Asymptotic Performance Levels Research Articles

Design, Fabrication, and Preliminary Validation of Patient-Specific Spine Section Phantoms for Use in Training Spine Surgeons Outside the Operating Room/Theatre.

Pedicle screw fixation (PSF) demands rigorous training to mitigate the risk of severe neurovascular complications arising from screw misplacement. This paper introduces a patient-specific phantom designed for PSF training, extending a portion of the learning process beyond the confines of the surgical room. Six phantoms of the thoracolumbar region were fabricated from radiological datasets, combining 3D printing and casting techniques. The phantoms were employed in three training sessions by a fifth-year resident who performed full training on all six phantoms; he/she placed a total of 57 pedicle screws. Analysis of the learning curve, focusing on time per screw and positioning accuracy, revealed attainment of an asymptotic performance level (around 3 min per screw) after 40 screws. The phantom's efficacy was evaluated by three experts and six residents, each inserting a minimum of four screws. Initial assessments confirmed face, content, and construct validity, affirming the patient-specific phantoms as a valuable training resource. These proposed phantoms exhibit great promise as an essential tool in surgical training as they exhibited a demonstrable learning effect on the PSF technique. This study lays the foundation for further exploration and underscores the potential impact of these patient-specific phantoms on the future of spinal surgical education.

Target templates and the time course of distractor location learning

When searching for a shape target, colour distractors typically capture our attention. Capture is smaller when observers search for a fixed target that allows for a feature-specific target template compared to a varying shape singleton target. Capture is also reduced when observers learn to predict the likely distractor location. We investigated how the precision of the target template modulates distractor location learning in an additional singleton search task. As observers are less prone to capture with a feature-specific target, we assumed that distractor location learning is less beneficial and therefore less pronounced than with a mixed-feature target. Hierarchical Bayesian parameter estimation was used to fit fine-grained distractor location learning curves. A model-based analysis of the time course of distractor location learning revealed an effect on the asymptotic performance level: when searching for a fixed-feature target, the asymptotic distractor cost indicated smaller distractor interference than with a mixed-feature target. Although interference was reduced for distractors at the high-probability location in both tasks, asymptotic distractor suppression was less pronounced with fixed-feature compared to mixed-feature targets. We conclude that with a more precise target template less distractor location learning is required, likely because the distractor dimension is down-weighted and its salience signal reduced.

Letting the Struggling Saudi EFL Readers Take Lead: How Teachers Transform English Language Instruction

The paper intends to divulge and argue the major reading problems Saudi students face and flaws in contemporary research that affects a lot on developing their reading skills. The problems and pitfalls related to reading skill, prime facie, seem traditional but widely discussed; hitherto, remain unsettled in the arena of language learning. The researcher tries to explore and shed light on these problems while achieving different asymptotic levels of performance, constrained and unconstrained skills to observe and experience how far and fast the Saudi EFL learners master the reading skills in and out of classroom settings at Jazan University. It is solely based on experience and observational data that the researcher has collected on his students’ everyday classroom performance. The paper also monitors how far the previous findings contributed to overcome struggling readers’ problems and improve their reading abilities and suggests how recognizing these major occurring problems may endow with an authentic and viable initiative for planning reading instruction and interventions. Hence, the present study aims to provide in-depth examination and interpretation of struggling Saudi EFL learners’ problems and challenges meting out different texts in structure and related aspects on different reading tasks. The paper concludes with some vital suggestions that would indubitably help learners and teachers practice in realia to lessen anxiety, achieve desired outcomes and evolve educational policies for language instruction, evaluation and assessment.

Initial performance predicts improvements in computerized cognitive training: Evidence from a selective attention task.

Computerized cognitive training (CCT) has been found to improve a range of skills such as attention, working memory, inhibition control, and decision making. However, the relationship between the initial performance, amount of improvement, time constant, and asymptotic performance level in CCT is still unclear. In the current study, we performed selective attention training on college students and addressed this issue by mathematically modeling the learning curve with an exponential function. Twenty-nine students completed approximately 10 days of CCT. Presentation time served as the dependent variable and was measured by three-down/one-up adaptive algorithms. We fitted an exponential function to the estimated block thresholds during CCT and obtained three learning parameters (amount of improvement, time constant, and asymptotic performance level) for all subjects. The initial performance was defined by the sum of the amount of improvement and the asymptotic performance level. Pearson correlation analyses were conducted between the initial performance and the three leaning parameters. The initial performance was positively correlated with the amount of improvement and asymptotic performance level, but was negatively correlated with the time constant. The time constant was negatively correlated with the amount of improvement and asymptotic performance level. Poorer initial performance was linked to a larger amount of improvement, shorter time constant, and higher asymptotic threshold, which supported the compensation account. Our results may help improve the present understanding of the nature of the CCT process and demonstrate the advantages of using a customized training protocol to enhance the efficiency of cognitive training in practical applications.

