Have you ever struggled to remember a new phone number because the old one keeps coming to mind? Or tried to learn a new language but keep making grammar mistakes based on your native language? These examples highlight the challenges posed by interference effects in our cognitive processes.
Interference effects can slow down and reduce the accuracy of our mental and physical tasks, impacting everything from learning new information to interacting with technology or developing skill sets during simulator training. While some types of interference will impact task performance immediately, others influence how we learn over time. Just as inattentional blindness can cause us to miss obvious stimuli in our environment, interference effects illustrate how conflicting cognitive processes can impede our performance and learning. In this blog, we will explore the different types of interference effects—Stroop, Garner, Proactive, and Retroactive—discuss their mechanisms, and provide strategies to mitigate their impact for better cognitive performance.
What Are Interference Effects?
Interference effects occur when different cognitive processes conflict, leading to slower and less accurate performance on tasks. This often happens because our brains have limited attentional resources. When multiple stimuli or tasks compete for these resources, it can cause errors and slow down our processing speed. Some types of interference affect our immediate task performance, such as Stroop and Garner interference, while others, like proactive and retroactive interference, affect our ability to learn over time.
Understanding Performance vs. Learning
Understanding the difference between performance and learning is crucial in this context. Performance refers to the execution of a skill at a specific time and in a specific situation, which is observable and measurable during training or task execution. Learning, on the other hand, is a relatively permanent change in the capability to execute a skill, which can only be inferred and is typically assessed during a delayed retention period after the training. While performance can be observed immediately, learning outcomes are better understood over a longer period.
Types of Interference Effects
Stroop Interference
Stroop interference occurs when an irrelevant aspect of a stimulus triggers a mental process that interferes with relevant processes. A classic example is the Stroop test, where color words printed in incongruent ink colors (e.g., the word “red” printed in blue ink) cause delays in naming the ink color. The automatic process of reading interferes with the task of naming the color. Research indicates that the anterior cingulate cortex (ACC) plays a key role in detecting and resolving conflicts between competing cognitive processes. This phenomenon is crucial in user interface design, where text color should match the function to avoid confusion. For further reading, see MacLeod, 2015 and Huster et al., 2009.
Garner Interference
Garner interference occurs when an irrelevant aspect of a stimulus triggers a mental process that interferes with relevant processes. For example, the time it takes to name shapes is greater when they are placed next to shapes that change with each presentation. Distraction by irrelevant changes requires additional cognitive resources to filter out, increasing cognitive load. To minimize such interference, design elements should avoid unnecessary variations that distract from the main task. Relevant research can be found in Duncan & Humphreys, 1989 and Treisman & Gelade, 1980.
Proactive Interference
Proactive interference occurs when existing memories interfere with learning new information. A common example is the difficulty in learning a new language due to interference from one’s native language. Previously learned information competes with new information during the encoding process. Gradually introducing new material in learning environments can help mitigate proactive interference. For a deeper understanding, see Underwood,1957 and Anderson & Neely, 1996.
Retroactive Interference
Retroactive interference happens when learning new information interferes with existing memories. For instance, learning a new phone number can cause difficulties in recalling an old one. New information overwrites or disrupts the retrieval of older information. Frequent review of previously learned material helps in retaining older information. Further insights can be found in Barnes & Underwood, 1959 and Wixted, 2004.
Conclusion
Interference effects highlight the complexities and limitations of human cognition. By understanding how different types of interference—Stroop, Garner, Proactive, and Retroactive—affect our mental processes, we can develop strategies to minimize their impact. Effective design, appropriate training, and thoughtful application of cognitive principles can significantly enhance our ability to perform tasks accurately and efficiently.
Additionally, contextual interference, which involves varying practice conditions to improve learning and performance, is another critical type of interference that should be considered, particularly in motor skills. You can read more about the contextual interference effect in this blog. Recognizing and mitigating interference effects can lead to better outcomes in various fields, particularly in high-stakes environments like healthcare. Apply these strategies in your design and learning processes to enhance cognitive performance and achieve more effective results.
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