Social postural coordination.

The goal of the current study was to investigate whether a visual coupling between two people can produce spontaneous interpersonal postural coordination and change their intrapersonal postural coordination involved in the control of stance. We examined the front-to-back head displacements of participants and the angular motion of their hip and ankle during a visual tracking task performed alone and paired. Our results showed that visually paired participants exhibited spontaneous coordination between the movements of their head, hip, and ankle. Moreover, the visual coupling modified the spontaneous intrapersonal ankle-hip coordination dynamics of participants and their performance during visual tracking. Generally, our findings demonstrated reciprocal relations between intrapersonal and interpersonal coordination during social interaction. (PsycINFO Database Record (c) 2011 APA, all rights reserved)     

Learning a new bimanual coordination pattern: Reciprocal influences of intrinsic and to-be-learned patterns.

Examined the following questions: (1) How do previously learned coordination patterns affect new learning (Exp 1)? and (2) How does new learning affect the performance of intrinsic coordination patterns (Exp 2)? In Exp 1, 12 20–24 yr olds practiced either a 45° or a 135° relative phase pattern for 4 days; in Exp 2, 7 21–24 yr olds practiced a 90° relative phase pattern over 6 days. Retention tests were conducted 4 wks after the last practice session in both experiments. Performance on both the in-phase (0°) and anti-phase (180°) patterns was also measured on each day. Results reveal that reciprocal effects between the intrinsic patterns and the new pattern were only temporary, and did not affect learning in any permanent way. Learning a new pattern was not differentially affected by its relation to an intrinsic pattern. (PsycINFO Database Record (c) 2010 APA, all rights reserved)     

Preferred and induced coordination modes during the acquisition of bimanual movements with a 2:1 frequency ratio.

The generalizability of the preferred in-phase and anti-phase coordination modes under isofrequency conditions to bimanual patterns with a 2:1 frequency ratio was studied. Experiment 1 dealt with spontaneously emerging coordination modes and showed that all participants converged to a similar relative phasing pattern, characterized by an alternation between synchronization of the same and opposite relative peak limb positions. This suggests that movement reversals were exploited as intermittent loci of control during multifrequency tasks. Experiment 2 involved the acquisition of a 2:1 ratio with a 90° phase offset and demonstrated the powerful effect of real-time visual relative motion feedback on performance. Removal of this augmented feedback source resulted in a deterioration of the coordination pattern, accompanied by a regression to the aforementioned spontaneous coordination modes. (PsycINFO Database Record (c) 2010 APA, all rights reserved)     

The influence of cue-task association and location on switch cost and alternating-switch cost.

Examined whether task-relevant information provided by task cues influences the magnitude of switch cost in a parallel manner in 74 Ss (aged 18-37 yrs). Cues presented prior to a trivalent stimulus indicated which of three tasks to perform. These cues either had a preexisting association with the to-be-performed task, or a recently learned association with the task. The results paralleled the effects of stimulus bivalence: substantial switch cost with recently learned cue-task associations and greatly reduced switch cost with preexisting cue-task associations. This suggests that both stimulus-based and cue-based information can activate the relevant task set. Alternating-switch cost was also observed with both preexisting and recently learned cue-task associations, only when all tasks were presented in a consistent spatial location. When spatial location was used to cue the to-be-performed tasks, no alternating-switch cost was observed, suggesting that different processes may be involved when tasks are uniquely located in space. Specification of the nature of these processes may prove to be complex, as post-hoc inspection of the data suggested that for the spatial cue condition, the alternating-switch cost may oscillate between cost and benefit, depending on the relevant task. (PsycINFO Database Record (c) 2010 APA, all rights reserved)     

Positive transfer and negative transfer/antilearning of problem-solving skills.

In problem-solving research, insights into the relationship between monitoring and control in the transfer of complex skills remain impoverished. To address this, in 4 experiments, the authors had participants solve 2 complex control tasks that were identical in structure but that varied in presentation format. Participants learned to solve the 2nd task on the basis of their original learning phase from the 1st task or learned to solve the 2nd task on the basis of another participant's learning phase. Experiment 1 showed that, under conditions in which the participant's learning phase was experienced twice, performance deteriorated in the 2nd task. In contrast, when the learning phases in the 1st and 2nd tasks differed, performance improved in the 2nd task. Experiment 2 introduced instructional manipulations that induced the same response patterns as those in Experiment 1. In Experiment 3, further manipulations were introduced that biased the way participants evaluated the learning phase in the 2nd task. In Experiment 4, judgments of self-efficacy were shown to track control performance. The implications of these findings for theories of complex skill acquisition are discussed. (PsycINFO Database Record (c) 2010 APA, all rights reserved)     

Evolution of behavioral attractors with learning: Nonequilibrium phase transitions.

