Selective learning enabled by intention to learn in sequence learning

This study investigated whether a target sequence that people intend to learn is learned selectively when it is interleaved with another (non-target) sequence. Three experiments used a serial reaction time task in which different spatial and color stimuli occurred alternately. Each of the two interleaved sequences had structural regularity. Participants in an intentional learning group were instructed to learn the target (spatial) sequence whereas those in an incidental learning group were not. In Experiments 1 and 2 spatial and color sequences were correlated. Results showed that the intentional group learned the spatial sequence better than the incidental group and learned it independently of the color sequence, whereas the incidental group learned the two sequences as a combined sequence. In Experiment 3 the sequences were uncorrelated. Results showed that the intentional group was no longer superior in learning the spatial sequence. Findings indicate that the intention to learn a target sequence enables selective learning of it only when it is correlated with a non-target sequence.     

Incidental task sequence learning: perceptual rather than conceptual?

In four experiments we investigated whether incidental task sequence learning occurs when no instructional task cues are available (i.e. with univalent stimuli). We manipulated task sequence by presenting three simple binary-choice tasks (colour, form or letter case decisions) in regular repeated or random order. Participants were required to use the same two response keys for each of the tasks. We manipulated response sequence by ordering the stimuli so as to produce either a regular or a random order of left versus right-hand key presses. When sequencing in both, or either, separate stream (i.e. task sequence and/or response sequence) was changed to random, only those participants who had processed both sequences together showed evidence of sequence learning in terms of significant response time disruption (Experiments 1-3). This effect disappeared when the sequences were uncorrelated (Experiment 4). The results indicate that only the correlated integration of task sequence and response sequence produced a reliable incidental learning effect. As this effect depends on the predictable ordering of stimulus categories, it suggests that task sequence learning is perceptual rather than conceptual in nature.     

Contextual dependencies in motor skills

The development of contextual dependencies during motor skill acquisition was examined. Environmental context was varied along intentional and incidental dimensions. Intentional stimuli were defined as essential for achieving skilled performance, whereas incidental stimuli were defined as those that have the potential to become associated with specific tasks due to their selective presence in the learning environment. Experiment 1 demonstrated the occurrence of contextual dependencies for the learning of four-key typing sequences. Contextual dependencies were diminished in Experiment 2 when the number of keys used in the sequences was reduced. In Experiment 3, a retention condition was incorporated, in which both the intentional and the incidental stimuli were not available; this confirmed that task difficulty mediated the development of contextual dependencies. These findings are discussed with respect to the incorporation of environmental contextual stimuli with memorial representations of movement information.     

Learning of event sequences is based on response-effect learning: further evidence from a serial reaction task

Four experiments provide converging evidence that serial learning in a serial reaction task is based on response-effect learning, mediated by the learning of the relations between a response and the stimulus that follows it. In Experiment 1, the authors varied the stimulus sequence and the response-stimulus relations while holding the response sequence constant. Learning effects depended on the complexity of the response-stimulus relations but not on the stimulus-stimulus relations. In Experiment 2, transfer of serial learning from 1 stimulus sequence to another was only found when both sequences had identical response-stimulus relations. In Experiment 3, a variation of the stimulus sequence alone had no effect on serial learning, whereas in Experiment 4 learning effects increased when the response-stimulus relations but not the stimulus-stimulus relations were simplified. These findings suggest that serial learning is based on mechanisms of voluntary action control.     

Operating characteristics of the implicit learning system supporting serial interception sequence learning

The memory system that supports implicit perceptual-motor sequence learning relies on brain regions that operate separately from the explicit, medial temporal lobe memory system. The implicit learning system therefore likely has distinct operating characteristics and information processing constraints. To attempt to identify the limits of the implicit sequence learning mechanism, participants performed the serial interception sequence learning (SISL) task with covertly embedded repeating sequences that were much longer than most previous studies: ranging from 30 to 60 (Experiment 1) and 60 to 90 (Experiment 2) items in length. Robust sequence-specific learning was observed for sequences up to 80 items in length, extending the known capacity of implicit sequence learning. In Experiment 3, 12-item repeating sequences were embedded among increasing amounts of irrelevant nonrepeating sequences (from 20 to 80% of training trials). Despite high levels of irrelevant trials, learning occurred across conditions. A comparison of learning rates across all three experiments found a surprising degree of constancy in the rate of learning regardless of sequence length or embedded noise. Sequence learning appears to be constant with the logarithm of the number of sequence repetitions practiced during training. The consistency in learning rate across experiments and conditions implies that the mechanisms supporting implicit sequence learning are not capacity-constrained by very long sequences nor adversely affected by high rates of irrelevant sequences during training.     

