The deficiency of attention bias to emotional prosody in the teenagers with autism spectrum disorders: A perceptual mode of low efficiency
收稿日期: 2017-01-9 网络出版日期: 2018-06-01
Received: 2017-01-9 Online: 2018-06-01
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情绪注意偏向是指与中性刺激相比, 情绪刺激会引起个体的优先加工。为了探讨ASD青少年听觉通道的情绪注意偏向是否存在缺陷, 并进一步考察目标任务的知觉负载水平是否影响ASD青少年情绪韵律的注意偏向, 研究先后采用oddball范式、双任务范式呈现中性、快乐和愤怒韵律。实验1结果发现, ASD被试在不同情绪韵律类别下的反应时均长于TD被试。实验2结果发现, 在提供注意指示条件下, 即使在高知觉负载水平上, ASD被试的情绪韵律检测能力及错误率也与普通被试相似, 但对于情绪韵律的反应时与中性韵律无差异。结果表明, 知觉负载对ASD青少年情绪韵律注意偏向的影响是有限度的, 该群体听觉通道的情绪注意偏向存在缺陷, 主要表现为对情绪韵律知觉效率的相对低下。
情绪注意偏向是指与中性刺激相比, 情绪刺激会引起个体的优先加工。为了探讨ASD青少年听觉通道的情绪注意偏向是否存在缺陷, 并进一步考察目标任务的知觉负载水平是否影响ASD青少年情绪韵律的注意偏向, 研究先后采用oddball范式、双任务范式呈现中性、快乐和愤怒韵律。实验1结果发现, ASD被试在不同情绪韵律类别下的反应时均长于TD被试。实验2结果发现, 在提供注意指示条件下, 即使在高知觉负载水平上, ASD被试的情绪韵律检测能力及错误率也与普通被试相似, 但对于情绪韵律的反应时与中性韵律无差异。结果表明, 知觉负载对ASD青少年情绪韵律注意偏向的影响是有限度的, 该群体听觉通道的情绪注意偏向存在缺陷, 主要表现为对情绪韵律知觉效率的相对低下。
Emotional attention bias refers that emotional stimuli usually get priority of attention over the neutral stimuli, which has been frequently replicated in normal participants. However, previous studies reported that teenagers with autism spectrum disorders (ASD) had atypical attention patterns of processing emotional faces and pictures, that is, their first attention was located at the neutral stimuli instead of the emotional stimuli. According to the perceptual load theory, some studies demonstrated the deficiency of attention bias to emotions in the teenagers with ASD was due to the perceptual load of the main task was too high for them, so that they can’t process the emotion. Till now, little has been known about the ASD teenagers’ attention in processing auditory emotional stimuli, although emotional expression also actually depends on the changes of acoustic cues in the speech prosody. To testify the generality of attention bias to cross-model emotions in the teenagers with ASD, we extended the experimental materials to emotional prosody. In present study, 14 teenagers with ASD and 17 typical developing (TD) people were recruited in two experiments. The participants were required to complete a main task while the emotional prosody voices were presented as the deviated task-irrelevant stimuli. In Experiment 1, the participants were instructed to ignore sounds and to classify the pictures. In Experiment 2, we adopted a dual-task paradigm, which required participants to respond to the target letters first and then to point whether they hear the novel emotional prosody. And in experiment 2, we also manipulated the level of perceptual load through changing the similarity between the letters in virtual round. Results showed that: (1) Reaction time of ASD subjects were longer than TD subjects under any different emotions rhyme categories. (2) Whether in high or low perceptual load, reaction times and error rates of the main task as well as accuracy of emotional prosody detection task between two groups of participants have no significant differences. In providing notice indicating conditions, even in a high perceptual load level, ASD subjects of emotional rhythm detection capability and error rates are similar to TD subjects, but for emotional rhythm react time with neutral rhythm no difference. These findings revealed that ASD have the similar attention processing level with TD in attention conditions. The results of two studies strongly suggested that the attention bias to emotional prosody was deficient in the teenagers with ASD, which was consistent with the results from visual channels and the teenagers with ASD have defect on emotional attention bias in auditory channel, main showed low perception efficiency on emotional rhythm perception.
Emotional attention bias refers that emotional stimuli usually get priority of attention over the neutral stimuli, which has been frequently replicated in normal participants. However, previous studies reported that teenagers with autism spectrum disorders (ASD) had atypical attention patterns of processing emotional faces and pictures, that is, their first attention was located at the neutral stimuli instead of the emotional stimuli. According to the perceptual load theory, some studies demonstrated the deficiency of attention bias to emotions in the teenagers with ASD was due to the perceptual load of the main task was too high for them, so that they can’t process the emotion. Till now, little has been known about the ASD teenagers’ attention in processing auditory emotional stimuli, although emotional expression also actually depends on the changes of acoustic cues in the speech prosody. To testify the generality of attention bias to cross-model emotions in the teenagers with ASD, we extended the experimental materials to emotional prosody. In present study, 14 teenagers with ASD and 17 typical developing (TD) people were recruited in two experiments. The participants were required to complete a main task while the emotional prosody voices were presented as the deviated task-irrelevant stimuli. In Experiment 1, the participants were instructed to ignore sounds and to classify the pictures. In Experiment 2, we adopted a dual-task paradigm, which required participants to respond to the target letters first and then to point whether they hear the novel emotional prosody. And in experiment 2, we also manipulated the level of perceptual load through changing the similarity between the letters in virtual round.
Results showed that: (1) Reaction time of ASD subjects were longer than TD subjects under any different emotions rhyme categories. (2) Whether in high or low perceptual load, reaction times and error rates of the main task as well as accuracy of emotional prosody detection task between two groups of participants have no significant differences. In providing notice indicating conditions, even in a high perceptual load level, ASD subjects of emotional rhythm detection capability and error rates are similar to TD subjects, but for emotional rhythm react time with neutral rhythm no difference. These findings revealed that ASD have the similar attention processing level with TD in attention conditions.
The results of two studies strongly suggested that the attention bias to emotional prosody was deficient in the teenagers with ASD, which was consistent with the results from visual channels and the teenagers with ASD have defect on emotional attention bias in auditory channel, main showed low perception efficiency on emotional rhythm perception.
胡金生, 李骋诗, 王琦, 李松泽, 李涛涛, 刘淑清.
HU Jinsheng, LI Chengshi, WANG Qi, LI Songze, LI Taotao, LIU Shuqing.