Individual difference predictors of learning and generalization in perceptual learning.

Given appropriate training, human observers typically demonstrate clear improvements in performance on perceptual tasks. However, the benefits of training frequently fail to generalize to other tasks, even those that appear similar to the trained task. A great deal of research has focused on the training task characteristics that influence the extent to which learning generalizes. However, less is known about what might predict the considerable individual variations in performance. As such, we conducted an individual differences study to identify basic cognitive abilities and/or dispositional traits that predict an individual's ability to learn and/or generalize learning in tasks of perceptual learning. We first showed that the rate of learning and the asymptotic level of performance that is achieved in two different perceptual learning tasks (motion direction and odd-ball texture detection) are correlated across individuals, as is the degree of immediate generalization that is observed and the rate at which a generalization task is learned. This indicates that there are indeed consistent individual differences in perceptual learning abilities. We then showed that several basic cognitive abilities and dispositional traits are associated with an individual's ability to learn (e.g., simple reaction time; sensitivity to punishment) and/or generalize learning (e.g., cognitive flexibility; openness to experience) in perceptual learning tasks. We suggest that the observed individual difference relationships may provide possible targets for future intervention studies meant to increase perceptual learning and generalization.

Cognitive performance is enhanced if one knows when the task will end

In two studies, participants performed a switching task, and we provided to only half of them feedback on goal progress (how much of the task still remains). Importantly, this feedback did not inform participants on how well they performed. We found that participants in the feedback condition achieved a higher asymptotic level of performance, reported less fatigue and took shorter breaks between blocks compared to the control condition. These results suggest that asymptotic level of performance reflects not only ability (as is commonly assumed in the literature) but also motivation. We suggest that when people know when a focal task would end, they invest more effort in it because foregoing other activities becomes less costly (i.e., opportunity cost of engaging in the focal activity decreases) and because knowing when a task would end frees the actor from the need to conserve effort. These results suggest a simple, effective and costless way to improve cognitive performance that may be applied in educational and organizational settings.

Environmental Enrichment Expedites Acquisition and Improves Flexibility on a Temporal Sequencing Task in Mice.

Environmental enrichment (EE) via increased opportunities for voluntary exercise, sensory stimulation and social interaction, can enhance the function of and behaviours regulated by cognitive circuits. Little is known, however, as to how this intervention affects performance on complex tasks that engage multiple, definable learning and memory systems. Accordingly, we utilised the Olfactory Temporal Order Discrimination (OTOD) task which requires animals to recall and report sequence information about a series of recently encountered olfactory stimuli. This approach allowed us to compare animals raised in either enriched or standard laboratory housing conditions on a number of measures, including the acquisition of a complex discrimination task, temporal sequence recall accuracy (i.e., the ability to accurately recall a sequences of events) and acuity (i.e., the ability to resolve past events that occurred in close temporal proximity), as well as cognitive flexibility tested in the style of a rule reversal and an Intra-Dimensional Shift (IDS). We found that enrichment accelerated the acquisition of the temporal order discrimination task, although neither accuracy nor acuity was affected at asymptotic performance levels. Further, while a subtle enhancement of overall performance was detected for both rule reversal and IDS versions of the task, accelerated performance recovery could only be attributed to the shift-like contingency change. These findings suggest that EE can affect specific elements of complex, multi-faceted cognitive processes.

