短时记忆提取机制研究

该实验操作探测数字在记忆集中的位置来研究短时记忆的提取机制。结果发现：用Ｓｔｅｒｎｂｅｒｇ范式研究短时记忆提取机制存在缺限：操作记忆集不能反映被试的搜索过程。该研究显示：短时记忆的提取不是以自始至终或平行扫描为前提。短时记忆的提取机制受记忆集大小的影响较大。记忆集小于３时,短时记忆的提取是系列自中断扫描;记忆集大于３时,短时记忆的提取以记忆项目的痕迹强度为依据。     

空间路线学习中的前向测试效应

空间路线信息学习中的前向测试效应及其机制有待检验。研究以虚拟背景下的住宅小区为实验材料, 要求被试学习同一场景4个方向的路线信息(实验1)以及4个不同场景(实验2)的路线信息。结果表明, 在路线1~3的测试中, 同一场景下路线信息相似性高, “隔离”干扰的难度大, 在测试过程中的干扰率高于不同场景的路线信息。在路线4的测试中, 两个实验中测试组的回忆正确率均显著高于重学组, 干扰率则显著低于重学组, 出现了前向测试效应。这些发现表明, 测试可以通过“隔离”来自先前学习信息的前摄干扰来增强后续空间信息的学习。研究结果揭示了空间路线学习中的前向测试效应及其机制, 支持前摄抑制减少理论, 证实了前向测试效应在生活中具有广阔的应用性。     

Lexical retrieval constrained by sound structure: the role of the left inferior frontal gyrus

Positron emission tomography was used to investigate two competing hypotheses about the role of the left inferior frontal gyrus (IFG) in word generation. One proposes a domain-specific organization, with neural activation dependent on the type of information being processed, i.e., surface sound structure or semantic. The other proposes a process-specific organization, with activation dependent on processing demands, such as the amount of selection needed to decide between competing lexical alternatives. In a novel word retrieval task, word reconstruction (WR), subjects generated real words from heard non-words by the substitution of either a vowel or consonant. Both types of lexical retrieval, informed by sound structure alone, produced activation within anterior and posterior left IFG regions. Within these regions there was greater activity for consonant WR, which is more difficult and imposes greater processing demands. These results support a process-specific organization of the anterior left IFG.     

SPT效应的自动突显机制:来自输出监测的证据

研究采用"对回忆的再认"范式,从输出监测的角度考察了操作效应的提取机制。实验1结果显示,被试操作任务条件下的自由回忆的系列位置成绩缺乏首因效应,却拥有扩展的近因效应;被试操作任务条件下的"对回忆的再认"成绩显著差于语词任务下的成绩,差异具体表现在组块2~9、10、11和12上,表明在上述组块,被试操作任务条件下的提取存在自动突显,即操作效应得益于这些组块在提取时的自动突显。实验2结果显示,在类别测验下,被试操作任务和语词任务的自由回忆成绩拥有相似的系列位置曲线,而"对回忆的再认"结果同实验1。研究认为自由回忆的系列位置效应与自动突显机制之间不存在直接的因果关系,而"对回忆的再认"范式则能敏感地测量出操作效应的提取机制。     

Cognitive neuroscience of aging: contributions of functional neuroimaging

By revealing how brain activity during cognitive performance changes as a function of aging, studies using positron emission tomography (PET) and functional magnetic resonance imaging (fMRI) are contributing to the development of a new discipline of Cognitive Neuroscience of Aging. This article reviews functional neuroimaging studies of cognitive aging in the domains of visual perception, episodic memory encoding and semantic memory retrieval, episodic memory retrieval, implicit memory, and working memory. The most consistent finding of these studies was that brain activity tends to be less lateralized in older adults than in younger adults. This finding is conceptualized in terms of a model called Hemispheric Asymmetry Reduction in Old Adults (HAROLD). According to a compensation hypothesis, bihemispheric involvement could help counteract age-related neurocognitive decline, whereas, according to a dedifferentiation hypothesis, it reflects a difficulty in recruiting specialized neural mechanisms.     

Relations between episodic memory, suggestibility, theory of mind, and cognitive inhibition in the preschool child

The development of episodic memory, its relation to theory of mind (ToM), executive functions (e.g., cognitive inhibition), and to suggestibility was studied. Children (n= 115) between 3 and 6 years of age saw two versions of a video film and were tested for their memory of critical elements of the videos. Results indicated similar developmental trends for all memory measures, ToM, and inhibition, but ToM and inhibition were not associated with any memory measures. Correlations involving source memory was found in relation to specific questions, whereas inhibition and ToM were significantly correlated to resistance to suggestions. A regression analysis showed that age was the main contributor to resistance to suggestions, to correct source monitoring, and to correct responses to specific questions. Inhibition was also a significant main predictor of resistance to suggestive questions, whereas the relative contribution of ToM was wiped out when an extended model was tested.     

The representation of multiplication facts: developmental changes in the problem size, five, and tie effects

In this study, we investigated the development of basic effects that have been found in single-digit multiplication arithmetic: the problem size, five, and tie effects. Participants (9-, 10-, and 11-year-olds and adults) performed a production task on simple multiplication. The procedure replicated study [Canadian Journal of Psychology, Vol. 39, pp. 338-366], but the results show that the gradual decrease of the problem size effect ends in sixth grade. We report analyses on raw latencies and state trace analyses that take into account reaction time scaling as a function of age. The results show that 11-year-olds do not differ significantly from adults on any of the three effects. Before 11 years of age, interesting developmental changes occur.     

Contrasting effects of phonological priming in aphasic word production

Two fluent aphasics, IG and GL, performed a phonological priming task in which they repeated an auditory prime then named a target picture. The two patients both had selective deficits in word production: they were at or near ceiling on lexical comprehension tasks, but were significantly impaired in picture naming. IG's naming errors included both semantic and phonemic paraphasias, as well as failures to respond, whereas GL's errors were mainly phonemic and formal paraphasias. The two patients responded very differently to phonological priming: IG's naming was facilitated (both accuracy and speed) only by begin-related primes (e.g. ferry-feather), whereas GL benefited significantly only from end-related primes (e.g. brother-feather), showing no more than a facilitatory trend with begin-related primes. We interpret these results within a two-stage model of word production, in which begin-related and end-related primes are said to operate at different stages. We then discuss implications for models of normal and aphasic word production in general and particularly with respect to sequential aspects of the phonological encoding process.     

Age of acquisition effects in picture naming: evidence for a lexical-semantic competition hypothesis

In many tasks the effects of frequency and age of acquisition (AoA) on reaction latencies are similar in size. However, in picture naming the AoA-effect is often significantly larger than expected on the basis of the frequency-effect. Previous explanations of this frequency-independent AoA-effect have attributed it to the organisation of the semantic system or to the way phonological word forms are stored in the mental lexicon. Using a semantic blocking paradigm, we show that semantic context effects on naming latencies are more pronounced for late-acquired than for early-acquired words. This interaction between AoA and naming context is likely to arise during lexical-semantic encoding, which we put forward as the locus for the frequency-independent AoA-effect.