Online Tutorial Task 3

Making Sense of Our Senses

Smell (Task B: Satiation)

The scent is noticeably less intense after the first exposure of approximately 5 to 10 minutes to the saturated tissue. However, the smell is apparently becoming stronger during the second exposure. This phenomenon is called satiation but to be more specific, it is the occurrence of olfactory fatigue (Anonymous, n.d). Olfactory fatigue is also known as olfactory adaptation or nose blindness. Normally, we have adapted or temporarily lose the ability to distinguish the smell when we are exposed to the same odour stimulus for a long period of time. The importance of olfactory fatigue is to avoid the overload of stimuli for the central nervous system during the prolonged exposure.

The sensitivity is regained and restored when I left the area for a few minutes to breathe some fresh air, because the olfactory receptors are not depolarized anymore, and everything goes back to the initial previous state. The cation channels are once again open. Thus, when I came back, the smell was notably becoming stronger during the second exposure. This is due to the fact that the odourant is stimulating the olfactory neurons which are interpreted as the smell of the perfume. After a while, the olfactory fatigue phenomenon will then kick in and the smell will again seem less intense (Chapter, 2005).

Regarding the mechanism of olfactory fatigue, the odourant or chemical normally depolarizes the olfactory receptors, and after the G-protein mediated secondary messenger response, adenylyl cyclase is activated. This leads to an increased concentration of cyclic adenosine monophosphate (cAMP or cyclic AMP) within the cell that opens particular calcium ion channels. After some time, with the aid of Ca2+/calmodulin-dependent protein kinase II, the incoming calcium ions initiate olfactory fatigue through preventing further opening of cation channels. In addition, the phosphodiesterase enzyme which cleaves the cyclic AMP will also be activated by the calcium ions. After prolonged exposure to the same odourant, this whole process results in desensitization of the olfactory receptors (Dougherty et al., 2005).

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Sensation and Perception

Sensation and perception are the two factors which complement and balance each other which help us recognize as well as establish meaningful information about our stimuli. Regarding sensation, the activated sensory receptor induces nerve impulses that pass to the brain; then the brain coordinates and interprets the input through perception as well as allows us to sense the stimulus as image, pain or taste (including memories and emotions).

Without sensation, perception is not possible to take place. Likewise, without perception, we are unable to recognize the sensation because the brain cannot process it for us. Sensory stimulus shapes our perception, as the information provided by sensory stimulation is only processed by the brain into a meaningful pattern so that we will able to know the sensation.

Eyes (vision), ears (hearing), nose (smell), skin (touch) and tongue (taste) form the sensory system. While these are the different primary functions, they also have other functions, such as the ear, which also serves as an organ for balance. We adapt to shifts in our surroundings in our daily lives. This stimulus-response not only helps to identify change but also to avoid harm to the body (Anonymous, n.d).

The body itself has limited resources at its disposal, so the resources would be rapidly drained, and the body would be exhausted if there was a response to any stimulus that reached the absolute threshold. Therefore, from the perspective of development, it is necessary for the body to provide pathways that mitigate the need for surplus energy to sustain different body functions. Mechanisms have been established by the human body that allows us to be inclined towards appropriate stimuli and avoid any irrelevant responses.

Typically, most people would love to get rid of pain (nociception) since the experience of painfulness is distressing and does not seem to have apparent value. Yet this is our body's way of giving out a warning that something is wrong and in need of our immediate attention through the perception of pain. Without pain, we will never realize we have accidentally drink boiling water or that we should rest a strained back after going through an intense workout (Anonymous, n.d).

Besides, the human sensory system and sensitivity play prominent parts in the process of communication because feedback and noise that can affect the communication mechanism are taken into account. Communicating deals with cues, verbal and non-verbal means which suggests that the atmosphere in which the contact takes place is guarded by pictures as well as sound. Thus, it is vital for the communicator to take into account on all facets of feeling, vision, hearing, adaptation, hearing and colour perception in order to prevent any abysmal description (Philipatawura, 2010).

