Feedback

Feedback,  or  response-produced  feedback,  consists  of  all  the  information  an  individual  receives as a result of a practice trial of a motor skill, classically divided into two parts—intrinsic and extrinsic. Intrinsic feedback is all of the information one receives  naturally,  such  as  vision,  audition,  and proprioception.  Extrinsic  feedback  is  information  provided  over  and  above  intrinsic  feedback, often by a teacher, coach, or experimenter. In the laboratory, tasks or procedures are used such that the  learner  typically  cannot  detect  how  well  one has met the task goal, and then extrinsic feedback is  manipulated  to  access  its  effects  on  learning. Using this method, augmented feedback has been considered a key variable in the learning process, without  which  learning  does  not  occur  at  all.  It operates to guide the learner to the correct movement  pattern.  The  learner  uses  this  information to  correct  errors  on  subsequent  trials,  until  the desired  skill  level  is  achieved.  Researchers  distinguish between two types of augmented feedback: (1)  knowledge  of  results  (KR),  provided  after  a trial  about  the  movement  outcome  in  relation  to its goal, and (2) knowledge of performance (KP), provided during or after the movement about the nature of the movement pattern. Even though KR and KP may, on occasion, have somewhat different functions in the learning process, both seem to follow the same principles in the way  they  affect skill  learning.  Therefore,  here  we  refer  to  them both as feedback.

Research related to the role of feedback in the learning  of  motor  skills  has  a  relatively  long  history  dating  from  the  early  1900s.  The  view  of the  role  feedback  plays  in  the  learning  process has  changed  throughout  this  time  and  continues to  change.  The  following  sections  describe  how our  understanding  of  the  functions  of  feedback has  developed  from  the  early  views  (1900–1970) to  the  second  phase  (1980–2000)  and  current research (2000–present).

Early Views: 1900–1970

Toward  the  beginning  of  the  previous  century, psychologists saw feedback as having primarily a reinforcing role. In particular, Edward Thorndike’s law  of  effect  stated  that  actions  tended  to  be repeated  if  they  had  pleasant  or  rewarding  consequences  and  avoided  if  they  were  followed  by unpleasant  or  punishing  effects;  thereby,  it  provided  an  account  of  feedback’s  role  in  learning. Much  of  this  early  research  was  guided  by  animal  (occasionally  human)  research  showing,  for example,  that  feedback  delays  and  feedback  frequency  had  negative  and  positive  effects  on  animal  learning,  respectively.  Starting  in  about  the 1950s,  researchers  such  as  Edward  A.  and  Ina M.  Bilodeau  focused  more  on  the  informational role  of  feedback.  Feedback  was  considered  vital for  continued  improvement  with  practice,  and learning  often  did  not  seem  to  occur  without  it. Practice  without  feedback  was  thought  to  allow performance  to  drift  away  from  the  goal  movement  pattern  and  to  weaken  the  memory  representation  of  the  movement.  This  view  is  also reflected  in  Jack  A.  Adams’s  (1971)  closed-loop theory  and  Richard  A.  Schmidt’s  (1975)  schema theory  of  motor  learning.  In  both  theories,  the memory representation of a skill (perceptual trace in  Adams’  theory;  recall  and  recognition  schemata in Schmidt’s theory) was thought to develop as  a  function  of  practice  and  feedback.  That  is, the  greater  the  number  of  trials  with  feedback  a person had performed, the stronger memory representations  were  assumed  to  be,  and  the  better the person’s ability both to perform and to detect and   correct   errors   without   augmented   feedback. According to this view, feedback would be most  effective  if  it  was  provided  frequently  and immediately. In the 1980s, these ideas began to be questioned.