Anticipatory response control in motor sequence learning: evidence from stimulus-response compatibility

Three experiments using a serial four-choice reaction-time (RT) task explored the interaction of sequence learning and stimulus-based response conflict. In Experiment 1, the spatial stimulus-response (S-R) mapping was manipulated between participants. Incompatible S-R mappings produced much higher RTs than the compatible mapping, but sequence learning decreased this S-R compatibility effect. In Experiment 2, the spatial stimulus feature was made task-irrelevant by assigning responses to symbols that were presented at unpredictable locations. The data indicated a Simon effect (i.e., increased RT when irrelevant stimulus location is spatially incompatible with response location) that was reduced by sequence learning. However, this effect was observed only in participants who developed an explicit sequence representation. Experiment 3 replicated this learning-based modulation of the Simon effect using explicit sequence-learning instructions. Taken together, the data support the notion that explicit sequence learning can lead to motor 'chunking', so that pre-planned response sequences are shielded from conflicting stimulus information.     

The influence of the response–stimulus interval on implicit and explicit learning of stimulus sequence

Three experiments investigated the influence of the response-stimulus interval (RSI) on implicit and explicit learning of stimulus sequences. Participants responded to numerals presented in predetermined positions with alternating long and short RSIs. Half of the participants were instructed explicitly to learn the position sequence. In the transfer phase of Experiments 1 and 2, changing RSI patterns reduced the expression of incidental and intentional learning of position sequence. In Experiment 3 the position sequence was transformed, except that sub-sequences demarcated by long RSIs remained unchanged; this greatly reduced the expression of intentional learning, and slightly reduced that of incidental learning. These results indicate that in implicit learning, stimulus sequences are learned under the constraints of RSIs, whereas in explicit learning, learning independent of RSIs, as well as learning constrained by RSIs, occurs.     

The role of stimulus-based and response-based spatial information in sequence learning

In 4 experiments, relational structures were independently varied in stimulus and response sequences in a serial reaction time task. Moreover, the use of spatial and symbolic stimuli and responses was varied between experiments. In Experiment 1, spatial stimuli (asterisk locations) triggered spatial responses (keystrokes); in Experiment 2, spatial stimuli triggered symbolic responses (verbal digit naming); in Experiment 3, symbolic stimuli (digits) triggered keystrokes; and in Experiment 4, digits triggered verbal responses. The results showed that there is a remarkably stronger effect of relational structures in spatial sequences than in symbolic sequences, irrespective of whether stimulus or response sequences are concerned. This suggests that learning is particularly effective for sequences of spatial locations. It is argued that spatial learning is a critical determinant for the debate on perceptual and motor learning.     

A Multinomial Model to Assess Fluency and Recollection in a Sequence Learning Task

We suggest that well-formedness judgements in conjunction with L.L. Jacoby's (1991) process dissociation procedure and an appropriate measurement model can be used to obtain measures of implicit and explicit sequence knowledge. We introduce a new measurement model designed specifically for the sequence learning task. The model assumes that sequence identification is based on recollection, perceptual or motor fluency, systematicity detection, and guessing. The model and the application of the process dissociation procedure were empirically evaluatedusing auditory eventsequences. In Experiment 1, the parameterreflecting recollection was higher in an intentional than in an incidental learning condition. Experiment 2 showed that random sequences interspersed among the systematic sequences during the acquisition phase may change this pattern of results. A manipulation of processing fluency in Experiment 3 was reflected in the appropriate model parameter. In sum, the new measurement model and the application of the process dissociation procedure appear to be useful tools in sequence learning research.     

Multidimensional sequence learning in patients with focal basal ganglia lesions

Parkinson's patients have been found to be impaired in learning movement sequences. In the current study, patients with unilateral basal ganglia lesions due to stroke were tested on a serial reaction time task in which responses were based on the spatial location of each stimulus. The spatial locations either followed a fixed sequence or were selected at random, with learning operationalized as the difference in reaction time between these two conditions. In addition, three response-to-stimulus intervals were used, and these either followed a fixed sequence or were randomized. Compared to control participants, the patients showed normal learning of the spatial and temporal sequences, as well as normal cross-dimensional learning. This was true for performance with either the contralesional or ipsilesional hand. Sequence learning was not correlated with maximum tapping rate, a simple measure of motor impairment. These results raise questions concerning the use of Parkinson's disease as a model for studying basal ganglia dysfunction.     

