synaesthesia Flashcards
What do the senses (eyes, ears, nose, mouth, skin) do in the process of perception?
The senses have specialized receptors that convert physical signals (e.g., light, sound, touch) into neural signals, which are then processed by the brain to create our perception of the world.
How does the brain perceive the world based on sensory input?
The brain combines sensory information from each sense (sight, hearing, touch, taste, and smell), integrates this with input from other senses, and uses stored knowledge and past experiences to construct our perception of the world.
How does the physical world differ from the perceived world?
The physical world is the reality that exists independent of us, while the perceived world is the brain’s interpretation of that reality. This can be influenced by context, expectations, and sensory biases (e.g., optical illusions or auditory illusions).
What is multi-sensory perception?
Multi-sensory perception refers to the integration of sensory information from multiple senses (such as sight and sound) to create a unified, coherent experience of the world, allowing for more accurate and efficient processing.
What are the advantages of multi-sensory perception?
- Efficiency: It allows for faster and more accurate processing than if each sense were processed in isolation.
- Coherence: It helps create a single, coherent perception of the world, making it easier to navigate and respond to our environment.
- Action: It supports appropriate action by providing a richer, more integrated experience of reality.
What is the McGurk illusion?
The McGurk illusion occurs when conflicting visual and auditory stimuli cause a mismatch in perception. For example, when the sound “BA” is paired with the visual cue for “GA,” people often perceive the sound “DA” instead of either of the actual sounds.
What does fMRI show about the McGurk illusion?
fMRI studies show that when people watch someone’s lips move while hearing a sound, the auditory areas of the brain are activated, suggesting that visual information can influence auditory perception.
What is synaesthesia?
Synaesthesia is a neurological phenomenon where the stimulation of one sensory or cognitive pathway leads to automatic, involuntary experiences in another. For example, hearing music might evoke specific colors or seeing numbers may trigger spatial associations.
What are the defining characteristics of synaesthesia?
- Concrete perceptual experiences: The experiences are real sensory perceptions, not based on imagination or hallucination.
- Triggered by external stimuli or thoughts: Synaesthesia is evoked by specific sensory inputs or thoughts, not random or spontaneous like hallucinations.
- Automatic: The experiences are involuntary and cannot be suppressed or controlled by the individual.
What causes developmental synaesthesia?
Developmental synaesthesia appears to have a genetic basis, runs in families, and typically manifests in early childhood. It is persistent throughout a person’s life and can involve a variety of sensory crossovers (e.g., seeing colors for letters or sounds).
Is developmental synaesthesia more common in males or females?
Developmental synaesthesia is equally common in males and females, although some studies suggest it might be slightly more prevalent in women.
What often triggers developmental synaesthesia?
It is frequently triggered by linguistic stimuli, such as letters, numbers, or words, leading to experiences like color associations with specific letters or seeing sounds as shapes.
What causes acquired synaesthesia?
Acquired synaesthesia can result from brain injury, sensory deprivation (e.g., loss of sight), or pharmacological substances (e.g., psychedelics). Unlike developmental synaesthesia, it is temporary and may resolve once the cause is removed.
How can functional imaging prove synaesthesia is real?
Functional magnetic resonance imaging (fMRI) shows that synaesthetes have unique brain activity patterns. For example, when a synaesthete sees a letter or number, areas of the brain associated with color processing (e.g., left V4) light up, even though the stimuli aren’t inherently visual.
What did Nunn et al. (2002) discover about synaesthesia and brain activity?
Their study found that synaesthesia activates the left V4 region of the brain, which is involved in color processing, even when synaesthetes are associating color with non-visual stimuli like numbers or letters. This is not observed in non-synaesthetes.