Apart from that, sensory adaptation which is one of the elements of sensation is defined as the reduction in a receptor neuron's electrical responses over time despite the continuous presence of appropriated constant-strength stimulus. This shift is noticeable since the frequency of spikes produced inside the receptor neuron has gradually decreased. Although sensory adaptation decreases our awareness of a persistent stimulus, it is imperative in helping to free up our energy and resources to take care of other environmental stimuli around us. For instance, for dark adaptation, our eyes will slowly adapt to the darkness as we enter into a dark room or going out at night, through widening the pupils to let in more light. Correspondingly, our eyes adapt to the shrinking of pupils when we are under a bright light which is known as light adaptation (Anonymous, n.d).

Furthermore, we are not limited to solely sense of taste when we are eating. Food odourants are pushed back to locations containing olfactory receptors during the chewing process. This mixture of flavour and odour brings us a perception of flavour which allows us to enjoy the aromas of food.

Sensory receptors mechanisms make a substantial contribution to homeostasis. They obtain external and internal stimuli and by negative feedback mechanism, engage in homeostasis. We will not be able to receive data about our internal and external environment without sensory input. In order to maintain the internal climate constant, this information contributes to appropriate reflex and voluntary behaviours.

In general, our remarkable sensory abilities allow us to experience the most exciting and most unpleasant encounters as well as anything in between. In order to interact with the environment around us, our eyes, ears, nose, tongue and skin provide an interface for the brain. While it is easy to individually cover each sensory modality, we are species that have acquired the capacity to process several modalities as a unified real-world experience known as multimodal perception (Privitera, 2011).

Moving on to perception, we acquire information about the properties as well as the elements of our surroundings that are vital to our survival through the perception mechanism. Aside from constructing our experience and understanding of the world around us, it also enables us to act within our environment. Perception begins with bottom-up processing which includes receptors stimulation, generating electrical impulses that enter the brain's visual reception region. Top-down processing, which is synonymous with information accumulated in the brain, is also being involved in perception.

In interpreting human behaviour, perception is very crucial since each person perceives the environment and handles life issues diversely. Different individuals view and perceive the same situation differently. Thus, we are also able to foresee one’s behaviour in altered situations through comprehending their current perception of the environment. The needs of different individuals can be determined with the aid of perception since the perception of people is affected by their needs. If we want to get along with someone and try to see it from their point of view, we will be able to gain a new outlook on life and react more appropriately according to the situation when we put ourselves in their shoes (Anonymous, 2019).

Selective Attention is one of the components associated with perception in which it allows us to prioritize the important element while tuning out the insignificant details which leads to motivation. For example, as students, we will listen carefully to what our lecturers are conveying and ignore other conversations going on inside or outside the class.

Moreover, perception is also significant in generating more than factual output; it ingests an observation and incorporates an altered reality enriched with prior experiences. This phenomenon is known as perceptual expectancy. Additionally, perception also develops character and identity that determines individuals' various roles such as the perpetrator, the bigot, the self-righteous one and so on (Anonymous, 2019).

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Pheromone

Pheromone is defined as the chemical signal released by an individual which influences the behaviours and physiology of other individuals. A mixture of two Greek words: pherein (to transfer) and hormon (to excite) made up the term, pheromone (Karlson & Lüscher, 1959). Its meaning of transferring excitement can be seen in animal behaviours. For instance, a chemical known as bombykol will be released by female silk moth to draw the attention of male silk moth from miles away (Novotny as cited in Wysocki & Preti, 2004).

It is actually a debatable matter on the existence of pheromones in humans, but there is evidence which proves that humans can detect reproductive-related odours (Doty, 2010). Singh and Bronstad (2001) indicated a correlation between male's ratings of female's body odours and the menstrual cycle of females. Males classified the smell of T-shirts worn by females during the ovulatory stage of their menstrual cycle for three consecutive nights to be more pleasant as compared to the smell of shirts worn during their non-ovulatory phase. It is also found out that compared to smelling shirts worn by females far from ovulation phase, males had higher testosterone levels when they smelled T-shirts worn by females who were close to ovulation. Therefore, olfactory signals can reflect the degree of reproductive fertility of a female.

