8 minute read
Time Perception
By Heather Lo
Do you ever feel that time could not pass by anymore slower when you are almost late for school but are still waiting for 12A at Admiralty bus-stop? However, time feels like rushing past when we are on holiday and are having fun? To explain this, let us learn more about time perception.
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Definition and overview
Time perception is a fascinating and interesting phenomenon. It is one of the most important topics of neuropsychology (a branch of psychology that studies human behaviours with neurological observations). It is defined as how our brain estimates time intervals and duration. By studying how patients with dorsolateral prefrontal right cortex lesions perceive time differently from those with intact right cortex, neuroscientists believe that the dorsolateral prefrontal right cortex is the region most involved in time perception. Time perception can be explained from the neuropsychological, cognitive psychological, philosophical and other perspectives. In this article, we will focus on the neuropsychological foundation of time perception.
Every one of us has an internal clock. Time perception can be accurate, but sometimes it can be inaccurate. The inaccuracy of our time perception is not the result of a malfunctioning internal clock. In fact, the perception of time is a complex neural mechanism that can be influenced by our emotional state, level of attention, memory and diseases. It shows our ability to adapt to events happening around us. Time flies more quickly when we are busy or having something fun. However, minutes drag by when we are bored, worried, anxious or frustrated.
Theoretical explanation of time perception
Neuropsychologists believe humans have a system to govern time perception. They proposed different theories to explain the mechanism of time perception.
The most well-known model, which is also the earliest one to explain time perception, is called the scalar expectancy theory. This theory can be explained by the pacemaker-switch-accumulator mechanism. It suggests that our brain perceives time as a synchronized ticking of our internal clock. The closing action of the switch in the pacemaker is controlled by our attention. When the stimulus is focused, the impulses flow to the accumulator. The switch then reopens, interrupting the flow of the impulses. Therefore, the time intervals are calculated. When the time interval speeds up, it makes us feel that time is passing slowly. When we stop paying attention to time, the beats are not counted. As a result, it appears that the duration is shorter than in reality (that is, time is passing quickly).
In 2005, Professor Warren H. Meck proposed a physiological model to explain time perception. It suggests that the vibrating activities of brain cells in the upper cortex support time perceived by our brain. The vibration of each cell creates a beat. Cells in the dorsal striatum, at the base of the forehead, then detect the frequency of vibration. Hence, the time is estimated.
Chess Stetson, Matthew P. Fiesta, and David M. Eagleman conducted a study on “time-slowing ” during frightening events. In their study, participants were asked to experience free fall. They were asked to estimate the time between the beginning of the fall and landing on the ground. The results find that participants estimated the duration of their own free falls 36% longer than the others ’ . The results suggest that our brain estimates duration based on the amount of data and memory we store. The more data our brain receives within the period of time, we perceive that the duration is much longer than its actual duration. When participants experience the fall on their own, their brains accumulate a tremendous amount of memory in an unusually short period of time. Therefore, they estimate that the duration of the falls is a much longer duration. On the other way round, if our brain receives very little data, we feel that time passes very quickly. When participants were asked to watch others ’ free falls and estimate the duration of their falls. In other words, these participants did not have the first-hand experience of the fall. The duration they estimated was shorter than that estimated by those who did the free fall.
Conclusion
This article discussed the neuropsychological foundation of time perception. Time perception changes with our emotional state, level of attention, memory and diseases. It can be used to explain various time-related daily experiences and observations.
References https://hbr.org/2016/05/different-cultures-see-deadlinesdifferently#:~:text=Western%20cultures%20tend%20to%20view,operations%2C%20 by%20milestones%20and%20deadlines.&text=Other%20cultures%20perceive%20ti me%20as%20cyclical%20and%20endless. https://www.ncbi.nlm.nih.gov/pmc/articles/PMC4142010/ https://www.theguardian.com/science/2013/jan/01/psychology-time-perceptionawareness-research https://link.springer.com/content/pdf/10.3758/BF03194099.pdf https://storage.googleapis.com/plos-corpusprod/10.1371/journal.pone.0001295/1/pone.0001295.pdf?X-GoogAlgorithm=GOOG4-RSA-SHA256&X-Goog-Credential=wombat-sa%40plosprod.iam.gserviceaccount.com%2F20210330%2Fauto%2Fstorage%2Fgoog4 _ request &X-Goog-Date=20210330T162659Z&X-Goog-Expires=3600&X-GoogSignedHeaders=host&X-GoogSignature=30204db7e3185882cc7368db795f246d53a
By Christine Pang
Introduction to Bipolar Disorder (BD) – diagnostics, symptoms & identification:
Bipolar disorder is one of the most distinguishable mental illnesses in the course of history because of its apparent symptoms – extreme shifts in the mood, activity levels, and energy of bipolar patients. It is also known as the manic depressive disorder because of the emotional “highs ” and “lows ” experienced by its patients. During a hypomanic or manic episode (mania), bipolar patients have the following characteristics and symptoms: feeling elated, adventurous, and confident; sleeping very little, approximately 2-3 hours a day; yet being able to maintain a high energy level, feeling extremely restless and impulsive, talking a lot, and speaking very quickly with racing thoughts. On the contrary, during a depressive episode, bipolar patients have almost completely opposite behaviours: feeling upset, worthless, or hopeless; sleeping too much to the extent that it disrupts their daily functioning; isolating themselves from social interactions, or even attempting suicide.
