The Friendly Gene

This past summer, I was fortunate enough to get a scholarship, which funded an NGO internship in Oaxaca, Mexico for four weeks. I worked at a school that taught children of all ages (infants to teenagers) who have been diagnosed with Down syndrome. Because my Spanish was not exactly comprehensible at first, I had a hard time communicating with the students. However, one of the students sensed my timidity with the language and would occasionally strike up a conversation with me, speaking with a tone of support and patience. Every other day, we had an hour designated to a “dance party,” which was sometimes their only form of exercise. I, again, was shy at first, but one of the little boys grabbed me and started spinning and tossing me around the dance floor. When I met many of the children, they greeted me with a big hug and a kiss on the cheek. When one of the students upset another, their classmates would help the teacher in consoling both parties. Throughout my years, I have sat in many classrooms with my peers, and never have I seen so much caring and affection among students, especially a class with such diverse intellectual levels. My experience in Oaxaca has prompted my interest in the disease, specifically what, if anything, having this genetic disorder does to an individual in terms of how he or she expresses and perceives emotional behaviors.

According to Wikipedia.org, Down syndrome, also known as Trisomy 21, is a genetic disorder that is characterized by the existence of either parts of or an entire additional 21st chromosome (1). Such a mutation leads to cognitive disabilities as well as physical abnormalities, especially in height and facial appearance. Convergent with my observations of the students I worked with, people with Down syndrome have a wide range of cognitive propensities. While one student would need help with counting, another had speech and language deficits. A common problem many of the students had was with fine motor control; practice of writing and coloring were the main activities of the day for most of the students. In spite of these differences in adolescence, many studies have shown that at early developmental stages, children with Down syndrome develop much in the same ways as their peers, including the development of emotional interactions (2). Heimann and Tijus note that children with Down syndrome develop in the same course as those without illness, only occurring at a slower pace (3). Then, my question is, how dependent is social development on time compared to other forms of intellect?

In researching this paper, cognition was not my main concern. While there is an undeniable overlap between cognition and behavior, I am more interested in exploring the neurobiological basis for personality development and, in so doing, generating a possible explanation for the “friendly gene.” Localization of functions within the brain is a thoroughly researched scientific premise, and has led to many breakthroughs in science and understanding the brain. By ascribing these behavioral differences to a neurobiological facet, perhaps more can be uncovered about the nature of the disease and, more generally, why we (all humans) behave and respond the way we do.

Williams, Wishart, Pitcairn, & Willis (2005) make note of the role the limbic system, specifically, the amygdala, plays in social development. They cite previous research showing amygdala lesions in primates can lead to “social disinhibition and [these animals] are perceived by other primates as being more approachable” (4). As limbic structures, including the amygdala, have been shown to be reduced in size in individuals with Down syndrome, there is evidence for a possible neurological link here. In a similar vein, Carvajal and Iglesias (2002) discuss the muscular reflexes of infants with Down syndrome, noting that there tends to be difficulties with “turning off” arousal responses. These findings further indicate a presence of emotional disinhibition and perhaps can be seen as a predictor for later life social skills. Other than these few brief mentions, very few articles I found touched directly upon a neurological link to behavioral differences of children with Down syndrome, and even fewer regarded the affection and positivism that I encountered daily.

This was a very surprising, and somewhat disappointing, outcome of my research. Although I did not find much on the biological bases, many of the articles, did touch upon the “friendly gene” as seemingly common knowledge. An article entitled “If people with Down Syndrome ruled the world,” written by Dennis McGuire, the Director of Psychosocial services at the Adult Down Syndrome Center of Park Ridge, Illinois was one such example. The very first item McGuire mentioned of his hypothetical universe was that “affection, hugging, and caring for others would make a big comeback” (5). While my summary of observations was based on a limited number of individuals of a certain socioeconomic status, culture, and age, it seems Mr. McGuire, whose observations are surely based on a pool of individuals with greater variability than my own, also found the most prominent and noteworthy characteristic of his patients to be their unremitting friendliness towards others.

Interestingly, research suggests that these children are aware (perhaps subconsciously) of their social strengths and utilize them to counterbalance their deficiencies in other areas of functioning (6). Though some researchers even credit the mysterious social skills as being the impetus for their studies, few actually examine these findings from a neurobiological standpoint. Instead, many reports of children and infants with Down syndrome focus on imitation behaviors, as well as various tasks of cognitive functioning.

A study done by Fidler, Barrett and Most looked at age differences in smiling frequency and relative personality traits among people with Down syndrome. They note that the literature prior to contemporary coding schemes reported that infants with Down syndrome exhibited less frequent and expressive emotions. However, with the design of coding systems such as Ekman and Friesen’s Facial Action Coding System, which allow for a more objective coding, findings show that, although they display more low-intensity smiles, the number of smiles overall are actually higher than in typically developing children (7). Other research also shows a delay in expression of only negative emotions (6), revealing a possible divergent formation of positive and negative emotions among such individuals. Furthermore, Fidler, et al. (2005), reveals that this amicable behavior, whatever it is attributed to, decreases with age. In parallel, as these adolescents get older, they also display less attention-seeking behaviors, but seem to become more anxious. It is unclear whether any of these things are related to one another or the disease itself. Perhaps the most intriguing aspect of this paper is that it is dependent on time, which seems to have a great effect on an individual’s emotional and affective development.

