Dissociable neural systems of sequence learning

Although current theories all point to distinct neural systems for sequence learning, no consensus has been reached on which factors crucially define this distinction. Dissociable judgment-linked versus motor-linked and implicit versus explicit neural systems have been proposed. This paper reviews these two distinctions, yet concludes that these traditional dichotomies prove insufficient to account for all data on sequence learning and its neural organization. Instead, a broader theoretical framework is necessary providing a more continuous means of dissociating sequence learning systems. We argue that a more recent theory, dissociating multidimensional versus unidimensional neural systems, might provide such framework, and we discuss this theory in relation to more general principles of associative learning and recent imaging findings.     

Redundant sensory information does not enhance sequence learning in the serial reaction time task

In daily life we encounter multiple sources of sensory information at any given moment. Unknown is whether such sensory redundancy in some way affects implicit learning of a sequence of events. In the current paper we explored this issue in a serial reaction time task. Our results indicate that redundant sensory information does not enhance sequence learning when all sensory information is presented at the same location (responding to the position and/or color of the stimuli; Experiment 1), even when the distinct sensory sources provide more or less similar baseline response latencies (responding to the shape and/or color of the stimuli; Experiment 2). These findings support the claim that sequence learning does not (necessarily) benefit from sensory redundancy. Moreover, transfer was observed between various sets of stimuli, indicating that learning was predominantly response-based.     

Training Motor Sequences: Effects of Speed and Accuracy Instructions

Participants practiced a fixed 3- and a fixed 6-key press sequence for 144 times each. In the speed group, they were instructed to execute their sequences fast without bothering much about errors while the accurate group was instructed to be careful and prevent errors. In the test phase, participants executed series of 3 and 6 responses (a) when all element-specific stimuli were displayed in the familiar order, (b) in response to just the familiar first stimulus, and (c) by responding to random stimuli. The speed instruction yielded stronger sequencing skill while the accuracy instruction developed stronger reaction skill.     

Intentional Teaching Facilitates Young Children's Comprehension and Use of a Symbolic Object

Children are exposed to symbolic objects that they have to learn to use very early in life. The authors’ aim was to examine whether it is possible to intentionally teach young children the symbolic function of an object. They employed a search task in which children had to use a map to find a toy. Experiment 1 revealed that with no instruction 3-year-, 10-month-old children were quite successful; 3-year-, 6-month-olds showed a divided performance; and 3-year-, 0-month-olds failed. With this baseline, Experiment 2 compared the performance of 3-year-, 0-month-olds in three different conditions: no-instruction, complete instruction (before the task begins), and teaching (complete instruction plus corrective feedback); only children in the teaching condition succeeded. However, children 6 months younger, 2-year-, 6-month-olds, failed despite teaching that was provided (Study 3). This research shows that at some points in development instruction is not enough; intentional teaching in communicative contexts is the mechanism that boosts symbolic understanding in early childhood.     

Effect of Practice on Effector Independence

The authors' primary purpose in the present experiment was to determine if practice changes the extent to which simple motor sequences are effector independent. Contralateral and ipsilateral effector transfers were assessed in 24 participants after 1 (200 trials) and 4 (800 trials) days of practice. The response sequence became increasingly effector dependent; the response structure and the scaling of force on the effector transfer tests were no better after 4 days of practice than after only 1 day, even though retention performance improved substantially. Those results are consistent with the notion that participants refine their movements over extended practice by exploiting the unique characteristics of the effectors. The additional practice results in a more effective movement when the same effectors are used but is of little value when different effectors are required.     

Corrigendum

Mild to moderate Parkinson's disease shows more denervation in the posterodorsal striatum and sparing of the anteroventral striatum. Dopaminergic medications can interfere with anteroventral striatum function by overdosing this relatively intact structure. The authors determined how regional striatal denervation affects medication-associated sequence learning impairment in Parkinson's disease. Eighteen Parkinson's patients performed motor sequence learning on and off levodopa. Patients underwent ¹¹C-dihydrotetrabenazine positron emission tomography scans to measure nigrostriatal denervation. Patients with more preserved putamen were more likely to exhibit levodopa-associated sequence learning impairments. Furthermore, the ratio of denervation in the anterior to posterior dorsal putamen predicted the level of learning differences on and off levodopa. These results demonstrate that the spatial pattern of nigrostriatal dopaminergic denervation predicts medication responsiveness for motor sequence learning.     

