Nature and Nurture

Conceptualizations  of  the  factors  affecting  skill acquisition  and  the  demonstration  of  expertise generally  reflect  qualities  associated  with  biological factors such as genes (nature) or those related to  environmental  or  experiential  factors  such  as training and coaching (nurture).

Historical Background

Although  the  conceptualization  of  the  nature versus  nurture  debate  can  be  traced  at  least  to Platonic  and  Aristotelian  discussions  of  human nature  in  ancient  Greece,  more  contemporary discussions  usually  start  with  Francis  Galton’s 1874  English  Men  of  Science:  Their  Nature  and Their  Nurture;  Galton  may  have  taken  his  title from  Shakespeare’s  The  Tempest  (Act  4.1)—“a born  devil,  on  whose  nature  Nurture  can  never stick.”  Galton’s  approach  was  very  clearly  influenced by the work of his cousin, Charles Darwin, and  focused  on  the  stable,  biological  factors  that are  transferred  from  one  generation  to  the  next (known  as  heritability,  the  proportion  of  variance in a population attributed to genetic factors). Alternately, some researchers see human development  as  starting  from  a  blank  slate  (tabula  rasa) with no innate traits or characteristics, and that all forms of learning and behavior result from interactions with our environment. This extreme nurture viewpoint is demonstrated by behaviorist John B. Watson’s famous boast:

Give me a dozen healthy infants . . . and my own specified   world   to   bring   them   up   in,   and   I’ll guarantee to take any one at random and train him to  become  any  type  of  specialist  I  might  select— doctor, lawyer, artist . . . regardless of his talents, penchants, tendencies, abilities, vocations and race of his ancestors. (1998, p. 82)

The  history  of  this  debate  in  psychology  is marked by radical shifts in opinion, usually driven by  social  and  cultural  factors.  For  example,  after World  War  II,  political  and  intellectual  thought changed to reflect the perspective that differences between  individuals  resulted  from  opportunities and experience. This perspective was deemed more socially  acceptable  than  ideologies  that  sought  to separate  individuals  on  the  basis  of  biology  since this  latter  approach  was  so  strongly  associate with Nazism. A similar social change occurred in 2001, after the publication of the human genome when researchers advanced positions based on the ultimate power of biology for understanding interindividual differences. James Watson, codiscoverer of the structure of DNA and a key developer of the Human Genome Project, said, “We used to think our future was in the stars. Now we know it is in our genes.” More recently, we have seen a change in direction, at least in some fields of psychology and education, as researchers focus on the solitary role of deliberate practice (a nurture-related variable) in creating the expert performer. The role of nature and nurture factors in sport and exercise is reviewed as follows.

Nature Determinants

Nature  determinants  focus  on  stable  biological factors.  Each  person  is  the  product  of  a  unique sequence  of  genetic  material,  half  coming  from one’s mother and the other half from one’s father in  the  form  of  chromosomes.  This  genetic  material  (DNA,  or  deoxyribonucleic  acid)  is  made  up of a combination of four chemical bases—adenine, thymine, guanine, and cytosine (abbreviated A, T, G, and C), which group together into base pairs (A with T and G with C) and links of these base pairs form discrete sequences of DNA called genes. Each gene corresponds to a specific biological outcome; for example, the COL5A1 gene found in humans on chromosome 9, encodes for a specific collagen protein  relevant  to  flexibility  of  ligaments  and tendons. Within the normal population, there are multiple variants of this gene, which produces the variability seen across a population. This variability  results  from  different  alleles  (a  variant  in  the gene  sequence)  and  is  known  as  a  polymorphism (the  occurrence  of  many  forms  of  a  given  gene). Your  individual  collection  of  genes  (estimated  to be  between  20,000  and  25,000  genes  containing about  3  billion  base  pairs)  is  referred  to  as  your genotype.