情绪韵律(Emotional Prosody)是由音高、强度、时长等声学线索变化构成的一种副言语信息, 可以反映讲话者不同的情绪状态(Frühholz, Ceravolo, & Grandjean, 2012)。对于以社会交流和情绪理解困难为核心症状的孤独症谱系障碍(Autism Spectrum Disorders, ASD)者来说, 如何解读他人情绪不仅是当前研究的一个热点, 也是该障碍早期诊断和临床干预的重要着眼点。已有研究发现, ASD者的情绪韵律识别普遍上存在以下几个缺陷。首先, ASD者对不同情绪效价的韵律识别存在不平衡, 他们识别由外部情境引发的悲伤和快乐韵律的准确性, 明显高于由内部愿望和信念引发的失望、尴尬和自豪等情绪, 这主要源于该人群缺少对他人和自我心理状态的归因能力(Jones et al., 2011)。其次, 从情绪韵律识别过程来看, 知觉功能促进化模型(Enhanced Perceptual Functioning Model, EPFM)指出, ASD者在加工初期对音高、音强等低级声学线索过度敏感, 这会造成情绪韵律的早期解码偏差(O’Connor, 2012)。最后, 由于ASD者的弱中央统合(Weak Central Coherence, WCC)特点, 后期整合阶段他们倾向于根据语义或语境辨别讲话者情绪, 而不是综合情绪韵律与多种言语信息后再判断(Le Sourn-Bissaoui, Aguert, Girard, Chevreuil, & Laval, 2013)。一项关于情绪韵律加工的发展性研究发现, 普通儿童从10岁才开始发展对情绪韵律优先加工的敏感性(Waxer & Morton, 2011), 而ASD研究领域则缺乏明确的界定。但有研究表明, ASD青少年的早期注意模式, 即情绪注意定向方面与普通被试存在很大差异, 表现为首次注视点和首次注视时间均偏向于非情绪场景刺激(Santos et al., 2012)。情绪注意定向是对目标刺激的初级锁定过程, 是注意偏向的基础阶段, 由于视听觉加工通道的差异, 与视听相关的情绪注意定向结果可能并不具有一致性。以往研究发现, ASD青少年的听觉敏感性较视觉更高, 在执行时序判断时, 听觉较普通人更加敏感, 而视觉则无差异(Kwakye, Foss-Feig, Cascio, Stone, & Wallace, 2011)这意味着ASD的青少年听觉通道的情绪注意定向是否表现出和视觉通道一致的特点尚不明确。
在日常会话中人们不会刻意关注情绪信息, 讲话者表情和语气的变化会引起注意系统的自动化加工。一般来说, 与中性刺激相比, 情绪刺激会引起个体更快且更多的注意和优先加工, 这就是情绪注意偏向(Emotional Attention Bias) (白学军, 贾丽萍, 王敬欣, 2013)。从注意偏向的过程来看, 该过程主要包括注意定向加速、注意解除困难和注意回避三个成分。对于普通个体而言, 他们在社会生活中逐渐形成了对情绪信息的敏感性, 当情绪刺激出现时, 他们会表现出注意定向加速, 随后也可能表现出注意解除困难(Cisler & Koster, 2010; Sheppes, Luria, Fukuda, & Gross, 2013)。而ASD人群可能并非如此, 例如, ASD成人的研究则发现该人群不像普通人那样首先注意情绪信息, 而是更偏爱非情绪刺激(Sasson, Pinkham, Weittenhiller, Faso, & Simpson, 2016)。虽然, 已有研究已发现ASD人群存在情绪注意偏向缺陷, 但其背后原因还不清楚, 且在ASD青少年群体中该问题尚不明确。
知觉负载理论(The Perceptual Load Theory)认为, 个体在进行目标任务时, 对无关刺激的注意和加工程度取决于目标任务的知觉负载量。具体来说, 当目标任务耗尽所有可用认知资源时, 个体对无关刺激的注意加工就会削弱甚至消失。相反, 当目标任务不需要占用过多资源时, 剩余资源就会自动地加工无关刺激(Lavie, 2005)。近年来, 研究者将知觉负载理论延伸至跨通道领域。被试在高低知觉负载水平下完成一项视觉辨别任务, 并同时报告是否听到一个纯音。结果发现, 个体的听觉检测敏感性随着视觉知觉负载水平的升高而降低, 当视觉处于高知觉负载条件下时, 被试对纯音的漏报率达79%, 明显高于低知觉负载条件(Macdonald & Lavie, 2011; Raveh & Lavie, 2015)。可见, 听觉和视觉在一定程度上享有共同的注意资源。此外, 知觉负载理论自提出以来便在不同人群的研究中得以验证。例如, 有研究发现, 65~79岁的老年人和儿童与年轻人相比, 只有在较低的知觉负载水平下才可以对无关刺激进行加工, 这是由于前两组人群的注意能力缺陷所致(Karalunas, Huang-Pollock, & Nigg, 2012)。同理, ASD的注意缺陷一直被认为是该人群的主要症状, 即使成年阶段也是如此。例如, 已有研究发现, 任务的知觉负载水平会影响ASD者的刺激检测能力, 即随着任务知觉负载水平的升高, ASD被试对刺激的加工和检测能力下降(Hessels, Hooge, Snijders, & Kemner, 2014)。据此, 本研究的另一目的是确定ASD青少年表现出的情绪注意偏向缺陷是否是由于目标任务知觉超载造成, 目标任务可能会消耗他们的大量认知资源, 导致没有资源用于情绪韵律的注意偏向加工, 造成加工困难。
综上所述, 情绪韵律识别缺陷阻碍了ASD者日常社交活动的有效进行, 由于听觉是日常社交活动中信息传递的主要通道, 如果能以情绪注意偏向角度从听觉通道研究ASD青少年的情绪韵律识别问题及其原因对于探索ASD社交障碍进而开发有针对性的干预训练方案将具有重要的理论和实际意义。据此, 本研究设置2个实验：实验1要求被试忽略韵律声音, 对屏幕上的图片分类, 通过控制新异情绪韵律出现的频率, 检验被试是否存在情绪韵律注意偏向。研究假设：如果ASD被试在听觉通道也存在注意偏向缺陷, 那么, ASD被试在3种韵律条件下, 图片判断的反应时和错误率将没有差异, 而普通被试的图片判断速度会受快乐和愤怒韵律的影响。实验2采用双任务范式在实验1基础上进一步确定ASD被试情绪韵律注意偏向是否存在, 并考察知觉负载在其中的作用。在控制了目标任务的知觉负载水平后, 要求被试注意并报告是否听到情绪韵律。如果ASD被试的情绪韵律注意偏向缺陷是因为目标任务知觉超载, 那么高知觉负载下, ASD被试目标任务的表现和情绪韵律检测能力会大幅下降。
本实验采用Max, Widmann, Kotz, Schröger和Wetzel (2015)研究普通被试如何注意和加工无关情绪声音的范式。将不同情绪韵律以oddball形式呈现, 要求被试忽略声音, 只判断屏幕上图片的类别, 通过计算并比较不同情绪韵律试次下被试判断图片的错误率和反应时, 检验ASD者是否存在情绪韵律注意偏向。
从某市孤独症障碍者综合服务中心选取13~20岁的ASD青少年被试17名, 其中3人由于未完成实验而被排除, 最终有效被试14人, 均为男性。所有ASD被试均经过正规医院诊断, 符合DSM-V、ICD-10等精神病学专业诊断标准, 韦氏全量表智力大于70, 无明显语言障碍, 符合高功能孤独症标准, 且无其他精神或神经障碍、遗传疾病和重大身体残障等。另外, 从辽宁师范大学、辽宁师范大学附属中等职业技术专业学校选取身体健康的典型发育(typical development, TD)被试18名作为对照组, 其中1人由于未完成实验而被排除, 最终有效被试17人, 均为男性。被试年龄和智力情况见表1。
表1 被试样本的基本情况M (SD)
|基本情况||ASD (n = 14)||TD (n = 17)||t||p|
|年龄(岁)||16.93 (1.194)||16.18 (0.53)||0.92||0.365|
|韦氏言语智力||96.07 (9.54)||102.00 (9.27)||-1.74||0.091|
|韦氏操作智力||102.93 (11.61)||108.65 (8.49)||-1.58||0.124|
|韦氏全量表智力||102.36 (12.33)||107.65 (9.72)||-1.34||0.192|
请一名播音主持专业女生分别以中性、愤怒和快乐的情绪语调发出无意义音节da, 每种情绪录制12次, 声音是单声道16位采样, 采样率为44100 Hz。借助praat软件(Boersma & van Weenink, 2001)对音频材料的音高进行分析。相对于中性韵律(132 Hz), 愤怒的情绪音高更高(188 Hz), t(11) = 28.12, p < 0.001。同样地, 快乐的情绪音高也更高(192 Hz), t(11) = 23.18, p < 0.001。将上述声音编辑为时长200 ms, 音强80 dB的音频材料。为保证情绪韵律符合要求, 请不参与实验的30名同学(15男, 15女)评定每个声音的韵律类型(愤怒、快乐、中性、其他)。计算每个声音情绪韵律的识别率, 最终在三种音频材料中选择识别率最高的三个作为实验材料, 识别率分别为93.3%、96.7%和90%。
采用2(被试：ASD组和TD组)×3(韵律类型：中性、愤怒和快乐)的两因素混合实验设计, 其中被试类别为组间变量, 韵律类型为被试内变量。因变量为图片判断的反应时和错误率。
被试进入隔音室, 坐在电脑前并戴好耳机, 将音量调至合适大小。实验采用E-prime 2.0软件编程及搜集数据。整个实验流程见图1, 情绪韵律以oddball形式呈现, 快乐和愤怒韵律为新异刺激, 中性韵律为标准刺激。为了让被试熟悉图片材料, 实验开始前要求被试在没有声音的情况下完成图片判断任务, 准确率达到80%后进入正式实验。此时, 告知被试尽量忽略耳机中的声音, 集中注意力判断屏幕上的图片。正式实验分为2组, 每组150个试次, 服饰和动物图片各半, 且中性韵律占80%, 愤怒和快乐韵律各占10%。每组情绪韵律的呈现顺序是伪随机的。如图2所示, 每个试次开始时, 屏幕中央先呈现一个1000 ms的十字注视点, 随后, 呈现200 ms的目标图片和韵律声音。接着出现1800 ms的空屏, 要求被试对图片进行判断, 服饰按F(左)键、动物按J (右)键, 按键在组间及左右手间平衡。
注：第一行为目标任务图片, 第二行为韵律声音, 同时呈现200 ms; 黑色为中性韵律, 绿色为快乐韵律, 红色为愤怒韵律; 第三行为正确反应。彩图见电子版。
表2 两组被试在oddball任务中的反应时和错误率M (SD)
