During everyday life, its easy to take language for granted. You go about your day able to almost seamlessly communicate with others. However, when you’re in a foreign country where you don’t speak the language, it’s impossible not to notice. Language becomes a thing you think about every day, trying to pick up words and hoping you’re pronouncing the words correctly. When we were talking about animal language in class, it made me wonder why do we have such an advanced way of communicating with each other. We had learned about various ways that animals communicate in some of my previous classes, however, humans have always found a difference in our language that we believe makes it unique. So, what is it that allows us to have the ability to create complex languages?
Picture of me on the phone. Picture credits: Genevieve Wilson
Lai et al. (2001) found that the Foxp2 gene plays a large role in our ability to speak by studying the DNA of people who had a language disorder. According to Schreiweis et al. (2019), the gene is found in throughout many species of animals, however, humans have a slightly different version of it. In order to study the effects of the difference, they altered the gene in mice to resemble the human version and compared them to mice with the normal mouse gene. They found that the human version of the gene caused more neurons to express Foxp2 than the normal mouse version did in areas where there was a lot of expression. However, they also found that in areas of the brain without a lot of Foxp2 expression, the human version caused even less expression than the normal mouse gene did.
Castellucci et al. (2016) also studied the effects of Foxp2 in mice, however, they studied the effects of getting rid of the gene instead. Because mice who don’t have the gene at all end up dying as juveniles, they studied mice with only one copy of the gene and its impacts on mating calls. They found that the mice with only one copy of Foxp2 didn’t produce sounds longer than 75 ms while the mice with both copies did. They also found that the mice with only one copy of the gene produced more consistent sounds than the mice with both copies.
All of this was super interesting, but mice are a little different from people. So, what is it that Foxp2 does in people? For obvious reasons, there haven’t been experiments with Foxp2 in humans but there have been more studies done on the family that Lai et al (2001) studied. For example, Schulze et al. (2018) used this family to study Foxp2’s effects on working memory, or the memory of what just happened. They first gave both the family members with the mutation and controls with the normal gene an IQ test. They then did various memory tests such as giving them a sentence, asking them to say if it was true or false, then asking them to repeat the last word. They found that the people with the altered Foxp2 gene did worse on the tasks than the control participants did. This could indicate that language is important in our working memory or that the Foxp2 gene also plays a role in working memory. Emmorey et al. (2017) also looked at the association between working memory and language, but without looking at the Foxp2 gene. They studied 3 groups of people: monolingual English speakers, deaf American Sign Language speakers, and people who spoke both languages. They had the participants perform various tasks such as being shown a simple picture, for example a letter, and having to remember which direction it was facing. They found that the way that you speak does have an impact on how you remember things, but most of their results seemed to apply to how you remember language.
The idea that language could impact memory was fascinating, but human experiments can’t prove a cause. Schreiweis et al. (2014) did an experiment in mice where they compared mice with the human version of Foxp2 with the wildtype mice. They trained the two groups of mice to a maze and found the human version of the gene did impact the mice’s learning. However, they said that the reason for the change still wasn’t known. Language obviously plays a large role in human cultures; however, it seems like there is still a lot that is unclear about how we are able to talk. It’s crazy how much one gene can impact our ability to communicate with one another. However, I think for now I would settle for learning some other languages instead of understanding language itself.
Works Cited
Castellucci, G. A., Mcginley, M. J., & Mccormick, D. A. (2016). Knockout of Foxp2 disrupts vocal development in mice. Scientific Reports, 6(1), 1-12. doi:10.1038/srep23305
Emmorey, K., Giezen, M. R., Petrich, J., Spurgeon, E., & O’Grady Farnady, L. (2017). The relation between working memory and language comprehension in signers and speakers. Acta psychologica, 177, 69–77. doi:10.1016/j.actpsy.2017.04.014
Lai, C. S., Fisher, S. E., Hurst, J. A., Vargha-Khadem, F., & Monaco, A. P. (2001). A forkhead-domain gene is mutated in a severe speech and language disorder. Nature, 413, 519-523. doi:https://doi.org/10.1038/35097076
Schreiweis, C., Bornschein, U., Burguière, E., Kerimoglu, C., Schreiter, S., Dannemann, M., … Graybiel, A. M. (2014). Humanized Foxp2 accelerates learning by enhancing transitions from declarative to procedural performance. Proceedings of the National Academy of Sciences of the United States of America, 111(39), 14253–14258. doi:10.1073/pnas.1414542111
Schreiweis, C., Irinopoulou, T., Vieth, B., Laddada, L., Oury, F., Burguiere, E., . . . Groszer, M. (2019). Mice carrying a humanized Foxp2 knock-in allele show region-specific shifts of striatal Foxp2 expression levels. Cortex. doi:10.1101/514893
Schulze, K., Vargha-Khadem, F., & Mishkin, M. (2018). Phonological working memory and FOXP2. Neuropsychologia, 108, 147–152. doi:10.1016/j.neuropsychologia.2017.11.027
Photos:
Me on the phone. [Personal photograph taken in Paris apartment]. (2019, June 28).
Taken by Genevieve Wilson