Second Phase: 1980–2000

The second major phase of feedback research was initiated and inspired by an influential review of the feedback  literature  by  Alan  W.  Salmoni,  Richard A.  Schmidt,  and  Charles  B.  Walter  in  1984.  It became clear that many of the earlier studies had shortcomings,  most  notably  a  lack  of  retention or transfer tests to assess the more permanent, or learning,  effects  of  different  feedback  manipulations (e.g., temporal delays, frequencies, precision). Inferring  learning  from  the  performance  of  different groups during the practice phase—that is, under the  influence  of  different  feedback  conditions— became  unacceptable.  Instead,  it  was  argued,  the use of delayed tests under common conditions was crucial  to  assessing  stable  learning  effects  of  various  experimental  variables  including  augmented feedback.  Importantly,  Salmoni  et  al.  provided  a new  conceptual  framework  for  feedback,  which was  formalized  as  the  guidance  hypothesis.  The term referred to the role of feedback in guiding the performer to the correct movement pattern during the learning process. Aside from this positive function of feedback, several potentially negative effects of frequent feedback were proposed as well. In particular,  it  was  hypothesized  that  the  learner,  with very  frequent  feedback,  could  become  dependent on the augmented feedback, thereby neglecting the processing  of  intrinsic  feedback,  which  would  be necessary  for  the  development  of  intrinsic  error detection  and  correction  mechanisms.  Frequent feedback  was  also  assumed  to  result  in  excessive variability  in  performance,  as  it  would  prompt learners to constantly correct even small (perhaps acceptable)  errors  (so-called  maladaptive  short-term  corrections)  that  perhaps  reflected  inherent variability  in  the  motor  system.  The  result  would be the development of a less stable movement representation. The guidance hypothesis therefore suggested a positive influence of frequent, immediate, or  precise  feedback  during  practice  while  it  was present, but it could have a detrimental impact on learning if it were overdone.

Numerous  studies  examining  various  feedback manipulations  provided  support  for  the  guidance idea. These studies typically used feedback manipulations  that  in  some  way  attempted  to  reduce the  detrimental  effects  of  frequent  feedback  by encouraging learners to attend to and utilize their intrinsic feedback. For example, reducing the relative frequency of feedback (reduced percentage of trials after which feedback is provided) was found to enhance learning compared with feedback after every  trial  (100%  feedback).  Also,  summary  or average feedback (feedback for individual trials or as an average, respectively, presented only after a set of trials has been completed) have been shown to  be  more  beneficial  for  learning  than  feedback after every trial. Furthermore, bandwidth feedback (feedback provided only when errors exceed a certain predetermined bandwidth) appears to reduce movement   variability   and   enhance   learning. Finally, delaying feedback, even by a few seconds, and  asking  learners  to  estimate  their  errors  prior to  receiving  feedback  have  been  demonstrated  to yield  more  effective  learning  outcomes  than  providing feedback immediately after the completion of the movement, or concurrently with the execution of a movement.

The  guidance  hypothesis  had  an  important impact on motor learning research. It has contributed  to  a  better  understanding  of  how  feedback influences  performance  and  learning.  Yet,  even though there has been considerable support for the guidance  hypothesis,  this  support  comes  primarily from studies using relatively simple laboratory tasks  or  involving  situations  in  which  learners were  deprived  of  intrinsic  outcome  information and therefore had to rely on the augmented feedback  provided  by  the  experimenter.  In  recent years, it has become clear that the guidance view does  not  provide  a  comprehensive  description  of the  various  functions  of  feedback  in  the  process of (complex) motor skill learning. One important factor that influences the effectiveness of feedback, and  that  qualifies  the  influence  of  the  feedback frequency,  is  the  attentional  focus  induced  by  it. Furthermore,  there  is  converging  evidence  that feedback  has  not  only  an  informational  role,  but that its motivational influence on learning is more important than previously thought.

Current Research: 2000–Present

Feedback and Focus of Attention

Studies  have  consistently  shown  that  feedback or  preperformance  instructions  promoting  an external  focus  of  attention—whereby  attention  is directed  to  the  movement  effect  on  the  environment (e.g., the motion of implement, trajectory of a  ball)—enhances  learning  compared  with  those instructions inducing an internal focus by directing one’s attention to one’s body movements. That is, a  simple  change  in  the  wording  of  feedback  can elicit  an  external  or  internal  focus  and  produce markedly  different  learning  results.  For  example, references  to  the  movement  of  a  golf  club  have been shown to be more effective than those related to the performer’s arm movements. External focus advantages for learning have been found for many different types of motor skills, different age groups, and levels of expertise.

