Preference for less segmented fixed-time components in concurrent-chain schedules of reinforcement

A concurrent-chain procedure was used to examine choice between segmented and less segmented response-independent schedules of reinforcement. A pair of independent, concurrent variable-interval 60-s schedules were presented in the initial link, along with a 1.5-s changeover delay. A chained fixed-interval fixed-time and its corresponding tandem schedule constituted the terminal links. The length of the fixed-interval schedule in the terminal link was varied between 5 s and 30 s while that of the fixed-time schedule was kept at 5 s over conditions. The first components of both terminal-link schedules were accompanied by the same stimulus. Except in the baseline condition, the onset of the second component of the terminal-link chained schedule was accompanied by either a localized (key color) or a nonlocalized (dark houselight) stimulus change. Stimulus conditions were constant during the terminal-link tandem schedule. With three exceptions, pigeons demonstrated a slight preference for the tandem over the chained schedule in the terminal link. Furthermore, this preference varied inversely with the length of the first component. In general, these results are consistent with previous studies that reported an adverse effect on choice by segmenting an interval schedule into two or more components, but they are inconsistent with studies that reported preference for signaled over unsignaled delay of reinforcement.     

Converging measures of speech segmentation in preverbal infants

Two studies using novel extensions of the conditioned head-turning method examined contributions of rhythmic and distributional properties of syllable strings to 8-month-old infants' speech segmentation. The two techniques introduced exploit fundamental, but complementary, properties of representational units. The first involved assessment of discriminative response maintenance when simple training stimuli were embedded in more complex speech contexts; the second involved measurement of infants' latencies in detecting extraneous signals superimposed on speech stimuli. A complex pattern of results is predicted if infants succeed in grouping syllables into higher-order units. Across the two studies, the predicted pattern of results emerged, indicating that rhythmic properties of speech play an important role in guiding infants toward potential linguistically relevant units and simultaneously demonstrating that the techniques proposed here provide valid, converging measures of infants' auditory representational units.     

词边界信息在句中的分布

用经过删除的语音歧义句作材料,研究了词边界信息在句中的分布。结果说明,在歧义句中歧义音节是最重要的切分线索;向歧义音节的前后过渡也对词切分有贡献;歧义音节和过渡以外的部分在一定条件下对切分有帮助。     

Resting autonomic activity in adults who stutter and its association with self-reports of social anxiety

PurposeThe purpose of this study was to investigate resting autonomic activity in adults who stutter (AWS) compared to adults who do not stutter (ANS) and the relationship this has on self-reports of social anxiety.MethodsThirteen AWS and 15 ANS completed the Social Interaction Anxiety Scale (SIAS; Mattick & Clark, 1998) and Brief Fear of Negative Evaluation (BFNE; Leary, 1983). Following this, measures of skin conductance levels (i.e. index of sympathetic activity) and respiratory sinus arrhythmia (i.e. index of parasympathetic activity) were taken during a 5-minute resting, baseline period. Independent sample t tests were used to assess differences between groups on self-reports of anxiety (SIAS, BFNE) and resting autonomic levels (SCL, RSA). Separate multiple regression analyses were performed in order to assess the relationship between self-reports of anxiety and autonomic measures.ResultsResults showed significantly higher mean SCL and lower mean RSA levels in the AWS compared to the ANS at resting, baseline. Regression analysis showed that self-reports from the SIAS had a significant effect on RSA levels for the AWS but not the ANS. No significant effects were found for BFNE on RSA. Nor was there a significant effect from SIAS or BFNE on SCL levels for either group.ConclusionFindings suggest that resting RSA levels may be a physiological marker for social anxiety levels in adults who stutter.     

职场排斥对员工家庭的溢出效应：归属需求和工作家庭区隔偏好的作用

以往研究证实了职场排斥会对员工组织内诸多方面产生危害, 然而关于职场排斥向组织外部特别是家庭领域的溢出效应还知之甚少。本研究基于资源保存理论构建了一个有调节的中介效应模型, 探讨职场排斥对员工家庭贬损和家庭满意度的溢出效应和具体机制, 研究结果表明：(1)职场排斥对员工家庭贬损有显著正向作用, 对家庭满意度有显著负向作用; (2)工作压力中介了职场排斥与家庭贬损和家庭满意度的关系; (3)员工归属需求调节了职场排斥对工作压力的影响, 同时调节了工作压力在职场排斥与家庭贬损、家庭满意度之间的中介效应; (4)员工工作家庭区隔偏好调节了工作压力对家庭贬损和家庭满意度的作用, 并且调节了职场排斥通过工作压力对家庭贬损和家庭满意度的中介效应。     

