The need for consistency in training, motor learning, technical preparation, and competition is well understood by coaches, athletes, and applied sport psychology (SP) consultants. A number of factors, however, can interfere with athletes’ ability to perform or learn at an appropriate level during training, technical preparation, and competition. The term interference addresses the decrease in performance due to conflicts between different cognitive modules or motor structures within the human action system in a specific environmental constellation.
Interference in Cognitive Learning and Verbal Memory
In the psychological realm, interference is mostly discussed in the context of memory and learning. Interference is addressed as a memory problem that occurs when a learning process is impaired because of an existing, stabilized memory structure or when the activation of consolidated memory representations is affected because of newly learned material. Interference in learning with verbal material has been observed and studied for more than
100 years. Notably, the studies of the German psychologist Georg Elias Müller opened up new perspectives on the topic of memory consolidation. While the studies of Hermann Ebbinghaus (1885) hypothesized forgetting as a function of time, Müller and his student Alfred Pilzecker provided evidence for interference-based memory loss and an interference-based decrease of learning. The term retroactive interference was coined by Müller and describes the phenomenon seen in memory in which newly learned material affects the recall performance of previously learned information. In the opposite direction, proactive interference specifies the phenomena that—depending on the task—previously learned information potentially impairs the learning of new information. Proactive interference is commonly explained as competition between two learning processes that are based on the same cognitive resources. From this point of view, in the case of retroactive interference, the learning of new material influences the consolidation of previously learned material in memory. During proactive interference, consolidated memory information is challenged by new information and inhibits the consolidation of new information in memory. Subsequent studies have found that similarity between the information already stored in memory and the new material affects the learning process and causes interference.
Interference in Motor Learning and Motor Memory
In motor control research, interference is mostly discussed in the context of motor learning. The learning of new skills is based on previously learned sensory-motor patterns that are stored in memory. In general, there are two possible types of interactions between previously learned skills and recently acquired skills: (1) a positive and supportive interaction called transference or (2) a negative interaction called motor interference. Transference was originally addressed by researchers like Nikolai A. Bernstein and is explained as the facilitation of learning as a result of similarity between the required motor pattern and the existing stored pattern, while conversely, motor interference is mostly hypothesized as a negative overlap (i.e., dissimilarity) between the coordination patterns of previously learned motor actions and the structure of a recently acquired skill. From this point of view, learning to crawl could generally facilitate skills like canoeing because of similarities in motor structures (transference), while techniques in sports like tennis and badminton at the same time seem to be related at a surface level but suffer from interference because of significant differences between the relevant sensory-motor structures at a functional level.
Charles H. Shea and other researchers addressed the topic of contextual interference and compared performance during practice of a motor task under randomized and blocked conditions. They found that practicing the task in a blocked order, repetitively and under stable conditions (low contextual interference), resulted in better performance than did practicing the task under randomized conditions (high contextual interference). Interestingly, however, when the performance between random and blocked practice was compared, these and other studies revealed that the random practice group showed superior performance to the blocked practice group. It has been hypothesized that in the short term, reduced interference supports the learning process of simple motor skills, but in the long term, randomized practice supports the establishment of more stable representations in motor memory and leads to better performance compared to the more artificial (low contextual interference) conditions.
Interference Between Motor Control and Verbal Memory
Until now, the phenomenon of interference has been mostly investigated in the area of verbal memory research, isolated from motor learning and vice versa. Interference in the context of motor learning has often been discussed as it relates to memory resources, but it remains unclear whether or not motor planning and verbal working memory share common cognitive resources. In our daily life, verbal memorization and motor action are often performed together—for instance, remembering a list of consumables in a shop while walking along the shop floor and searching for the next product.
In the research area concerning the learning and storage of lists in working memory, the serial position effect is a stable finding. This effect is observed when subjects memorize and recall a sequence of items. Subjects are best able to memorize the items presented at the beginning of the list (primacy effect) and the end of the list (recency effect). This recall paradigm has often been used to learn about interference in verbal memory. Combining a motor task and a verbal memory task could lead to two kinds of interference: cognitive interference or motor interference. In the case of cognitive interference, the memorization of verbal lists would decrease the motor performance; conversely, the opposite would be true in the motor interference scenario. In a variety of tasks such as replanning of motor actions and sequential motor planning in unimanual and bimanual coordination, researchers like Matthias Weigelt, Mark G. Fischman, and Marnie A. Spiegel have investigated in recent years the interference between motor planning and recall performance. In multiple experiments, they found evidence for the so-called motor interference hypothesis—that is, that motor planning reduces memory performance of verbal items because of the challenge between these two entities.
- Logan, S. W., & Fischman, M. G. (2011). The relationship between end-state comfort effects and memory performance in serial and free recall. Acta Psychologica, 137, 292–299.
- Shea, J. B., & Morgan, R. L. (1979). Contextual interference effects on the acquisition, retention, and transfer of a motor skill. Journal of Experimental Psychology: Human Learning & Memory, 5, 179–187.
- Spiegel, M. A., Koester, D., Weigelt, M., & Schack, T. (2012). The costs of changing an intended action: Movement planning, but not execution, interferes with verbal working memory. Neuroscience Letters, 509,82–86.