There is strong evidence that genotypic features affect  health,  fitness,  and  performance  outcomes. For  instance,  using  both  heritability  statistics and  individual  genetic  markers,  data  from  the HERITAGE  Family  Study  have  shown  that  specific genotypes are better suited for aerobic activities.  Since  the  publication  of  the  human  genome in  2001,  hundreds  of  genes  and  polymorphisms related either directly or indirectly to performance and fitness phenotypes have been identified. Some of  these  candidates  include  the  COL5A1  gene mentioned earlier as well as genes for the cardiovascular  catalyst  angiotensin-converting  enzyme (ACE), and the skeletal muscle protein alpha-actin type 3 (ACTN3), which have had varying degrees of  success  explaining  interindividual  differences in  performance.  Moreover,  despite  the  considerable  attention  given  to  the  search  for  individual genes  responsible  for  athletic  achievement,  the manifestation  of  any  biological  or  psychological effect is likely the result of a complex interaction of thousands of genes, and as a result, identification of individual genes that account for meaningful variation in sportor exercise-related outcomes is extremely difficult.

Nurture Determinants

Few  researchers  dispute  the  important  role  of the  environment  (nurture)  in  determining  health and  fitness  related  outcomes.  In  the  social  and behavioral sciences, few relationships are as robust as the one between practice and achievement. The power  law  of  practice  is  a  mathematical  model of  this  relationship  whereby  improvements  occur quite  rapidly  at  the  onset  of  practice  but  become more  difficult  to  obtain  (requiring  greater  practice) as the performer becomes more skillful. This law (or derivations of it) has been widely applied and is proposed to describe human learning of perceptual–motor skills ranging from learning to roll cigars and reading text upside down, to scoring a layup in basketball or hitting a bull’s-eye in darts.

Studies  from  the  field  of  human  expertise and  expert  performance  have  also  supported the  relationship  between  training  and  ultimate achievement.  For  example,  the  proposition  of deliberate  practice,  developed  by  psychologist Anders  Ericsson,  is  based  on  the  notion  that proper  training  (deliberate  practice)  performed at  the  appropriate  period  of  biological  and  cognitive  development  is  a  necessity  for  the  acquisition of expertise in any domain, including sports. Ericsson’s  (1996)  extensive  work  on  the  acquisition  of  expert  performance  has  shown  that  an individual’s  level  of  performance  in  any  domain is  determined  by  the  amount  of  time  spent  performing “a well- defined task with an appropriate difficulty level for the particular individual, informative  feedback,  and  opportunities  for  repetition and correction of errors” (pp. 20–21).

In addition to the primacy of practice or training  to  explaining  human  achievement  in  sport, other  environmental  factors  are  important.  For example, Joseph Baker and Sean Horton proposed a  number  of  secondary  factors  that  facilitate  the acquisition  of  appropriate  training  and  practice, including  obvious  factors  like  access  to  proper coaches and having supportive parents, as well as less obvious factors, such as growing up in talent hotbeds or being born at the right time of year to take advantage of relative age effects.

Interactions of Nature and Nurture

Although  discussions  in  sport  and  exercise  psychology generally focus on nurture-related factors, it  is  clear  that  most  health,  fitness,  and  performance  outcomes  result  from  both  nature  and nurture.  Perhaps  the  clearest  example  of  nature– nurture interaction (or gene x environment interaction)  comes  from  medicine  and  relates  to  the condition  phenylketonuria  (PKU).  This  genetic disorder  causes  brain  damage  and  progressive mental  retardation  in  100%  of  individuals  with the  genetic  marker  for  this  condition;  however, PKU  is  highly  treatable  if  individuals  eliminate phenylalanine  from  their  diet.  In  this  example, a  quality  with  perfect  heritability  (PKU)  is  not expressed because of an environmental manipulation (dietary change). Importantly, the DNA that causes this condition remains unchanged; the individual simply does not express the PKU condition. Although  examinations  of  gene  environment interactions  are  rarely  examined  in  sport  and exercise psychology, it is likely that similar effects occur. For example, the COL5A1 gene, by affecting  injury  risk,  likely  constrains  the  amount  and intensity  of  training  individuals  in  certain  sports (e.g.,  sprinting)  can  perform  throughout  their development.