Learning a bimanual coordination task (synchronization to a visually specified phasing relation) was studied as a dynamical process over 5 days of practicing a required phasing pattern. Systematic probes of the attractor layout of the 5 Ss' coordination dynamics (expressed through a collective variable, relative phase) were conducted before, during, and after practice. Depending on the relationship between the initial coordination dynamics (so-called intrinsic dynamics) and the pattern to be learned (termed behavioral information, which acts as an attractor of the coordination dynamics toward the required phasing), qualitative changes in the phase diagram occurred with learning, accompanied by quantitative evidence for loss of stability (phase transitions). Such effects persisted beyond 1 wk. The nature of change due to learning (e.g., abrupt vs gradual) is shown to arise from the cooperative or competitive interplay between behavioral information and the intrinsic dynamics. (PsycINFO Database Record (c) 2010 APA, all rights reserved)     

Implicit learning of visuospatial sequences in schizophenia.

The authors examined whether patients with schizophrenia learned sequential patterns in a probabilistic serial response time task in which pattern trials alternated with random ones. Patients showed faster and more accurate responses to pattern trials than to random trials, but controls showed greater sensitivity to patterns. The highest level of regularity learned in both groups was information about runs of 3 events. Pattern learning occurred largely outside of awareness, as participants could not describe patterns. Controls with higher memory spans learned the sequential pattern better than those with lower memory spans, suggesting that working memory influences implicit pattern learning. Pathology in motor sequencing systems and poor working memory may lead to deficits in learning sequence structure in schizophrenia. (PsycINFO Database Record (c) 2010 APA, all rights reserved)     

Postural coordination modes considered as emergent phenomena.

The coordination of multiple body segments (torso and legs) in the control of standing posture during a suprapostural task was studied. The analysis was motivated by dynamical theories of motor coordination. In 2 experiments it was found that multisegment postural coordination could be described by the relative phase of rotations around the hip and ankle joints. The effective length of the feet, the height of the center of mass, and the amplitude of head motions in a visual tracking task were varied. Across these variations, 2 modes of hip-ankle coordination were observed: in-phase and anti-phase. The emergence of these modes was influenced by constraints imposed by the suprapostural tracking task, supporting the idea that such tasks influence postural control in an adaptive manner. Results are interpreted in terms of a dynamical approach to coordination in which postural coordination modes can be viewed as emergent phenomena. (PsycINFO Database Record (c) 2010 APA, all rights reserved)     

Attentional load associated with performing and stabilizing preferred bimanual patterns.

This study aimed to determine whether the stability of preferred coordination patterns could be modified intentionally and whether such stabilization involved an additional attentional load. Eight participants performed in-phase and anti-phase bimanual coordination patterns, a reaction time (RT) task, and several dual tasks (coordination + RT) that manipulated attentional priority by requiring either shared attention, priority to the coordination task, or priority to the RT task. Results showed that RT was smaller for in-phase than anti-phase. Moreover, attentional manipulations led to a trade-off between pattern stability and RT performance. This suggests that performing and intentionally stabilizing a coordination pattern incur a central cost that depends on the coordination pattern's dynamic properties. Thus, this study opens a conceptual and methodological bridge between information processing and dynamic approaches to coordination. (PsycINFO Database Record (c) 2010 APA, all rights reserved)     

Training for attentional control in dual task settings: A comparison of young and old adults.

The authors examined whether the learning and performance of dual tasks by young and old adults could be enhanced through training. Adults were trained with either a fixed-priority or variable-priority training strategy on a monitoring task and an alphabet-arithmetic task and then transferred to a scheduling and a paired-associates running memory task. Participants in the variable priority condition learned the monitoring and alphabet-arithmetic tasks more quickly and achieved a higher level of mastery on these tasks than did those in the fixed-priority condition. Moreover, participants trained with the variable priority technique showed evidence of the development of automatic processing and a more rapid rate of learning and higher level of mastery of the transfer tasks than did the fixed-priority participants. These results are discussed in terms of the mechanisms that underlie learning and performance of dual tasks and with respect to potential applications. (PsycINFO Database Record (c) 2010 APA, all rights reserved)     

Attention is required for acquisition but not expression of new response biases.

