{"id":23563,"date":"2018-04-02T10:31:54","date_gmt":"2018-04-02T14:31:54","guid":{"rendered":"https:\/\/www.tun.com\/blog\/?p=23563"},"modified":"2022-03-16T12:06:29","modified_gmt":"2022-03-16T16:06:29","slug":"blood-flow-changes-reveal-emotions","status":"publish","type":"post","link":"https:\/\/www.tun.com\/blog\/blood-flow-changes-reveal-emotions\/","title":{"rendered":"Subtle Blood Flow Changes Can Reveal Your Emotions"},"content":{"rendered":"

Subtle changes in blood flow color around the face reveal the mood we\u2019re in, even before our faces move to form the expression we want, according to a groundbreaking <\/span>study<\/span><\/a> by The Ohio State University.<\/span><\/p>\n

This is the first study <\/span>to ever document connections between blood flow color change and facial expression without facial movement<\/span>. The researchers found that people are able to correctly identify the expression of another person up to 75 percent of the time, based only on shifts in blood flow color around areas of the face, including the cheeks, chin, eyebrows, and nose. <\/span><\/p>\n

The paper is published in the <\/span>Proceedings of the National Academy of Sciences<\/span><\/a>. <\/span><\/p>\n

A New Hypothesis <\/b><\/h2>\n

To begin this study, researchers took hundreds of photos of human expressions — happiness, sadness, anger, disgust, surprise and more — and looked at the scientific process behind facial movement. <\/span><\/p>\n

Upon observing these expressions, the researchers noted a large number of blood vessels located between the skin and facial muscles. This led to the hypothesis that before the face even moves to form an expression, humans visually communicate emotion through subtle changes in blood flow color. <\/span><\/p>\n

The researchers further developed this hypothesis by asking two questions:<\/span><\/p>\n

    \n
  1. Are there color changes that are unique to each emotional expression?<\/span><\/li>\n
  2. Are these color changes visible to other humans? <\/span><\/li>\n<\/ol>\n

    Testing the First Question<\/b><\/h2>\n

    To test the first part of the hypothesis, the researchers broke down hundreds of facial expression images by separating them into two color channels, a red-green channel and a blue-yellow channel. Then, via computer analysis, they found that different facial expressions formed unique color patterns. <\/span><\/p>\n

    \u201cThere\u2019s a little bit of every color everywhere,\u201d<\/span> Aleix Martinez<\/span><\/a>, cognitive scientist and professor of<\/span> electrical and computer engineering<\/span><\/a> at OSU, said in a statement.<\/span><\/p>\n

    The researchers found that touches of red, green, blue, and yellow were found in every emotion, but organized in different amounts or locations around the face. For example, they found that disgust creates a blue-yellow cast around the lips and a red-green cast around the nose and forehead, while happiness is usually conveyed with red cheeks and temples and a little blue around the chin. <\/span><\/p>\n

    \u201cPrevious research has studied the hypothesis that facial muscle movements transmit emotion,\u201d said Martinez. \u201cIn the present work, we study the novel hypothesis that blood flow changes, observed as variations in facial color, also transmit emotion. We show results in favor of this hypothesis. We also show that these two signals (facial muscle movements and color) are at least partially independent from one another.\u201d <\/span><\/p>\n

    Testing the Second Question<\/b><\/h2>\n

    After finding strong results from the first part of the hypothesis, the researchers set out to test whether or not these color changes are enough for people to identify a distinct facial expression. <\/span><\/p>\n

    To test this question, the researchers superimposed different color channels on pictures of faces with neutral expressions. They then showed these photos to 20 participants and asked them to identify the expression each person was conveying, by choosing from a list of 18 emotions. The emotions included both basic expressions like \u201chappy\u201d or \u201cangry,\u201d as well as compound expressions such as \u201chappily surprised\u201d or \u201csadly angry.\u201d <\/span><\/p>\n

    The researchers found that the participants guessed right most of the time. In the neutral photos colorized to look happy, the researchers guessed the expression correctly 70 percent of the time. In addition, the participants guessed sadness correctly 75 percent of the time and anger correctly 65 percent of the time. <\/span><\/p>\n

    This proved that participants were able to successfully identify a person\u2019s emotion without ever seeing the face move. <\/span><\/p>\n

    In a second experiment, the researchers showed the participants facial expressions of happiness, sadness, and other emotions, and put incorrect color formulations on top of them. For example, in some photos the researchers superimposed happy colors atop an image of person whose facial expression indicated sadness, and vice versa. In this experiment, participants noticed that something about the images looked wrong, even if they couldn\u2019t quite identify why. <\/span><\/p>\n

    \u201cParticipants could clearly identify which images had the congruent versus the incongruent colors,\u201d Martinez said in a statement.<\/span><\/p>\n

    Computers vs. Humans<\/b><\/h2>\n

    In addition to testing this theory on human participants, the researchers tested the neutral-faced images on a computer using emotion-identifying algorithms that they developed. <\/span><\/p>\n

    The computer scored a bit higher than humans, detecting happiness correctly 90 percent of the time and the compound emotion \u201chappily surprised\u201d correctly 85 percent of the time. In addition, the computer detected anger correctly 80 percent of the time, sadness 75 percent of the time, fear 70 percent of the time, and \u201cfearfully disgusted\u201d 65 percent of the time. <\/span><\/p>\n