Visual Attention and Search

Visual Attention

Visual Search

• Definition: The process of finding a specific target among distractors in a visual environment
• Key concepts:
  • Pop-out effect: When a target stands out from the background due to its unique features (e.g., color, shape)
  • Serial search: The process of searching for a target by fixating on individual items in a sequence
  • Parallel search: The process of searching for a target by processing multiple items simultaneously

Eye Movements

• Definition: The movement of the eyes to focus on specific areas of interest in a visual environment
• Key concepts:
  • Saccades: Rapid movements of the eyes between fixation points
  • Fixations: Periods of stable gaze on a specific location
  • Scanpaths: The sequence of saccades and fixations in a visual search task

Selective Attention

• Definition: The ability to selectively focus on relevant information while ignoring irrelevant information
• Key concepts:
  • Bottom-up processing: Attention driven by stimulus properties (e.g., color, shape)
  • Top-down processing: Attention driven by expectations, goals, and prior knowledge

Feature Integration Theory

• Definition: A theory proposing that attention is required to integrate features of an object into a unified percept
• Key concepts:
  • Features: Basic elements of an object's representation (e.g., color, shape, orientation)
  • Binding: The process of integrating features into a coherent object representation

Binding Problem

• Definition: The challenge of explaining how features are integrated into a coherent object representation
• Key concepts:
  • Feature binding: The process of linking features to a specific object
  • Object-based attention: Attention focused on specific objects rather than individual features

Visual Attention

Visual Search

• Visual search is the process of finding a specific target among distractors in a visual environment.
• The pop-out effect occurs when a target stands out from the background due to its unique features, such as color or shape.
• Serial search involves searching for a target by fixating on individual items in a sequence.
• Parallel search involves processing multiple items simultaneously to find a target.

Eye Movements

• Eye movements involve the movement of the eyes to focus on specific areas of interest in a visual environment.
• Saccades are rapid movements of the eyes between fixation points.
• Fixations are periods of stable gaze on a specific location.
• Scanpaths are the sequence of saccades and fixations in a visual search task.

Selective Attention

• Selective attention is the ability to selectively focus on relevant information while ignoring irrelevant information.
• Bottom-up processing involves attention driven by stimulus properties, such as color or shape.
• Top-down processing involves attention driven by expectations, goals, and prior knowledge.

Feature Integration Theory

• Feature integration theory proposes that attention is required to integrate features of an object into a unified percept.
• Features are basic elements of an object's representation, such as color, shape, or orientation.
• Binding is the process of integrating features into a coherent object representation.

Binding Problem

• The binding problem is the challenge of explaining how features are integrated into a coherent object representation.
• Feature binding involves linking features to a specific object.
• Object-based attention involves attention focused on specific objects rather than individual features.

Visual Attention

Visual Search

• Visual search is the process of actively looking for a specific target or feature within a visual environment.
• It is goal-directed, selective, and active, requiring effort and attentional resources.
• There are three types of visual search:
  • Feature search: searching for a specific feature (e.g. color, shape)
  • Conjunctive search: searching for a combination of features
  • Spatial search: searching for a target in a specific location
• Two prominent theories of visual search are:
  • Guided Search Theory: top-down processing guides attention to relevant features
  • Feature Integration Theory: attention is directed to the most relevant features through feature integration

Change Blindness

• Change blindness is the inability to detect changes in a visual scene, even when the changes are significant.
• There are three types of change blindness paradigms:
  • Flicker paradigm: rapid sequence of images with a change occurring between images
  • Mud splat paradigm: change occurs during a brief distraction (e.g. a flash of light)
  • Change detection paradigm: change occurs during a continuous visual presentation
• The causes of change blindness include:
  • Inattention: lack of attention to the changing area or feature
  • Limited capacity: limited processing capacity, making it difficult to detect changes
  • Sensory limitations: limitations in visual perception, such as limited resolution or sensitivity
• Change blindness has real-world implications, including:
  • Driving: contributing to accidents due to failure to detect changes in the road or surroundings
  • Security: making it difficult to detect security threats, such as changes in surveillance footage