Throughout a lifetime of interaction with the physical environment, people develop a strong bias to respond on the same side as the location of a target object, even when its location is irrelevant to the task at hand. Recent research has shown that this compatibility bias can be overridden with relatively brief but focused training. To better understand how such training affects preexisting response biases, we investigated whether attention is required to acquire and express a new bias to respond on the opposite side, thus creating an incompatibility bias. Participants practiced making responses on the opposite side from left and right tones and then made responses based on the frequencies (high or low) of the same tones. As in previous research, practice with a spatially incompatible mapping eliminated the compatible bias in the Simon task. The addition of an attention load (continuous secondary tracking task) during practice prevented learning the new response bias. However, once the new bias was learned, it overrode the compatibility bias regardless of available attentional resources. We suggest that not only can a quickly learned response bias overwhelm preexisting biases that are acquired over years of experience but that recently learned and older, preexisting biases are similarly affected by attention load. (PsycINFO Database Record (c) 2010 APA, all rights reserved)     

The influence of type and token frequency on the acquisition of affixation patterns: Implications for language processing.

Rules, and exceptions to such rules, are ubiquitous in many domains, including language. Here we used simple artificial grammars to investigate the influence of 2 factors on the acquisition of rules and their exceptions, namely type frequency (the relative numbers of different exceptions to different regular items) and token frequency (the number of exception tokens relative to the number of regular tokens). We familiarized participants to either a prefixation pattern (where regulars started with /ZaI/ and exceptions ended with /ZaI/) or a suffixation pattern (where regulars ended with /ZaI/ and exceptions started with /ZaI/). We show that the type and the token frequency of regular items and exceptions influence in different ways what participants can learn. For the exceptions to be learned, they have to occur sufficiently often so that participants can memorize them; this can be achieved by a high token frequency. However, a high token frequency of the exceptions also impaired the acquisition of the regular pattern. In contrast, the type frequency of the patterns seemed to determine whether the regular pattern could be learned: When the type frequency of the regular items was sufficiently high, participants successfully learned the regular pattern even when the exceptions were played so often that 66% of the familiarization items were exceptions. We discuss these findings in the context of general learning mechanisms and the role they may play in language acquisition. (PsycINFO Database Record (c) 2010 APA, all rights reserved)     

Visual discrimination learning and strategy behavior in the fat-tailed dunnarts ( Sminthopsis crassicaudata ).

Fat-tailed dunnarts (Sminthopsis crassicaudata) were trained on visual discrimination learning-set, reversal-set, and spatial delayed-alternation tasks. The learning set involved 36 2-way black-and-white pattern discriminations and 5 probe reversals. Ten reversals of a black-and-white pattern discrimination were followed by 5 novel tasks. Spatial alternation was tested at delays up to 20 s. Learning-set and reversal-set formation, including 1-trial learning and spontaneous transfer from learning set to reversals and vice versa, was found. Learning-set-experienced dunnarts showed no retention of previously learned tasks 1 week after testing but demonstrated consistently high Trial 2 performance, indicating the retention of a response strategy. Delayed-alternation tasks were learned up to 10-s delays. These results provide the first evidence of a visually guided "win-stay, lose-shift" strategy in a marsupial. (PsycINFO Database Record (c) 2010 APA, all rights reserved)     

Investigating the cause of language regularization in adults: Memory constraints or learning effects?

When language learners are exposed to inconsistent probabilistic grammatical patterns, they sometimes impose consistency on the language instead of learning the variation veridically. The authors hypothesized that this regularization results from problems with word retrieval rather than from learning per se. One prediction of this, that easing the demands of lexical retrieval leads to less regularization, was tested. Adult learners were exposed to a language containing inconsistent probabilistic patterns and were tested with either a standard production task or one of two tasks that reduced the demands of lexical retrieval. As predicted, participants tested with the modified tasks more closely matched the probability of the inconsistent items than did those tested with the standard task. (PsycINFO Database Record (c) 2011 APA, all rights reserved)     

Object recognition versus object discrimination: Comparison between human infants and infant monkeys.

