Fessler et al (2005)

• Examine one evolutionary explanation of behavior.
• Elevated disgust sensitivity in the first trimester of pregnancy
• Aim


  To investigate if disgust sensitivity in the first trimester of pregnancy was elevated as predicted.
• Procedure


  - A Web-based survey was completed by 691 women recruited through pregnancy-related Web sites.

  - No compensation was offered for participation. The women's mean age was 28.1 years.

  - On the Web-based questionnaire, the participants (1) indicated their current level of nausea using a 16-point scale and (2) answered questions to test their disgust sensitivity in eight different areas (e.g. food; contact with animals, body products, and dead animals; hygiene; contact with toilets)
• Results

  - Overall, disgust sensitivity related to food and body products in women in the first trimester was higher compared to those in the second and third trimesters.

  - Disgust was particularly elevated in relation to food, which was exactly what the researchers had predicted

  - Food-borne diseases are particularly dangerous to women in the first trimester and therefore it was predicted that disgust sensitivity related to food would be high. This was supported by the results.

  - The results may indicate that nausea and vomiting are evolved behavior because they limit the likelihood that pregnant women will eat dangerous food.
• Conclusions

  Food-borne diseases are particularly dangerous to women in the first trimester and therefore it was predicted that disgust sensitivity related to food would be high. This was supported by the results. The results may indicate that nausea and vomiting are evolved behaviour because they limit the likelihood that pregnant women will eat dangerous food.
• strengths


  - findings are supported by other studies showing that images that threaten the immune system are judged as more disgusting
• limitations

  - self reports may not be reliable

  - not an effective way of measuring disgust
• ethical considerations

  It is difficult to test evolutionary theories and not much is known about the life of early humans. Also, evolutionary explanations tend to focus on biological factors and underestimate cultural influences.