Sequence learning by action and observation: Evidence for separate mechanisms

In the Serial Reaction Time (SRT) task, participants respond to a set of stimuli the order of which is apparently random, but which consists of repeating sub‐sequences. Participants can become sensitive to this regularity, as measured by an indirect test of reaction time, but can remain apparently unaware of the sequence, as measured by direct tests of prediction or recognition. Some researchers have claimed that this learning may take place by observation alone. We suggest that observational learning may be due to explicit acquired knowledge of the sequence, and is not mediated by the same processes which give rise to learning by action. In Expt 1, we show that it is very difficult to acquire explicit sequence knowledge under dual task conditions, even when participants are told that a regular sequence exists. In Expt 2, we use the same conditions to compare actors, who respond to the sequence during learning, and observers, who merely watch the stimuli. Furthermore, we manipulate the salience of the sequence, in order to encourage learning. There is no evidence of observational learning in these conditions, despite the usual effects of learning being demonstrated by actors. In Expt 3, we show that observational learning does occur, but only when observers have no secondary task and even then only reliably for a sequence which has been made salient by chunking subcomponents. We conclude that sequence learning by observation is mediated by explicit processes, and is eliminated under conditions which support learning by action, but make it difficult to acquire explicit knowledge.     

TRIADIC INSTRUCTION OF CHAINED FOOD PREPARATION RESPONSES: ACQUISITION AND OBSERVATIONAL LEARNING

This research examined whether constant time delay would be effective in teaching students with moderate mental retardation in triads to perform chained tasks and whether observational learning would occur. Three chained snack preparation tasks were identified, and each student was directly taught one task. The other 2 students observed the instruction. The instructed student told the observers to watch and to turn pages of a pictorial recipe book. The teacher provided frequent praise to the instructed student based on performance and to the observers for watching the instruction and turning pages. A multiple probe design across students and tasks was used to evaluate the instruction. The results indicated that each student learned the skill he or she was taught directly, and the observers learned nearly all of the steps of the chains they observed. The implications for classroom instruction and future research in observational learning are discussed.     

Motor learning by observation: Evidence from a serial reaction time task

This study sought evidence of observational motor learning, a type of learning in which observation of the skilled performance of another person not only facilitates motor skill acquisition but does so by contributing to the formation of effector-specific motor representations. Previous research has indicated that observation of skilled performance engages cognitive processes similar to those occurring during action execution or physical practice, but has not demonstrated that these include processes involved in effector-specific representation. In two experiments, observer subjects watched the experimenter performing a serial reaction time (SRT) task with a six-item unique sequence before sequence knowledge was assessed by response time and/or free generation measures. The results suggest that: (1) subjects can acquire sequence information by watching another person performing the task (Experiments 1-2); (2) observation results in as much sequence learning as task practice when learning is measured by reaction times (RTs) and more than task practice when sequence learning is measured by free generation performance (Experiment 2, Part 1); and (3) sequence knowledge acquired by model observation can be encoded motorically--that is, in an effector-specific fashion (Experiment 2, Part 2).     

Intention in motor learning through observation

The purpose of this experiment was to assess whether learning an action through observation is enhanced by the intention to reproduce the observed behaviour. Two groups of participants observed a model practise a timing task and performed a 24-hour delayed retention test. Participants in the first group of observers were explicitly instructed that they would be required to execute the timing task that they had observed as accurately as possible during the delayed retention test. Observers in the second group were instructed that they would be required to describe as accurately as possible the behaviour that they had observed. A control group of participants, who did not observe the model, was also administered the delayed retention test. The results of the retention test indicated that absolute timing (parameterization) was learned by the observers to the same extent with or without intention to reproduce the task. Indeed, on the retention test absolute timing for the two groups of observers was as effective as that for the models. However, observing with an intention to reproduce the task was beneficial for learning the movement's relative timing structure. Results are discussed with respect to a potential mechanism by which intention enhances observation.     

Intention in motor learning through observation

The purpose of this experiment was to assess whether learning an action through observation is enhanced by the intention to reproduce the observed behaviour. Two groups of participants observed a model practise a timing task and performed a 24-hour delayed retention test. Participants in the first group of observers were explicitly instructed that they would be required to execute the timing task that they had observed as accurately as possible during the delayed retention test. Observers in the second group were instructed that they would be required to describe as accurately as possible the behaviour that they had observed. A control group of participants, who did not observe the model, was also administered the delayed retention test. The results of the retention test indicated that absolute timing (parameterization) was learned by the observers to the same extent with or without intention to reproduce the task. Indeed, on the retention test absolute timing for the two groups of observers was as effective as that for the models. However, observing with an intention to reproduce the task was beneficial for learning the movement's relative timing structure. Results are discussed with respect to a potential mechanism by which intention enhances observation.     

