本文是心理学专业的Essay范例,题目是“Understanding Consciousness in Psychology(心理学中的意识理解)”,意识没有一个真正的定义,然而神经心理学家和哲学家一致认为,意识是对我们精神状态的一种意识;经历,感觉和感觉。意识研究被描述为“生物科学中最重要的问题”(Searle, 2005),在过去的15年里,研究和兴趣不断增长,有超过15000篇关于意识主题的科学文章发表。 There is no one true definition of consciousness, however the consensus of neuropsychologists and philosophers alike is that consciousness is an awareness of our mental states; experiences, sensations and feelings. The study of consciousness is described as “the most important problem in the biological sciences” (Searle, 2005) and over the last fifteen years research and interest has grown, evident by more than 15,000 scientific articles on the topic of consciousness being published. Consciousness can be considered to be both subjective and objective. Scientists and philosophers alike have been researching in the hope to find an objective definition and understanding of consciousness; based on observable phenomena such as neuronal activity. However, consciousness is also subjective as conscious or mental experiences are said to be personal, individual phenomenon. 意识可以被认为是主观的和客观的。科学家和哲学家们一直在进行研究,希望找到对意识的客观定义和理解;根据观察到的现象,比如神经元活动。然而,意识也是主观的,因为意识或心理经验被认为是个人的,个体的现象。 Pinker (1997) broke down the consciousness into three subjective matters, the first being sentience, which refers to experiences that take place within the mind and can be modified by individual bias, this includes raw feelings and the reporting of experiences in first person tense. The second of matter is the access of information, the ability to describe the content of the mental experience without the ability to report how the content was accumulated by the nervous system. The third subject was self-knowledge, which is having accurate information about the self. There are two classical perspectives of consciousness, dualism and materialism. Dualism holds the viewpoint that the physical phenomena of the brain and mental phenomena are two separate units. There are three forms of dualism, the pure form, popular dualism and property dualism. The three forms all share the opinion that conscious experience is beyond the scope of physical science. This is termed Epiphenomenalism; there are no causal effects on the brain from mental phenomena that has derived from various brain activities. 有两种经典的意识观点,二元论和唯物主义。二元论认为大脑的物理现象和精神现象是两个独立的单位。二元论有三种形式:纯形式二元论、通俗二元论和财产二元论。这三种形式都认为意识经验超出了物理科学的范围。这被称为副现象论;从各种各样的大脑活动中产生的心理现象对大脑没有因果影响。 Materialism is the contrary of dualism, materialism states that the mind and the body are both physical mediums and that consciousness is derived from physical properties. Science has proved that there are specific parts of the brain that play specific roles in mental processing and studies of individuals with lesions in particular areas show there this damage to a region can cause a person’s emotional state to change. There are many forms of materialism but the most recognised are philosophical behaviourism materialism, which emphasises a person’s capabilities and dispositions because they can be measured, unlike the inner experiences, mental imagery and thoughts they may not be shared with others. Reductive materialism states that there are physical states or processes in the brain that are identical to mental states, however it is difficult to decipher mental processes to specific locations in the brain. (Gazzaniga, 2002: 656) 有很多形式的唯物主义,但最公认的是哲学行为主义唯物主义,它强调一个人的能力和性格,因为它们可以测量,不像内部经验,心理意象和思想,它们可能不与他人分享。还原唯物主义认为,大脑中存在着与心理状态相同的物理状态或过程,但很难将心理过程解释到大脑的特定位置。(Gazzaniga, 2002: 656) There are many domain specific specialised systems in the brain that interact in unique ways to produce sensations of conscious experience. People are aware of auditory, visual, tactile and olfactory sensations, particularly those that we pay attention to, however, we are unaware of the majority of mental process that take place and contribute to conscious experience as we perceive it; we are not aware of the brain processes that precede mental phenomena. There are many theories trying to explain consciousness and in most of these scientists are investigate neurological processes in the brain to figure out which of the many neurological processes cause consciousness. Two particular scientists that have attempted to do just that are Christof Koch, a cognitive and behavioural biologist and Susan Greenfield, a pharmacologist. They both agree that the actions of neurons are the key to consciousness but we are far from understanding exactly how. The aim of Koch and Greenfield’s (2006) research was to find the neuronal correlates of consciousness (NCC), that is the brain activity that matches up with specific conscious experience. 