Feedback  that  directs  performers’  attention  to their  own  body  movements  causes  them  to  use  a more conscious mode of control, which constrains the  motor  system  and  interferes  with  automatic control  processes  (the  constrained-action  hypothesis).  In  contrast,  by  adopting  an  external  focus on the intended movement effect, performers use a more automatic type of control that makes use of unconscious, fast, and reflexive processes. Studies have  shown  associations  of  external  attentional foci and various measures of automaticity—including  reduced  attentional  demands,  reduced  premovement  times  (more  efficient  motor  planning), high-frequency (reflexive) movement adjustments, and reduced muscular activity. The result of adopting an external focus is typically enhanced motor performance  and  learning,  as  seen  in  increased movement effectiveness and efficiency.

Not only does feedback promoting an external focus  of  attention  lead  to  more  effective  learning than  feedback  referring  to  body  movements,  but the previously found benefits of a reduced relative to a high-feedback frequency have been found to be reversed. That is, despite the informational content being the same, feedback inducing an external focus  is  most  effective  when  it  is  provided  frequently  (e.g.,  100%),  whereas  feedback  inducing an internal focus is least effective when it is given frequently.  The  interaction  of  feedback  frequency and  attentional  focus,  as  well  as  the  overall  benefits of external relative to internal focus feedback, cannot be explained by extant conceptualizations of feedback (e.g., guidance hypothesis).

One possibility is that at least some of the learning benefits of reduced feedback frequencies found in previous studies were not primarily due to learners’  becoming  dependent  on  frequent  augmented feedback.  Rather,  the  detrimental  effects  of  frequent feedback may have been because of constant internal  focus  reminders,  with  those  (negative) effects  being  attenuated  under  reduced  feedback conditions.  The  interactive  effects  of  feedback frequency  and  attentional  focus  would  be  consistent  with  the  concept  that  experiencing  less  of  a detrimental influence (limited use of an impairing thought  such  as  an  internal  focus  of  attention)  is good, as more of a good thing (frequent reminders to maintain a beneficial external focus) is good.

It has been suggested that the mere mention of body parts like fingers, arms, or feet—within internal focus feedback or instructions—might provoke a  focus  on  the  self  and  ensuing  self-regulatory activity.  Efforts  to  manage  self-related  thoughts and emotions may be so demanding that available attentional  capacity  is  exceeded  and  performance suffers.  In  contrast,  when  feedback  promotes  an external focus, a focus on the self is reduced. The mechanisms  underlying  the  beneficial  effects  of feedback  inducing  an  external  focus  may  not  be dissimilar  to  those  responsible  for  the  learning advantages seen when feedback is given about successful  trials,  or  when  it  suggests  above-average performance relative to a peer group. These types of feedback are discussed next.

Feedback After Successful Trials

Until recently, most researchers were concerned with the informational function of feedback, that is,  its  role  in  providing  information  about  an individual’s performance relative to the task goal. Similarly,  practitioners  often  see  performance feedback  from  this  perspective.  For  instance,  a coach  might  identify  deviations  from  the  optimal technique  in  an  athlete’s  movement  patterns  and suggest corrections. While such feedback plays an important  role  in  any  learning  process,  a  somewhat  underappreciated  aspect  of  feedback  has been its influence on the performer’s motivational state.  Recent  findings  demonstrate  that  positive (or  negative)  feedback  affects  motor  learning  via its motivational influence.

Providing  learners  with  feedback  after  good trials,  as  opposed  to  poor  trials,  has  consistently been  shown  to  result  in  more  effective  learning. In  several  studies,  feedback  about  task  performance  (i.e.,  accuracy  of  throwing  an  object  at  a target) was provided after each of several blocks of practice  trials.  However,  it  was  provided  on  only half of those trials. Unbeknownst to the learners, they  were  given  feedback  either  about  their  most effective trials or about their least accurate trials.

Participants  receiving  feedback  after  their  best trials  demonstrated  more  effective  learning  on  a retention  test.  Thus,  feedback  emphasizing  successful performance, while ignoring less successful attempts,  benefited  learning.  This  effect  has  been linked  to  participants’  enhanced  intrinsic  motivation.  Learners  often  appear  to  have  a  relatively good  feel  for  how  they  perform,  and  instructor feedback indicating errors may not only be superfluous, but it can also irritate learners or heighten concerns about the self that may hamper learning (see below).

