脑的感知觉无意识加工及其研究进展

该文从无意识加工与认知、脑结构,神经网络的关系等三个层面,阐述了近年来认知神经科学在无意识研究方面的进展。主要就无意识与意识的相互转化、无意识加工与认知层次、脑结构之间的关联性、突触的联结方式等问题进行了讨论,并对认知神经科学如何研究无意识与意识问题提出展望,     

On the Correlation between Synchronized Oscillatory Activities and Consciousness

Recent experiments have shown that the amplitudes of cortical gamma band oscillatory activities that occur during anesthesia are often greater than amplitudes of similar activities that occur without anesthesia. This result is apparently at odds with the hypothesis that synchronized oscillatory activities constitute the neural correlate of consciousness. We argue that while synchronization and oscillatory patterning are necessary conditions for consciousness, they are not sufficient. Based on the results of a binocular rivalry study of Fries et al. (1997), we propose that the degrees of oscillatory strength and synchronization of neuronal activities determine the degree of awareness those activities produce. On the other hand, the overal firing rates of neurons in cortical sensory areas are not correlated with the degree of awareness the activities of those neurons produce. The results of the experiment of Fries et al. (1997) appear to conflict with the results of another binocular rivalry experiment, in which monkeys were trained to pull a lever in order to report which stimulus object was being perceived (Leopold & Logothetis, 1996). In the latter experiment, it was demonstrated that the firing rates of neurons in striate cortex did not change during perceptual alterations, while 90% of neurons in inferior and superior temporal cortices changed their firing rate when the perceived image changed. This result led to the conclusion that activities in temporal cortex are correlated with visual awareness, but those in striate cortex are not. We argue that activities in temporal cortex contribute little, if anything, to perceptual awareness, and that their primary function is computational. Thus the correlation between the firing rates of neurons in these areas and the responses of the monkeys is due to the recognition of a particular stimulus object, which in turn is due to the computations made there.     

CONSCIOUSNESS AND THE MACHINE

Abstract. We consider only the relationship of consciousness to physical reality, whether physical reality is interpreted as the brain, artificial intelligence, or the universe as a whole. The difficulties with starting the analysis with physical reality on the one hand and with consciousness on the other are delineated. We consider how one may derive from the other. Concepts of universal or pure consciousness versus local or ego consciousness are explored with the possibility that consciousness may be physically creative. We examine whether artificial intelligence can possess consciousness as an extension of the interrelationship between consciousness and the brain or material reality.     

Instructed versus shaped human verbal behavior: Interactions with nonverbal responding

Undergraduate students' presses on left and right buttons occasionally made available points exchangeable for money. Blue lights over the buttons were correlated with multiple random-ratio random-interval components; usually, the random-ratio schedule was assigned to the left button and the random-interval to the right. During interruptions on the multiple schedule, students filled out sentence-completion guess sheets (e.g., The way to earn points with the left button is to...). For different groups, guesses were shaped with differential points also worth money (e.g., successive approximations to “press fast” for the left button), or were instructed (e.g., Write “press slowly” for the left button), or were simply collected. Control of rate of pressing by guesses was examined in individual cases by reversing shaped or instructed guesses, by instructing pressing rates, and/or by reversing multiple-schedule contingencies. Shaped guesses produced guess-consistent pressing even when guessed rates opposed those characteristic of the contingencies (e.g., slow random-ratio and fast random-interval rates), whereas guesses and rates of pressing rarely corresponded after unsuccessful shaping of guesses or when guessing had no differential consequences. Instructed guesses and pressing were inconsistently related. In other words, when verbal responses were shaped (contingency-governed), they controlled nonverbal responding. When they were instructed (rule-governed), their control of nonverbal responding was inconsistent: the verbal behavior sometimes controlled, sometimes was controlled by, and sometimes was independent of the nonverbal behavior.     

Adaptive warning signals adjusted to driver passenger conversation: Impact of system awareness on behavioral adaptations