Abstract WP110: Spontaneous Motor Recovery After Cerebrolysin Treatment in a Mouse Model of Stroke

Background and Purpose: Most functional upper extremity motor recovery occurs in the first 4 weeks after ischemic stroke in humans and in the first week in rodent models. The majority of functional recovery in humans is spontaneous (i.e. occurs as a result of endogenous repair processes rather than rehabilitative interventions). In mouse models of stroke, recovery is impaired when post-stroke rehabilitation is delayed and there is very little spontaneous recovery. Cerebrolysin is a polypeptide preparation shown to enhance neuronal plasticity and to promote motor recovery in patients after stroke. In mice, we tested the hypothesis that Cerebrolysin can act early after stroke to enhance spontaneous motor recovery. Methods: Adult C57Bl/6 mice were trained to perform a skilled prehension task to an asymptotic level of performance, after which they underwent photocoagulation-induced stroke in the caudal forelimb area (rodent primary motor cortex). The mice were then randomized to receive Cerebrolysin or saline injections beginning 24-hours post-stroke. Both groups were then retrained at the same prehension task by a blinded investigator. Stroke volumes were compared using immunohistochemistry. Results: We have previously shown that training-associated recovery of prehension is complete if training is initiated after a 1-day delay but incomplete if training is initiated after a 7-day delay, even with additional training days. However, daily Cerebrolysin administration after stroke was associated with complete recovery of prehension by day 8, even in the absence of training. Stroke volumes were similar across all groups. Conclusions: We conclude that Cerebrolysin administration during an early time window can lead to spontaneous recovery of motor function without a protective effect on stroke volume. This is one of the first demonstrations of spontaneous motor recovery in a rodent stroke model. Our mouse model, with all of the attendant genetic benefits, should allow us to determine at the cellular and molecular level how endogenous plasticity and medications like Cerebrolysin interact to mediate recovery.

Potential for intermittent stimulation of nucleus basalis of Meynert to impact treatment of alzheimer's disease

ABSTRACTThe brain's cholinergic arousal pathways decline in parallel with the brain's executive functions in aging and Alzheimer's Disease. The frontline and currently most effective approach to treating Alzheimer's disease is the administration of cholinesterase inhibitors, which, in a dose dependent manner, improve the symptoms of cognitive decline over the first months of treatment before further decline occurs. We recently showed that intermittent deep brain stimulation of the nucleus basalis of Meynert improves working memory function in young adult monkeys, and that this improvement depended on cholinergic function. Within minutes, the monkeys’ ability to remember stimuli over a delay period improved. Over months, the monkeys performed the working memory task better even in the absence of stimulation. Here, we show historical data from our monkey colony in which more than two dozen animals have performed the same behavioral task to asymptotic performance levels. Using a distribution based on our historical data, we estimate that the monkeys receiving intermittent stimulation leapt over the performance level of 32–44 percent of peer animals in the first several months after stimulation was initiated. Implications for a parallel increase in cognitive function for early Alzheimer's patients are discussed.

Disruption of M1 Activity during Performance Plateau Impairs Consolidation of Motor Memories.

Upon exposure to a new sensorimotor relationship, motor behaviors iteratively change early in adaptation but eventually stabilize as adaptation proceeds. Behavioral work suggests that motor memory consolidation is initiated upon the attainment of asymptotic levels of performance. Separate lines of evidence point to a critical role of the primary motor cortex (M1) in consolidation. However, a causal relationship between M1 activity during asymptote and consolidation has yet to be demonstrated. The present study investigated this issue in male and female participants using single-pulse transcranial magnetic stimulation (TMS) to interfere with postmovement activity in M1 in two behavioral phases of a ramp-and-hold visuomotor adaptation paradigm. TMS was either provided after each trial of the ramp phase of adaptation when a gradual increase in the visuomotor rotation caused movements to be changing, or after each trial of the hold phase of adaptation when the rotation was held constant and movements tended to stabilize. Consolidation was assessed by measuring performance on the same task 24 h later. Results revealed that TMS did not influence adaptation to the new visuomotor relationship in either condition. Critically, however, TMS disruption of M1 activity selectively impaired consolidation of motor memories when it was provided during the hold phase of adaptation. This effect did not take place when TMS was delivered over adjacent dorsal premotor cortex or when motor behaviors in late adaptation were prevented from plateauing. Together, these data suggest that the impaired consolidation stemmed from interference with mechanisms of repetition-dependent plasticity in M1.SIGNIFICANCE STATEMENT The present work demonstrates that TMS disruption of M1 activity impairs the consolidation of motor memories selectively when performance reaches asymptotic levels during sensorimotor adaptation. These findings provide evidence for a causal contribution of M1 to motor memory formation when movements tend to repeat, likely through mechanisms of repetition-dependent plasticity.