Infant facial expressions are often observed because emotional interaction in early life has been shown to affect psychological development; such findings can also possibly be applied to later life speech development. As I experienced with many of the students I worked with, verbal communication abilities are often damaged. These students adapted and were able to communicate through gestures and facial expressions. Roberts, Price & Malkin (2007) report that although language does not decline with age, individuals with Down syndrome often display poor speech intelligibility (8). They note many possible attributions, including perception and motor functioning, but with no mention of the limbic system, amygdala, or social skills whatsoever. It seems that the relationship between language development and early-age emotion expression has not been deeply explored.

My frustrations with this paper topic are due to the lack of research regarding neurological ties to the social functioning of this population. There appears to be evidence in the direction toward discovering a biological link, but, in order to do so, the research must take every aspect of development into account: social, affective, cognitive, muscular, and neurological functioning, perhaps revealing a link to the speech centers. This, I do not deny, is not an easy task, but there must be something to be said for this phenomenon. Why is it that individuals with other chromosomal-related diseases, like Fragile X syndrome, do not share this behavioral phenotype? In fact, men with Fragile X are said to exhibit shyness (9). Personally, I like the idea that this is something that develops as a compensatory mechanism. Fidler and Nadel (2007) even go so far as to say some individuals develop an “over-reliance on social strategies” when dealing with cognitive tasks that require instrumental thinking (10). Perhaps, then a positive feedback loop develops and the more these children utilize their social disinhibitions (so long as they are getting positive responses), they begin to rely on these skills to solve a problem. Thus, they do not need to rely as much on other routes of thought, and the weaker these skills become. Of course, this still disregards the need (or desire?) for a link to the brain. The amygdala-lesion theory is intriguing, but the amygdala is a largely complex structure with many functions other than social development. Thus, there is much more to be said and discovered on the topic, but with persistence and patience, great strides can be made towards one day truly understanding the brain.

References

1) Wikipedia.org

http://en.wikipedia.org/wiki/Down_syndrome

2) Carvajal, Fernando & Iglesias, Jaime (2002). Face-to-face emotion interaction studies in Down syndrome infants. International Journal of Behavioral Development, 26 (2), 104-112.

http://jbd.sagepub.com/cgi/content/abstract/26/2/104

3) Heimann, Mikael & Tijus, Tomas. Early imitation among children with autism and children with Down syndrome: different or similar developmental pathways?

http://www.isisweb.org/ICIS2000Program/web_pages/group322.html

4) Williams, Katie; Wishart, Jennifer; Pitcairn, Tom; & Willis, Diane (2005). Emotion recognition by children with Down syndrome: Investigation of specific impairments and error patterns. American Journal on Mental Retardation, 110 (5), 378-392.

http://aaidd.allenpress.com/aamronline/?request=get-document&doi=10.1352%2F0895-8017(2005)110%5B378:ERBCWD%5D2.0.CO%3B2

5) McGuire, Dennis. If people with Down syndrome ruled the world. From NADS.org:

http://www.nads.org/pages_new/news/ruletheworld.html

6) Cicchetti, Dante & Beeghly, Marjorie. Children With Down Syndrome: A Developmental Perspective. Cambridge University Press. Preview Available at Google Books:

http://books.google.com/books?hl=en&id=Io9iUTxBWaIC&dq=cicchetti+beeghly+down+syndrome&printsec=frontcover&source=web&ots=kKIkin-qpw&sig=_IMGD5uTcP26u4b0omn9oAZAWkY#PPT1,M1

7) Fidler, Deborah; Caplovitz Barrett, Karen; & Most, David (2005). Age-related differences in smiling and personality in Down syndrome. Journal of Developmental and Physical Disabilities, 17 (3), 263-280.

http://www.springerlink.com/content/jv795t4482417739/

8) Roberts, Joanne; Price, Johanna; & Malkin, Cheryl (2007). Language and communication development in Down syndrome. Mental Retardation and Development Disabilities Research Reviews, 13, 26-35.

http://www3.interscience.wiley.com/cgi-bin/abstract/114129930/ABSTRACT

9) Wikipedia.org

http://en.wikipedia.org/wiki/Fragile_X

10) Fidler, Deborah & Nadel, Lynn (2007). Education and children with Down syndrome: Neuroscience, development and intervention. Mental Retardation and Development Disabilities Research Reviews, 13, 262-271

http://www3.interscience.wiley.com/cgi-bin/abstract/116325669/ABSTRACT