When looking at that title, you might think, “Wow, that’s a lot of words I don’t know about.” But don’t sweat it because once we cover the terminology, everything else is easy to understand.
The n-back task is a psychology and neuroscience practice that helps us partly assess the working memory and its capacity. This task is a good companion tool when combined with valid cognitive tests. Compared to neurotypical individuals, individuals with dementia have significantly lower working memory capacity. In this article, we will briefly go over the concept of working memory, explain the process of the N-Back task and whether it can help diagnose dementia.
What Is Working Memory and How Does It Work?
Working memory is a cognitive system possessing a limited capacity that can store information temporarily. This system is essential for reasoning and directing our decision-making and behaviour.
Working memory tasks include keeping someone’s address in mind while listening to instructions on how to get there. Or understanding the meaning of a story while listening to the sequence of events. Working memory helps you hold on to data long enough to use it.
Several developmental disabilities and intellectual disorders can cause memory problems, including ADHD, autism, Down syndrome, Rett syndrome, and developmental language disorder. In addition to affecting long-term and visual memory, these conditions often disrupt working memory as well.
N-Back Task: An Assessment Tool in Cognitive Tests
Often used as an assessment in psychology and cognitive neuroscience, the n-back task measures a part of working memory and working memory capacity. Wayne Kirchner invented the n-back in 1958. In addition to improving working memory and working memory capacity, some scientists believe that N-Back improves fluid intelligence as well.
How Does an N-Back Task Work and Can It Really Help Diagnose Dementia?
Typically, participants need to observe a series of visual cues and react whenever a visual cue appears that is the same as the prior one shown in N trials previously.
In other words, the n-back task examines working memory by involving memory functions. Potentially an efficient way to detect early dementia of the Alzheimer’s type.
Depending on the N, there can be one trial, two, three, or more. It is harder to complete a task if the number is higher. In addition to N, the speed of presentation and the size of the visual cue set appear to affect performance.
To be more clear, let’s say you watch a sequence of letters or numbers while taking a 2-Back test. The letter M appears and then reappears two letters forward. You need to react to the letter M because, in this task, N equals 2, and the letter M is the same as the letter you saw two trials ago. This being said, as the number of “N” increases, the task will become more difficult.
N-back tasks have become increasingly popular for dementia-related disorders testing and training, which has led to much controversy.
What Are the Effects of the N-Back Task on Our Working Memory?
Working memory is measured by the n-back task in several ways. There is no clear indication of which aspect of working memory is analyzed. There is some evidence that the N-back is not a pure measure of working memory but that it may be able to detect subtle differences in cognitive abilities.
On the one hand, some studies discovered that the task produces medium-sized to strong ties when compared with compound measures of complex memory span, when calculating average scores across multiple n-back task versions or when using recall versions of the task. Other research found that the n-back task mainly connects with measures of simple memory span.
What Are Some Other Ways to Administer the N-Back Task?
Two-back and three-back tasks are common versions in which participants respond to visual cues presented two or three trials earlier. As control conditions, zero-back and one-back versions are also common practices.
The 2003 paper by Susanne Jaeggi also proposes a dual n-back task. Two independent sequences are presented simultaneously in a dual-task paradigm, typically one auditory and one visual.
There are also online dual-n-back tasks available on several smartphone apps and websites.
What Is the Use of This Task in Tutoring and Rehabilitation?
N-backs are now available outside of laboratory settings, clinical settings, and medical settings. This task is used by tutoring companies in conjunction with other cognitive tasks to allegedly improve their clients’ fluid intelligence. Tutoring companies and psychologists also use the task to improve the focus of people with ADHD and rehabilitate those who suffer traumatic brain injuries or dementia. They measure different results based on each situation.
For example, increased reaction time with poor working memory threshold occurs objectively in individuals with dementia compared to non-neurodivergent people.
Experiments have shown that practicing this task can improve focus for up to eight months following training.
Is the N-Back Task Valid?
It remains a matter of debate whether training on the n-back or similar tasks can improve performance long-term. Or even if the effects of training are transient, and whether the effects of training generalize to general cognitive processing, such as fluid intelligence. Researchers question the transferability of memory training, despite the claims of commercial providers.
In fact, in 2012, researchers found that dual n-back training did not improve fluid intelligence in two studies. The study concluded that there was no transfer of training’s effects to other cognitive abilities. However, based on a meta-analysis of twenty studies, n-back training improved general fluid intelligence by an average of three to four points of IQ, according to a 2014 publication. As you can imagine by now, a critical review of this meta-analysis took place in January 2015 due to the small-study effects.
In a more recent and extended meta-analysis in January 2017, researchers found that n-back training improves unrelated n-back training tasks but not unrelated working memory.
Researchers must carefully interpret the results derived from n-back tasks, particularly when the results vary based on reaction times or accuracy. Moreover, researchers should distinguish between errors and oversight errors in addition to reporting accuracy.
Since the n-back task lacks clear associations with other working memory tasks, in-depth analyses of n-back task performance may help reveal more about its validity, neural connections, and use in applied neuropsychology.