***TASK*** the task is to summarize an input biomedical literature in six sentences 
    ***INPUT*** the input is a biomedical literature 
    ***OUTPUT*** the output is the summary of an input biomedical literature in six sentences 
    ***DOCUMENTATION*** 
    ***EXAMPLES*** 
    Input: The goal of the current study was to explore learning and short-term retention using a modified serial reaction time task . The multi-finger sequence task was design ed to present repeated and r and om sequences in a completely interleaved fashion , giving participants within block , variable practice , on the two types of sequences . Eighteen younger adults ( Mage = 24 years ) and 15 older adults ( Mage = 65 years ) participated in the experiment . Participants were asked to respond on a piano keyboard to a visual stimulus that appeared in one of four squares on the computer screen . They were not informed that one of the sequences presented would repeat . Sequence-specific learning , within-day and across-days , was inferred from differences in accuracy and reaction time between repeated and r and om sequences . Age equivalence was observed in sequence-specific learning and retention across days , and suggests that older adults may benefit from variable practice Although implicit motor sequence learning is rather well understood in young adults , effects of aging on this kind of learning are controversial . There is first evidence that working memory ( WM ) might play a role in implicit motor sequence learning in young adults as well as in adults above the age of 65 . However , the knowledge about the development of these processes across the adult life span is rather limited . As the average age of our population continues to rise , a better underst and ing of age-related changes in motor sequence learning and potentially mediating cognitive processes takes on increasing significance . Therefore , we investigated aging effects on implicit motor sequence learning and WM . Sixty adults ( 18–71 years ) completed verbal and visuospatial n-back tasks and were trained on a serial reaction time task ( SRTT ) . R and omly varying trials served as control condition . To further assess consolidation indicated by off-line improvement and reduced susceptibility to interference , reaction times ( RTs ) were determined 1 h after initial learning . Young and older but not middle-aged adults showed motor sequence learning . Nine out of 20 older adults ( compared to one young/one middle-aged ) exhibited some evidence of sequence awareness . After 1 h , young and middle-aged adults showed off-line improvement . However , RT facilitation was not specific to sequence trials . Importantly , susceptibility to interference was reduced in young and older adults indicating the occurrence of consolidation . Although WM performance declined in older participants when load was high , it was not significantly related to sequence learning . The data reveal a decline in motor sequence learning in middle-aged but not in older adults . The use of explicit learning strategies in older adults might account for the latter result Age-related implicit learning deficits increase with sequence complexity , suggesting there might be limits to the level of structure that older adults can learn implicitly . To test for such limits , we had 12 younger and 12 older adults complete an alternating serial reaction time task containing subtle structure in which every third trial follows a repeating sequence and intervening trials are determined r and omly . Results revealed significant age deficits in learning . However , both groups did learn the subtle regularity without explicit awareness , indicating that older adults remain sensitive to highly complex sequential regularities in their environment , albeit to a lesser degree than younger adults Explicit and implicit memory for a cognitive-motor sequence was studied in elderly and young adults . Implicit memory was examined in a serial reaction-time paradigm in which sequences of h and postures repeated cyclically , then shifted to r and om sequences . Two control groups received r and om sequences throughout . Movement times ( MTs ) across the first 4 blocks did not improve more in the elderly-repeated than in the elderly-r and om group . In contrast , the young-repeated group showed greater improvement in MT across these blocks than the young-r and om group . MT was less affected in the elderly than in the young by shifts between repeated and r and om sequences , indicating impaired implicit memory . Explicit memory , which was assessed by free recall and cued recall , also was impaired in the elderly . Diminished implicit memory in the elderly could not be explained solely by the possible intrusion of conscious re collection strategies Little is known about how children acquire new motor sequences . In particular , it is not clear if the same learning progression observed in adults is also present in childhood nor whether motor skills are acquired in a similar fashion across development . In the present study we used the multi-finger sequencing task ( MFST ) , a variant of the serial reaction time ( SRT ) task , to study motor sequence learning , across two consecutive days , in three cross-sectional sample s of children aged 6 , 8 , and 10 years , and a control sample of adults . In the MFST , participants reproduced 10-element sequences of key presses on an electronic keyboard , using four fingers of the right h and . Each block of practice included 10 intermixed trials of a Repeated ( REP ) sequence and four trials of R and om ( RAN ) sequences . Performance was assessed by examining changes in accuracy , a component of the task that requires the association of the visual stimulus with the motor response , and response synchronization , a component that requires fine-grained sensorimotor