Stimulus-dependent modulation of perceptual and motor learning in a serial reaction time task

In two experiments, we investigated the impact of spatial attributes on the representation acquired during a serial reaction time task. Two sequences were used, in which structural regularities occurred either in the horizontal or in the vertical locations of successive stimuli. After training with the dominant hand, participants were required to respond with the non-dominant hand to either the original sequence or to a mirror-ordered version of the original sequence that required finger movements homologous to those used during training. We observed that a difference in reaction times between the two transfer conditions was smaller in the vertical sequence than in the horizontal sequence. This pattern of results was independent of whether three fingers (Experiment 1) were used or only one finger (Experiment 2) was used for responding. This result suggests that perceptual and motor learning mechanisms may be weighted differently depending on the context in which the stimulus is presented.     

Organization of visuo-spatial serial memory: interaction of temporal order with spatial and temporal grouping

This study investigates whether memory for sequences of spatial locations can be represented hierarchically, that is, as successive groups containing the order of constituent locations. Two grouping manipulations are used: Temporal grouping, based on the verbal serial memory literature, and spatial grouping, based on recent empirical work on visuo-spatial serial memory. In Experiment 1, we examine the relationship between spatial grouping and temporal order and showed that recall performance increases when both temporal and spatial organization correlate, but decreases when they clash. Experiments 2 and 3 show that the latter result is confounded by differences in path length (length of spatial path defined by the locations) between conditions, and that no effect of the spatial organization is observed when path length is controlled for. In Experiment 4, an alternative method to spatial grouping, temporal grouping, is used to induce hierarchical organization. A recall advantage is found in the temporal grouping condition. The results suggest that hierarchical representations can be imposed on order information for visuo-spatial sequences, either when participants have pre-existing knowledge about the form of the path formed by the sequence or when temporal boundaries delimit chunks; that increased path length is the cause of the performance decrement observed when dots from separate spatial groups are presented successively; and that path length and more generally sequence characteristics should be taken into account in designing future research on visuo-spatial serial memory.     

Context dependent learning in the serial RT task

This study investigated the development of contextual dependencies for sequential perceptual-motor learning on static features in the learning environment. In three experiments we assessed the effect of manipulating task irrelevant static context features in a serial reaction-time task. Experiment 1 demonstrated impaired performance after simultaneously changing display color, placeholder shape, and placeholder location. Experiment 2 showed that this effect was mainly caused by changing placeholder shape. Finally, Experiment 3 indicated that changing context affected both the application of sequence knowledge and the selection of individual responses. It is proposed either that incidental stimulus features are integrated with a global sequence representation, or that the changed context causes participants to strategically inhibit sequence skills.     

Integration of temporal and ordinal information during serial interception sequence learning

The expression of expert motor skills typically involves learning to perform a precisely timed sequence of movements. Research examining incidental sequence learning has relied on a perceptually cued task that gives participants exposure to repeating motor sequences but does not require timing of responses for accuracy. In the 1st experiment, a novel perceptual-motor sequence learning task was used, and learning a precisely timed cued sequence of motor actions was shown to occur without explicit instruction. Participants learned a repeating sequence through practice and showed sequence-specific knowledge via a performance decrement when switched to an unfamiliar sequence. In the 2nd experiment, the integration of representation of action order and timing sequence knowledge was examined. When either action order or timing sequence information was selectively disrupted, performance was reduced to levels similar to completely novel sequences. Unlike prior sequence-learning research that has found timing information to be secondary to learning action sequences, when the task demands require accurate action and timing information, an integrated representation of these types of information is acquired. These results provide the first evidence for incidental learning of fully integrated action and timing sequence information in the absence of an independent representation of action order and suggest that this integrative mechanism may play a material role in the acquisition of complex motor skills.     

Are correlated streams of information necessary for implicit sequence learning?

We investigated whether the existence of correlated streams of information is necessary for incidental sequence learning to occur. We ran three separate experiments with a total of 201 undergraduate students. Each experiment had at least one condition with two streams of sequenced information that were correlated. The correlations differed in terms of the kind of responses that were required, the kind of tasks and stimuli, the on-screen locations at which they occurred and how they were combined. Only in conditions with correlated sequences was implicit sequence learning found. Our results suggest that the presence of correlated streams of information may be the main pre-requisite for implicit sequence learning.     