Modern Conceptualizations

Most   evolutionary   psychologists   and   geneticists  have  moved  away  from  the  nature–nurture conceptualization  on  the  basis  that  it  is  too  limited  to  explain  the  nuances  of  the  interactions that  occur  throughout  human  development.  As  a result,  researchers  have  developed  more  comprehensive  models  of  these  relationships.  For  example, dynamic systems theory presumes that human behavior  is  best  seen  as  the  interaction  of  different  systems  (biologic,  social,  psychological)  with development  being  emergent,  nonlinear  and  multi-determined.  From  this  theoretical  standpoint, genetic  diversity  is  responsible  for  some  variability  in  the  differences  between  individuals  in  how they  respond  to  different  experiences  and  beneficial changes like performance adaptations happen when  there  is  a  favorable  interaction  with  important environmental constraints. For example, there is growing consensus in the study of human obesity that  the  contribution  of  genetic  factors  is  exacerbated  in  North  American  environments  that  are high in caloric availability.

In evolutionary psychology, focus is on the differences  between  obligate  and  facultative  adaptations. Obligate adaptations occur no matter what environment  a  person  experiences  while  facultative  adaptations  are  sensitive  to  environmental variations.  The  fact  that  sugar  tastes  sweet  and lemons taste sour (obligate adaptations) does not change if they are experienced in a different environment.  Other,  more  complex  qualities  reflect facultative  adaptations,  similar  to  if–then  statements.  The  attachment  style  one  has  as  an  adult (i.e.,  how  you  approach  long-term  relationships), for  example,  is  affected  by  the  level  of  trust  one had in their caregivers as a child. If a young person often  has  promises  broken  by  a  parent,  this  may lead to trust issues as an adult. Given that obligate adaptations do not typically vary across development, scientists in this area focus on how different developmental experiences affect the expression of facultative adaptations.

Another  important  element  in  this  discussion relates  to  the  emerging  concept  of  epigenetics, which shows that changes in gene expression can occur  through  modifications  to  the  genome  that do  not  involve  a  change  in  the  underlying  DNA sequence. This field of research suggests that experiences provide a stimulus for genes to be turned on or off. For example, a Swedish study showed that a single hard workout resulted in genes involved in energy metabolism being switched on, with harder work resulting in a stronger effect.

Collectively,  research  on  the  effects  of  biology and  experience  on  human  behavior  and  performance  indicate  that  the  nature  versus  nurture dichotomy is ineffective for explaining the dynamics of how these factors interact and the complexity of this process.

References:

  1. Baker, J., & Davids, K. W. (2007). Sound and fury, signifying nothing? Future directions in the naturenurture debate. International Journal of Sport Psychology, 38, 135–143.
  2. Baker, J., & Horton, S. (2004). A review of primary and secondary influences on sport expertise. High Ability Studies, 15, 211–228.
  3. Carlsson, S., Andersson, T., Lichtenstein, P., Michaëlsson, K., & Ahlbom, A. (2006). Genetic effects on physical activity: Results from the Swedish twin registry. Medicine and Science in Sports and Exercise, 38, 1396–1401.
  4. Davids, K. W., & Baker, J. (2007). Genes, environment and sport performance: Why the nature-nurture dualism is no longer relevant. Sports Medicine, 37, 961–980.
  5. Davids, K. W., Button, C., & Bennett, S. J. (2008). Dynamics of skill acquisition: A constraints-led approach. Champaign, IL: Human Kinetics.
  1. Ericsson, K. A. (Ed.). (1996). The road to excellence. The acquisition of expert performance in the arts and sciences, sports and games. Mahwah, NJ: Erlbaum.
  2. Ericsson, K. A. (2007). Deliberate practice and the modifiability of body and mind: Toward a science of the structure and acquisition of expert and elite performance. International Journal of Sport Psychology, 38, 4–34.
  3. Klissouras, V. Geladas, N., & Koskolou, M. (2007). Nature prevails over nurture. International Journal of Sport Psychology, 38, 35–67.
  4. Pinker, S. J. (2002). The blank slate: The modern denial of human nature. New York: Viking Press.
  5. Watson, J. B. (1998). Behaviorism. New Brunswick, NJ: Transaction. (Original work published 1924)

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