Mind-reading without the scanner: Behavioural decoding of working memory content

ABSTRACT

Sophisticated machine learning algorithms have been successfully applied to functional neuroimaging data in order to characterize internal cognitive states. But is it possible to “mind-read” without the scanner? Capitalizing on the robust finding that the contents of working memory guide visual attention toward memory-matching objects, we trained a multivariate pattern classifier on behavioural indices of attentional guidance. Working memory representations were successfully decoded from behaviour alone, both within and between individuals. The current study provides a proof-of-concept for applying machine learning techniques to simple behavioural outputs (e.g., response times) in order to decode information about specific internal cognitive states.     

Play it again: neural responses to reunion with excluders predicted by attachment patterns

Reunion behavior following stressful separations from caregivers is often considered the single most sensitive clue to infant attachment patterns. Extending these ideas to middle childhood/early adolescence, we examined participants' neural responses to reunion with peers who had previously excluded them. We recorded event‐related potentials among nineteen 11‐ to 15‐year‐old youth previously classified on attachment interviews (11 secure and 8 insecure‐dismissing) while they played a virtual ball‐toss game (Cyberball) with peers that involved fair play, exclusion and reunion phases. Compared to secure participants, dismissing participants displayed a greater increment in the N2 during reunion relative to fair play, a neural marker commonly linked to expectancy violation. These data suggest a greater tendency toward continued expectations of rejection among dismissing children, even after cessation of social exclusion. In turn, the link between self‐reported ostracism distress and neural signs of negative expectancy at reunion was moderated by attachment, such that self‐reports were discordant with the neural index of expectancy violation for dismissing, but not for secure children. A video abstract of this article can be viewed at http://www.youtube.com/watch?v=qzoRel5c-4s .     

两例先天性无痛症患者的心理生理特点研究 Ⅱ.对致痛性强刺激的知觉和反应

本工作对两例先天性无痛症患者对于致痛性强刺激的知觉和反应进行了研究(例1女,10岁,例2男,13岁)。对照组为20例正常儿童,性别和年龄均与患儿相匹配。 结果:1),生活中痛:两例患儿均无(包括痛感觉和痛反应)。2)实验性痛:①痛感觉:两例患儿均无;②“痛”反应:例1有“痛”反应(脉搏和呼吸的变化以及行为反应明显,大致与正常儿童相似)。例2无“痛”反应(脉搏和呼吸的变化轻微,无行为反应,与正常儿童不同)。 由结果看来,先天性无痛症患者似乎可分为两种类型:不完全型(如同例1)和完全型(如同例2)。存在有“痛”反应而无痛感觉的无痛症患者。 本工作结果从另一侧面为痛的两成分学说提供了依据。     

汉语词类歧义解决初探

采用自定步速移动窗口阅读实验范式,考察汉语词类歧义解决过程。阅渎材料为含有单字词类歧义词的句子,歧义词前面的语境不提供明确的偏向性信息．后语境提供解歧信息。结果发现,主要用法和次要用法的句子都在解歧区比控制句阅读时间加长,表明汉语词类歧义解决没有即时受到歧义词两种用法的相对频率影响,而是在歧义词处暂时不进行完全的句法分配,延迟到获得充分解歧信息的时候才分配句法角色。这一结果支持词类歧义解决的延迟模型。     

IAT效应在不同目标概念水平上的差异研究

采用IAT实验设计,考察大学生对不同概念词的内隐态度之间的差别。结果发现,八组实验材料都产生了显著的IAT效应;不同性别的测验材料的IAT效应间不存在显著差异,不同喜好程度的测验材料的IAT效应间存在显著差异,且两个因素存在显著的交互作用。研究表明,IAT效应既可在上位概念水平上产生,亦可在下位概念水平上产生。     