integration and timing . Additionally , participants completed Recognition and Recall tests , to assess explicit knowledge of the repeated sequence . Overall , results showed a developmental progression in motor sequence learning within and across days of practice . Interestingly , the two behavioral measures showed different developmental trajectories . For accuracy , differences were greatest for the two youngest groups early in learning , and these groups also showed the greatest rate of improvement . However , by the end of Day 2 , only the 6-year-olds still lagged behind all other groups . For response synchronization , all child groups differed from adults early in learning , but both child and adult groups showed similar rates of improvement across blocks of practice . By the end of Day 2 , 10-year-olds reached adult levels of performance , whereas 6- and 8-year-olds did not . Taken together , the dissociation observed with our two behavioral measures of sequence learning is consistent with the hypothesis that accuracy or finger-stimulus association may rely on cortical pathways that show the greatest maturation between ages 6 and 10 ; whereas motor timing and sensorimotor integration may rely on subcortical pathways that continue to develop into young adulthood . Despite developmental differences across blocks of practice on both behavioral measures , there were no significant group differences for either the Recognition or Recall tests . We suggest that explicit knowledge of the MFST is not directly linked to task performance , thus challenging the implicit – explicit distinction in pediatric SRT studies assessing the developmental invariance model Trying to learn sometimes impairs implicit learning of artificial grammars and of control systems . We asked whether such negative effects of trying also occur in implicit learning of subtle sequential regularities and whether such effects vary with adult age . Young ( n=12 , age=20–23 ) and older ( n=24 , age=60–80 ) adults completed an alternating serial response time task in which predictable pattern events alternated with r and om ones in a visual/spatial display . Half of the participants were informed about the pattern and were instructed to try to discover it ( intentional instructions ) , and half were not ( incidental instructions ) . Age-related deficits in implicit learning occurred for both conditions . In addition , for the older group , but not for the younger one , intentional instructions impaired implicit pattern learning . This negative effect of trying to learn demonstrates another similarity among implicit learning tasks , supporting the view that some common processes underlie different forms of implicit learning 3 experiments examined serial pattern learning  in younger and older adults . Unlike the usual repeating pattern , the sequences alternated between events from a repeating pattern and those determined r and omly . The results indicated that no one was able to describe the regularity , but with practice every individual in all 3 age groups ( including old old ) became faster , more accurate , or both , on pattern trials than on r and om trials . Although this indicates that adults of all ages are able to learn second-order statistical dependencies in a sequence , age-related deficits were obtained in the magnitude of pattern learning . There were also age differences in what was learned , with only younger people revealing sensitivity to higher order statistical dependencies in the sequence . In addition , whereas younger people revealed evidence of their pattern learning in a subsequent conceptually driven production test , young-old and old-old people did not Visuomotor sequence learning was assessed in 4- to 10-year-old children using a serial reaction time ( SRT ) task with both r and om and sequenced trials . One-half of the children received exposure to the sequence prior to performing the  reaction time ( RT ) task .  In Experiment 1 , 7- and 10-year-old children demonstrated sequence-specific decreases in RT . As in the adult SRT literature , participants with explicit awareness of the sequence at the end of the session showed larger sequence-specific reaction time decrements than those without explicit awareness . Contrary to expectation , preexposure to the sequence did not reliably predict the level of awareness attained . Results from Experiment 2 indicate that 4-year-olds also demonstrate significant sequence learning on a variant of the SRT task . This article provides preliminary data regarding developmental changes in sequential learning and the development and use of implicit and explicit knowledge . Age-related differences emerged primarily in explicit rather than implicit knowledge The influence of structure and age on sequence learning was investigated by testing 24 young and 24 older participants for 10 sessions in an alternating serial response time task in which pattern trials alternated with r and om trials . Individuals encountered lag-2 or lag-3 structure , and learning was measured by the difference ( in response time and accuracy ) between pattern and r and om trials . Both ages learned lag-2 structure , but the young learned more than the older participants . Only the young people learned lag-3 structure , and they did so more slowly and to a lesser degree than they learned lag-2 structure . These age deficits in higher order sequence learning after extended practice are consistent with simultaneity theory and with theories positing that age-related deficits in neuromodulation lead to less distinctive representations Subjects performed a serial reaction time task ( adopted from Nissen & Bullemer , 1987 ) that contained a repeating pattern of spatial locations . In Experiment 1 , following 20 repetitions of a 10- or 16-element pattern , reaction time was equally disrupted