Besides, the prominent t-shirt sniffing experiment suggested that females favoured the smell of males with distinct chromosomes and immune systems over their own (Wedekind and Sandra, 1997). We definitely send certain odour signals in which human newborns know the smell of their mother’s breast from across the room. Humans send off a cloud of personal molecules in the Pigpen style that gives us special aroma profiles, which is why we might be able to tell who someone is only from their scent. Even though scent is theoretically not the same thing as pheromones, by affecting our mating decisions and our willingness to trust others, these smells may work in a similar way as well.

Pheromones may have contributed major changes in human reproductive function (Wyatt as cited in Cornwell et al., 2004); but their status is unconvincing in terms of signalling the quality of human mate and influencing the selection of mate (Jacob & McClintock, as cited in Cornwell et al., 2004). When humans seek for a potential mate, they are acutely sensitive to signal concordance (Thornhill and Gangestad, as cited in Cornwell et al., 2004). When compare to asymmetrical males, females prefer body odours collected from males with a high level of bilateral symmetry.

In addition, both males and females show likings for voices recorded from individuals with greater degrees of bilateral body symmetry than those with lower bilateral symmetry (Hughes et al. as cited in Cornwell et al., 2004). Besides, sexually dimorphic facial traits may also suggest the quality of the partner, and it has been hypothesized that hormones and signal fertility lead to distinctly feminine characteristics in females such as full lips as well bigger eyes. As for males, traits like heavy brows and a sharp jawline may suggest elevated testosterone levels, which may signify superiority (Mazur & Booth, 1998 as cited in Cornwell et al., 2004) or immunocompetence (Folstad & Karter, 1992 as cited in Cornwell et al., 2004).

Greater male fondness over female pheromones would be shown for females who prefer more masculinized faces whereas males who prefer more feminized faces should display a corresponding tendency towards female pheromones.

In terms of mating choice, other than faces, attractiveness also takes accounts genetic diversity, immunocompetence as well as physical health (Rhodes et al. as cited in Hare et al., 2017). Although it has limited accuracy, faces are still used to determine sexual faithfulness. (Berry as cited in Hare et al., 2017). Females are marginally more accurate at chance in determining an unfamiliar male face for the aspect of unfaithfulness (Rhodes et al. as cited in Hare et al., 2017), while males are slightly better at chance in selecting the most unfaithful one out of two females (Leivers et al. as cited in Hare et al., 2017).

If androstadienone and estratetraenol are indeed considered as human pheromones, it can therefore affect reproductively related behaviours like perceptions of a potential partner’s attractiveness or infidelity. Besides, androstadienone enhances mood, emphasize on attention and also modulates biological endpoints. For women's sexual arousal and pleasure, a good mood and heightened focus are critical (Verhaeghe et al., 2013).

Apart from that, lots of variables are involved in the attractiveness of body odour also involves a lot of variables, and our prior experiences will also influence how we feel about a scent. This is due to the receptor cells in our nasal cavities transfer information to our brain’s main olfactory bulb, which transmits it to the limbic system, which situated right beside the memory-making hippocampus as well as emotion-inducing amygdala. This suggests that scent is also embedded in memory. I might feel elated when I smell laksa because it reminds me of the breakfast I always have enjoyed with my family since childhood which further proves that pheromones will increase our mood as well.

Lastly, it is also quite interesting that if females stay in a room together, pheromones will cause their menstrual cycles to eventually align even though this idea had mixed support from scientific research. It was also reported that the research managed to relate the synchronization of the menstrual cycles of women to unconscious odour cues which are known as the McClintock effect (McClintock, 1971). If a group of females were exposed to the scent of sweat smell by other females, their menstrual cycles will either hastened or slowed down, relying on whether the sweat was gathered before, during or after the phase of ovulation. McClintock (1971) claimed that the pheromone collected before ovulation reduced the ovarian cycle, whereas the ovarian cycle was lengthened by the pheromone collected during ovulation. Nevertheless, recent critiques of McClintock’s research methodology have been questioned on its validity.

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References