中学生知识获得过程是从情景记忆向语义记忆转化的过程

本研究探讨中学生的知识掌握过程。针对2001—2002年度上学期教学内容,对初中二年级学生的四门课程分别进行两次测验。对于每道选择题,学生首先选择正确答案,然后指出记忆的意识状态：记住的、知道的、猜测的。结果发现,学生记忆意识类型的转变(由记住向知道)取决于课程类型、保持时间和学生等级。对于不同课程,学生占优势的意识类型不同,自然学科知道的反应占优势,社会学科记住的反应占优势;优等生知道的反应多于其他学生;随着学习时间的延长,中学生的意识类型发生了由记住向知道的转变,这表明知识掌握过程中,中学生的知识表征发生了由情景记忆向语义记忆的转变。     

汉语词汇产生中音、形、义三种信息激活的时间进程

采用图-词干扰范式和图片命名方法,探讨语音、语义、字形在汉语词汇产生中激活的时间进程与特点。选择与目标图片名称(如“羊”)具有同音(“阳”)、语义相联(“牛”)、字形相似(“丰”)或无关控制(“冷”)等四种关系的干扰字,依SOA条件呈现在将要被命名的图片上,发现图片命名时间受干扰字的影响：语义干扰效应存在于较早期的SOA(0ms)条件中,在较晚期SOA(150ms)时有很大的减弱;语音促进效应和字形促进效应同时强烈地存在于早期和晚期SOA。实验发现了词条选择(语义激活)和音位编码(语音提取)在激活时间上的重叠现象,与传统的独立两阶段模型的预期存在明显矛盾,倾向于支持交互作用理论的观点。     

年龄、焦虑与情节记忆之内容与来源的关系

将情节记忆区分为内容记忆和来源记忆,筛选年老和年轻的高、低特质焦虑者完成记忆任务,以探讨情节记忆年老化的选择性和变异性及其与焦虑之间的联系。两项实验结果表明来源记忆是否随增龄而有选择性受损受来源性质影响,与来源呈现方式和来源识记意识性无关。焦虑干扰了老年组的记忆操作,是老年人情节记忆存在个体差异的原因之一;但焦虑对青年组没有不利影响,提示焦虑调节两类记忆的年龄差异。     

当代西方社会科学哲学发展的三种态势

从历史的角度看,社会科学哲学的历史发展并不存在一个连续和统一的过程.曼尼卡斯(Peter T.Manicas)把社会科学哲学的历史发展大致分为四个阶段,每个阶段都有与之相对应的主题[1]:第一个阶段开始于西方哲学和科学的肇始——主题是古希腊城邦;第二个阶段开始于文艺复兴晚期,延续到法国革命——主题是西方现代性;第三个阶段大约是在19世纪——主题是科学观念与人文科学观念之争;第四个阶段是现在,开始于20世纪50年代——主题是实证主义与反自然主义关于人文科学观念的争论.     

Make‐or‐Break: Chasing Risky Goals or Settling for Safe Rewards?

Humans regularly pursue activities characterized by dramatic success or failure outcomes where, critically, the chances of success depend on the time invested working toward it. How should people allocate time between such make‐or‐break challenges and safe alternatives, where rewards are more predictable (e.g., linear) functions of performance? We present a formal framework for studying time allocation between these two types of activities, and we explore optimal behavior in both one‐shot and dynamic versions of the problem. In the one‐shot version, we illustrate striking discontinuities in the optimal time allocation policy as we gradually change the parameters of the decision‐making problem. In the dynamic version, we formulate the optimal strategy—defined by a giving‐up threshold—which adaptively dictates when people should stop pursuing the make‐or‐break goal. We then show that this strategy is computationally inaccessible for humans, and we explore boundedly rational alternatives. We compare the performance of the optimal model against (a) a myopic giving‐up threshold that is easier to compute, and even simpler heuristic strategies that either (b) only decide whether or not to start pursuing the goal and never give up or (c) consider giving up at a fixed number of control points. Comparing strategies across environments, we investigate the cost and behavioral implications of sidestepping the computational burden of full rationality.