有很多理论试图解释意识,在大多数理论中,科学家都在研究大脑中的神经过程,以找出是哪些神经过程导致了意识。有两位特别的科学家试图做到这一点,他们是认知和行为生物学家克里斯托弗·科赫(Christof Koch)和药理学家苏珊·格林菲尔德(Susan Greenfield)。他们都认为神经元的活动是意识的关键,但我们还远不能确切地理解这是如何实现的。Koch和Greenfield(2006)研究的目的是找到意识的神经元相关(NCC),即与特定意识经验相匹配的大脑活动。 Koch’s (2006) theory states that “for each conscious experience, a unique set of neurons in particular brain regions fires in a specific manner”. There are unique NCCs for each conscious experience, for example there would be separate neuronal actions for a sensation (feeling), recognising a person in a crowd or recognising an object that is unique to that specific conscious experience. A change in the NCC alters or eliminates the associated representation of the experience being perceived. Koch (2006) believes that pyramidal neurons, long-range projection neurons, that link the back and the front of the cortex form coalitions and fire in a unique way. Different coalitions give rise to different behavioural representations of different stimuli from the senses. For instance when a person sees someone they may know in a crowd, a combination of neurons fire together for a fraction of a second. The signal reaches the anterior of the cortex, where executive functions such as planning and perception are processed, from the posterior of the cortex, where visual stimuli is first processed. If another persons calls out a name a different combination of neurons would fire together in the auditory cortex. Two-way communication between the front and the back of the cortex is created by the coalition of the pyramidal neurons and this is what could cause focus consciousness on a particular stimuli. What is not known is whether all the pyramidal neurons in the cerebral cortex are involved in NCC at any one time or whether it is a select few and if so which set constitute which conscious perception. Susan Greenfield’s (2006) theory states that “consciousness is generated by a quantitative increase in holistic functioning of the brain.” There is not a specific region in the brain or a specific set of neurons that account for conscious; rather it is an assembly of neurons that contributes to consciousness. “For each conscious experience, neurons across the brain synchronise into coordinated assemblies then disband.” The size of the assembly is related to the level of consciousness, for example during sleep the assembly will be relatively small due to the limited external stimuli not engaging neurons and would increase as one wakes up perhaps in response to the loud sound of an alarm clock. Theses ‘assemblies’ of neurons seem to occupy the right space and timescale for experiences of consciousness. Greenfield (2006) favours this theory as it accounts for everyday phenomena such as wakefulness from sleep and dreams; action of anaesthetics and the existence of self-consciousness. Not all researchers in this field believe that there is a distinct system in the brain that produces consciousness or the conscious sense of a coherent self. Rather it is the computational operations of the association cortices; the prefrontal association areas, dorsolateral prefrontal association cortex and the parietal association cortex which is the most densly interconnected region of the association cortex, that consciousness is an outcome of (Kandel et al, 2000). Association areas in the cerebral cortex, are thought to be involved in higher processing of information in the brain that is neither motor nor sensory, they take in information and react to generate an appropriate response to the stimuli presented. Individuals with lesions in the association cortices exhibit a loss, restriction or selective awareness of the self and the world around them. (Jackson, ) 并不是这一领域的所有研究人员都相信,大脑中有一个独特的系统来产生意识或对连贯自我的有意识感觉。相反,这是联合皮层的计算操作;前额叶关联区域、背外侧前额叶关联皮层和顶叶关联皮层是关联皮层中连接最紧密的区域,认为意识是(Kandel等,2000)的结果。大脑皮层中的关联区域被认为参与了大脑中非运动或感觉信息的高级处理,它们接收信息并对呈现的刺激做出反应。