Even though kale is having a moment as a vegetable (and kale salad is certainly one of my favorites), most folks would agree that carrots taste better than kale. A new study, covered by multiple news outlets, has demonstrated that even in utero, fetuses agree. They seem to be able to tell the difference between carrots and kale, and they like carrots better!
As you can imagine, this study was a media darling. Here are some excerpts of a report on this study as covered by journalists at CNN.
The scientists used in-utero facial expressions to infer how babies felt about what their parent had eaten:
Fetuses create more of a “laughter-face” in the womb when exposed to the flavor of carrots consumed by their mother and create more of a “cry-face” response when exposed to kale [...]
The study looked at the healthy fetuses of 100 women between the ages of 18 and 40 years who were between 32 and 36 weeks pregnant in northeast England.
From this, 35 women were [assigned at random] into an experimental group that consumed an organic kale capsule, 35 were put into a group that took a carrot capsule, and 30 were put into a control group that was not exposed to either flavor.
After a waiting period of 20 minutes post-consumption, the women underwent 4D ultrasound scans, which were compared to 2D images of the fetuses.
Lip corner pulling, suggestive of a smile or laughter, was significantly higher in the carrot group compared to the kale and control group. Whereas ... casting down of the lower lip...– suggestive of a crying face – [was] much more common in the kale group than the other groups.
Questions
1. Using the table below, classify the three main variables mentioned in this study (hint: One variable was manipulated and two were measured)
| Variable name (conceptual variable) | How was this variable operationalized? | What are this variable's levels? | Was this a manipulated or measured variable? | Was this an IV or a DV? |
2. Was the independent variable manipulated as independent groups or within-groups?
3. Which of the four basic experimental designs was used: posttest only? pretest-posttest? repeated measures? concurrent measures? Explain your answer.
4. Sketch a little bar graph of the results of the "lip pulling" result.
5. Can this study support the causal claim that "eating a carrot pill causes fetuses to make a smiling face"? Apply the three causal criteria.
6. The CNN study mentioned the following in their reporting. Which of the four big validities is this addressing?
Participants were asked not to consume any food or flavored drinks one hour before their scans. The mothers also did not eat or drink anything containing carrot or kale on the day of their scans to make sure it would not influence the results.
7. The 100 fetuses in this study were not a random sample of any population--they were a convenience sample. Why do you think these researchers did not prioritize external validity in this study? Do you think that's a major problem, or not?
8. Use the Internet to find other media coverage of this study--note any similarities and differences in how the journalists discuss the findings.
Here's a link to the original empirical article (paywalled).