Human infants (aged 12–32 mo old) and adults learned a delayed nonmatching-to-sample (DNMS) task and single- and multiple-pair discrimination tasks using nonverbal procedures previously used with monkeys. Infants learned discriminations rapidly and at a young age (12 mo), but they required prolonged training and maturation before learning the DNMS task. Adults learned all tasks rapidly. After learning the DNMS task to criterion, memory performance declined systematically in an inverse relation to age. The dissociation in ability of infants on the DNMS vs discrimination tasks closely resembles the dissociation previously reported with infant monkeys (J. Bachevalier & M. Mishkin, 1984). Results from both infant humans and monkeys support a neurocognitive maturational model. (PsycINFO Database Record (c) 2010 APA, all rights reserved)     

Problem structure and the use of base-rate information from experience.

This article is concerned with the use of base-rate information that is derived from experience in classifying examples of a category. The basic task involved simulated medical decision making in which participants learned to diagnose hypothetical diseases on the basis of symptom information. Alternative diseases differed in their relative frequency or base rates of occurrence. In five experiments initial learning was followed by a series of transfer tests designed to index the use of base-rate information. On these tests, patterns of symptoms were presented that suggested more than one disease and were therefore ambiguous. The results reveal a consistent but complex pattern. Depending on the category structure and the nature of the ambiguous tests, participants use base-rate information appropriately, ignore base-rate information, or use base-rate information inappropriately (predict that the rare disease is more likely to be present). To our knowledge, no current categorization model predicts this pattern of results. To account for these results, a new model is described incorporating the ideas of property or symptom competition and context-sensitive retrieval. (PsycINFO Database Record (c) 2010 APA, all rights reserved)     

Origins of coordination and team effectiveness: A perspective from game theory and nonlinear dynamics.

Coordination occurs when 2 or more people do the same or complementary tasks at the same time; it takes several forms. The form of coordination studied here was similar to behavior at a 4-way stop traffic intersection. The performance task involved 12 4-person groups and a special card game. Split-plot analysis of variance (ANOVA) showed that coordination rules were implicitly learned and then transferred successfully to new rules of similar difficulty and that coordination can occur without verbal mediation or leadership actions. Transfer of coordination was less positive to a task of greater difficulty. Nonlinear regression showed that fixed-point attractors could be extracted from all learning curves. The difficult shift contained a second chaotic process and a critical utility threshold at which the difficult rule could be mastered or not. (PsycINFO Database Record (c) 2010 APA, all rights reserved)     

Mutual interpersonal postural constraints are involved in cooperative conversation.

The research was designed to evaluate interpersonal coordination during conversation with a new measurement tool. The experiment uses an analysis based on recurrence strategies, known as cross recurrence quantification, to evaluate the shared activity between 2 postural time series in reconstructed phase space. Pairs of participants were found to share more locations in phase space (greater recurrence) in conditions where they were conversing with one another to solve a puzzle task than in conditions in which they conversed with others. The trajectories of pairs of participants also showed less divergence when they conversed with each other than when they conversed with others as well. This is offered as objective evidence of interpersonal coordination of postural sway in the context of a cooperative verbal task. (PsycINFO Database Record (c) 2010 APA, all rights reserved)     

Effect of small cue–response separation on pattern discrimination in macaques (Macaca fuscata and M. mulatta).

Three studies with 17 macaque and 6 rhesus monkeys examined the effect of small cue–response separations on Ss' pattern discriminations. When training on a pattern discrimination with a cue–response separation was discontinued during performance at the chance level, there was no saving on the rate of learning a 2nd task (with identical cues but a different cue–response separation) relative to the performance of naive control Ss. By contrast, when training was discontinued at a performance level a little better than chance, there was significant saving on learning a 2nd task. After learning the 2nd task, a 3rd task with new pattern cues was learned, with marked saving on the duration of performance at the chance level. Results indicate that during the initial stage of performance at the chance level, monkeys do not attend to cues if there is even a small separation between the cue and the response site. (25 ref) (PsycINFO Database Record (c) 2010 APA, all rights reserved)     

Blocking in category learning.

Many theories of category learning assume that learning is driven by a need to minimize classification error. When there is no classification error, therefore, learning of individual features should be negligible. The authors tested this hypothesis by conducting three category-learning experiments adapted from an associative learning blocking paradigm. Contrary to an error-driven account of learning, participants learned a wide range of information when they learned about categories, and blocking effects were difficult to obtain. Conversely, when participants learned to predict an outcome in a task with the same formal structure and materials, blocking effects were robust and followed the predictions of error-driven learning. The authors discuss their findings in relation to models of category learning and the usefulness of category knowledge in the environment. (PsycINFO Database Record (c) 2010 APA, all rights reserved)