|反应时(ms)||589.16 (120.03)||588.97 (129.68)||586.87 (71.99)||425.73 (99.65)||430.03 (113.75)||401.26 (105.77)|
|错误率||0.16 (0.12)||0.15 (0.10)||0.12 (0.09)||0.06 (0.04)||0.05 (0.04)||0.05 (0.03)|
对反应时数据进行重复测量方差分析的结果也显示, 被试的主效应显著, F(1, 29) = 7.00, p = 0.013, η2 = 0.19。事后比较发现, ASD被试在愤怒、快乐、中性三种韵律类型上的反应时均长于TD被试。韵律类型主效应不显著, F(2, 58) = 1.83, p = 0.169。被试类别和韵律类型的交互作用也不显著, F(2, 58) = 0.44, p = 0.604。无论韵律类型如何, TD被试的反应速度都快于ASD被试。两组被试在三种韵律条件下图片判断的平均反应时, 见图3A。
对错误率做重复测量方差分析显示, 被试的主效应显著, F(1,29) = 14.18, p = 0.001, η2 = 0.33。事后比较发现, ASD被试在愤怒、快乐、中性三种韵律类型上的错误率均高于TD被试。韵律类型主效应不显著, F(2, 58) = 1.46, p = 0.242; 被试和韵律类型交互作用也不显著, F(2, 58) = 0.89, p = 0.400。反应时和错误率结果均未发现情绪韵律类型的主效应及其与被试类别的交互作用, 而只发现了被试类别的主效应。两组被试在三种韵律条件下图片判断的平均错误率, 见图3B。
由于实验1未发现韵律类别的主效应及其与被试类别的交互作用, 因此, 无法判断ASD被试的注意偏向是否存在缺陷。为进一步对ASD者的情绪韵律知觉偏向问题进行探索, 并确定知觉负载对ASD者情绪韵律识别的影响, 故设置实验2。实验2以Raveh和Lavie (2015)探讨知觉负载对TD被试检测无关声音影响的研究为基础, 包含了一个双任务范式。通过改变屏幕上字母的相似性控制了目标任务的知觉负载水平, 既要求被试对目标字母反应, 又要注意并指出是否听到情绪韵律。
采用2(被试：ASD组和TD组)×3(韵律类型：愤怒、快乐、中性)×2(知觉负载水平：高和低)的三因素混合实验设计, 其中被试为组间变量, 韵律类型和知觉负载水平为组内变量。因变量为被试辨别目标字母的反应时和错误率, 以及情绪韵律的正确检测率。
被试进入隔音室, 坐在电脑前并戴好耳机, 将音量调至合适大小。实验任务采用E-prime 2.0软件编程及搜集数据。如图4所示, 每个试次开始时会在屏幕中央呈现1000 ms的十字注视点。之后呈现字母圆200 ms, 同时呈现韵律声音。随后, 呈现1800 ms的空屏。被试须在字母圆和空屏呈现的共2 s时间被试用左手按键盘对目标字母进行尽快且准确的判断, F键表示看到目标字母X, J键表示看到目标字母N。接下来, 屏幕中央出现100 ms的问号标志, 呈现1900 ms的空屏, 被试须在问号和空屏呈现的共2s时间内尽快且准确判断是否听到情绪韵律。右手按鼠标左键表示听到情绪韵律, 按鼠标右键表示没有听到。为了方便被试反应, 在键盘和鼠标上分别贴上起提示作用的贴纸。
正式实验开始前, 先给被试呈现带有新异韵律刺激的慢速演示试次。随后有12个正常的练习试次, 其中2个试次随机呈现新异情绪韵律。正式实验分为2组, 每组有150个试次, 目标任务负载水平高低各半, 且中性韵律占80%, 愤怒和快乐韵律共占20%, 韵律声音的呈现顺序是伪随机的。正式实验完成后, 被试要完成包含150个试次的控制任务。此任务不需要被试搜索目标字母, 只判断是否听到情绪韵律。控制任务的目的是为了表明, 正式实验中被试无法检测到情绪韵律是目标任务知觉超载造成的, 而不是情绪韵律知觉或识别的固有缺陷。
将每组中前4个试次和新异情绪(愤怒、快乐)韵律出现后的连续2个试次的结果剔除。分析字母判断任务的正确率和反应时前删除情绪韵律检测错误的试次。每组被试在不同韵律类型和知觉负载水平下, 字母判断任务的平均反应时见表3、图5。对反应时结果采用2(被试：ASD组和TD组)×3(韵律类型：愤怒、快乐、中性)×2(知觉负载水平：高和低)三因素重复测量方差分析。结果显示, 知觉负载水平主效应显著, F(1, 29) = 144.13, p < 0.001, η2 = 0.83。这说明, 被试在高知觉负载水平下对字母判断的速度明显长于低知觉负载水平。韵律类型主效应也显著, F(2, 58) = 7.78, p = 0.001, η2 = 0.21。可见, 与中性韵律相比, 新异情绪韵律会引起被试反应时增加。被试的主效应不显著, F(1, 29) = 0.27, p = 0.607。总体上, 两组被试在判断目标字母时不存在反应时差异。
表3 两组被试在字母判断任务中的反应时M (SD)
|低||618.84 (127.41)||654.02 (144.84)||553.12 (83.09)||648.98 (135.02)||632.25 (140.32)||593.60 (111.13)|
|高||863.93 (143.28)||753.06 (151.50)||748.23 (154.48)||839.98 (127.54)||819.49 (82.68)||797.96 (108.23)|
知觉负载水平、韵律类型和被试类别的三者交互作用显著, F (2, 58) = 3.22, p = 0.047, η2 = 0.100。简单效应分析发现：TD组被试在高、低知觉负载条件下, 愤怒和快乐情绪类别的反应时除高知觉负载的快乐韵律外, 均显著长于中性类别, 表现出了显著的注意偏向效应。ASD被试在高、低知觉负载条件下均未发现情绪类别的反应时显著差异, 这意味着该组被试没有出现对情绪韵律的注意偏向。两组被试在三种情绪类别条件下均体现出高负载较低负载更长的反应时, 体现出了显著的知觉负载效应。
对错误率数据采用2(被试：ASD组和TD组)×3(韵律类型：愤怒、快乐、中性)×2(知觉负载水平：高和低)三因素重复测量方差分析。表4、图6为两组被试在不同情绪韵律类型和知觉负载水平下字母判断任务的平均错误率。方差分析结果显示, 知觉负载水平主效应显著, F(1,29) = 99.43, p < 0.001, η2 = 0.774。韵律类型主效应显著, F(2,58) = 14.56, p ≤ 0.001, η2 = 0.334。这表明, 目标任务知觉负载水平越高, 被试字母判断的错误率越高, 并且愤怒、快乐情绪韵律条件下的错误率高于中性韵律条件。被试类型主效应不显著, F(1, 29) = 0.32, p = 0.575, 不存在任何交互作用(ps ≥ 0.456)。
表4 两组被试在字母判断任务中的错误率M (SD)
|低||0.19 (0.17)||0.13 (0.11)||0.07 (0.05)||0.24 (0.18)||0.16 (0.14)||0.08 (0.06)|
|高||0.49 (0.18)||0.40 (0.14)||0.36 (0.13)||0.46 (0.06)||0.40 (0.16)||0.37 (0.06)|
反应时结果表明, 在有注意提示情况下, TD被试出现了显著的情绪韵律知觉偏向效应, 而ASD被试依旧没有产生类似效应, 但却同TD被试一样, 出现了知觉载荷效应, 甚至在知觉超载条件下也表现出与TD被试相同的反应时水平。而错误率结果与反应时结果有所差异, 即无论在高、低知觉负载条件下, ASD被试在愤怒、快乐情绪韵律条件下的错误率均高于中性条件, 呈现出了错误率的注意偏向效应。而知觉载荷上两组被试呈现出了相同的趋势, 即目标任务知觉负载水平越高, 被试字母判断的错误率越高。这些结果意味着, 在有注意提示情况下, ASD被试可能以较低的加工效率完成情绪韵律的加工, 而知觉负载对其不产生影响。
从原始数据中, 重新纳入有效试次进行后续分析, 字母判断错误的试次不计入检测任务的数据分析。两组被试在不同知觉负载水平下各类情绪韵律的平均检测率见表5, 平均检测率即被试在不同知觉负载水平下正确检测情绪韵律的试次数除以该知觉负载试次总数。以被试类别(ASD组和TD组)为组间变量、以知觉负载水平(高和低)为组内变量, 以情绪韵律的平均检测率为因变量进行两因素重复测量方差分析。结果显示, 知觉负载水平主效应显著, F(1, 29) = 49.34, p < 0.001, η2 = 0.59。事后比较结果表明, 随着知觉负载由低变高, 被试的情绪韵律检测率下降。同时, 被试的主效应不显著, F(1, 29) = 3.16, p = 0.175。这说明, 在注意提示条件下, ASD被试和TD被试的情绪韵律检测率没有差异, 二者有非常相似的情绪韵律加工水平。被试和知觉负载水平的交互作用也不显著, F(2, 58) = 2.35, p = 0.256。
表5 两组被试在不同知觉负载水平下情绪韵律的平均检测率M (SD)
|低||100% (2.4%)||93.33% (2.1%)||100% (1.8%)||93.33% (3.3%)||93.33% (2.3%)||100% (2.1%)|
|高||86.67% (2.0%)||93.33% (1.9%)||100% (2.7%)||86.67% (3.0%)||80.00% (1.6%)||100% (2.8%)|
此外, 控制任务中, 所有被试的情绪韵律正确识别率均大于96%, 且不存在组间差异。这表明, 不同知觉负载水平下, 被试情绪韵律检测率的差异并不是由于个体情绪韵律知觉或反应的固有缺陷所致。
本研究先后采用oddball范式及双任务范式, 通过控制情绪韵律、知觉负载等因素, 首次考察了ASD青少年的情绪韵律注意偏向问题。实验1结果发现, ASD被试在愤怒、快乐和中性情绪韵律类型条件下的反应时均长于TD组, 并未发现情绪韵律类型及其与被试组别之间的交互作用。之前有研究同样以5~17岁的ASD儿童及青少年为被试, 采用视频游戏法, 要求被试对不同情绪韵律和语义混合的句子进行偏好选择。结果发现TD被试会优先加工情韵律的句子, ASD被试则不存在这种偏好。研究者认为, TD被试更容易被情绪韵律吸引并优先加工, 但ASD被试难以区分情绪韵律和语义的优先顺序(Brooks & Ploog, 2013)。据此, 本研究假设, ASD被试可能存在听觉通道的情绪韵律注意偏向缺陷。但实验1结果与研究假设略有出入, 由于情绪韵律类别主效应及其与被试类别的交互作用不显著, 该结果无法证明ASD者是否存在注意偏向缺陷。这一结果可做如下探讨：