Social-Comparative Feedback

Effects of normative feedback—which involves norms such as a peer group’s actual or false average  performance  or  improvement  scores  that are  provided  in  addition  to  the  learner’s  own scores—have  been  examined  in  a  related  line  of research. Normative information is a potent basis for  evaluating  one’s  own  performance.  Favorable comparisons with others typically result in perceptions  of  competence,  increased  self-efficacy,  and motivation,  while  negative  comparisons  have  the opposite  effect.  Importantly,  normative  feedback also  has  differential  effects  on  motor  learning, with  learning  being  enhanced  by  positive  relative to  negative  or  no  normative  feedback.  In  other studies,  bogus  feedback  about  a  peer  group’s average  block-to-block  improvement  resulted  in enhanced learning if it conveyed to the learner that one’s own improvement was greater than average, compared  to  less  than  average.  Thus,  favorable social-comparative  feedback  affects  the  degree  to which task skill is retained.

Positive  normative  feedback  not  only  leads to  improved  outcome  scores  but  also  produces qualitative  differences  in  participants’  control  of movements, such as greater automaticity in movement  control.  It  is  interesting  that  positive  feedback benefits learning compared with both control conditions  without  comparison  information  and negative  normative  feedback  conditions,  which have  similar  effects.  This  suggests  that  the  latter conditions  may  trigger  thoughts  about  the  self (similar  to  feedback  inducing  an  internal  focus), and  ensuing  self-regulatory  activities  in  attempts to manage thoughts and affective responses, which hamper learning of the primary task. In contrast, when  one  is  purportedly  performing  well  (above average),  such  self-related  concerns  and  activities to suppress them might be unnecessary—with the consequence that learning is enhanced.

For ethical reasons, providing false feedback in practical settings would not seem to be appropriate.  However,  the  findings  suggest  feedback  that implies  one  is  an  effective  performer,  or  the  provision of positive, competence-affirming feedback is  critical  for  learning.  While  many  practitioners may intuitively provide such feedback, others may be more focused on correcting errors—with unintended consequences for motivation and learning.

Conclusion

The  view  of  how  feedback  functions  in  the  process of motor skill learning has changed over the past  few  decades.  It  is  now  clear  that  the  role  of feedback  goes  far  beyond  providing  reinforcement  or  guidance  to  the  goal  movement.  There is mounting evidence for the motivational role of feedback—which  not  only  has  an  indirect  effect by increasing the amount of practice—but a direct impact on motor learning. The learning of motor skills  not  only  involves  the  fine-tuning  of  motor programs and movement parameters but requires effective  self-regulation  of  cognitive  and  affective processes,  as  well  as  attentional  focus  demands. A  more  integrated  perspective  on  motivational and  informational  aspects  of  feedback  in  motor learning  research  will  benefit  future  theoretical conceptualizations—and  should  also  yield  practical  motor  skill  learning  insights,  as  neutral  task information is not easily found in the natural social contexts in which movement skills are learned.

References:

  1. Lewthwaite, R., & Wulf, G. (2010). Social-comparative feedback affects motor skill learning. Quarterly Journal of Experimental Psychology, 63, 738–749.
  2. Salmoni, A. W., Schmidt, R. A., & Walter, C. B. (1984). Knowledge of results and motor learning: A review and critical reappraisal. Psychological Bulletin, 95, 355–386.
  3. Schmidt, R. A., & Lee, T. D. (2011). Augmented feedback. In R. A. Schmidt & T. D. Lee (Eds.), Motor control and learning (5th ed., pp. 393–427). Champaign, IL: Human Kinetics
  4. Wulf, G., Chiviacowsky, S., Schiller, E., & Gentilini Ávila, L. T. (2010). Frequent external-focus feedback enhances learning. Frontiers in Psychology, 1, doi: 10.3389/fpsyg.2010.00190
  5. Wulf, G., & Shea, C. H. (2004). Understanding the role of augmented feedback: The good, the bad, and the ugly. In A. M. Williams & N. J. Hodges (Eds.), Skill acquisition in sport: Research, theory and practice (pp. 121–144). London: Routledge.

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