Information Processing, Memory, and Performance Under Stress: Decision Stage 2

Information Processing and Memory in Movement Control

Learning Objectives

• Describe memory systems and their roles in responding to stimuli.

• Identify limitations that affect each stage of the information processing model.

• Characterize how performance is affected under conditions of increased stress.

Information Processing Model

Stages of Information Processing

The information processing model describes how humans perceive, interpret, and respond to stimuli. It is often conceptualized as a sequence of stages:

• Stimulus Identification: Recognizing and interpreting sensory input.

• Response Selection: Choosing an appropriate response from possible alternatives.

• Movement Programming: Organizing and initiating the chosen response.

Factors influencing the speed of information processing include:

1. Number of stimulus-response alternatives

2. Stimulus-response compatibility

3. Population stereotypes

4. Amount of practice

Anticipation can hasten response speed, while memory can affect the choice of response to stimuli.

Memory Systems

Definition and Components

Memory is the process of retaining information over time. It plays a crucial role in determining responses to stimuli and consists of three main components:

• Short-term sensory store (STSS)

• Short-term memory (STM)

• Long-term memory (LTM)

Stages of Memory

The flow of information through memory systems can be summarized as follows:

• Sensory Memory: Receives sensory input; unattended information is lost.

• Short-Term Memory: Receives attended information; unrehearsed information is lost.

• Long-Term Memory: Receives encoded information from STM; some information may be lost over time.

Maintenance rehearsal helps retain information in STM, while encoding transfers information to LTM. Retrieval brings information from LTM back to STM for use.

Short-Term Sensory Store (STSS)

• Stores large amounts of sensory information (auditory, visual, kinesthetic) for a very brief period.

• Duration: A few seconds for auditory information, approximately 250 milliseconds for visual information.

Example: The Sperling Experiment (1960) demonstrated the brief capacity of visual sensory memory by showing participants a grid of letters for a fraction of a second and testing recall.

Short-Term Memory (STM)

• Temporary holding place for information (e.g., a phone number given verbally).

• Without rehearsal, information is quickly lost (about 30 seconds without attention).

• Rehearsal and attention are key to retaining information in STM and transferring it to LTM.

Long-Term Memory (LTM)

• Stores well-learned information collected over a lifetime; duration is effectively unlimited.

• Consolidation from STM to LTM requires effort and rehearsal.

• Learning is evidenced by successful transfer of information from STM to LTM.

Limitations in Information Processing

Stimulus Identification

• Parallel Processing: Ability to process multiple streams of information simultaneously.

• Inattention Blindness: Failure to notice unexpected stimuli when attention is focused elsewhere.

• Sustained Attention: Ability to maintain focus on relevant stimuli over extended periods; affected by motivation, arousal, fatigue, and environmental factors.

Response Selection

• Controlled Processing (System 2): Slow, effortful, limited capacity, involves language and logic, explicit, serial processing.

• Automatic Processing (System 1): Fast, effortless, high capacity, nonverbal, implicit/associative, parallel processing.

Automatic Processing (System 1)	Examples	Controlled Processing (System 2)	Examples
Fast	Answer to 2+2=?	Slow	Focus attention on clowns at a circus
Effortless	Read words on large billboards	Effort required	Count the number of 'a's on a slide
High capacity	Drive a car on an empty road	Limited capacity	Fill out a tax form
Implicit/Associative	Orient to sudden noise	Logical/Procedural	Wait for starter's pistol in a race
Parallel processing	Detect hostility in a voice	Serial processing	Park in a narrow space

Based on Daniel Kahneman's "Thinking, Fast and Slow" (2011).

Developing Automaticity

• Automaticity is developed through extensive practice, especially under consistent conditions.

• Very fast processing is effective in stable environments but can lead to errors if the environment changes unexpectedly.

Response Selection and Distraction

• Distracted Driving: The main limitation is in response selection, not just movement programming. Phone conversations increase cognitive load, reducing capacity for response selection.

• Walking/Texting: Texting while walking slows walking speed by 20% and increases the likelihood of failing to check for safety (Thompson et al., 2013).

Movement Programming Limitations

• Psychological Refractory Period (PRP): Delay in responding to the second of two closely spaced stimuli. If the second stimulus occurs 50–200 ms after the first, response to the second is delayed by at least 100 ms.

Double Stimulation Paradigm

• Subjects respond to two stimuli presented closely in time (stimulus-onset asynchrony, SOA).

• Delays occur due to interference in programming both responses rapidly.

• When SOA is very short (<40 ms), responses may be grouped and executed simultaneously.

Timing Considerations of the PRP

• If $S_2 < 50$ ms, $S_1$ and $S_2$ are treated simultaneously.

• If $50 < S_2 < 200$ ms, $RT$ for $S_2 = 1\ RT + 100$ ms.

• If $S_2 > 200$ ms, $RT$ for $S_2 = 1\ RT$.

The Information Processing Bottleneck

• When two stimuli are presented in close succession, the second must wait until the response programming stage is clear, causing a bottleneck and increased reaction time for the second response.

Performance Under Conditions of Increased Stress

Arousal and the Inverted-U Principle

• Performance varies with arousal level, following an Inverted-U relationship.

• Low arousal: Wide attentional focus, but may pick up irrelevant information.

• High arousal: Narrowed focus, fewer stimuli detected, slower reaction time.

• Optimal performance occurs at moderate arousal, where focus is balanced.

Equation: The Inverted-U is a conceptual model, not a strict mathematical equation, but can be represented as:

$Performance = -a(Arousal - b)^2 + c$

where $a$, $b$, and $c$ are constants determining the curve's shape and peak.

Variations of the Inverted-U Principle

• Task complexity and individual differences shift the optimal arousal point.

• Complex tasks or individuals who function best under calm conditions have lower optimal arousal.

• Simple tasks or those who thrive under pressure have higher optimal arousal.

Perceptual Narrowing

• Under stress and high arousal, the perceptual field shrinks, focusing attention on the most relevant stimuli.

• This mechanism helps prioritize important information but may exclude other relevant cues.

Choking Under Pressure

• Occurs when performers change their routine or fail to adapt to stress, leading to performance failure.

• Increased rewards can paradoxically decrease performance (inverted-U between performance and reward).

• Attentional Control Theory of Anxiety (Eysenck et al., 2007): Anxiety reduces attention to the current goal in the presence of threatening stimuli.

• Neural mechanisms involve reward and motor preparation structures; high reward can distract from motor preparation.

Summary

• Memory, attention, and perceptual processes all affect performance at different stages of the information processing pipeline for movement control.

• Understanding these processes is essential for optimizing performance, especially under stress.

Next class: Effector control