首先, 为避免词汇语义加工的干扰, 实验1使用物品图片为实验材料。两组被试可能对图片刺激的认知经验有所差异, 进而导致当前结果, 例如有研究发现ASD青少年人群普遍缺乏世界知识, 对常识经验理解能力不足(Norbury, 2005)。在本研究中, 这一特点可能致使其判断时间更长。相反, 对照组被试的判断整体较快, 甚至出现天花板效应, 即无论在何种情绪韵律类别下, TD被试的反应时均快于ASD被试, 因而掩盖了实验处理效应。其次, 从结果来看, TD被试和ASD被试的反应时结果在情绪韵律类别上呈现了类似的变化趋势, 尚且推测TD被试也存在注意偏向缺陷。但以往研究却已表明, 普通人存在对情绪韵律的注意偏向(Buchanan et al., 2000), 这种注意偏向的存在是个体对情绪韵律信息自动化加工的证据。人类自出生起就会表现出对视觉通道情绪信息的敏感性, 普通个体早在10岁左右已经开始发展对情绪韵律优先加工的敏感性, 进入青少年时期则趋于稳定(Waxer & Morton, 2011)。故此, 有关TD被试存在注意偏向缺陷的推测并不可靠。本研究结果虽无法证明两组被试对情绪韵律的注意偏向是否存在困难, 但却至少表明ASD和TD被试在总体的反应速度上确有差异。而二者对情绪韵律的知觉偏向是否存在缺陷, 或者呈现怎样的差异需进一步论证。
总之, 根据以上分析推论可知, 实验1很可能是因为实验控制不够完善, 因而未发现与情绪韵律有关的显著效应。鉴于以上问题, 本研究转而采用双任务范式, 使用了比图片刺激更为简单基础的字母为材料, 而不涉及过多的生活常识, 继续探索ASD青少年在情绪韵律加工过程中的注意偏向问题, 并引入认知载荷变量进一步考察该人群情绪韵律注意偏向缺陷与知觉负载的关系, 以探索ASD青少年的情绪韵律注意偏向是否受知觉超载的影响。Bertels, Kolinsky, Bernaerts和Morais (2011)最早采用一种听觉版本的情绪视觉空间线索任务来探索个体听觉通道的情绪注意偏向, 该任务以录制好的情绪词作为情绪线索。但采用该实验范式和听觉材料探讨个体听觉通道的情绪注意偏向存在一定问题。首先, 该研究范式不适合听觉刺激的呈现, 因为作为线索呈现的情绪词平均时长为780 ms, 这在一定程度上干扰了线索与目标之间的SOA, 从而污染返回抑制效应结果。其次, 相对于视觉通道的情绪信息, 以录播形式呈现的情绪词需要被试对词语语义进行分析和理解, 该过程复杂且耗时, 也容易对结果造成影响。相比之下, 本研究采用的双任务范式在听觉刺激呈现方面表现出了一定优势, 既可以通过控制情绪韵律出现的频率来达到引起被试注意偏向的目的, 又排除了返回抑制范式中对线索和目标间SOA的干扰。
实验2通过控制屏幕上字母的相似性, 操纵了目标任务的知觉负载水平, 发现随着目标任务知觉负载水平由低变高, 两组被试的字母辨别能力下降。这与之前关于TD被试的研究一致, 控制字母相似性的方法可以成功改变目标任务的知觉负载水平(Macdonald & Lavie, 2011; Molloy, Griffiths, Chait, & Lavie, 2015)。并且, 实验2要求被试在对目标字母反应后, 指出是否听到情绪韵律, 发现即使知觉超载, ASD被试对目标任务的表现和情绪韵律检测能力也没有大幅下降, 这排除了该人群没有剩余认知资源用于情绪信息注意的推测。该结果与近年来关于ASD儿童及青少年被试的研究结果相似, 当增加视觉通道的知觉负载时, ASD被试均会表现出正常甚至优于TD被试的无关刺激检测能力(Wolff, Chmielewski, Beste, & Roessner, 2017)。ASD群体的这种优势可以用知觉功能促进化模型来解释, 该模型认为, 与普通人群相比, ASD群体普遍具有 正常甚至优势的低水平知觉加工能力(Mottron, Dawson, Soulières, Hubert, & Burack, 2006; Tillmann & Swettenham, 2017)。
总体上, 实验1要求被试忽略韵律声音, 而实验2采用双任务范式, 要求被试注意韵律声音并报告是否听到情绪韵律, 以此强化被试的注意水平。结果显示, ASD青少年被试可以加工情绪韵律, 且正确检测率也与TD被试相似, 但对情绪韵律的加工时间上较TD被试更长。本研究结果表明, 同实验1相比, 实验2的注意指示有效的激发了两组被试对于情绪韵律注意的社会动机, 从而使二者在不同程度上体现出了对情绪韵律信息的关注。实验1和实验2的不同结果可能来自于是否提供注意指示。值得关注的是, 本研究虽然发现, 在提供注意指示条件下, ASD被试在字母判断任务中的错误率以及在情绪韵律判断任务及情绪韵律检测率方面与TD被试无差异, 但在字母任务的反应时上, 并没有表现出对情绪韵律的注意偏向。有研究者认为, ASD群体普遍表现出对社会信息的忽视在一定程度上与该人群社会动机背后的奖励环路受损密切相关, 例如, 杏仁核、纹状体和眶额皮层环路受损, 以及特定的神经肽和神经传导物质调节功能异常等(Bachevalier & Loveland, 2006)。这些发现说明, 该人群的情绪注意偏向会受到社会动机背后神经环路可用性的影响。实验2中, 注意指示的提供对ASD被试的社会动机激发启动了一定作用, 但相比TD被试, 这种提示相对有限。这也意味着, ASD青少年在加工情绪韵律上体现出了较低的效率。社会动机理论(Social Motivation Theory)认为, 情绪刺激会激活社会动机机制, 建立情绪与内在奖励之间的联系, 促进情绪理解和社会沟通的强化学习, 进而形成情绪注意偏向(Chevallier, Kohls, Troiani, Brodkin, & Schultz, 2012)。但从本研究结果来看, 可能ASD青少年被试对社会线索不感兴趣, 社会动机机制难以被情绪刺激激活, 无法自发地构建内在奖励并产生积极心理意义, 从而表现出情绪信息不敏感。
最后, 研究也存在一定局限性。一方面, 实验的声音材料选取了愤怒、快乐和中性三种情绪韵律, 这三种情绪效价是目前ASD者情绪加工与识别研究中使用最频繁的, 但类别相对简单。未来研究可以不断增加情绪效价的多样性, 特别是增添一些复杂的情绪韵律, 例如, 惊讶、厌恶、尴尬和自豪等, 从而更全面地考察ASD青少年的情绪韵律注意偏向缺陷是否存在效价上的特异性。另一方面, 实验1并没有发现情绪韵律的主效应或交互作用, 且普通被试在图片判断任务中的正确率接近100%。这表明该任务对普通被试来说可能过于简单, 也可能表明实验的试次个数相对不足。未来研究可进一步增加样本容量和试次个数, 在确保实验效度的情况下更为客观地考察ASD被试的情绪韵律注意偏向特点。
在提供注意指示条件下, ASD青少年存在情绪韵律注意偏向缺陷, 表现为情绪韵律加工效率低下。ASD青少年情绪韵律注意偏向缺陷与知觉超载无关。
The orbitofrontal- amygdala circuit and self-regulation of social-emotional behavior in autism,
Individuals with an autistic spectrum disorder are impaired not only in understanding others' mental states, but also in self-regulation of social-emotional behavior. Therefore, a model of the brain in autism must encompass not only those brain systems that subserve social-cognitive and emotional functioning, but also those that subserve the self-regulation of behavior in response to a changing social environment. We present evidence to support the hypothesis that developmental dysfunction of the orbitofrontal-amygdala circuit of the brain is a critical factor in the development of autism and that some of the characteristic deficits of persons with autism in socio-emotional cognition and behavioral self-regulation are related to early dysfunction of different components of this circuit. A secondary hypothesis posits that the degree of intellectual impairment present in individuals with autism is directly related to the integrity of the dorsolateral prefrontal-hippocampal circuit of the brain. Together, these hypotheses have the potential to help explain the neurodevelopmental basis of some of the primary manifestations of autism as well as the heterogeneity of outcomes.
Emotional attention bias under inhibition paradigm
Effects of emotional spoken words on exogenous attentional orienting,
