The Colors of Diffusion on Pinterest (Extract)

Color is a ubiquitous perceptual stimulus that is often linked with psychological functioning in humans[1]. For example, in 1979, a director at the American Institute for Biosocial Research began observing curious psychological variation in his patients — variation seemingly rooted in what colors he showed them. To test his theory, he convinced the directors of a naval prison to paint their cells pink, believing pink would calm the inmates. What he found was fascinating. Rates of violent behavior fell dramatically after exposure to the plain pink walls. According to the Navy's follow-up report, “Since the initiation of this procedure…there have been no incidents of erratic or hostile behavior”[2].

In addition to inducing calm, colors can evoke powerful reactions like warmth, relaxation, danger and energy[3–6–3]. In short, they have remarkable power to move us emotionally. For example, prior work has shown that Red is associated with excitement, Yellow with cheerfulness and Blue with comfort[7]. In this paper, we ask: Might these phenomena documented in lab experiments also affect online behavior? Could color drive how we act on social media?

Recently, we have seen image-sharing communities truly take off — sites such as Pinterest, Imgur and Tumblr, just to name a few. A key research challenge for communities like these is uncovering the mechanisms by which content spreads from person to person (or “diffuses,” adopting the term from the academic literature). For example, a study of the most widely shared New York Times stories found that they tend to “inspire awe” in their readers[8]. While we have results like this for text and network structure (e.g., Bakshy et al.[9]and Sun et al.[10]), as far as we know, we have no such similar results on what makes images diffuse widely. It is within this context that we make the leap from color to diffusion: Is there a link between them?

In this paper, we aim to answer whether color stimulations affect behavior online. We adopt Pinterest as our research site. Pinterest is a rapidly growing social network based on images. Drawing on a corpus of one million images crawled from Pinterest, we find that color significantly drives how far an image diffuses (to what extent it is adopted by other users), even after partially controlling for user activity and network structure. Specifically, Red, purple and pink seem to promote diffusion, while Green, Blue and Yellow suppress it. As far as we know, this is the first result describing how image features affect diffusion. Our work bridges the gap between online user behavior and psychology studies of color. In addition to contributing to the ongoing research conversation surrounding diffusion, we believe these findings suggest future research to uncover the impact of color on other aspects of online user behavior, and to use more sophisticated computer vision techniques. For example, could we apply advanced computer vision techniques to relate an image's macro-properties (outside vs. inside, natural vs. cityscape) to the image diffuses?

For designers, our findings shed light on engagement on large social sites. Recently, for example, many mobile applications let users transform their photos with image filters. Instagram popularized this technique, but similar features can be found in Flickr's latest mobile app. The filters typically change saturation, brightness, and color distributions. Our results can be used to guide the design of these filters. For example, filters that increase an image's saturation or enhance its warmness maybe likely to increase diffusion — a highly sought-after form of engagement.