PSY2014/L01/01^ Mon Oct 07 09:05:00 BST 2024

Key Questions
- Can attention affect perception?
- How much of our conscious experience captures our perception?
- What are the neural mechanisms controlling attention and perception?

Attention is crucial for conscious perception.
Example: Invisible Gorilla experiment demonstrates how individuals can miss significant changes when not attending.
Magicians exploit attention to distract and perform tricks unnoticed.

Attention is the process by which the mind selects from various stimuli that interact with our senses.
- This applies to visual, auditory, and somatosensory domains.
Conscious experience only captures what is attended to.

Coined in 1953, describing the ability to focus on a single conversation at a noisy party while filtering out others.
It represents a form of divided attention that demonstrates how we can selectively attend.

Early vs. Late Selection Models
- Early Selection Theory:
  - Attention filters information in the earliest processing stages (e.g., sensory registration).
  - The sheer volume of sensory input necessitates an early filter to manage processing capacity.
- Late Selection Theory:
  - Attention affects perception at later processing stages (e.g., semantic analysis).
  - Even unattended stimuli can influence conscious perception, demonstrated by name recognition in conversations.

Early selection believed due to high capacity of sensory inputs (e.g., pet-vision of cats).
Electroencephalography studies show response modulation in early auditory evoked potentials for attended sounds.

Tasks revealing that salient info, such as ones own name, can be processed even when attention is directed elsewhere.
The combination of both theories suggests attention selects at both early and late stages.

Exogenous Attention
- Automatic, driven by external stimuli (e.g., sudden noise captures focus).
- Known as bottom-up attention.
Endogenous Attention
- Voluntary, sustained attention where focus can be maintained based on internal goals.
- Known as top-down attention.
Inhibition of Return
- Mechanism which prevents attentional resources from returning to a previously attended location if stimulus is irrelevant.

Feature-selective Attention
- Focusing on specific features (e.g., color, shape) within a scene prior to spatial attention.
- Example: Searching for a red object among green ones is facilitated by color attention.
Object-Based Attention
- Attention can spread automatically across an object, enhancing processing of features associated with that object.
- Demonstrated through the faster identification of changes on the same object compared to different objects.

Receptive fields of specific neurons in primates demonstrate the impact of attention on firing rates according to what stimuli is prioritized.
Use of retinotopic mapping allows for localized examination of visual processing regions in the brain for attention studies. Imaging Studies (e.g., fMRI) Studies use flickering checkerboard stimuli to investigate early selection in visual areas, showing that attention modulates activation in specific cortical areas like V1, V2, and V4. V4 is particularly involved in processing color and form, and attention enhances neuronal responses in this area, indicating its role in feature-based attention. When attention is directed towards color or shape, the increased neural activity in V4 reflects the enhanced perception of these features. Summary Attention facilitates perception by selectively filtering information. Different forms of attention (exogenous, endogenous, spatial, feature-based, and object-based) interact and influence perceived reality. Neural mechanisms underpinning attention reveal complex interactions of cognitive processes and sensory input, which have implications in understanding visual perception.

Studies use flickering checkerboard stimuli to investigate early selection in visual areas, showing that attention modulates activation in specific cortical areas like V1, V2.

Attention facilitates perception by selectively filtering information.
Different forms of attention (exogenous, endogenous, spatial, feature-based, and object-based) interact and influence perceived reality.
Neural mechanisms underpinning attention reveal complex interactions of cognitive processes and sensory input, which have implications in understanding visual perception.