for both younger and older people when the sequence became r and om . In Experiment 2 , the response times for subjects encountering the 10-element pattern were compared with those of subjects encountering a r and om sequence . These response time functions diverged at the same point in training for the 2 age groups . Thus , on this indirect measure of response time facilitation , both experiments revealed age similarity in the rate of pattern learning . In contrast , on a subsequent direct test of pattern learning that required prediction , the younger people earned a higher percentage correct score than the older in both experiments . Age-related dissociations between direct and indirect measures of learning and comparisons with memory-impaired population s are discussed The present research was intended to examine the sequence learning ability of elderly people — with a focus on comparing sequences with different structural characteristics and on properly assessing explicit knowledge . Experiment 1 showed that learning-related improvements in serial reaction time task performance were greater for young than elderly subjects , and elderly subjects were especially poor at learning a sequence with complex structural characteristics . Measures of recognition memory showed that neither young nor elderly subjects showed above-chance explicit knowledge of the sequences . Experiment 2 was design ed to test the validity and sensitivity of the explicit recognition measures by comparing young subjects in groups given all r and om trials , given sequence trials with implicit instructions , or given sequence trials with explicit instructions . Experiment 2 confirmed the sensitivity of the recognition measures to explicit knowledge , so it is concluded that group effects in Exp . 1 reflect age-related differences in implicit learning Practice of different tasks in a r and om order induces better retention than practicing them in a blocked order , a phenomenon known as the context ual interference ( CI ) effect . Our purpose was to investigate whether the CI effect exists in sequence learning , such that practicing different sequences in a r and om order will result in better learning of sequences than practicing them in blocks , and whether this effect is affected by aging . Subjects practice d a serial reaction time task where a set of three 4-element sequences were arranged in blocks or in a r and om order on 2 successive days . Subjects were divided into 4 groups based on a 2-GROUP ( young or old ) by 2-ORDER  ( r and om or blocked practice ) between-subject design . Three days after practice ( Day 5 ) , subjects were tested with practice d and novel sequences to evaluate sequence-specific learning . The results replicate the CI effect in sequence learning in both young and older adults . Older adults  retained sequences better when trained in a r and om condition than in a blocked condition , although the r and om condition incurs greater task switching costs in older adults during practice . Our study underscores the distinction between age-related effects on learning vs. performance , and offers practical implication s for enhancing skill learning in older adults Adult age differences in learning and retention of a nonverbal sequence were examined using the serial reaction-time task of Nissen and Bullemer ( 1987 ) , with 20 younger and 20 older Ss . An asterisk appeared in one of 4 spatial locations , and the Ss responded with a corresponding key press . The first 4 blocks each contained 10 repetitions of a 10- or 16-element spatial sequence , and the 5th block contained a r and om sequence . The difference between response time on Blocks 5 and 4 served as an indirect measure of pattern learning . The direct measure was accuracy in a final generation block in which the Ss predicted which location would appear next . Results were similar to those with verbal material s ; the indirect measure revealed age similarity for patterns of both lengths , but the direct measure yielded age differences favoring the young . For both ages and types of measures , the long patterns led to poorer learning than did the short patterns Two experiments examined age-related differences in implicit serial learning using the M. J. Nissen and P. Bullemer ( 1987 ) task . Younger adults and 2 sample s of older adults who differed in educational attainment , occupational status , and verbal ability were given a 10-trial repeating sequence embedded in 100-trial blocks . On each trial , participants pressed a key that matched a design ated spatial location . Implicit learning was inferred from the difference in RT between a r and om sequence trial block and the immediately preceding block with the repeating sequence . Results indicated that negative transfer effects were comparable for the younger and higher ability older adults , but lower ability older adults showed less evidence of implicit learning . On an explicit task , younger and higher ability older adults were more accurate than the lower ability older adults . The implication s of these findings for current views on implicit learning in adulthood are discussed Motor impairments are prevalent in children with autism spectrum disorder . The Serial Reaction Time Task , a well-established visuomotor sequence learning probe , has produced inconsistent behavioral 
    Output:
    
Our findings on typical development strongly support a model of age-related changes ( Model 2a or 2b ) and show that mixed findings regarding the developmental trajectory during childhood can be explained by method ological differences across studies .
Applying these conclusions to systematic review s of studies of ASD and SLI makes it clear that there is a strong need for the inclusion of multiple age groups in these clinical studies to model  procedural learning in atypical development .