Attentional biases linked to emotional stimuli were investigated in healthy people using an auditory adaptation of the cueing paradigm. Specifically, we investigated whether both validity effects elicited by predictive, endogenous cues and the Inhibition of Return phenomenon (IOR; Posner & Cohen, 1984) elicited by unpredictive, exogenous cues are influenced by the emotional content of spoken words. Supporting the idea that exogenous orienting is not an encapsulated phenomenon (Stolz, 1996), we found abolished IOR for negative words (Experiments 3 and 4). Thus, attention would not be prevented from returning to the previously explored location of a negative word. On the contrary, no emotional modulation of the validity effects was observed (Experiments 1 and 2), suggesting that the intervention of resource-demanding orienting strategies increased cognitive load and thus prevented any emotional modulation. Still, facilitative, nonspatial effects of negative words were found when initial attentional shifts elicited by the cue were both exogenous and endogenous (Experiment 1), but not when they were exclusively endogenous (Experiment 2). These results highlight the importance of both the negativity of a stimulus and the automaticity of attentional shifts in eliciting spatial and nonspatial attentional effects.
Speak and unSpeak with PRAAT,
Many linguists use recorded speech in their research. In descriptive work, visual representations of such recordings (mostly oscillograms) are often annotated with IPA symbols and other labels, and then used to illustrate a phenomenon or defend a certain position regarding the nature of some phonetic or phonologi- cal property of the language in question. In phonetic and psychophysical research some parameter of the recorded speech (like tempo or intensity) is often altered, after which the new sound thus obtained is used in an experiment to test the sensitivity of the human ear, or brain, to certain speech properties.The introduction of the computer has brought about a virtual revolution in the linguistic sciences with respect to the usage of speech recordings. A lab full of cumbersome machinery has now been replaced by one PC, Mac or workstation, on which anyone who puts his mind to it can record, annotate and modify speech with some simple commands or a few mouseclicks. Even the calculation of some speech parameters that were rather complicated to obtain in the past (like pitch and spectral analysis) but fre- quently used in phonetic research nonetheless, are now often just one or two mouseclicks away.As a result, a growing number of colleagues (R)nd use for (R)les with speech sounds in their linguistic explorations. The needs of this group are served by a rather small number of software packages designed for the representation, annotation and analysis of speech (and much more in many cases). In my opinion, one of these stands out in many ways. It is called ``PRAAT''; the imperative form of to speak in Dutch. Since this package is rapidly gaining in popularity, we have decided to devote some attention to it in this issue. First, one of the authors, Paul Boersma, introduces the package and outlines its impressive functionality. Then, an experienced user, Vincent van Heuven, highlights some of the advan- tages and disadvantages of using PRAAT in everyday phonetic research.It is my sincere hope that these two goodies will convince even more linguists to download PRAAT and experiment with it a little. They will see that incorporating, for example, some oscillograms of minimal pairs in their work is as easy as ABC. Their publications will undoubtedly be the better (and the livelier) for it.
Attention to emotional tone of voice in speech perception in children with autism,
A video game was developed to assess speech perception in 13 children with autism spectrum disorders (ASD) and 13 children with typical development (TYP), ages 5–17 years old. Children listened to pre-recorded sentences varying in content (e.g., “Bob parked a van” vs. “Tim shut a door”) and prosody (i.e., enthusiastic vs. grouchy tone of voice). During training, children learned to select one of two sentences differing in both content and prosody (e.g., enthusiastic “Bob parked a van” vs. grouchy “Tim shut a door”). At testing, children listened to test probes comprising re-combinations of the content and prosodic features of the training sentences. Testing indicated that both groups showed accurate discrimination of the training sentences from the re-combined test probes. However, whereas TYP children showed a preference to select the sentence with enthusiastic prosody over its grouchy counterpart, children with ASD did not. Thus, children with ASD show atypical attention to emotional tone of voice, even though they show no deficit in perceiving prosody.
