Read why color doesn’t exist. (An additional resource about visual information and the role of brain processing that might help you
Listen to Anil Seth describe perception: How does your brain construct your conscious reality (transcript at this link)
Answer questions
- Examine the pictures of flowers above, the first in visible light and the second in ultraviolet light (or how bees see the flowers, which requires a special lens for humans to view, since ultraviolet light is outside the visible light spectrum). Why are humans sensitive to only certain types of stimuli? For example, why don’t we see ultraviolet light like bees? How is it possible that the colors of the same flower look very different depending on the organism viewing them?
- Perception is reality. Is this a true statement? Include an example to support your argument. Where do individual differences seem to arise in the way we perceive the world?
- While we often discuss each sense individually, multisensory integration is required for a full picture of the world. Hypothesize why the super additive effect of multisensory integration exists. What are the benefits of this effect to human perception? Is multisensory integration useful for our perception of the world? How does the organization of the brain support multimodal integration?
Respond to two examples in 75-100 words each
example 1
Humans are sensitive to only certain types of stimuli due to the specific properties of our sensory receptors and the evolutionary adaptations that have shaped our perception. For instance, our eyes contain photoreceptors (cones) that are sensitive to visible light but not to ultraviolet (UV) light, unlike bees, which can see UV light because their eyes have different photoreceptor types. This difference in perception allows bees to see patterns on flowers that guide them to nectar, enhancing their foraging efficiency (Briscoe & Chittka, 2001). The variation in flower color appearance across species illustrates how sensory systems evolve to meet specific ecological needs, resulting in different perceptual experiences.
The statement “perception is reality” is true to an extent because our perception shapes our understanding of the world, but it is also subjective and constructed by our brain. For example, optical illusions demonstrate how our brain interprets visual information in ways that differ from physical reality, indicating that perception is not a direct reflection of the external world. Individual differences in perception arise from genetic variations, past experiences, and cultural influences, leading to unique ways of interpreting sensory information (Seth, 2017). These differences highlight that while perception forms our reality, it is inherently subjective and variable.
The superadditive effect of multisensory integration, where combined sensory inputs result in enhanced perception, exists because it allows for more accurate and efficient processing of environmental information. This integration benefits human perception by providing a more comprehensive understanding of the world, improving our ability to respond to complex stimuli. For instance, integrating visual and auditory information can enhance speech comprehension in noisy environments (Stein & Stanford, 2008). The brain supports multimodal integration through interconnected neural pathways and specialized regions like the superior colliculus and association cortices, which process and combine sensory inputs to create a unified perceptual experience (Ghazanfar & Schroeder, 2006).
example 2
1. Sensory organs have evolved to become sensitive to certain types of stimuli in human beings. The human eye can only see light in the wavelength range of about 400-700 nanometers due to the limitations of photoreceptors, rods, and cones, which enable us to move around and avoid danger in our natural habitats (Riddle, 2016). Bees, however, are capable of viewing ultraviolet light, particularly in the range that falls between 300 and 400 nanometers, which circumscribes the diagrams on flowers beyond human perception (Riddle, 2016). These patterns lead the bees to seek nectar, which makes them even more effective as pollinators. This is a situation whereby, given that the colors of flowers are out to reflect the different wavelengths of light, they appear different to different organisms because their visual systems have adapted to different wavelengths of light. For instance, bees can easily see ultraviolet patterns on flowers. Additionally, they are invisible to human beings, and this shows the various ways species can interact with their immediate environment.
2. ‘Perception is reality’ is accurate because reality is perceived according to sensory inputs that are processed by the brain. For instance, color is an example of phenomenal qualities that are actually constructed at the brain level out of reflected light wavelength data. Anil Seth states that “the conscious reality is built in the brain through the phenomenon of prediction and the integration of sensory data”, which, in other words, indicates that we see what we want to or expect to see (NPR & TED Staff, 2018). Perceptional differences exist since individuals receive stimuli through their senses in different ways, are adjusted by their experiences in life, are framed by cultural background, and may even be predetermined genetically by the different sensory receptors every human being is endowed with. This means that one person may receive a different message from another even though they were exposed to the same notion, which clearly points to the fact that reality is indeed relative.
3. Having a better understanding of the superadditive effect of multisensory integration is essential because integrating multiple forms of sensory information helps to improve the brain’s capacity to interpret and react to different forms of stimuli. Through this integration, there is enhancement of accuracy and efficiency of analysis of our environment. For example, combined coding of an object by vision and hearing allows for more accurate localization of a sound source than with vision or hearing alone (Mo & Morgado, 2022). This has a positive impact on human perception, given that it enhances our ability to perceive, recognize, and act on stimuli, an imperative for our presence in this world. The brain comprises connections that enable the combination of information from different senses in the superior colliculus and the multisensory zone in the cortex.
