Effects of Practice upon the Metabolic Cost of Mental Work

Two experiments with isopods, Armadillidium vulgare, were reported. In Experiment I, two groups of five Ss each learned to run a T maze to escape light and heat. Both original learning (OL), and relearning (RL) the next day, were to a criterion 9/10 correct. Between OL and RL one group was immobilized (I), and the other group was given the opportunity for activity (A). The I treatment resulted in greater savings on RL than did the A treatment, and it was thus concluded that A is a retroaction treatment. Experiment II was like I except that all Ss were extinguished immediately following OL, and then given either A or I until RL. In this experiment, the A treatment led to no savings, but the I treatment produced negative savings (more trials on RL relative to OL). It was concluded that the A treatment had retroactively interfered with extinction, and this result was discussed as analogous to differential spontaneous recovery in favor of the A group. It was concluded that Liberman's (4, 5) theory (that spontaneous recovery is due to the forgetting of extinction) is supported by the result of Experiment II.     

英汉双语者二语口语产生中音韵编码过程的同化机制

本研究运用事件相关电位技术,结合时空微态分割分析法,考察英汉双语者二语口语产生过程中音韵编码过程的同化与顺应机制。研究中采用图词干扰即时命名任务,比较英汉双语者的汉语产生过程中音韵编码的加工单元与汉语母语者的汉语产生过程还是与英语母语者的英语产生过程的特点类似。反应时结果发现汉汉组、英汉组与英英组都出现显著的音节效应。事件相关电位的结果发现英汉双语者的汉语产生过程中出现了音素效应,与其英语产生过程的特点类似,音素效应在英语和汉语的产生过程中都出现在图画呈现后的200～250 ms之间,而汉语母语者的汉语产生过程中仅发现了音节效应,出现在250～300 ms之间。时空微态分割分析发现英汉双语者在汉语产生的音韵编码过程与英语母语者在英语产生过程所对应的脑电微态成分相同,仅在持续时间上存在显著差异;其微态成分不同于汉语母语者的汉语产生过程。上述结果表明英汉双语者汉语产生的音韵编码过程与英语作为母语时的产生过程相似,而与汉语作为母语时的产生过程不同。英汉双语者的汉语产生过程采用了母语同化机制。     

汉语口语词汇产生的音韵编码单元：内隐启动范式的ERP研究

本研究中选择英语水平低的汉语母语者,排除作为二语的英语音韵编码单元(音素)可能对汉语口语词汇产生过程的影响后,运用事件相关电位技术,考察了汉语口语产生过程中音节和音素效应的时间进程。实验采用内隐启动范式,要求被试看到提示词之后说出对应的目标词。事件相关电位分析结果发现,音节效应出现在线索词呈现后的100～400 ms之间,音素效应出现在500～600 ms之间,波形表现为相关条件比无关条件的波形更正。这表明在词汇选择之后的音韵编码阶段讲话者首先提取的单元是音节,而音素效应出现的时间窗口可能是音韵编码阶段后期或者是语音编码阶段,结果验证了合适编码单元假说的观点。     

定向遗忘的编码加工机制

有目的的遗忘(定向遗忘)需要耗费认知努力吗?有研究发现, 定向遗忘可能是被动衰减的结果, 即F项目(需要遗忘的项目)未获得有效复述是选择性复述了R项目(需要记住的项目)造成的, 这一加工过程不需要认知努力; 但也有研究表明, 定向遗忘过程可能是遗忘线索诱发的对记忆加工的主动抑制, 需要耗费认知努力, 脑认知研究中发现的前额叶ERPs成分为这一机制提供了证据。还有一种观点认为, 定向遗忘编码过程可能同时包含主动抑制与被动衰减, 但是尚不清楚两种加工机制相互作用的方式。为进一步澄清定向遗忘编码阶段的认知机制, 未来研究需要将非认知因素纳入考察, 并关注不同人群的定向遗忘特征, 在此基础上尝试解决理论争议。     

