Evolved Human Behaviors: Nonverbal Communication


Facial Expressions
Many facial expressions have been identified as having an innate basis in humans. The evidence for this assertion comes from three lines of evidence:

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Play faces


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Smiling by a chimp and similarity between chimp and human expressions

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Play faces by a blind infant and deaf-blind child.

Other facial expressions that are seen cross-culturally (many of which are also seen in non-human primates) include expressions of anger and rage (Fig 3), worry or anxiety (Fig 4), and fear faces (Fig 5). An anger face is characterized by the lips tightly drawn across the teeth. Interestingly, there are gender differences in the ability of males and females to read these emotions, with females more capable (more on this is here). With rage, the lips are so tightly drawn over the teeth that the teeth are exposed. Fear faces are characterized by the cheeks tightly drawn back so that side teeth are exposed. The corners of the mouth by be drawn up (almost like a smile), or down).

Coy or flirtatious behavior is also seen across cultures (Fig 6). Typically, the female looks sideways at the male until she catches his attention, Then she turns away and down with a smile, usually while maintaining eye contact. She then turns again toward the male, shows a full smile, but either covers it with her hand or by looking down. These behavior patterns are only seen in females and show up very early in their development. You can watch an example of coy behavior here (from the Human Ethology Film Archives). The intensity of the coy or flirtatious behavior can be intensified with the use of a pout (fig 7). Again, these behaviors are not seen in males. Other examples of female flirtatious behavior is here.

Body language and gestures.
Body language and gestures can also be used for communicating emotional states. These gestures are seen cross-culturally around the world. A few are also seen in non-human primates.

Some video clips of gesticulation are here.

Required Reading on the gestural origins of human language.


Project Outline.
The need to use gestures while speaking is so deeply ingrained in our behavior that we will gesticulate while speaking to someone on the phone. For this project you will record the frequency of gestures used under a variety of conditions.

To record the behavior of your subjects, seek pairs of subjects that are in the process of eating. Avoid recording data from conversations that include more than two people. Good places to record data include a fast food restaurant, food court at a mall, or people at an outdoor event. You will need to record male-male, male-female, female-male, and female-female interactions. Each of the pairs need to be recorded twice using different subjects. A data chart for you to print out in Excel format can be found here. Choose subjects that are of similar age.

Record the behavior of the speaker for 10 minutes. As the conversation switches back and forth, pay attention to only the first person. Put hatch marks in the Excel chart each time the subject shows the corresponding behavior. Email your completed data form to me. I will collate the data for the entire class and will post it on the web site. Your report should be on the pooled class data. Pooled class data are HERE

Report

  1. Which behaviors are most often seen?
  2. Is there a difference in the frequency of behaviors between a male and female.
  3. Are there differences in the frequency of behaviors for same-sex vs. opposite sex pairs?
  4. Discuss your data from an evolutionary point of view.