On the way in which vocal expressions can convey emotional information, especially in powerful experiences, and on the importance of the visual context
Expression of feelings and identifications are a central element in interpersonal interaction and communication. This is a non-verbal channel that includes facial expressions, voice and body posture. When this channel goes wrong due to a brain injury (for example, in a neurodegenerative disease such as Parkinson's, stroke or congenital syndromes), the ability to communicate with others, decipher their emotional state and convey personal and internal messages, thoughts and feelings is impaired.
Prof. Hillel Aviezer from the Department of Psychology at the Hebrew University, together with his team, researches the way in which people - healthy and those suffering from neurological diseases - express, recognize and experience emotion. Their goal is to understand the neuropsychological mechanisms of emotional expressions and the causes of their disruption. "Every situation and interaction between people involves emotion," says Prof. Aviezer, "and in many neurological diseases the ability to express the face or recognize it in others is impaired, which causes distress for the patient and his family members (in Parkinson's, for example, the face becomes expressionless and lifeless - 'face mask'). This makes it difficult to communicate, express difficulty, receive feedback. Then the voice expressions - an emotional-acoustic expression - enter the picture."
The latest research done in Prof. Aviezer's laboratory, led by doctoral student Doron Atias and with the help of a research grant from the National Science Foundation, the researchers wanted to examine the decoding of other people's emotions based on the voice. Atias: "Voice expressions are no less important and widespread than facial expressions, but they have hardly been studied. And the few studies that were done on them were based on the voices of actors in the laboratory who expressed emotion and not on voices that people produce in everyday life. We wanted to test how well these expressions can convey emotional information and we focused on situations where a powerful emotion is expressed."
The researchers collected on the Internet a variety of voices from videos in which people expressed positive and negative emotions, in extreme situations. For example, of women who reacted to the news of their daughter's pregnancy, to breaking into their house (a horrifying hoax) and the soldier's son who returned home. They evaluated the authenticity of the videos using parameters such as the style of photography, the type of situation recorded and the intensity of the emotional experience of the subject of the photography. "There is a record of real and strong emotion here. This is not an experience that can be reproduced in a laboratory," explains Atias.
The researchers played the voice expressions to the subjects and asked them to rate how positive or negative they sounded to them, and how powerful the emotion was perceived to be. It was found that the subjects were unable to distinguish between the voice expressions produced in positive situations and those produced in negative situations,
In the first experiment, the researchers played the voice expressions to 39 subjects (students), and asked them to rate how positive or negative they sounded to them (on a scale of minus 5 to 5) and how powerful the emotion was perceived (is it a storm of emotions or a minor and calm experience). It was found that the subjects were unable to distinguish between the vocal expressions produced in positive situations and those produced in negative situations, and they all sounded negative to them. The researchers also found that the more powerful the emotion, the more negative the voice expression sounded.
Prof. Aviezer: "These findings raise the question of how much voice expression alone can provide information about the other's emotional experience, especially when it is powerful. From this we understand the importance of the visual context in which the vocal expression is heard. A correct interpretation of the emotional experience and reducing its ambiguity probably also requires a visual component."
In the second experiment, the researchers cooperated with the lottery. They received from him about 150 voice recordings of people immediately after they heard from Arela about the amount they had won, all original, and asked to check how the size of the amount affects the vocal expression and its interpretation. They played the voices to American students from Princeton University (who of course do not understand Hebrew) and they were asked to rank them on the same positive-negative scale. It was found that votes that responded to an amount smaller than NIS 250,000 were seen as positive, and votes that responded to amounts higher than NIS 250,000 were seen as negative. That is, the higher the amount and the intensity of the emotion, the more the interpretation of the voice expression was incorrect. "This case also teaches us that it is difficult to rely on the expression of the voice alone in order to correctly interpret the emotion of the other person," notes Prof. Aviezer.
In the third experiment, the researchers wanted to check how it is still possible to interpret an emotion based on vocal expression alone, and the importance of the visual context. To do this, they planted the voices from the first experiment inside videos that describe a negative or positive situation. Each vocal expression was planted in both a positive and a negative video. For example, voices of joy and jubilation were planted in the video where a woman meets a burglar and in the video where she meets a loved one years later. The videos were shown to a variety of Israeli subjects, from all ends of the social spectrum, and it was found that even when the voices were originally taken from positive situations and when from negative situations, the way they were interpreted was completely dependent on the visual context. For example, a voice of joy planted in a video about a burglar is interpreted by the subjects as a scared voice, and a voice of fear planted in a video about an exciting meeting with a loved one is interpreted as happy. That is, even in this experiment it was found that the visual context is an extremely essential element in the interpretation of the vocal-emotional expression of the other person.
Life itself:
Prof. Hillel Aviezer, married with four children (ages 4 to 22) and lives in Modi'in. Expresses a theoretical interest in skydiving and climbing walls, and likes to eat cheese. Doron Atias, a fellow of the Azrieli Foundation, lives in Tel Aviv with his partner Maya. In his spare time he looks for parking, practices yoga and plays football. In addition, he volunteers at the Yizhar Association, which works to minimize the harm of drugs and prostitution in Israel.
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