LESSON 6: Attention – Selective, Divided, and Executive Control

Bottleneck Model

Broadbent used this metaphor to describe how the human brain can only process a limited amount of information at once.

Limited capacity

Human attention cannot process all incoming stimuli simultaneously.

Filter mechanism

Information is selected based on physical properties (pitch, loudness, location).

Early selection

Only the chosen channel is processed for meaning; unattended inputs are blocked, held, or discarded. Purpose: Prevents overload by prioritizing what seems most relevant.

Sensory Input

The raw information we receive from our environment through our senses (sight, sound, touch, smell, taste).

Limited Capacity

The idea that human attention cannot process all incoming sensory inputs at the same time.

Late Selection

A theory suggesting that all inputs are initially processed for meaning, but the final selection of what we attend to happens later in the process.

Overload Prevention

The purpose of the bottleneck filter — to protect the brain from being overwhelmed by too much information at once.

Anne Treisman

Proponent of Feature Integration Theory

Feature Integration Theory

That attention is the glue that binds separate features—like color, shape, and motion—into a single, coherent perception.

Daniel Kahnman

Proponent if Capacity Model

Capacity Model

Treats attention as a finite mental resource—like energy that must be distributed wisely among tasks. This approach is justified by both psychological evidence and everyday experience

Limited Capacity Principle

• The brain cannot process all stimuli simultaneously.

• Attention acts as a regulator, ensuring that mental energy is directed where it’s most needed

Dynamic Allocation

attention is not fixed — it’s dynamically distributed based on two interacting factors

Two interacting factors in dynamic allocation

Arousal Level and Task Demands

Arousal level: Too low

You feel drowsy or distracted; attention is weak.

Arousal Level: Optimal

You’re alert and focused; attention is balanced.

Arousal level: Too high

You become anxious or overwhelmed; attention becomes unstable. This means your mental energy must be at the right level to perform efficiently.

Low demands

Simple tasks (walking, listening to music) require little attention.

High demands

Complex tasks (studying, driving) consume more mental resources. When demands exceed available capacity, performance drops.

Divided attention

Splitting focus between two or more tasks.

The frontal lobe

• Manages task-switching and executive control.

  • Acts like the brain’s “manager,” deciding which task gets priority and when to switch.

• In divided attention, it tries to juggle multiple tasks (e.g., listening while writing).

• This constant switching consumes cognitive resources, which explains why performance drops when tasks compete.

The anterior cingulate cortex

• Monitors conflicts between tasks.

  • Detects when two tasks interfere with each other (e.g., reading while someone talks).

  • It signals the brain to resolve the conflict, but this monitoring itself uses up attention.

  • That’s why multitasking often feels mentally exhausting — it is constantly flagging overlaps.