Recognition of emotional prosody and verbal components of spoken language: An fMRI study,
This study examined the neural areas involved in the recognition of both emotional prosody and phonemic components of words expressed in spoken language using echo-planar, functional magnetic resonance imaging (fMRI). Ten right-handed males were asked to discriminate words based on either expressed emotional tone (angry, happy, sad, or neutral) or phonemic characteristics, specifically, initial consonant sound (bower, dower, power, or tower). Significant bilateral activity was observed in the detection of both emotional and verbal aspects of language when compared to baseline activity. We found that the detection of emotion compared with verbal detection resulted in significant activity in the right inferior frontal lobe. Conversely, the detection of verbal stimuli compared with the detection of emotion activated left inferior frontal lobe regions most significantly. Specific analysis of the anterior auditory cortex revealed increased right hemisphere activity during the detection of emotion compared to activity during verbal detection. These findings illustrate bilateral involvement in the detection of emotion in language while concomitantly showing significantly lateralized activity in both emotional and verbal detection, in both the temporal and frontal lobes.
The social motivation theory of autism,
Abstract The idea that social motivation deficits play a central role in Autism Spectrum Disorders (ASD) has recently gained increased interest. This constitutes a shift in autism research, which has traditionally focused more intensely on cognitive impairments, such as theory-of-mind deficits or executive dysfunction, and has granted comparatively less attention to motivational factors. This review delineates the concept of social motivation and capitalizes on recent findings in several research areas to provide an integrated account of social motivation at the behavioral, biological and evolutionary levels. We conclude that ASD can be construed as an extreme case of diminished social motivation and, as such, provides a powerful model to understand humans' intrinsic drive to seek acceptance and avoid rejection. Copyright 2012 Elsevier Ltd. All rights reserved.
Mechanisms of attentional biases towards threat in anxiety disorders: An integrative review,
A wealth of research demonstrates attentional biases toward threat in the anxiety disorders. Several models have been advanced to explain these biases in anxiety, yet the mechanisms comprising and mediating the biases remain unclear. In the present article, we review evidence regarding the mechanisms of attentional biases through careful examination of the components of attentional bias, the mechanisms underlying these components, and the stage of information processing during which the biases occur. Facilitated attention, difficulty in disengagement, and attentional avoidance comprise the components of attentional bias. A threat detection mechanism likely underlies facilitated attention, a process that may be neurally centered around the amygdala. Attentional control ability likely underlies difficulty in disengagement, emotion regulation goals likely underlie attentional avoidance, and both of these processes may be neurally centered around prefrontal cortex functioning. The threat detection mechanism may be a mostly automatic process, attentional avoidance may be a mostly strategic process, and difficulty in disengagement may be a mixture of automatic and strategic processing. Recommendations for future research are discussed.
Specific brain networks during explicit and implicit decoding of emotional prosody,
Abstract To better define the underlying brain network for the decoding of emotional prosody, we recorded high-resolution brain scans during an implicit and explicit decoding task of angry and neutral prosody. Several subregions in the right superior temporal gyrus (STG) and bilateral in the inferior frontal gyrus (IFG) were sensitive to emotional prosody. Implicit processing of emotional prosody engaged regions in the posterior superior temporal gyrus (pSTG) and bilateral IFG subregions, whereas explicit processing relied more on mid STG, left IFG, amygdala, and subgenual anterior cingulate cortex. Furthermore, whereas some bilateral pSTG regions and the amygdala showed general sensitivity to prosody-specific acoustical features during implicit processing, activity in inferior frontal brain regions was insensitive to these features. Together, the data suggest a differentiated STG, IFG, and subcortical network of brain regions, which varies with the levels of processing and shows a higher specificity during explicit decoding of emotional prosody.
Is there a limit to the superiority of individuals with ASD in visual search?,
Superiority in visual search for individuals diagnosed with autism spectrum disorder (ASD) is a well-reported finding. We administered two visual search tasks to individuals with ASD and matched controls. One showed no difference between the groups, and one did show the expected superior performance for individuals with ASD. These results offer an explanation, formulated in terms of load theory. We suggest that there is a limit to the superiority in visual search for individuals with ASD, related to the perceptual load of the stimuli. When perceptual load becomes so high that no additional task-(ir)relevant information can be processed, performance will be based on single stimulus identification, in which no differences between individuals with ASD and controls have been demonstrated.
A multimodal approach to emotion recognition ability in autism spectrum disorders,
Abstract Background:68 Autism spectrum disorders (ASD) are characterised by social and communication difficulties in day-to-day life, including problems in recognising emotions. However, experimental investigations of emotion recognition ability in ASD have been equivocal, hampered by small sample sizes, narrow IQ range and over-focus on the visual modality. Methods:68 We tested 99 adolescents (mean age 15;6 years, mean IQ 85) with an ASD and 57 adolescents without an ASD (mean age 15;6 years, mean IQ 88) on a facial emotion recognition task and two vocal emotion recognition tasks (one verbal; one non-verbal). Recognition of happiness, sadness, fear, anger, surprise and disgust were tested. Using structural equation modelling, we conceptualised emotion recognition ability as a multimodal construct, measured by the three tasks. We examined how the mean levels of recognition of the six emotions differed by group (ASD vs. non-ASD) and IQ (≥ 80 vs. < 80). Results:68 We found no evidence of a fundamental emotion recognition deficit in the ASD group and analysis of error patterns suggested that the ASD group were vulnerable to the same pattern of confusions between emotions as the non-ASD group. However, recognition ability was significantly impaired in the ASD group for surprise. IQ had a strong and significant effect on performance for the recognition of all six emotions, with higher IQ adolescents outperforming lower IQ adolescents. Conclusions:68 The findings do not suggest a fundamental difficulty with the recognition of basic emotions in adolescents with ASD.
Decomposing attention-deficit/hyperactivity disorder (ADHD)-related effects in response speed and variability,
OBJECTIVE: Slow and variable reaction times (RTs) on fast tasks are such a prominent feature of attention-deficit/hyperactivity disorder (ADHD) that any theory must account for them. However, this has proven difficult because the cognitive mechanisms responsible for this effect remain unexplained. Although speed and variability are typically correlated, it is unclear whether single or multiple mechanisms are responsible for group differences in each. RTs are a result of several semi-independent processes, including stimulus encoding, rate of information processing, speed-accuracy trade-offs, and motor response, which have not been previously well characterized. METHOD: A diffusion model was applied to RTs from a forced-choice RT paradigm in two large, independent case-control samples (NCohort 1 = 214 and NCohort 2 = 172). The decomposition measured three validated parameters that account for the full RT distribution and assessed reproducibility of ADHD effects. RESULTS: In both samples, group differences in traditional RT variables were explained by slow information processing speed, and unrelated to speed-accuracy trade-offs or nondecisional processes (e.g., encoding, motor response). CONCLUSIONS: RT speed and variability in ADHD may be explained by a single information processing parameter, potentially simplifying explanations that assume different mechanisms are required to account for group differences in the mean and variability of RTs.
Altered auditory and multisensory temporal processing in autism spectrum disorders,
Autism spectrum disorders (ASD) are characterized by deficits in social reciprocity and communication, as well as by repetitive behaviors and restricted interests. Unusual responses to sensory input and disruptions in the processing of both unisensory and multisensory stimuli also have been reported frequently. However, the specific aspects of sensory processing that are disrupted in ASD have yet to be fully elucidated. Recent published work has shown that children with ASD can integrate low-level audiovisual stimuli, but do so over an extended range of time when compared with typically developing (TD) children. However, the possible contributions of altered unisensory temporal processes to the demonstrated changes in multisensory function are yet unknown. In the current study, unisensory temporal acuity was measured by determining individual thresholds on visual and auditory temporal order judgment (TOJ) tasks, and multisensory temporal function was assessed through a cross-modal version of the TOJ task. Whereas no differences in thresholds for the visual TOJ task were seen between children with ASD and TD, thresholds were higher in ASD on the auditory TOJ task, providing preliminary evidence for impairment in auditory temporal processing. On the multisensory TOJ task, children with ASD showed performance improvements over a wider range of temporal intervals than TD children, reinforcing prior work showing an extended temporal window of multisensory integration in ASD. These findings contribute to a better understanding of basic sensory processing differences, which may be critical for understanding more complex social and cognitive deficits in ASD, and ultimately may contribute to more effective diagnostic and interventional strategies.