联合皮质受损的个体表现出对自我和周围世界的缺失、限制或选择性意识。(杰克逊) Patients whose primary visual areas in the cerebral cortex are damaged have no conscious experience of any visual stimuli as far as they are aware i.e. they are completely blind. If a spot of light was shone to various locations of their visual filed they would not respond to it and be unaware of the light. However, when told there a spot of light was being presented to them and asked to point in the direction that the light was coming from they would point in the correction direction but state that they had no awareness of the light. This phenomenon has been termed ‘Blindsight’ and was studied in detail using patient DB by Weiskrantz (1986). Patient DB was also able to identify and localize other objects that were presented to him in the blindspot of the retina. Like other patients, DB insisted that he could not see the object or the light, yet the guesses of the localization of objects were significantly correct. It is thought that perhaps blindsight occurs using other visual pathways without conscious awareness of the stimuli. The somatosensory sensory system has been used to study consciousness. Epilepsy is a neurological disorder characterised by the loss of consciousness and convulsions. The concept of ‘Split Brain’ was introduced by Roger Sperry (1981) who studied patients that had a certain form of epilepsy that involves abnormal electrical activity in one hemisphere and spreads to the other via the corpus collosum that connects the right and left cerebral hemispheres. The corpus callosum consists of millions of nerve fibres that cross from one hemisphere to the other, connecting association areas with the cerebral cortex. It was found that cutting nerve fibres of the corpus callosum thus disconnecting the two hemispheres helped some epilepsy patients by eradicating the seizures. There was evident brain damage or loss of intelligence; however integration between the two hemispheres was no longer there and the hemispheres operated separately. (Thompson, 2000: 461-464) 躯体感觉系统已被用来研究意识。癫痫是一种神经系统疾病,其特征是失去意识和抽搐。“裂脑”的概念是由Roger Sperry(1981)提出的,他研究了患有某种形式的癫痫的患者,这些患者的一个半球有异常的电活动,并通过连接左右大脑半球的胼胝体(corpus collosum)传播到另一个半球。胼胝体由从一个半球到另一个半球的数百万神经纤维组成,连接着与大脑皮层相关的区域。研究发现,切断胼胝体的神经纤维,切断大脑两个半球的连接,有助于部分癫痫患者消除癫痫发作。有明显脑损伤或智力丧失;然而,两个半球之间的整合不再存在,两个半球各自独立运作。(汤普森,2000:461 - 464) Figure 2 shows the right and left hemispheres split by the severing of the corpus callosum and their associated functions. The left visual field projects to the right visual cortex and the right visual field projects to the left visual cortex; and this is the same for sensory input from the hands. In split brain patients the right hemisphere looses it’s ability of verbal comprehension which is a function of the left hemisphere. Patients presented with an object would recognize the object but were unable to name the object. Similarly the left hemisphere lost some functions that would have been supported by the integration of the right hemisphere. The study of split brain patients with epilepsy did not give conclusive answers about consciousness, the investigation revealed that the hemispheres respond to stimuli individually thus potentially having different inputs of awareness and consciousness. Researchers have attempted to understand consciousness by applying a Reductionist approach; by dividing the concepts of consciousness into different components. The three main concepts of consciousness proposed by John Searle (1995) and Thomas Nagel were subjectivity, unity and intentionality. Subjectivity of consciousness refers to our conscious experiences of the world being individual and unique. A person is much more aware of their own conscious states, ideas, moods, sensations and feelings that those of others. A person appreciates the conscious experiences of others by relating and referring them to their own. The question, are there common conscious characteristics in different individuals, is posed and one would think so if the individuals are experiencing the same world. The problem with this component is that science is objective Unity or the unitary nature of consciousness component states that our conscious experiences come to us as a unified whole. All sensory modalities are melded into a single conscious experience; we can see, feel, smell, touch and hear something at the same time. Conscious experiences are whole and continuous. We speak in whole sentences but we do not pat attention to how the sentence was constructed. Intentionality refers to the mental content of a conscious experience or the non-physical meaning of the sensations experienced at any given moment. 