Patterns, chunks, and hierarchies in serial reaction-time tasks

The impact of relational structures (i.e., the systematicity of relations between successive items) on incidental sequence learning was investigated in a serial reaction-time (SRT) task while keeping constant the statistical structure. In order to assess the influence of relational structures in stimulus and response sequences separately, the strength of relational patterns in sequences of digits as stimuli and of keystrokes as responses was orthogonally varied. In Exps. 1 and 2, the variation of relational patterns was mainly effective in the keystroke sequence. In Exp. 2, in addition to the variation of relational patterns, the presentation of stimuli was delayed at serial positions that were incongruent with the relational structure. The results show that these incongruent pauses reduced the learning of strongly structured sequences of keystrokes but improved the learning of weakly structured sequences. Experiment 3 suggests that even higher-order relations between elementary patterns are utilized to accelerate responses. The data are interpreted as evidence for the impact of relational patterns, in addition to statistical redundancies, on the formation of chunks. Reasons are discussed for the finding that relational chunking was more pronounced in the keystroke than in the digit sequences. Received: 25 June 1998 / Accepted: 3 December 1998     

What matters in implicit task sequence learning: perceptual stimulus features, task sets, or correlated streams of information?

Implicit task sequence learning may be attributed to learning the order of perceptual stimulus features associated with the task sequence, learning a series of automatic task set activations, or learning an integrated sequence that derives from 2 correlated streams of information. In the present study, our purpose was to distinguish among these 3 possibilities. In 4 separate experiments, we replicated and extended a previous study by Heuer, Schmidtke, and Kleinsorge (2001). The presence or absence of a sequence of tasks, as well as that of a sequence of different task-to-response mappings, was manipulated independently within experiments. Evidence of implicit sequence learning was found only when correlated sequences of tasks and mappings were present. No sequence learning effects were found when only a single task sequence or a single mapping sequence was present, even when the structure of the single sequence was identical to the structure of the integrated sequence of task-mapping combinations. These results suggest that implicit task sequence learning is not dependent on either perceptual learning of stimulus features or automatic task-set activation per se. Rather, it appears to be driven by correlated streams of information.     

外显、内隐记忆中不同认知方式个体的社会定向

以中文双字词为实验材料,分别从两个层面探讨场依存个体与场独立个体对社会词或非社会词的记忆有无偏向。实验一采用双任务,分散注意学习条件,实验二引入加工分离程序(PDP)。研究结果表明:(1)在双任务分散注意学习条件下,场依存个体对非目标社会词存在记忆偏向。(2)在内隐记忆成绩上,场依存个体对社会词存在记忆偏向,场独立个体对非社会词存在记忆偏向。     

Automatic and intentional activation of task sets.

Four experiments examined automatic and intentional activation of task sets in a switching paradigm. Experiment 1 demonstrated incidental task sequence learning that was not accompanied by verbalizable task sequence knowledge. This learning did not affect task shift cost and may be attributed to automatic task-set activation. In Experiment 2, both shift cost and learning effect increased when the response-cue interval was short, indicating the influence of residual, persisting activation of the preceding task set. In Experiment 3, learning disappeared with a long cue-stimulus interval (CSI), which resulted in a strong preparation effect. This preparation, however, reduced reaction time level but was not specific to task shifts. Finally, Experiment 4 showed that a within-subject C     

Symmetry in haptic and in visual shape perception

Four experiments tested the hypothesis that bilateral symmetry is an incidental encoding property in vision, but can also be elicited as an incidental effect in touch, provided that sufficient spatial reference information is available initially for haptic inputs to be organized spatially. Experiment 1 showed that symmetry facilitated processing in vision, even though the task required judgments of stimulus closure rather than the detection of symmetry. The same task and stimuli failed to show symmetry effects in tactual scanning by one finger (Experiment 2). Experiment 3 found facilitating effects for vertically symmetric open stimuli, although not for closed patterns, in two-forefinger exploration when the fore-fingers had previously been aligned to the body midaxis to provide body-centered spatial reference. The one-finger exploration condition again failed to show symmetry effects. Experiment 4 replicated the facilitating effects of symmetry for open symmetric shapes in tactual exploration by the two (previously aligned) forefingers. Closed shapes again showed no effect. Spatial-reference information, finger movements, and stimulus factors in shape perception by touch are discussed.