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The influence of sleep on motor skill consolidation has been a research topic of increasing interest. In this study, we distinguished general skill learning from sequence-specific learning in a probabilistic implicit sequence learning task (alternating serial reaction time) in young and old adults before and after a 12-h offline interval which did or did not contain sleep (p.m.–a.m. and a.m.–p.m. groups, respectively). The results showed that general skill learning, as assessed via overall reaction time, improved offline in both the young and older groups, with the young group improving more than the old. However, the improvement was not sleep-dependent, in that there was no difference between the a.m.–p.m. and p.m.–a.m. groups. We did not find sequence-specific offline improvement in either age group for the a.m.–either p.m. or p.m.–a.m. groups, suggesting that consolidation of this kind of implicit motor sequence learning may not be influenced by sleep. [ABSTRACT FROM AUTHOR]

Knowledge of sequential relationships enables future events to be anticipated and processed efficiently. Research with the serial reaction time task (SRTT) has shown that sequence learning often occurs implicitly without effort or awareness. Here, the authors report 4 experiments that use a triplet-learning task (TLT) to investigate sequence learning in young and older adults. In the TLT, people respond only to the last target event in a series of discrete, 3-event sequences or triplets. Target predictability is manipulated by varying the triplet frequency (joint probability) and/or the statistical relationships (conditional probabilities) among events within the triplets. Results reveal that both groups learned, though older adults showed less learning of both joint and conditional probabilities. Young people used the statistical information in both cues, but older adults relied primarily on information in the 2nd cue alone. The authors conclude that the TLT complements and extends the SRTT and other tasks by offering flexibility in the kinds of sequential statistical regularities that may be studied as well as by controlling event timing and eliminating motor response sequencing. [ABSTRACT FROM AUTHOR]

In the serial reaction time task (SRTT), a sequence of visuo-spatial cues instructs subjects to perform a sequence of movements which follow a repeating pattern. Though motor responses are known to support implicit sequence learning in this task, the goal of the present experiments is to determine whether observation of the sequence of cues alone can also yield evidence of implicit sequence learning. This question has been difficult to answer because in previous research, performance improvements which appeared to be due to implicit perceptual sequence learning could also be due to spontaneous increases in explicit knowledge of the sequence. The present experiments use probabilistic sequences to prevent the spontaneous development of explicit awareness. They include a training phase, during which half of the subjects observe and the other half respond, followed by a transfer phase in which everyone responds. Results show that observation alone can support sequence learning, which translates at transfer into equivalent performance as that of a group who made motor responses during training. However, perceptual learning or its expression is sensitive to changes in target colors, and its expression is impaired by concurrent explicit search. Motor-response based learning is not affected by these manipulations. Thus, observation alone can support implicit sequence learning, even of higher order probabilistic sequences. However, perceptual learning can be prevented or concealed by variations of stimuli or task demands. [ABSTRACT FROM AUTHOR]

Recent studies have reported age deficits in learning sequences that contain subtle sequential regularities [e.g., Curran (1997) Psychological Research, 60(1-2), 24; D. V. Howard et al. (2004) Psychology and Aging, 19(1), 79; Howard, J. H. Jr, & Howard, D. V. (1997). Psychololgy and Aging, 12(4), 634]. This finding is of potential theoretical interest, but the contribution of sequence event timing to this deficit has not been investigated. This study used an alternating serial reaction time task to examine implicit sequence learning in young adults when event timing mimicked that experienced by older adults in previous research. We varied the response-to-stimulus interval directly in Experiment 1 and indirectly by degrading the stimuli to influence response time in Experiment 2. Results indicate that these "aged" young adults learned the higher-order sequence structure implicitly, but they learned less than young controls and more than old adults on some measures of implicit learning in both experiments. In addition, these two different experimental manipulations produced distinct patterns of deficits despite having nearly identical effects on event sequence timing. These findings suggest that event timing alone cannot explain the age deficits observed in high-order implicit sequence learning. [ABSTRACT FROM AUTHOR]

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 random trials. Individuals encountered lag-2 or lag-3 structure, and learning was measured by the difference (in response time and accuracy) between pattern and random 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. [ABSTRACT FROM AUTHOR]

Presents a study that examined whether age-related deficits in implicit learning begin in middle age. Pattern sensitivity by age and processing speed; Information on the use of serial reaction time; Determination of median reaction time.