The Timing Effects of Accent Production in Periodic Finger-Tapping Sequences

When subjects are required to produce short sequences of equally paced finger taps and to accentuate one of the taps, the interval preceding the forceful tap is shortened and the one that immediately follows the accent is lengthened. Assuming that the tapping movements are triggered by an internal clock, one explanation attributes the mistiming of the taps to central factors: The momentary rate of the clock is accelerated or decelerated as a function of motor preparation to, respectively, increase or decrease the movement force. This hypothesis predicts that the interre-sponse intervals measured between either tap movement onsets or movement terminations (taps) will show the same timing pattern. A second explanation for the observed interval effects is that the tapping movements are triggered by a regular internal clock but the timing of the successive taps is altered because the forceful movement is completed in less time than the other tap movements are. This “peripheral” hypothesis predicts regular timing of movement onsets but distorted timing of movement terminations. In the present study, the trajectories of the movements performed by subjects were recorded and the interresponse intervals were measured at the beginning and the end of the tapping movements. The results of Experiment 1 showed that neither model can fully explain the interval effects: The fast forceful movements were initiated with an additional delay that took into account the small execution time of these movements. Experiment 2 reproduced this finding and showed that the timing of the onset and contact intervals did not evolve with the repetition of trial blocks. Therefore, the assumption of an internal clock that would trigger the successive movements must be rejected. The results are discussed in the framework of a modified two-stage model in which the internal clock, instead of triggering the tapping movements, provides target time points at which the movements have to produce their meaningful effects, that is, contacts with the response key. The timing distortions are likely to reflect both peripheral and central components.     

Deriving relations at multiple levels of complexity following minimal instruction: A demonstration

Recommendations for achieving generalized instructional outcomes often overlook the capacity for generative learning for most verbally competent humans. Four children (ages 5–8) participated in this project. In Study 1, we provided decontextualized discrete trial teaching to establish arbitrary relations between colors, pictures of characters, and researcher motor actions. All participants engaged in derivative responding, providing evidence of relational framing. Subsequently, we demonstrated that, with no additional instruction, these derivatives contributed to effective action within a socially valid context (i.e., Candyland gameplay). Study 2 extended the demonstration by teaching frames of opposition. Following teaching, all participants engaged in novel and contextually appropriate responding that entailed the derivation of both coordination and opposition between untrained stimuli. This outcome demonstrates how teaching simple relations can result in learning that manifests at higher levels of complexity (i.e., relational networking), providing some evidence that there can be socially valid benefits to decontextualized discrete trial instruction.     

Nonverbal communication during the learner lesson with a professional driving instructor: A novel investigation

BackgroundFundamental for the development of the driving and road use skills of the young driver is learning to drive through driving instruction and, in graduated driver licensing programs such as in Australia, driving supervision. In Queensland young drivers are required to log a minimum of 100 h supervised practice, with recent research revealing that parents provide most of this supervision. Queensland also offers young drivers a 10-h 3-for-1 bonus for professional driving instruction, such that one hour of professional instruction can be logged as three hours of practice, to a maximum of 30 logbook hours. Recent research efforts have begun to provide insight into the nature of the verbal instruction of both parents and professional instructors, and into the nonverbal communication between parents and learners. However nothing is known regarding the nonverbal communication between professional instructors and learners.MethodTen learner lessons (five male learners) with four professional instructors (four males) were captured via GoPro cameras. The nonverbal communication during the first, middle, and last 10 min of each lesson was coded as being posture and body orientation, gestures, facial expressions, proximity, humour, and eye contact, within the context of the accompanying verbal communication according to the value of (a) eager, or (b) cautious; the valence of (a) neutral, (b) positive, or (c) negative; and the purpose of (a) rapport, or (b) communication.ResultsOverall, posture and body orientation was the most common mechanism of nonverbal communication, while facial expressions and proximity were the least common mechanisms of nonverbal communication. In general the beginning, the middle, and the end of the lessons were characterised by a plethora of neutral, cautious interactions, and positive, eager interactions. However it is noteworthy that the rates at which learners and instructors engaged in these behaviours were found to change across the lesson. Specifically learners actively communication nonverbally through mechanisms such as eye contact, facial expressions and humour, while instructors appeared to manage building rapport and communicating safe vehicle and road use through nonverbal communication such as gestures, facial expressions and posture and body orientation, summarised in a model comprising a continuum of instruction.DiscussionWhile nonverbal communication is fundamental for effective verbal communication, and on occasion can replace verbal communication, and as such the professional – and the parental – driving lesson should optimise the use of nonverbal communication, at this time the optimal nature of nonverbal communication remains unknown. In addition, optimal verbal and nonverbal communication specifically suited to the driving context which involves a dynamic environment outside the vehicle, and at times a dynamic environment inside the vehicle, remains yet to be identified. The research findings provide unique insight into the nature of the nonverbal communication used by both learner drivers and professional driving instructors, in addition to the continuum of instruction model. As such, the findings provide a solid foundation for future research into, and guidance regarding, optimising the learner driving lesson.     

高低情感开放性者概率内隐序列学习进程差异

大五人格情感开放性子量表(openness/feeling)能否预测内隐序列学习的问题存在争议。本研究采用概率性内隐序列学习范式, 比较高低情感开放性者在各反应刺激间隔(response stimulus interval, 即RSI)的差异。发现：(1) RSI = 0 ms和250 ms, 高分组在转移组块后习得高概率序列, RSI = 500 ms及以上在其之前习得; 所有RSI点低分组都在其之前习得。每个RSI点只有高分组习得低概率序列。证明随RSI增加两者内隐进程有本质差异, openness/feeling子量表可预测内隐序列学习个体差异。(2)低概率序列可作为测量概率性内隐序列学习及个体差异的新指标, 经典转移组块、再认、生成任务的测量效果却十分有限。