Distracted and confused?: Selective attention under load,
The ability to remain focused on goal-relevant stimuli in the presence of potentially interfering distractors is crucial for any coherent cognitive function. However, simply instructing people to ignore goal-irrelevant stimuli is not sufficient for preventing their processing. Recent research reveals that distractor processing depends critically on the level and type of load involved in the processing of goal-relevant information. Whereas high perceptual load can eliminate distractor processing, high load on ‘frontal’ cognitive control processes increases distractor processing. These findings provide a resolution to the long-standing early and late selection debate within a load theory of attention that accommodates behavioural and neuroimaging data within a framework that integrates attention research with executive function.
Emotional speech comprehension in children and adolescents with autism spectrum disorders,
Abstract We examined the understanding of emotional speech by children and adolescents with autism spectrum disorders (ASD). We predicted that they would have difficulty understanding emotional speech, not because of an emotional prosody processing impairment but because of problems drawing appropriate inferences, especially in multiple-cue environments. Twenty-six children and adolescents with ASD and 26 typically developing controls performed a computerized task featuring emotional prosody, either embedded in a discrepant context or without any context at all. They must identify the speaker's feeling. When the prosody was the sole cue, participants with ASD performed just as well as controls, relying on this cue to infer the speaker's intention. When the prosody was embedded in a discrepant context, both ASD and TD participants exhibited a contextual bias and a negativity bias. However ASD participants relied less on the emotional prosody than the controls when it was positive. We discuss these findings with respect to executive function and intermodal processing. LEARNING OUTCOMES: After reading this article, the reader should be able to (1) describe the ASD participants pragmatic impairments, (2) explain why ASD participants did not have an emotional prosody processing impairment, and (3) explain why ASD participants had difficulty inferring the speaker's intention from emotional prosody in a discrepant situation. Copyright 2013 Elsevier Inc. All rights reserved.
Visual perceptual load induces inattentional deafness. Attention, Perception,,
Distraction by emotional sounds: Disentangling arousal benefits and orienting costs,
Unexpectedly occurring task-irrelevant stimuli have been shown to impair performance. They capture attention away from the main task leaving fewer resources for target processing. However, the actual distraction effect depends on various variables; for example, only target-informative distractors have been shown to cause costs of attentional orienting. Furthermore, recent studies have shown that high arousing emotional distractors, as compared with low arousing neutral distractors, can improve performance by increasing alertness. We aimed to separate costs of attentional orienting and benefits of arousal by presenting negative and neutral environmental sounds (novels) as oddballs in an auditory-visual distraction paradigm. Participants categorized pictures while task-irrelevant sounds preceded visual targets in two conditions: (a) informative sounds reliably signaled onset and occurrence of visual targets, and (b) noninformative sounds occurred unrelated to visual targets. RESULTS confirmed that only informative novels yield distraction. Importantly, irrespective of sounds' informational value participants responded faster in trials with high arousing negative as compared with moderately arousing neutral novels. That is, costs related to attentional orienting are modulated by information, whereas benefits related to emotional arousal are independent of a sound's informational value. This favors a nonspecific facilitating cross-modal influence of emotional arousal on visual task performance and suggests that behavioral distraction by noninformative novels is controlled after their motivational significance has been determined. (PsycINFO Database Record
Inattentional deafness: Visual load leads to time-specific suppression of auditory evoked responses,
Due to capacity limits on perception, conditions of high perceptual load lead to reduced processing of unattended stimuli (Lavie et al., 2014). Accumulating work demonstrates the effects of visual perceptual load on visual cortex responses, but the effects on auditory processing remain poorly understood. Here we establish the neural mechanisms underlying “inattentional deafness”—the failure to perceive auditory stimuli under high visual perceptual load. Participants performed a visual search task of low (target dissimilar to nontarget items) or high (target similar to nontarget items) load. On a random subset (50%) of trials, irrelevant tones were presented concurrently with the visual stimuli. Brain activity was recorded with magnetoencephalography, and time-locked responses to the visual search array and to the incidental presence of unattended tones were assessed. High, compared to low, perceptual load led to increased early visual evoked responses (within 100 ms from onset). This was accompanied by reduced early (65100 ms from tone onset) auditory evoked activity in superior temporal sulcus and posterior middle temporal gyrus. A later suppression of the P3 “awareness” response to the tones was also observed under high load. A behavioral experiment revealed reduced tone detection sensitivity under high visual load, indicating that the reduction in neural responses was indeed associated with reduced awareness of the sounds. These findings support a neural account of shared audiovisual resources, which, when depleted under load, leads to failures of sensory perception and awareness.SIGNIFICANCE STATEMENT The present work clarifies the neural underpinning of inattentional deafness under high visual load. The findings of near-simultaneous load effects on both visual and auditory evoked responses suggest shared audiovisual processing capacity. Temporary depletion of shared capacity in perceptually demanding visual tasks leads to a momentary reduction in sensory processing of auditory stimuli, resulting in inattentional deafness. The dynamic “push–pull” pattern of load effects on visual and auditory processing furthers our understanding of both the neural mechanisms of attention and of cross-modal effects across visual and auditory processing. These results also offer an explanation for many previous failures to find cross-modal effects in experiments where the visual load effects may not have coincided directly with auditory sensory processing.
Enhanced perceptual functioning in autism: An update, and eight principles of autistic perception,
We propose an “Enhanced Perceptual Functioning” model encompassing the main differences between autistic and non-autistic social and non-social perceptual processing: locally oriented visual and auditory perception, enhanced low-level discrimination, use of a more posterior network in “complex” visual tasks, enhanced perception of first order static stimuli, diminished perception of complex movement, autonomy of low-level information processing toward higher-order operations, and differential relation between perception and general intelligence. Increased perceptual expertise may be implicated in the choice of special ability in savant autistics, and in the variability of apparent presentations within PDD (autism with and without typical speech, Asperger syndrome) in non-savant autistics. The overfunctioning of brain regions typically involved in primary perceptual functions may explain the autistic perceptual endophenotype.
The relationship between theory of mind and metaphor: Evidence from children with language impairment and autistic spectrum disorder,
Abstract Happ茅 (1993) proposed that theory of mind (ToM) understanding was necessary for comprehension of metaphorical expressions. The current study investigated the role of both ToM and language ability in metaphor understanding. Ninety-four children aged 8 15 years with communication impairments were grouped according to language ability and autistic symptomatology in the first instance, and then according to ToM performance. Their performance on a metaphor task was compared to 34 typically developing age-matched peers. These analyses showed that only children with language impairment, with or without concurrent autistic features, were impaired on the metaphor task. Furthermore, possession of first-order ToM skills did not ensure metaphor comprehension. Instead, semantic ability was a stronger predictor of performance on the metaphor task. These results are considered with reference to the view that ToM understanding is necessary for the comprehension of metaphor.
Auditory processing in autism spectrum disorder: A review,
Abstract For individuals with autism spectrum disorder or 'ASD' the ability to accurately process and interpret auditory information is often difficult. Here we review behavioural, neurophysiological and imaging literature pertaining to this field with the aim of providing a comprehensive account of auditory processing in ASD, and thus an effective tool to aid further research. Literature was sourced from peer-reviewed journals published over the last two decades which best represent research conducted in these areas. Findings show substantial evidence for atypical processing of auditory information in ASD at behavioural and neural levels. Abnormalities are diverse, ranging from atypical perception of various low-level perceptual features (i.e. pitch, loudness) to processing of more complex auditory information such as prosody. Trends across studies suggest auditory processing impairments in ASD are most likely to present during processing of complex auditory information and are more severe for speech than for non-speech stimuli. The interpretation of these findings with respect to various cognitive accounts of ASD is discussed and suggestions offered for further research. Copyright 漏 2011 Elsevier Ltd. All rights reserved.
Load-induced inattentional deafness. Attention, Perception,,
Lightening the load: Perceptual load impairs visual detection in typical adults but not in autism,
Autism spectrum disorder (ASD) research portrays a mixed picture of attentional abilities with demonstrations of enhancements (e.g., superior visual search) and deficits (e.g., higher distractibility). Here we test a potential resolution derived from the Load Theory of Attention (e.g., Lavie, 2005). In Load Theory, distractor processing depends on the perceptual load of the task and as such can only be eliminated under high load that engages full capacity. We hypothesize that ASD involves enhanced perceptual capacity, leading to the superior performance and increased distractor processing previously reported. Using a signal-detection paradigm, we test this directly and demonstrate that, under higher levels of load, perceptual sensitivity was reduced in typical adults but not in adults with ASD. These findings confirm our hypothesis and offer a promising solution to the previous discrepancies by suggesting that increased distractor processing in ASD results not from a filtering deficit but from enhanced perceptual capacity.
