2. Cognitive psy_vision_audition_feb21

Cognitive Psychology

Cognitive Psychology Department:

Maria de Lourdes NoboaContact: noboa.maria@ppk.elte.hu

Visual and Auditory Perception

Key Areas of Focus: Visual perception, auditory perception

Visual Perception

Understanding Visual Perception:

• Environmental stimulus: Light from objects (e.g., a tree) serves as the initial sensory input.

• Steps in Visual Processing:

  • Step 1: Environmental Stimulus (the tree).

  • Step 2: Light is reflected from the object, creating an image on the retina.

  • Step 3: Receptor processes occur where receptors in the retina transform light into electrical signals.

  • Step 4: Neural processing takes place as signals travel through a network of neurons to the brain.

The Role of Light in Vision:

• Visible Light: The only part of the electromagnetic spectrum that is visible to humans.

Anatomy of the Eye

Components:

• Cornea: Provides 80% of the eye's focusing power.

• Lens: Contributes the remaining 20% through accommodation (changing shape to focus images).

Visual Acuity and Receptors

Types of Receptors in Retina:

• Rods: Specialized for night vision, low light intensity, and have low resolution.

• Cones: Responsible for color perception, high light intensity sensitivity, and high resolution.

Distribution:

• Fovea: Contains only cones, providing the highest visual acuity and detail.

• Peripheral Retina: Has both rods and cones, with a higher concentration of rods compared to cones.

Visual Disorders

• Macular Degeneration: Affects the fovea and surrounding area, resulting in loss of central vision.

• Retinitis Pigmentosa: Degeneration of the retina that leads to peripheral vision loss, causing 'tunnel vision'.

Dark Adaptation & Visual Pigments

Pigments:

• Chemicals located in receptors that influence our perception and adaptation to light changes, especially in darkness.

Auditory Pathway and Coding

Auditory Processing:

• Auditory signals are transmitted through pathways such as the cochlear and auditory nerve pathways to the brain.

• Temporal Coding: Refers to the relationship between sound frequency and the timing of nerve firing.

Auditory Perception:Functions of Hearing:

• Key Functions:

  • Communication

  • Alertness to dangers

  • Localization of objects in the environment

  • Recognition of familiar sounds and objects

Understanding Sound:

• Definitions:

  • Physical Definition: Sound is defined as changes in pressure in air or other mediums.

  • Perceptual Definition: It is the experience of sound when it is heard.

• Physical Properties:

  • Amplitude: Corresponds to the size of pressure changes, measured in decibels (dB).

  • Frequency: The rate at which sound waves cycle, measured in hertz (Hz).

Auditory Processing Steps

Basic Process:

• Sound waves produce mechanical vibrations that travel through the auditory system.

• Inner and outer hair cells in the cochlea play crucial roles in encoding sound information.

Object and Scene Perception

Complexity of Visual Perception:

• Challenges:

  • The inverse projection problem requires the perceptual system to infer the cause of images displayed on the retina.

  • Depth perception relies on various cues, including binocular and monocular indicators.

Perceptual Organization Processes:

• Grouping: Involves combining elements to form coherent perceptual objects.

• Segregation: The process of distinguishing objects from their background or from each other.

The Gestalt Principles of Organization

Key Principles:

• Proximity: Elements that are close together are grouped into a single object.

• Similarity: Similar elements are recognized as belonging to the same group.

• Continuation: Diagrams are perceived as continuous, even when interrupted.

• Closure: The mind fills in gaps to perceive incomplete shapes as complete forms.

Face and Object Processing

Holistic Processing of Faces:

• Special case: Holistic processing is critical for effective face recognition.

• Developmental Differences: There are distinctions in the abilities for recognizing faces compared to objects, which change through maturation.

Prosopagnosia:

• A condition where individuals experience difficulty with face recognition while maintaining the ability to recognize other types of objects intact.

Regularities in Environment

Semantic Regularities:

• Contextual expectations influence how individuals recognize and interpret objects.

Conclusion

Cognitive Psychology:

• Integrates studies of visual and auditory perception to enhance understanding of human interaction with the environment.