Paradoxical Motor Recovery From a First Stroke After Induction of a Second Stroke

Background and objective. Prior studies have suggested that after stroke there is a time-limited period of increased responsiveness to training as a result of heightened plasticity—a sensitive period thought to be induced by ischemia itself. Using a mouse model, we have previously shown that most training-associated recovery after a caudal forelimb area (CFA) stroke occurs in the first week and is attributable to reorganization in a medial premotor area (AGm). The existence of a stroke-induced sensitive period leads to the counterintuitive prediction that a second stroke should reopen this window and promote full recovery from the first stroke. To test this prediction, we induced a second stroke in the AGm of mice with incomplete recovery after a first stroke in CFA. Methods. Mice were trained to perform a skilled prehension (reach-to-grasp) task to an asymptotic level of performance, after which they underwent photocoagulation-induced stroke in CFA. After a 7-day poststroke delay, the mice were then retrained to asymptote. We then induced a second stroke in the AGm, and after only a 1-day delay, retrained the mice. Results. Recovery of prehension was incomplete when training was started after a 7-day poststroke delay and continued for 19 days. However, a second focal stroke in the AGm led to a dramatic response to 9 days of training, with full recovery to normal levels of performance. Conclusions. New ischemia can reopen a sensitive period of heightened responsiveness to training and mediate full recovery from a previous stroke.

Influence of pharmacological manipulations of NMDA and cholinergic receptors on working versus reference memory in a dual component odor span task

Developed as a tool to assess working memory capacity in rodents, the odor span task (OST) has significant potential to advance drug discovery in animal models of psychiatric disorders. Prior investigations indicate OST performance is impaired by systemic administration of N-methyl-d-aspartate receptor (NMDA-r) antagonists and is sensitive to cholinergic manipulations. The present study sought to determine whether an impairment in OST performance can be produced by systemic administration of the competitive NMDA-r antagonist 3-(2-carboxypiperazin-4-yl)propyl-1-phosphonic acid (CPP; 3, 10, 17 mg/kg i.p.) in a unique dual-component variant of the OST, and whether this impairment is ameliorated by nicotine (0.75 mg/kg i.p.). Male Sprague-Dawley rats were trained to asymptotic level of performance on a 24-trial two-comparison incrementing nonmatching to sample OST. In addition, rats were administered a two-comparison olfactory reference memory (RM) task, which was integrated into the OST. The RM task provided an assessment of the effects of drug administration on global behavioral measures, long-term memory and motivation. Several measures of working memory (span, longest run, and accuracy) were dose dependently impaired by CPP without adversely affecting RM. Analysis of drug effects across trial blocks demonstrated a significant impairment of performance even at low memory loads, suggesting a CPP-induced deficit of olfactory short-term memory that is not load-dependent. Although nicotine did not ameliorate CPP-induced impairments in span or accuracy, it did block the impairment in longest run produced by the 10 mg/kg dose of CPP. Overall, our results indicate that performance in our 24 odor two-comparison OST is capacity dependent and that CPP impaired OST working, but not reference, memory.

Fluoxetine Maintains a State of Heightened Responsiveness to Motor Training Early After Stroke in a Mouse Model.

Data from both humans and animal models suggest that most recovery from motor impairment after stroke occurs in a sensitive period that lasts only weeks and is mediated, in part, by an increased responsiveness to training. Here, we used a mouse model of focal cortical stroke to test 2 hypotheses. First, we investigated whether responsiveness to training decreases over time after stroke. Second, we tested whether fluoxetine, which can influence synaptic plasticity and stroke recovery, can prolong the period over which large training-related gains can be elicited after stroke. Mice were trained to perform a skilled prehension task to an asymptotic level of performance after which they underwent stroke induction in the caudal forelimb area. The mice were then retrained after a 1- or 7-day delay with and without fluoxetine. Recovery of prehension after a caudal forelimb area stroke was complete if training was initiated 1 day after stroke but incomplete if it was delayed by 7 days. In contrast, if fluoxetine was administered at 24 hours after stroke, then complete recovery of prehension was observed even with the 7-day training delay. Fluoxetine seemed to mediate its beneficial effect by reducing inhibitory interneuron expression in intact premotor cortex rather than through effects on infarct volume or cell death. There is a gradient of diminishing responsiveness to motor training over the first week after stroke. Fluoxetine can overcome this gradient and maintain maximal levels of responsiveness to training even 7 days after stroke.