Exploring the influence of encoding format on subsequent memory

Distinctive encoding is greatly influenced by gist-based processes and has been shown to suffer when highly similar items are presented in close succession. Thus, elucidating the mechanisms underlying how presentation format affects gist processing is essential in determining the factors that influence these encoding processes. The current study utilised multivariate partial least squares (PLS) analysis to identify encoding networks directly associated with retrieval performance in a blocked and intermixed presentation condition. Subsequent memory analysis for successfully encoded items indicated no significant differences between reaction time and retrieval performance and presentation format. Despite no significant behavioural differences, behaviour PLS revealed differences in brain–behaviour correlations and mean condition activity in brain regions associated with gist-based vs. distinctive encoding. Specifically, the intermixed format encouraged more distinctive encoding, showing increased activation of regions associated with strategy use and visual processing (e.g., frontal and visual cortices, respectively). Alternatively, the blocked format exhibited increased gist-based processes, accompanied by increased activity in the right inferior frontal gyrus. Together, results suggest that the sequence that information is presented during encoding affects the degree to which distinctive encoding is engaged. These findings extend our understanding of the Fuzzy Trace Theory and the role of presentation format on encoding processes.     

Short-term memory in the pigeon: delayed-pair-comparison procedures and some results.

A discrete-trials, delayed-pair-comparison procedure was developed to study visual short-term memory for tilted lines. In four experiments, pigeons' responses on left or right keys were reinforced with food depending on whether a comparison stimulus was or was not the same as a standard stimulus presented earlier in the same trial. In Experimental I, recall was an increasing function of the exposure time of the to-be-remembered stimulus and was a decreasing function of the retention interval. In Experiment II, retroactive interference was investigated: recall was poorer after a retention interval during which was presented either a tilted line or contextual stimuli in the form of the illuminated experimental chamber. In Experiment III, a subject was required to engage, throughout the retention interval, in one or the other of two different behaviors, depending on which of two stimuli a subject was to remember. This mnemonic strategy vastly improved recall after 15- and 20-second retention intervals. In Experiment IV, the opposite end of the performance continuum was studied: by combining the effects of a larger stimulus set and the effects of what presumably was an increased memory load, performance was reduced to approximately chance levels after retention intervals shorter than 1 second.     

Planning at the Phonological Level during Sentence Production

In two picture–word interference experiments we examined whether phrase boundaries affected how far in advance speakers plan the sounds of words during sentence production. Participants produced sentences of varying lengths (short determiner + noun + verb or long determiner + adjective + noun + verb) while ignoring phonologically related and unrelated words to the verb of the sentence. Response times to begin producing both types of sentences were faster in the presence of a related versus unrelated distractor. The results suggest that the activation of phonological properties of words outside the first phrase and first and second phonological word affect onset of articulation during sentence production. The results are discussed in the light of previous evidence of phonological planning during multi-word production. Implications for the phonological facilitation effect in the picture–word interference paradigm are also discussed.The research reported in this article served as partial fulfillment of the requirements for the PhD degree at Harvard University for Tatiana T. Schnur     

汉语单音节词汇产生中的激活反馈

采取图画-词汇干扰实验范式,探索汉语词汇产生中词条选择和音韵编码两个阶段之间是否存在激活的反馈。实验一探索的是字形激活能否反馈至语义层产生语义激活,结果发现,与无关条件相比,目标图画(如“锯”)的字形中介(“镇”)的语义相关字(“村”)条件显著地延长了图画命名的时间。这表明在汉语词汇产生过程中,字形层的激活能反馈至语义层。实验二探索的是语音激活能否反馈至语义层产生语义激活,结果发现,与无关条件相比,目标图画(“梨”)的语音中介(“厘”)的语义相关字(“毫”)条件并未显著地影响图画命名的时间。这表明语音层的激活不能反馈至语义层,或者反馈回的激活太微弱不能影响图画命名过程。实验一和二的结果更倾向于支持词汇产生中词条选择和音韵编码两个阶段独立的观点。