Just another social scene: Evidence for decreased attention to negative social scenes in high-functioning autism,
The adaptive threat-detection advantage takes the form of a preferential orienting of attention to threatening scenes. In this study, we compared attention to social scenes in 15 high-functioning individuals with autism (ASD) and matched typically developing (TD) individuals. Eye-tracking was recorded while participants were presented with pairs of scenes, either emotional positive-neutral, emotional negative-neutral or neutral eutral scenes. Early allocation of attention, the first image fixated in each pair, differed between groups: contrary to TD individuals who showed the typical threat-detection advantage towards negative images, the ASD group failed to show a bias toward threat-related scenes. Later processing of stimuli, indicated by the total fixation to the images during the 3-s presentation, was found unaffected in the ASD group. These results support the hypothesis of an early atypical allocation of attention towards natural social scenes in ASD, that is compensated in later stages of visual processing.
Context effects on facial affect recognition in schizophrenia and autism: Behavioral and eye-tracking evidence,
Abstract Although Schizophrenia (SCZ) and Autism Spectrum Disorder (ASD) share impairments in emotion recognition, the mechanisms underlying these impairments may differ. The current study used the novel "Emotions in Context" task to examine how the interpretation and visual inspection of facial affect is modulated by congruent and incongruent emotional contexts in SCZ and ASD. Both adults with SCZ (n= 44) and those with ASD (n= 21) exhibited reduced affect recognition relative to typically-developing (TD) controls (n= 39) when faces were integrated within broader emotional scenes but not when they were presented in isolation, underscoring the importance of using stimuli that better approximate real-world contexts. Additionally, viewing faces within congruent emotional scenes improved accuracy and visual attention to the face for controls more so than the clinical groups, suggesting that individuals with SCZ and ASD may not benefit from the presence of complementary emotional information as readily as controls. Despite these similarities, important distinctions between SCZ and ASD were found. In every condition, IQ was related to emotion-recognition accuracy for the SCZ group but not for the ASD or TD groups. Further, only the ASD group failed to increase their visual attention to faces in incongruent emotional scenes, suggesting a lower reliance on facial information within ambiguous emotional contexts relative to congruent ones. Collectively, these findings highlight both shared and distinct social cognitive processes in SCZ and ASD that may contribute to their characteristic social disabilities. The Author 2015. Published by Oxford University Press on behalf of the Maryland Psychiatric Research Center. All rights reserved. For permissions, please email: firstname.lastname@example.org.
There’s more to anxiety than meets the eye: Isolating threat-related attentional engagement and disengagement biases,
Abstract Threat-related attentional biases represent a basic survival mechanism. These biases include an engagement bias involving rapid direction of attention toward threat and a disengagement bias involving slow direction of attention away from threat. The exact nature of these biases in healthy and anxious individuals remains controversial because of the challenges associated with accurately isolating each of these attentional biases. Combining a cognitive attentional task with classical conditioning using electric stimulation, we created a new paradigm that makes it possible to more clearly isolate these attentional biases. Utilizing this novel paradigm, we detected both types of attentional bias and differentiated between levels of trait anxiety, in which low- and high-trait anxiety individuals showed equal levels of engagement bias, but only high-trait anxiety individuals showed impaired disengagement from threat.
A standardized set of 260 pictures: Norms for name agreement, image agreement, familiarity, and visual complexity,
Abstract In this article we present a standardized set of 260 pictures for use in experiments investigating differences and similarities in the processing of pictures and words. The pictures are black-and-white line drawings executed according to a set of rules that provide consistency of pictorial representation. The pictures have been standardized on four variables of central relevance to memory and cognitive processing: name agreement, image agreement, familiarity, and visual complexity. The intercorrelations among the four measures were low, suggesting that they are indices of different attributes of the pictures. The concepts were selected to provide exemplars from several widely studied semantic categories. Sources of naming variance, and mean familiarity and complexity of the exemplars, differed significantly across the set of categories investigated. The potential significance of each of the normative variables to a number of semantic and episodic memory tasks is discussed.
Visual perceptual load reduces auditory detection in typically developing individuals but not in individuals with autism spectrum disorders,
Objective: Previous studies examining selective attention in individuals with autism spectrum disorder (ASD) have yielded conflicting results, some suggesting superior focused attention (e.g. on visual search tasks), others demonstrating greater distractibility. This pattern could be accounted for by the proposal (derived by applying the Load theory of attention, e.g. Lavie, 2005) that ASD is characterized by an increased perceptual capacity (Remington, Swettenham, Campbell, & Coleman, 2009). Recent studies in the visual domain support this proposal. Here we hypothesize that ASD involves an enhanced perceptual capacity that also operates across sensory modalities, and test this prediction, for the first time using a signal detection paradigm. Method: 17 neurotypical (NT) and 15 ASD adolescents performed a visual search task under varying levels of visual perceptual load while simultaneously detecting presence/absence of an auditory tone embedded in noise. Results: Detection sensitivity (d’) for the auditory stimulus was similarly high for both groups in the low visual perceptual load condition (e.g. 2 items: p = .391, d = 0.31, 95% CI [-.39, 1.00]). However, at a higher level of visual load, auditory d’ reduced for the NT group but not the ASD group leading to a group difference (p = .002, d = 1.2, 95% CI [.44, 1.96]). As predicted, when visual perceptual load was highest, both groups then showed a similarly low auditory d’ (p = .9, d = 0.05, 95% CI [-.65, .74]). Conclusions: These findings demonstrate that increased perceptual capacity in ASD operates across modalities.
Children’s judgments of emotion from conflicting cues in speech: Why 6-year-olds are so inflexible,
Abstract Six-year-old children can judge a speaker's feelings either from content or paralanguage but have difficulty switching the basis of their judgments when these cues conflict. This inflexibility may relate to a lexical bias in 6-year-olds' judgments. Two experiments tested this claim. In Experiment 1, 6-year-olds ( n =40) were as inflexible when switching from paralanguage to content as when switching from content to paralanguage. In Experiment 2, 6-year-olds ( n =32) and adults ( n =32) had more difficulty when switching between conflicting emotion cues than conflicting nonemotional cues. Thus, 6-year-olds' inflexibility appears to be tied to the presence of conflicting emotion cues in speech rather than a bias to judge a speaker's feelings from content.
Effects of the short-term learned significance of task-irrelevant sounds on involuntary attention in children and adults,
61The impact of learned significance of task-irrelevant deviant sounds on distraction was examined.61Performance was similarly modulated by significant deviant sounds in children and adults.61Post-deviant processing was modulated by deviant's significance in children only.61Attention control, particularly in the context of significant sounds, is immature in late childhood.
Working memory load affects repetitive behaviour but not cognitive flexibility in adolescent autism spectrum disorder
Abstract OBJECTIVES: Autism spectrum disorder (ASD) is associated with repetitive and stereotyped behaviour, suggesting that cognitive flexibility may be deficient in ASD. A central, yet not examined aspect to understand possible deficits in flexible behaviour in ASD relates (i) to the role of working memory and (ii) to neurophysiological mechanisms underlying behavioural modulations. METHODS: We analysed behavioural and neurophysiological (EEG) correlates of cognitive flexibility using a task-switching paradigm with and without working memory load in adolescents with ASD and typically developing controls (TD). RESULTS: Adolescents with ASD versus TD show similar performance in task switching with no memory load, indicating that 'pure' cognitive flexibility is not in deficit in adolescent ASD. However performance during task repetition decreases with increasing memory load. Neurophysiological data reflect the pattern of behavioural effects, showing modulations in P2 and P3 event-related potentials. CONCLUSIONS: Working memory demands affect repetitive behaviour while processes of cognitive flexibility are unaffected. Effects emerge due to deficits in preparatory attentional processes and deficits in task rule activation, organisation and implementation of task sets when repetitive behaviour is concerned. It may be speculated that the habitual response mode in ASD (i.e. repetitive behaviour) is particularly vulnerable to additional demands on executive control processes.
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