统一或意识组成部分的统一性质表明,我们的意识经验作为一个统一的整体来到我们这里。所有的感觉模式都融合成一个单一的意识体验;我们可以同时看到、感觉到、闻到、触摸和听到一些东西。意识经验是完整和连续的。我们说的是整句话,但我们不注意句子是如何构造的。意向性指的是一种意识经验的心理内容或任何特定时刻所经历的感觉的非物质意义。 When discussing the issue of consciousness, it is important to mention that there are different ‘States of Consciousness’. Conscious state is when a person is fully aware and awake. Persistent vegetative state is when a person is in a coma, which is defined as deep, unarousable unconsciousness and is often prolonged. Vegetative state, this is a coma-like state which is characterised by open eyes and the appearance of wakefulness but they are unaware of their surroundings and are unresponsive. Patients in a vegetative state demonstrate cycles of sleep and wakefulness and there is extensive damage to the cortex but the brainstem is intact. Epileptic loss of consciousness, which is a temporary loss of conscious due to an epileptic seizure and is characterised by diminished awareness and wakefulness. The latter three states of consciousness are actually states of unconsciousness and another state of unconsciousness can be induced by anaesthetic agents. The states of unconsciousness have common features such as, hypometabolism in parietal regions of the brain; blocked functional connectivity in corticocortical and thalamocortical areas and unresponsiveness to conscious stimuli. (Baars et al, 2003, 26:674) Figure 2 is a Positron Emission Tomography (PET) scan showing metabolism in the brain during four states of unconsciousness (1) Comatose, (2) Vegetative state, (3) Sleep and (4) general anaesthesia. The images in the first column of the scan shows the right lateral part of the brain, the images in the second column show the left lateral part of the brain and the third column displays a medial view of the left hemisphere. During the four states of unconsciousness there is a decrease in metabolism or blood flow compared with metabolism in resting conscious patients. There are regional differences in the decrease of metabolism in the different states of unconsciousness. 图2是正电子发射断层扫描(PET)显示四种无意识状态(1)昏迷,(2)植物人状态,(3)睡眠和(4)全身麻醉时大脑的代谢。第一列的图像显示的是大脑的右侧,第二列的图像显示的是大脑的左侧第三列显示的是左半球的内侧视图。在这四种无意识状态下,与休息状态下意识清醒的病人相比,新陈代谢或血流量减少。在不同的无意识状态下,代谢降低存在着区域差异。 In the persistent vegetative state large areas of the brain have a decrease in activity. (Baars et al, 2003: 26: 674) We might be able to begin to understand consciousness by exploring the unconscious processes that take place before a conscious experience and how the two states interact. Unconsciousness is defined as a state lacking normal awareness, occurring below the level of conscious thought or without sensation or cognition. Conscious processing involves conjunction which means the concurrence of processes, two things happening at the same time. In this instance it would be identifying the orientation or location of a stimulus and being aware of the stimulus at the same time. Unconsciousness involves disjunction which is the separation or disconnection of awareness of the stimulus and the features. A person can still exhibit behavioural responses to a stimulus while being unaware of the stimulus. (Gazanniga, 2002:660) The vast amount of research on the topic of consciousness in cognitive science does not supply a precise definition of consciousness. However, research does show that they are possible correlations between neuronal activity and consciousness but the exact processes are yet to be known. We know that our conscious states and awareness drives our behaviours and response but further research into conscious and unconscious states is perhaps needed to be able to answer the question ‘what is consciousness?’ 认知科学中关于意识的大量研究并没有为意识提供一个精确的定义。然而,研究确实表明,神经元活动和意识之间可能存在关联,但具体的过程尚不清楚。我们知道,我们的意识状态和意识驱动着我们的行为和反应,但也许需要对意识和无意识状态进行进一步的研究才能回答“意识是什么?” 留学生论文相关专业范文素材资料,尽在本网,可以随时查阅参考。本站也提供多国留学生课程作业写作指导服务,如有需要可咨询本平台。 |