The study investigated behavioral adaptation caused by warning signals that adaptively support drivers engaged in a passenger conversation. Novel advanced driver assistance systems (ADAS) could monitor the driver state to provide warnings adjusted to the driver’s current need for support. While first research indicates positive effects of dynamically adjusting ADAS, the overall safety potential of such adaptive systems remains unclear as little is known about adverse behavioral effects. Occasional inappropriate support due to an incorrect prediction of the current driver state might lead to critical situations when drivers are aware of the adaptive nature of the system and thus rely on the expected system behavior. To better understand behavioral adaptation to dynamically adjusting warnings, 46 participants driving on a test track reacted to two types of warnings (auditory, vibrotactile-auditory) while engaging in driver-passenger conversation or not. In a compensating warning strategy, vibrotactile-auditory warnings were displayed during conversations and auditory warnings in situations without conversation. This strategy was compared to a non-compensating warning strategy in which these assignments were reversed. The impact of behavioral adaptation was measured by considering reactions to simulated failures of these strategies. The role of system awareness for behavioral adaptation was investigated by manipulating awareness of these warning strategies across groups. We found that vibrotactile-auditory warnings reduced the detrimental effects of conversation on reaction times. Crucially, adverse behavioral adaptation was observed whenever an expected vibrotactile-auditory warning was replaced by an auditory warning but this effect was restricted to drivers in the awareness group. The results show that adaptive warning signals optimize the effectiveness of warnings during driver-passenger conversation but adverse behavioral adaptation develops when drivers are aware of the underlying warning strategy. This implies that future adaptive systems are less likely to be associated with behavioral adaptation if the adaptive nature of the system remains unnoticeable to the driver. Our findings could be used for developing and optimizing user-centered ADAS.     

Immediate and long-term priming effects are independent of prime awareness

Subliminal primes are assumed to produce weaker and short-lived effects on subsequent behavior compared to clearly visible primes. However, this difference in priming effect may be due to differences in signal strength, rather than level of awareness. In the present study we manipulated prime discriminability by using metacontrast masks and pseudomasks, while keeping the prime strength equal. This manipulation resulted in large differences in discriminability of the primes. However, both immediate response priming and long-term response priming (measured with conflict adaptation) was equal for the poorly discriminable and well discriminable primes, and equal for groups that differed markedly in terms of how well they could discriminate the primes. Our findings imply that discriminability of information is independent of both the immediate and long-term effects that information can have on behavior.     

Driving simulator validation with hazard perception

How should we assess the comparability of driving on a road and “driving” in a simulator? If similar patterns of behaviour are observed, with similar differences between individuals, then we can conclude that driving in the simulator will deliver representative results and the advantages of simulators (controlled environments, hazardous situations) can be appreciated. To evaluate a driving simulator here we compare hazard detection while driving on roads, while watching short film clips recorded from a vehicle moving through traffic, and while driving through a simulated city in a fully instrumented fixed-base simulator with a 90 degree forward view (plus mirrors) that is under the speed/direction control of the driver. In all three situations we find increased scanning by more experienced and especially professional drivers, and earlier eye fixations on hazardous objects for experienced drivers. This comparability encourages the use of simulators in drivers training and testing.     

方言经验对早期沪语儿童汉语语音意识的影响

已有研究对汉语儿童的英语语音意识进行研究,且取得了很多有价值的研究成果,但对方言儿童的汉语语音意识的研究很少。汉语是一种具有众多方言的独特语言,许多方言和标准语的语言体系有着显著差异。具有方言和普通话早期经验的双语儿童在汉语语音意识上是否存在优势,有两种不同的看法：一是从心理语言学层面上,母语学习中获得的语言能力或普遍语法能促进第二语言的学习;二是从语言学层面上来讲,母语对第二语言的学习存在干扰作用。那么双语儿童在汉语语音意识上比单一普通话儿童是否存在优势呢？本研究将进行调查。实验选取72名4岁、5岁和6岁学前儿童为被试,每个年龄组各24人,其中沪语儿童和单一普通话儿童各12名。采用听觉呈现方法对所选被试进行汉语语音意识水平的测试,包括声调意识、声母意识和韵母意识三部分,并收集儿童的口语资料。结果表明: 虽然沪语儿童声母意识和韵母意识主效应不显著,但沪语儿童语音意识总成绩和声调意识成绩均比单一普通话儿童高;沪语儿童汉语语音意识优势不受年龄的影响。本研究启示是,上海地区学前儿童学习标准语（普通话）之外应鼓励使用沪语。     

Olfactory awareness is positively associated to odour memory

We investigated the relationship between olfactory awareness and olfactory proficiency as determined by a set of standardised olfactory tasks. Olfactory awareness was indexed by scores in questionnaires focusing on odour interest, imagery ability, and prevalence of olfactory dreams. Nineteen subjects with high and 20 subjects with low odour awareness were presented with a set of standardised olfactory tasks: odour threshold, episodic odour recognition, and odour identification. The results showed that individuals with high odour awareness excelled in odour memory and identified more odours as compared with the low awareness group. Interestingly, odour naming ability exerted no influence on odour memory. Furthermore, high odour awareness was not related to a more sensitive olfactory sensory system as determined by olfactory threshold measurements.