Background
Humans function through sensory nerves and organs that coordinate with the brain to bring emotions and perform physical activities. The primary senses include taste, vision, hearing, touch, and smell. Smell describes how individuals perceive scents; the concept describes eyesight, hearing is the ability to perceive sound, touch involves contact, while taste describes the ability to identify different flavors through the tongue. This essay explains how some of these react in particular conditions through practical experiments.
Visual Senses
Rods and Cones
In experiment 1 A, I could identify the object shapes but could not tell the colors. As much as rods help in low light vision, cones are also light receptors that assist in identifying colors but in brighter light due to their small amounts in the eye compared to rods. Therefore, objects in darkness are recognizable in their shapes and physical form only. I was also able to identify and define the formation of objects at a peripheral angle since rods play a predominant role in peripheral vision. The same effect applies to stargazing, where stars are more defined at a peripheral angle than viewing at a straight angle.
Rods are more spread in the retina than cones which are more concentrated at the center bringing the averted vision, enabling better peripheral views (Allen et al., 2019). In brighter light, objects are recognizable in shape and color compared to low light in experiment 2A. Rods work better in darkness and are less light-sensitive, while cones are more sensitive to light which sends color signals to the brain through different wavelengths that define a particular color.
Experiment 1 B tested the ability to identify a blind spot and the afterimage effect. The bars of the cage remains in the blind spot after the mouse disappears because they are not a part of the mouse but objects used by the brain to fill the missing data of the mouse, creating an illusion of a complete mouse. When identifying the blind spot, a challenge occurs when both eyes are open because the visual field of one eye overlaps the other.
One can see an object in the blind spot because the brain generates the idea of the image by filling in or ignoring the non-existing parts. With the mouse in the cage, an individual sees the bars instead of the mouse because the mouse is the central focus of the blind spot, so when the brain tries to fill the missing details of the whole mouse, it focuses on the bars in compensating the missing parts of the mouse making them more visible.
In the afterimage experiment, I could see a black dot at the center of the circle, which appear with the peace symbol visible in the first circle only. Also, the peace symbol color changes from black to white in the ring. This experience describes a negative afterimage effect where the retina maintains the illusion of an object after a prolonged observation with a different color (Li & Sun, 2021). While observing the dot in the second circle, the after image persisted for approximately one minute.
Compensation and Optical Illusion
Blind people have the same hearing and smelling sense as individuals with sight. One explanation why blind people perceive smell and touch more than people with sight is that they practice and have more experience using these senses. The human eye consists of various receptors that take the visual information to the brain for perception and identification, which gives the shape, color, and definition of an object (Laeng et al., 2018). This exchange of information forms a communication path where the eye sends and receives data from the brain. Therefore, in some instances, a miscommunication occurs, sending the wrong or opposite information, creating an optical illusion.
Color Blindness and Standard Vision Test
I have never met a color-blind female since the majority population such a disorder are men. This is because they possess just one X chromosome. Moreover, I could distinguish the orange circle from the green and identify the red star. At 20 feet, I was also able to see the letter E clearly with both eyes open than a single eye. Consequently, the E becomes invisible with distance and disappears at 100 feet.
Taste and Smell
The Effect of Smell on Taste
In experimenting with how smell affects taste, a mint-flavored candy was used. On tasting the candy while pinching the nose, I could detect some sweetness and a cooling sensation, which became less cooling with repeated rinsing and tasting. I could smell the minty flavor on releasing the nose, which enhanced and spread the cooling sensation to the nose. The minty taste fades with continuous rinsing because the taste receptors adapt to the cooling effect inhibiting further communication to the brain. In identifying perfume concentration at different exposure times, the subject describes the perfume to have a strong scent on the first exposure.
After sniffing for ten minutes, the perfume’s scent fades to a mild concentration. After staying out of the room for fifteen minutes, the subject describes the fragrance as vital, but the effect is less intense than the first exposure. Kakutani et al (2021) explain that smell buds adapt the molecules of the fragrance, which block the passages making an individual immune to the scent.
Touch and sensitivity
Using a paper clip, I experimented with the difference of simultaneous spatial threshold at distances ranging from 1.5mm, 5mm, 10mm, and 20mm between the paper clip tips. At a 1.5mm distance, the subject confirmed touch by two ends on the back of the arm while indicating one tip on the palm on the same test. The remaining spaces showed two tips where the back of the hand had more spatial sensitivity than the palm. Fingertips had more spatial sensitivity than the other parts of the hand.
Temperature Perception
In the temperature perception experiment, the hand immersed in ice adapted to the freezing effect and became numb while the hand in hot water had a burning sensation which became more comfortable within a few minutes. In the lukewarm water, the hand from ice had a warm feeling while the other hand from hot water did not show much difference in temperature change. When a hand is put in ice, the cold receptors depolarize the temperatures quickly to gain an optimal state, while hot water receptors hyperpolarize, creating a slight temperature change (Yogev & Ciuha, 2021). Since cold receptors depolarize quickly, moving a cold hand to lukewarm water has minimal reaction due to the initial depolarization hence maintaining the coldness.
Hearing And Balance
The subject was able to intercept sound while staying still than when turning the head during the experiment. Staying still gives an individual more focus in intercepting the noise source because motion distracts the individual’s attention. Perceiving sound with an earbud blocking one ear is difficult since the hearing system receives different information from opposite sides that must be similar to identify the sound source (Kniep et al., 2017). Animals that can turn ears have more advantage in hearing because perking ears helps focus more on perceiving a particular sound from the surrounding noises. Vision helps in balancing the head’s position and directing body movement according to the physical surroundings. Alcohol affects a person’s ability to balance due to its influence on the brain hence the balance test for sobriety.
References
Allen, A. E., Martial, F. P., & Lucas, R. J. (2019). Form vision from melanopsin in humans. Nature Communications, 10(1). Web.
Kakutani, Y., Narumi, T., Kobayakawa, T., Kawai, T., Kusakabe, Y., Kunieda, S., & Wada, Y. (2017). Taste of breath: The temporal order of taste and smell synchronized with breathing as a determinant for taste and olfactory integration. Scientific Reports (Nature Publisher Group), 7, 1-9. Web.
Kniep, R., Zahn, D., Wulfes, J., & Walther, L. E. (2017). The sense of balance in humans: Structural features of otoconia and their response to linear acceleration. PLoS One, 12(4). Web.
Laeng, B., ⨯ Kenneth, G. K., Hagen, T., Bochynska, A., Lubell, J., Suzuki, H., & Okubo, M. (2018). The “face race lightness illusion”: An effect of the eyes and pupils? PLoS One, 13(8). Web.
Li, H., & Sun, P. (2021). Visual characteristics of afterimage under dark surround conditions. Energies, 14(5), 1404. Web.
Yogev, D., & Ciuha, U. (2021). Perception of thermal comfort during skin cooling and heating. Life, 11(7), 681. Web.