汉语阅读中词切分研究进展

词切分指读者在文本阅读过程中将词从句子或语篇中切分出来以促进文本阅读与加工的过程。本文对近20 年来汉语词切分研究成果总结发现:词间空格、词素特性、词意识、词汇预期均可作为词切分的依据; 汉语阅读存在词n和词n+1两种切分,两种切分过程中字词加工均遵循交互激活假设,切分词n过程中字词加工的交互激活特点表现为字词同等相互影响,切分词n+1过程中字词加工的交互激活特点更多表现为词汇加工影响字加工; 重叠歧义词切分遵循多重激活假设,其中被激活的单词之间的竞争机制符合竞争假设,左侧词汇在这一竞争中具有优势,此外,重叠歧义词的切分受到词频,语境的影响。     

即刻消退缺损的原因分析及其神经生物学机制

即刻消退缺损(immediate extinction deficit, IED)是指在条件性恐惧习得后, 立即进行的消退训练不能长期抑制恐惧记忆的现象。IED可能与消退起始时的应激水平和事件分割等因素有关。在高应激水平下, 消退记忆的巩固受损导致IED; 而在中等或较低的应激水平条件下, 即刻消退有效但效果可能容易受事件分割的影响。IED的神经生物学机制涉及应激激活蓝斑去甲肾上腺素能系统, 去甲肾上腺素引起杏仁核基底外侧核(basolateral amygdala, BLA)过度兴奋, 然后BLA通过投射突触抑制在恐惧消退中起核心作用的内侧前额叶神经元的活动。未来研究应注意即刻消退缺损引起的长期后果, 并深入探讨如何优化即刻消退在临床上的应用。     

Effects of midbrain central gray lesions on spontaneous and electrically induced aggression in the rat

Large electrolytic lesions were placed in the midbrain central gray of male rats. Their effects on hypothalamically induced aggression, switch-off behaviour, and locomotion were investigated. A number of these animals were also tested for territorial intermale aggression in order to compare electrically induced and spontaneous aggression. Large lesions resulted in an increase of the current threshold to induce aggression by hypo-thalamic stimulation. Smaller, but still quite large, lesions decreased the threshold current for hypothalamic aggression. After the operation a decrease in the threshold for switch-off was present, both in the experimental and the control group. Current thresholds for locomotion were decreased after the lesions only in the experimental group. Spontaneous aggression was temporarily decreased after the lesion. No indication was found that other behavioural elements of the animal were distorted by the lesion. The parallel between the effects on spontaneous and electrically induced aggression makes it attractive to ascribe a role to the neural circuit of hypothalamus and central gray in territorial aggression. However, even with large lesions the animals were still capable of fighting, hence the central gray is not indispensable. An attempt was made to explain the differential effects that differently sized central gray lesions have on hypothalamic aggression.     

Statistical learning of multiple speech streams: A challenge for monolingual infants

Language acquisition depends on the ability to detect and track the distributional properties of speech. Successful acquisition also necessitates detecting changes in those properties, which can occur when the learner encounters different speakers, topics, dialects, or languages. When encountering multiple speech streams with different underlying statistics but overlapping features, how do infants keep track of the properties of each speech stream separately? In four experiments, we tested whether 8‐month‐old monolingual infants (N = 144) can track the underlying statistics of two artificial speech streams that share a portion of their syllables. We first presented each stream individually. We then presented the two speech streams in sequence, without contextual cues signaling the different speech streams, and subsequently added pitch and accent cues to help learners track each stream separately. The results reveal that monolingual infants experience difficulty tracking the statistical regularities in two speech streams presented sequentially, even when provided with contextual cues intended to facilitate separation of the speech streams. We discuss the implications of our findings for understanding how infants learn and separate the input when confronted with multiple statistical structures.     

Infants' reasoning about opaque and transparent occluders in an individuation task

Two experiments document that conceptual knowledge influences 3-year-olds' extension of novel words. In Experiment 1, when objects were described as having conceptual properties typical of artifacts, children extended novel labels for these objects on the basis of shape alone. When the very same objects were described as having conceptual properties typical of animate kinds, children extended novel labels for these objects on the basis of both shape and texture. Moreover, providing a salient perceptual cue (Experiment 2) did not interfere with children's reliance on conceptual information in extending novel words: when an object with eyes was labeled with a novel word in the context of a story describing the object as an artifact, children extended the label on the basis of shape alone (i.e. as though the object were an artifact). These results, which challenge directly the position that 'dumb attentional mechanisms' can account for word learning, stand as evidence for the central role of conceptual information in mapping words to meaning.