasion, explains how knowledge of other people's actions can influence our own behavior. If, for example, we learn that we are using much more water than our neighbors, this could lead us to curb our water usage. Again, this happens because despite all the talk of "rugged individualism", we use other people's behavior as a guide to inform our own actions. This is why when shopping online, you will often see something to the effect of "Customers who bought this product also bought…" Such information serves as a cue to action rooted in social influence.

Like many "pop psychology" books out these days, Invisible Influence is rife with curious anecdotes used to illustrate specific points. Fortunately, the anecdotes in this book are often supported by psychological research showing how the social environment can be manipulated to explain, predict, and ultimately change behavior. I recommend this book to anyone who is curious as to how social influence shapes our behavior.

This book is particularly relevant to the market research professional trying to glean new shopper insights from the social sciences and gain a better understanding of consumer behavior. Human behavior is nothing if not complex, and well-designed studies should consider as many facets of it as possible, both seen and unseen.