Heuristics of evolutionary biology dictate that phylogenetically older processes are inherently more stable and resilient to disruption than younger processes. On the grounds that non-declarative behaviour emerged long before declarative behaviour, Reber argues that implicit learning is supported by neural processes that are evolutionarily older than those supporting explicit learning. Reber suggested that implicit learning thus leads to performance that is more robust than explicit learning. Applying this evolutionary framework to motor performance, we examined whether implicit motor learning, relative to (...) explicit motor learning, conferred motor output that was resilient to physiological fatigue and durable over time. In Part One of the study a fatigued state was induced by a double Wingate Anaerobic test protocol. Fatigue had no affect on performance of participants in the implicit condition; whereas, performance of participants in the explicit condition deteriorated significantly. In Part Two of the study a convenience sample of participants was recalled following a one-year hiatus. In both the implicit and the explicit condition retention of performance was seen and, contrary to the findings in Part One, so was resilience to fatigue. The resilient performance in the explicit condition after one year may have resulted from forgetting or from consolidation of declarative knowledge as implicit memories. In either case, implicit processes were left to more effectively support motor performance. (shrink)

The dream-lag effect refers to there being, after the frequent incorporation of memory elements from the previous day into dreams , a lower incorporation of memory elements from 2 to 4 days before the dream, but then an increased incorporation of memory elements from 5 to 7 days before the dream. Participants kept a daily diary and a dream diary for 14 days and then rated the level of matching between every dream report and every daily diary record. Baseline matching (...) was assessed by comparing all dream reports to all diary records for days that occurred after the dream. A significant dream-lag effect for the 5–7 day period, compared to baseline and compared to the 2–4 day period, was found. This may indicate a memory processing function for sleep, which the dream content may reflect. Participants’ and three independent judges’ mean ratings also confirmed a significant day-residue effect. (shrink)

Improvement in performance after the end of the training session, termed “Offline improvement,” has been shown in procedural learning tasks. We examined whether Offline improvement in learning a novel orthography depends on the type of reading instruction. Forty-eight adults received multisession training in reading nonsense words, written in an artificial script. Participants were trained in one of three conditions: alphabetical words preceded by direct letter instruction (Letter-Alph); alphabetical words with whole-word instruction (Word-Alph); and nonalphabetical (arbitrary) words with whole-word instruction (Word-Arb). (...) Offline improvement was found only for the Letter-Alph group. Moreover, correlation with a standardized measure of word reading ability showed that good readers trained in the Letter-Alph group exhibit greater Offline improvement, whereas good readers trained in the Word-Arb group showed greater Within-session improvement during training. These results suggest that different consolidation processes and learning mechanisms were involved in each group. We argue that providing a short block of direct letter instruction prior to training resulted in increased involvement of procedural learning mechanisms during training. (shrink)

Traumatic brain injury is a major cause of death and disability in Western society, and often results in functional and neuropsychological abnormalities. Memory impairment is one of the most significant cognitive implications after TBI. In the current study we investigated procedural memory acquisition by observational training in TBI patients. It was previously found that while practicing a new motor skill, patients engage in all three phases of skill learning–fast acquisition, between-session consolidation, and long-term retention, though their pattern of learning is (...) atypical compared to healthy participants. A different set of studies showed that training by observing a motor task, generally prompted effective acquisition and consolidation of procedural knowledge in healthy participants. The aim of our study was to evaluate the potential benefit of action observation in TBI patients. Examine the possibility of general improvement in performance between the first and second stage of the study. Investigate the link between patients’ ability to benefit from observational learning and common measures of injury.Materials and methodsPatients hospitalized after moderate to severe TBI, were trained by observation for the finger opposition sequence motor task. They were then tested for the observation-trained sequence and a similar control sequence, at two different time-points.Results revealed a significant difference in performance between the trained and untrained sequences, in favor of the trained sequence. An increase in performance for both sequences A and B toward the second session. The advantage for sequence A was stable and preserved also in the second session. Participants with lower moderate Functional Independence Measure scores gained more from observational-procedural learning, compared with patients with higher functional abilities.ConclusionOverall, these findings support the notion that TBI patients may achieve procedural memory consolidation and retention through observational learning. Moreover, different functional traits may predict the outcomes of observational training in different patients. These findings may have significant practical implications in the future, regarding skill acquisition methods in TBI patients. (shrink)