Neuropsychology and Bipolar Disorder:
So how can we explain the above traits of BD in a more scientific manner? What can we extrapolate from the neuropsychological perspective of BD? In fact, various neuropsychological studies have been carried out to examine the impairments in executive functioning, decision making, and goal achieving in both hypomanic and depressed bipolar patients to elucidate their state-and-trait-related changes.
In order to understand the neuropsychological functioning in bipolar patients, we first have to know the functional contributions of two brain components - the amygdala and ventromedial prefrontal cortex (PFC). The amygdala is critical for both punishment and reward based reinforcement associations, in which positive reinforcers add positive stimulus, and negative reinforcers remove aversive stimulus in order to maintain our “ normal” behaviours. It also contributes to the processing of emotional expressions. PFC is critical for the representation of reinforcement expectancies and decision making. Within the brain, the amygdala is the reaction centre that responds to threats, and the PFC is the reward centre. The amygdala develops earlier than the PFC and is associated with quick emotional responses.
In the hypomanic or manic phase of bipolar patients, it appears that the amygdala in the patient’ s brain is not sending appropriate signals and is providing misinformation to the PFC. The hypersensitivity of amygdala and the PFC give rise to risk-taking and reward-seeking behaviours, which manifest as impaired judgments, reckless actions, and dysregulation in goal pursuits. This cognitive dysfunction explains the talkative, confident, yet thoughtless or irrational characteristics of bipolar patients during their hypomanic or manic episodes.
On the other hand, in the depressive phase of bipolar patients, the abnormally elevated activity of the amygdala in the left prefrontal cortex of bipolar patients tends to inhibit serotonin. According to the serotonin hypothesis in depression, low levels of the neurotransmitters serotonin arouse sad, fearful, or agitated emotions which contribute to the depressive episodes of bipolar patients. Hence, the negative emotions engendered by serotonin inhibition causes disruption of daily functioning and withdrawal symptoms in depressive bipolar patients, such as hypersomnia (over-sleeping) and self-isolation in interpersonal relationships.
Social implications of bipolar disorder, misdiagnosis and solutions:
The critical functions of the amygdala and PFC as mentioned above are compromised in individuals with the disorder. Neuropsychological impairments and cognitive dysfunctions in bipolar patients can significantly contribute to social and occupational difficulties, reduced insight, increased risk of non-adherence (meaning that the patient actively decides not to use treatment or follow treatment recommendations) and a higher chance of relapse.
Bipolar disorder may often be misdiagnosed as “ unipolar ” depression because they both are associated with similar cognitive and neuropsychological deficits. To the present day, neuropsychologists still have not come to an agreement on the distinctive cognitive profiles of bipolar disorder and unipolar depression. Although studies have been carried out to compare the neuropsychological functioning in bipolar disorder and major depressive disorder, the evidence obtained could not be used to elucidate the differences between the two disorders due to the uncontrolled variables (like age, medication status, bipolar subtype etc.) which may affect the cognition of patients involved in the studies. Other than unipolar depression, bipolar disorder may also be misdiagnosed as attentiondeficit hyperactivity disorder (ADHD). When bipolar patients are in their manic phase, they tend to manifest symptoms that are very alike to ADHD, such as hyperactivity, impulsivity, attention and memory impairments. Both disorders have similar cognitive profiles which, likewise with bipolar disorder and depression, do not allow psychologists to clearly differentiate bipolar disorder and ADHD. The consequences of misdiagnosis of bipolar disorder are profound and destructive to patients as they would not be able to receive effective treatments to cure their mental illnesses. This may give rise to a greater number of recurrences and complications or more long-term episodes, both manic and depressive.
Despite the hurdles and difficulties faced by bipolar patients, evidence has shown that bipolar symptoms can be treated with certain psychiatric medications, which are known to act on the neurotransmitters (messenger chemicals) in the patients ’ brains. In the short term, medication can be offered to both manic or depressive bipolar patients to stabilize their physiological and mental states. In the long term, offering cognitive behavioural therapy to bipolar patients can help them to clear their emotional and social recovery goals. Coming up with a crisis plan can also help bipolar patients and their family members to know what to do when the patient shows any sort of early warning signs, symptoms or distress.
References:
https://www.mind.org.hk/mental-health-a-to-z/bipolar-disorder/about-bipolardisorder/
https://progress.im/en/content/how-does-brain-change-bipolar-disorder
https://www.ajmc.com/view/oct05-2151ps271
https://www.sciencedirect.com/science/article/abs/pii/S016517811630782X
As with all mental disorders, communication is key!
