Sensation
Sensation is the process where sensory receptors and the nervous system receive and interpret stimuli from the environment. It is the first stage in perceiving information, enabling us to experience sensations such as sight, hearing, smell, taste, and touch. Sensation involves converting physical stimuli into neural signals for the brain to process.
Stimuli
Stimuli are external or internal factors that can elicit a response in a biological system. They are the elements in the environment that are detected by and interact with sensory organs, leading to sensations and perceptions. Examples of stimuli include light, sound, temperature, pressure, chemical substances, and even …
Exteroception
Exteroception refers to the sensory process of perceiving external stimuli from the environment through the sensory systems. It involves the detection of information from outside the body.
Interoception
Interoception refers to the perception and awareness of interal bodily sensations. It involves the processing of signals originating from within the body, such as:
Interoception is crucial for maintaining homeostasis, the body’s internal balance, and contributes significantly to emotional experiences and self-awareness. It allows individuals to understand and interpret bodily signals, which can influence decision-making, emotional responses, and overall well-being.
Jacob von Uexkull
| Sensation | Perception |
|---|---|
| Does not require a brain | Requires a brain, albeit metaphorically |
| Comes first | Follows sensation |
| Requires stimuli | Can happen without stimuli |
| Low level, your phone can do that | High level, living organism stuff |
Perception
Perception is the cognitive process by which the brain interprets and makes sense of the information gathered by the sensory organs. It’s how we recognize, organize, and understand sensory information, transforming it into meaningful experiences of the world around us.
Perception is influenced by various factors, included attention, expectations, cultural background, and previous experiences, leading to individual differences in how people perceive the same stimulus.
Hallucination
Hallucinations are experiences where a person perceives something that isn’t present in the environment. These can be visual, auditory, or sensory perceptions with no external stimuli. Commonly associated with psychiatric conditions, neurological disorders, substance use, or extreme stress, hallucinations are distinct from illusions as they are entirely generated by the mind, not based on misinterpretations of real external stimuli.
The Ultimate Absences of Sensory Stimuli
Sensory deprivation tank where you can’t experience any stimuli.
Illusion
An illusion is a misperception or misinterpretation of a real external stimulus. In an illusion, the brain constructs a perception that deviates from reality, often due to misleading or confusing information presented to the senses. Illusions can affect various sensory modalities, including visual, auditory, and tactile senses.
Hubel and Weisel
Put electrodes in cat’s occipital cortex. Electrodes picked up signals of
firing patterns (electrical impulses) in the context of neurons. Showed the
cat pictures of a line rotating at specific angles. Found that some neurons
fired at specific angles (i.e. 90 degrees vertical, horizontal)
Figures Which Disturb
- Muller-Lyer optical illusion
- Ponzo illusion
- Hering figure
- Poggendorf figure
- Orbison figure
- Zollner figure
Size constancy
Size constancy
The brain has an assumption of parallel walls that overrides the fact that
people are changing sizes.
Dalmation art
Sunken vs raised dots
Our brains evolved under the sun, so when the light is at the top, we
perceieve the object as a volumetric sphere, and when the light is below, we
see the object as a concave object.
Bridget Riley
[[2021)](BBC Two HD Bridget Riley Painting the Line (2021|BBC Two HD Bridget Riley Painting the Line (2021)]].md)