Abstract T P86: Paradoxical Motor Recovery From a First Stroke By Re-opening a Sensitive Period With a Second Stroke

Background and Purpose: After stroke, there is a time-limited period of increased responsiveness to training due to heightened plasticity, which is thought to be induced by ischemia itself. Using a mouse model we have previously shown that most training-associated recovery after a caudal forelimb area (CFA - rodent primary motor cortex) stroke occurs in the first week and is attributable to reorganization in the medial premotor area (also called agranular medial cortex - AGm). The idea of a stroke-induced sensitive period leads to the counterintuitive prediction that a second stroke should reopen this window and lead to paradoxically enhanced recovery from the first stroke. To test this prediction, we induced a second focal stroke in the medial premotor area of mice with incomplete recovery after a first focal stroke in CFA. Methods: C57Bl/6 mice were trained to perform a skilled prehension (reach-to-grasp) task to an asymptotic level of performance after which they underwent photocoagulation-induced stroke in CFA. After a 7 day post-stroke delay, the mice were then retrained for 21 days. A second photocoagulation-induced stroke was then induced in the medial premotor area and the mice were re-trained for 8 days after only a one-day delay. Results: Focal CFA stroke led to a decrement in skilled prehension. Training-associated recovery of prehension begun 7 days after stroke induction was incomplete even with 21 days of training. At post-stroke day 21, a second focal stroke in the medial premotor area was induced, which now led to a dramatic response to training with recovery to normal performance after 8 days of training. Conclusions: Together, these data indicate that new ischemia can re-open a sensitive period and mediate full recovery from a previous stroke. Future work will need to characterize what the critical molecular pathways are that ischemia triggers.

Procedural learning, consolidation, and transfer of a new skill in Developmental Coordination Disorder

The aim of this study was to explore the differences in procedural learning abilities between children with DCD and typically developing children by investigating the steps that lead to skill automatization (i.e., the stages of fast learning, consolidation, and slow learning). Transfer of the skill to a new situation was also assessed. We tested 34 children aged 6–12 years with and without DCD on a perceptuomotor adaptation task, a form of procedural learning that is thought to involve the cerebellum and the basal ganglia (regions whose impairment has been associated with DCD) but also other brain areas including frontal regions. The results showed similar rates of learning, consolidation, and transfer in DCD and control children. However, the DCD children's performance remained slower than that of controls throughout the procedural task and they reached a lower asymptotic performance level; the difficulties observed at the outset did not diminish with practice.

Abstract W P99: A Time Window of Heightened Plasticity to Training After Ischemic Stroke in the Mouse is Extended By Fluoxetine if Provided Within the First Week After Stroke

Background: and purpose - Data in humans and in non-human animal models suggest that most recovery from motor impairment occurs in the first 4 weeks after stroke and is mediated in part by increased responsiveness to training in this short time period. We tested the hypothesis that there is a gradient of diminishing responsiveness to training in the first week after stroke in the mouse. We then tested whether fluoxetine can extend the time window over which large training-related gains can be expected. Methods: Adult C57Bl/6 mice were trained to perform a skilled prehension task to an asymptotic level of performance after which they underwent photocoagulation-induced stroke or sham stroke in the caudal forelimb area (CFA can be considered rodent primary motor cortex). The mice were then retrained after a 1- or 7-day delay in the presence or absence of fluoxetine injected IP daily beginning after a 1- or 7-day delay. Results: Training-associated recovery of prehension was complete if training was initiated after a 1-day delay but incomplete if training was initiated after a 7-day delay, even with additional training days. Daily fluoxetine administration after stroke was associated with complete recovery of prehension even if training was delayed 7 days but only if fluoxetine was administered beginning 1 day but not 7 days after stroke. Conclusions: We conclude that there is a sensitive period 7 days after stroke during which motor training is more likely to promote recovery and that this period can be extended by fluoxetine only if administration begins during the first week after stroke. Our mouse model, with all of the attendant genetic benefits, may allow us to determine at the cellular and molecular level how behavioral training and endogenous plasticity interact to mediate recovery.

