Information Processing and Motor Control

Exam Tip: Remember that because human attention is limited and often serial, "divided attention" usually results in a decrease in performance for both tasks being performed.

Memory Systems and Retrieval

Once information passes through the filter of attention, it must be stored. Memory is defined as the retention and subsequent retrieval of information. There are two primary ways we retrieve what we have stored: recognition (identifying something previously encountered) and recall (actively retrieving information from memory).

Memory Structures

The architecture of memory is divided into two main components:

• Short-term (working) memory: This handles immediate information. In children, abilities in this area improve through adolescence as they develop better coding and searching strategies.
• Long-term memory: This is the permanent storehouse of information.

Types of Memory

We can further categorize memory based on how consciously we access it:

• Explicit Memory (Declarative): This involves the conscious, deliberate recall of facts and events. For example, remembering the rules of a sport is an explicit memory task. This type of memory improves significantly during childhood as the hippocampus develops.
• Implicit Memory: This refers to memory that occurs without conscious, deliberate recall. This is critically linked to motor learning—the "muscle memory" that allows you to ride a bike or type on a keyboard without thinking about every individual movement.

Processing Speed and Motor Execution

The ultimate goal of the information-processing system is to produce movement. Processing speed is the time required for the brain to receive, interpret, and respond to information. In the context of motor control, we measure this through two distinct metrics:

1. Reaction Time: The interval between the onset of a stimulus (like a starting gun) and the initiation of a response (the first muscle contraction). This serves as a basic measure of processing speed.
2. Movement Time: The time taken to actually execute the physical movement once the response has already begun.

The Laws of Movement

To understand how speed and accuracy interact, we look to two fundamental principles:

Fitt’s Law and the Speed-Accuracy Tradeoff In motor control, there is an inherent tension between how fast you move and how precise you are. This is known as the speed-accuracy tradeoff. If you attempt to move faster, your accuracy typically decreases; if you want higher precision, you must slow down. Fitt's Law mathematically describes this relationship.

Hick’s Law Hick's Law addresses the complexity of the decision-making process. It states that as the information load or the number of possible choices increases, the processing time (specifically reaction time) also increases.

Worked Example: Imagine a tennis player.

• Reaction Time: The time from seeing the opponent hit the ball to the player's muscles starting to move.
• Movement Time: The time from the start of the swing to the racket hitting the ball.
• Hick's Law Application: If the opponent hits a standard serve, the player's reaction time is fast. If the opponent uses a complex variety of spins and serves, the player's reaction time increases because the "information load" is higher.