Brain Processing Speed

Why is processing speed important?

• The speed of performing basic cognitive operations (processing speed) is highly correlated with measures of intelligence.
• Processing speed may affect performance on all higher cognitive tasks
• Decreases in processing speed may be the primary factor underlying cognitive changes that arise with age

Processing Speed

The speed and efficiency of information processing may be fundamental components of intelligence. A number of researchers have demonstrated that performance on various tests of intelligence (e.g. IQ, vocabulary, reasoning ability, and other abstract tests) is correlated with reaction time - even a task as simple as hitting a button when it lights up. This relationship becomes even stronger when the task is slightly more complex, and incorporates elementary cognitive operations such as replacing numbers with letters [1].

In such a task, you may be given the following key:

1 = S
2 = U
3 = O
4 = M
5 = L

You must then replace a string of numbers (e.g. 5 2 4 3 1) with the corresponding letters as quickly as you can; your performance is a measure of your processing speed.

What do these simple, seemingly trivial measures have to do with an entity as broad and complex as intelligence?

Regardless of how you define intelligence, all intelligent thoughts - from analyzing literature to catching a baseball - arise from information processing in the brain, which is mediated by electrical signals traveling through networks of neurons. If these signals travel faster, the brain can process more information in a given amount of time, permitting access to more information when formulating thoughts.

The influence of processing speed on intelligence is particularly pervasive because intellectual activity is hierarchical - higher cognitive activities arise from the coordinated activities of more basic cognitive operations. Reasoning ability, for example, is dependent on the simultaneous availability and manipulation of several sources of information (knowledge, emotions, goals, problem-solving strategies, etc.) The speed of processing this assortment of information may have a potent impact on the eventual intellectual outcome.

Processing speed is crucial even for tasks with a substantial knowledge component, such as Lumosity's Word Bubbles. Your processing speed underlies not only the speed with which you scan your vocabulary for the appropriate words, but may also influence the size of that knowledge base in the first place.

Processing Efficiency

A complementary concept to processing speed is processing efficiency - the efficiency with which we perform basic cognitive operations. By minimizing the brain resources required to conduct a certain cognitive process, you not only expedite that process, but may also allow more information to be processed at one time. Thus by maximizing efficiency, we maximize speed; by maximizing speed, we maximize performance.

In fact, brain imaging studies have shown that people who perform well in complex spatial and memory tasks have lower levels of brain activity in the prefrontal cortex than those who perform more poorly [2]. Further, prefrontal cortex activity decreases with practice and performance improvement [2]. Thus, when you practice and improve at a specific task, from mastering a musical piece to exercising your working memory with Lumosity's Memory Match, your brain becomes faster and more efficient at that task.

The Aging Brain

Some research indicates that processing speed may be the primary factor contributing to age-related changes in cognition [3]. Processing speed declines consistently across the adult lifespan, thus compromising higher cognitive performance. It is possible that by challenging your cognitive abilities and pushing the limits of your processing speed, you may allay these age-related changes. Cognitive science research, including ongoing studies at Lumos Labs, hopes to soon shed light on this possibility.

Although there may not be one single factor underlying "intelligence," processing speed and efficiency are among the most basic and pervasive components. Other factors, including working memory and executive functions, are also likely to be involved.

References

1. Vernon PA, 1983. Speed of information processing and general intelligence. Intelligence 7, 53 - 70.

2. Rypma B, 2006. Neural correlates of cognitive efficiency. NeuroImage 33, 969 - 979.

3. Salthouse TA, 2000. Aging and measures of processing speed. Biological Psychology 54, 35 - 54.