Activation of extracellular signal-regulated kinase (ERK) and ΔFosB in emotion-associated neural circuitry after asymptotic levels of active avoidance behavior are attained

Avoidance susceptibility may constitute a vulnerability to develop anxiety disorders, and Wistar-Kyoto (WKY) rats exhibit unique features in their acquisition of avoidance behavior that appear to promote susceptibility to this form of learning, namely the absence of the commonly observed "warm-up" effect. The present study sought to determine if strain differences in acquired avoidance behavior, between WKY and Sprague Dawley rats, could be attributed to differences in dopamine-related plasticity, represented by extracellular signal-regulated kinase (ERK) activity, and prolonged neuronal activation, represented by ΔFosB accumulation, in three key areas of the brain: the medial prefrontal cortex (mPFC), dorsal striatum (DS), and basolateral amygdala (BLA). Consistent with earlier work, WKY rats exhibited a higher level of asymptotic performance of avoidance behavior, which included an absence of warm-up in the first few trials of later training sessions, and they exhibited more non-reinforced anticipatory responses in the single minute prior to the initiation of the first warning signal presentation of each training session. In the brain, phosyphorylated ERK2 (pERK2) activation was higher in avoidance trained rats in both the mPFC and DS, although the difference in DS was mostly observed in WKY rats. Avoidance-training was associated with higher levels of ΔFosB expression in the mPFC of SD rats, but not WKY rats. The strain differences in pERK2 activation in the DS and ΔFosB levels in the mPFC may underlie the strain-specific differences observed in warm-up, the emission of non-reinforced anticipatory responses, and general differences in asymptotic performance of active avoidance behavior. The mPFC and DS require further study as potential neural targets for understanding avoidance susceptibility and, as a result, anxiety vulnerability.

Medial Premotor Cortex Shows a Reduction in Inhibitory Markers and Mediates Recovery in a Mouse Model of Focal Stroke

Motor recovery after ischemic stroke in primary motor cortex is thought to occur in part through training-enhanced reorganization in undamaged premotor areas, enabled by reductions in cortical inhibition. Here we used a mouse model of focal cortical stroke and a double-lesion approach to test the idea that a medial premotor area (medial agranular cortex [AGm]) reorganizes to mediate recovery of prehension, and that this reorganization is associated with a reduction in inhibitory interneuron markers. C57Bl/6 mice were trained to perform a skilled prehension task to an asymptotic level of performance after which they underwent photocoagulation-induced stroke in the caudal forelimb area. The mice were then retrained and inhibitory interneuron immunofluorescence was assessed in prechosen, anatomically defined neocortical areas. Mice then underwent a second photocoagulation-induced stroke in AGm. Focal caudal forelimb area stroke led to a decrement in skilled prehension. Training-associated recovery of prehension was associated with a reduction in parvalbumin, calretinin, and calbindin expression in AGm. Subsequent infarction of AGm led to reinstatement of the original deficit. We conclude that with training, AGm can reorganize after a focal motor stroke and serve as a new control area for prehension. Reduced inhibition may represent a marker for reorganization or it is necessary for reorganization to occur. Our mouse model, with all of the attendant genetic benefits, may allow us to determine at the cellular and molecular levels how behavioral training and endogenous plasticity interact to mediate recovery.

Deficits in probabilistic classification learning and liability for schizophrenia

Patients with schizophrenia show deficits in skill learning. We tested the hypothesis that impaired skill learning is associated with liability for schizophrenia by determining if it is present in non-affected siblings of patients. This study examined cognitive skill learning in adolescent siblings of patients with childhood onset schizophrenia (COS), who are at high genetic risk for the disorder, and age-matched controls. A probabilistic classification task was used to assess cognitive skill learning, which has been shown to be impaired in patients with striatal dysfunction or schizophrenia. Differences between the groups emerged within the first 50 trials of training: the controls showed significant learning while the COS siblings did not. Furthermore, after extended training over 800 additional trials the siblings of COS probands reached a lower level of asymptotic performance than controls. These results suggest that a behavioral impairment in probabilistic classification learning in healthy, unaffected siblings mirrors the deficits seen in patients and thus may reflect genetic liability for the disease

Selecting the Better Model by Using Data, Occam's Razor, and a Little Common Sense: Reply to Ericsson

The issue is which model, practice-alone or innate talent affecting learning speed and limiting asymptotic performance level, better accounts for expertise development in international chess. The innate talent model does much better by the usual criteria. A study to determine what innate talent for chess might consist is now needed. Copyright © 2012 John Wiley & Sons, Ltd.