Especial Skills

An  especial  skill  is  a  unique  case  where  one  very specific variation of a motor skill exhibits a markedly  superior  task  performance  in  comparison  to performances  on  all  other  variations  within  the same skill class. This effect has been clearly demonstrated with basketball set shots from the regulation free-throw (foul) line, as well as with baseball pitches  over  the  regulation  pitching  distance.  To illustrate,  as  one  moves  closer  to  or  farther  from the  basketball  goal  there  is  typically  a  consistent change in the percentage of shots made, with accuracy decreasing linearly as the distance to the target is increased. However, for highly practiced players, the shooting percentage is significantly better than expected  at  exactly  15  feet  (4.57  meters)  straight out  from  the  basket—precisely  at  the  foul  line.  It is  reasoned  that  the  especial  skill  effect  emerges due to the massive amount of practice at that one variation of the skill relative to any other variant. The free-throw line is the only distance from which basketball players regularly and consistently practice set shots. This phenomenon is an example of the  specificity  principle  of  practice  taking  precedence  over  the  generality  principle  of  motor  skill development. It is of particular interest because no current theories of motor control have been able to satisfactorily explain the intricacies of the especial skill phenomenon.

Specificity and Generality of Motor Skills

The notion of specificity of training in motor skill learning and performance is well established. The more  that  conditions  of  the  performance  task match those that were present during practice, the greater the transfer of benefits from training to test performance.  The  same  shot  from  the  same  distance,  with  the  same  ball,  under  the  same  environmental conditions would be a classic example. The more those conditions are dissimilar, the less transfer is seen from training to test performance. It  is  reasoned  that  repeated  training  of  the  same skill under the same conditions builds up a strong memory  representation  for  the  correct  motor action.  Such  a  representation  would  be  at  best only partially correct if any condition for performing the skill was changed.

Specificity,  therefore,  poses  theoretical  problems  because  it  would  be  essentially  impossible for even an expert to practice every possible variation that they might encounter during motor skill challenges.  Under  most  normal  situations,  every motor  skill  execution  is  subject  to  differing  sensorimotor,  contextual,  or  processing  demands. To  explain  flexibility  in  performance,  theories  of generality  (most  prominently,  Schmidt’s  schema theory  of  motor  skill  learning)  suggest  that  performers build up general representations for each class of movement skill. Through practice the skill is  increasingly  capable  of  being  altered  to  match the demands of the task at any particular moment. The  performer  learns  the  common  coordination pattern for the skill class, and then learns the rules by  which  forces  and  timing  might  be  adjusted  to create the skilled action for that situation. As the performer adds experience and practice, improvement is seen across the whole skill class. General motor  program  concepts  can  be  used  to  explain, for example, how a basketball player can be accurate at jump shots from any one of numerous court positions  under  continuously  changing  dynamics of game play.

The  most  interesting  feature  of  especial  skills is  that  they  seem  to  be  an  example  of  specificity emerging within a landscape of generality. All basketball players can shoot set shots (a shot where the feet do not leave the ground) with a general level of  accuracy  commensurate  with  their  experience and  the  physical  difficulty  of  the  shot.  All  baseball  pitchers  can  throw  a  straight  fast-ball-style throw to a target of varying distances, again with accuracy varying according to experience and the physical demands of the throw. When the range of those variations is examined for patterns, theories of  generality  accurately  account  for  performance outcomes.  However,  in  the  particular  instance  of a case that is special to that sport—the one that is practiced  far  beyond  all  others—the  principle  of specificity appears to take precedence.

Explanations

Several theoretical explanations have been offered for  the  especial  skill  effect.  The  visual  context hypothesis  posits  that  certain  consistent  visual information, such as the particular angle of viewing,  may  enhance  perception–action  coordination under the one special condition. This concept received some support from research showing that 15-foot  set  shots  at  angles  different  than  straight out  from  the  basket  did  not  produce  the  effect. However,  other  studies  where  the  visual  context was  significantly  altered  have  nonetheless  demonstrated  especial  skills.  The  learned  parameters explanation suggests that repeated practice of one variation of a skill leads to optimization of movement  parameters,  such  as  force,  speed,  or  release angle,  for  that  specific  instance.  This  hypothesis has  received  some  research  support  when  weight of the ball was altered, but not supported in other research  when  the  ball  and  distance  were  constant but changing the visual angle eliminated the effect (different viewpoint, but identical movement parameters).  Another  hypothesis  is  that  experienced performers might develop a special general motor  program  used  solely  for  the  one  massively practiced  variation  of  the  task.  Hypothetically, this would be evidenced by kinematic information (relative  angles,  velocities,  or  accelerations  of  the involved joints and limbs) that shows unique coordination patterns for the especial skill in comparison to those common to the rest of the skill class. Yet, such kinematic analysis has failed to support this  explanation  with  basketball  shooting.  Lastly, it has been suggested that the phenomenon might be  simply  a  matter  of  confidence,  rather  than some difference in motor control per se. However, research has shown measures of performance efficacy  to  vary  independently  of  the  especial  skill effect.  In  fact,  such  psychological  measures  call into question any cognitive (conscious processing) explanations. In sum, the phenomenon has yet to receive a fully satisfactory theoretical explanation.

Conclusion

The  especial  skill  effect  is  interesting  because  it reflects high levels of practice or expertise, it may serve  as  a  marker  in  the  development  of  motor skill  expertise,  and  it  may  highlight  noncognitive aspects of human motor control.

References:

  1. Breslin, G., Hodges, N. J., Kennedy, R., Hanlon, M., & Williams, A. M. (2010). An especial skill: Support for a learned parameters hypothesis. Acta Psychologica, 134, 55–60.
  2. Keetch, K. M., Lee, T. D., & Schmidt, R. A. (2008). Especial skills: Specificity embedded within generality. Journal of Sport & Exercise Psychology, 30(6), 723–736.
  3. Keetch, K. M., Schmidt, R. A., Lee, T. D., & Young, D. E. (2005). Especial skills: Their emergence with massive amounts of practice. Journal of Experimental Psychology: Human Perception and Performance, 31, 970–978.
  4. Simons, J. P., Wilson, J., Wilson, G., & Theall, S. (2009). Challenges to cognitive bases for an especial motor skill at the regulation baseball pitching distance. Research Quarterly for Exercise and Sport, 80(3), 469–479.

 

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