Consistently modeling the same movement strategy is more important than model skill level in observational learning contexts

The experiment undertaken was designed to elucidate the impact of model skill level on observational learning processes. The task was bimanual circle tracing with a 90° relative phase lead of one hand over the other hand. Observer groups watched videos of either an instruction model, a discovery model, or a skilled model. The instruction and skilled model always performed the task with the same movement strategy, the right-arm traced clockwise and the left-arm counterclockwise around circle templates with the right-arm leading. The discovery model used several movement strategies (tracing-direction/hand-lead) during practice. Observation of the instruction and skilled model provided a significant benefit compared to the discovery model when performing the 90° relative phase pattern in a post-observation test. The observers of the discovery model had significant room for improvement and benefited from post-observation practice of the 90° pattern. The benefit of a model is found in the consistency with which that model uses the same movement strategy, and not within the skill level of the model. It is the consistency in strategy modeled that allows observers to develop an abstract perceptual representation of the task that can be implemented into a coordinated action. Theoretically, the results show that movement strategy information (relative motion direction, hand lead) and relative phase information can be detected through visual perception processes and be successfully mapped to outgoing motor commands within an observational learning context.     

Scheduling observational and physical practice: influence on the coding of simple motor sequences

The main purpose of the present experiment was to determine the coordinate system used in the development of movement codes when observational and physical practice are scheduled across practice sessions. The task was to reproduce a 1,300-ms spatial-temporal pattern of elbow flexions and extensions. An intermanual transfer paradigm with a retention test and two effector (contralateral limb) transfer tests was used. The mirror effector transfer test required the same pattern of homologous muscle activation and sequence of limb joint angles as that performed or observed during practice, and the non-mirror effector transfer test required the same spatial pattern movements as that performed or observed. The test results following the first acquisition session replicated the findings of Gruetzmacher, Panzer, Blandin, and Shea (2011) . The results following the second acquisition session indicated a strong advantage for participants who received physical practice in both practice sessions or received observational practice followed by physical practice. This advantage was found on both the retention and the mirror transfer tests compared to the non-mirror transfer test. These results demonstrate that codes based in motor coordinates can be developed relatively quickly and effectively for a simple spatial-temporal movement sequence when participants are provided with physical practice or observation followed by physical practice, but physical practice followed by observational practice or observational practice alone limits the development of codes based in motor coordinates.     

On the role of beliefs in observational flavor conditioning

In previous research (Baeyens, Vansteenwegen et al., 1996) we demonstrated that when observers consume a series of CS+ and CS−flavored drinks while simultaneously watching a videotaped model who synchronically drinks identical drinks and facially expresses his evaluation (dislike to CS+, neutral to CS−) of the liquids, the observers acquire a dislike for CS+ flavored relative to CS−flavored drinks. The aim of the present experiments was to test some predictions derived from a “direct conditioning” theory of such observational flavor learning. Using the same observational flavor conditioning procedure, we investigated (Exp. 1) the effect of manipulating the observers’ belief concerning the relationship between the drinks that they and the model were consuming (same/different/no information). Observational flavor conditioning was obtained when observers were led to believe that they were drinking the same drinks as the model did, and when they were not informed about this relationship, but not when told to be drinking different drinks. At the same time, however, the observers were not able to correctly identify the source of the model’s expression of dislike: They showed no CS-US contingency-awareness. Whereas the former finding suggests the causal involvement of conscious beliefs and cognitive inference processes in observational learning, the latter is more in line with the idea that the model’s facial expressions may act like a US’ which is automatically associated with the paired flavor CS+, without any involvement of conscious beliefs or cognitive inferences. These two crucial findings were replicated in Exp. 2. Also, we obtained evidence in this study that the belief manipulation affected learning through its influence on the observers’ attention for the model’s facial evaluative expressions. These results can be integrated either by a cognitive theory allowing the beliefs on which the inferences are based to be of an implicit nature, or by a “direct conditioning” theory that conceives of the US’ as an interpreted event, rather than as a mechanistically and invariantly acting physical entity.     

Is implicit sequence learning impaired in schizophrenia? A meta-analysis

Cognition in schizophrenia seems to be characterized by impaired performance on most tests of explicit or declarative learning contrasting with relatively intact performance on most tests of implicit or procedural learning. At the same time there have been conflicting results for studies that have used the Serial Reaction Time (SRT) task to examine implicit learning in people with schizophrenia. In the present research, we used meta-analysis to clarify whether or not people with schizophrenia show impaired performance on the SRT task. A systematic review found nine studies published in peer review journals that had each compared the performance of a group of people with schizophrenia with healthy controls on the standard SRT task or a variant of it. The resulting meta-analysis represented the responses of 205 participants with schizophrenia and 159 healthy controls on the SRT task. The analysis found that participants with schizophrenia perform less well than controls reflected by a pooled effect size of 0.51. A secondary analysis of all nine studies found that they all reported a point estimate of the change in reaction time between sequence and random trials that was greater for the controls. We conclude that there is a moderate impairment in implicit sequence learning among people with schizophrenia and speculate on the implications of this for understanding this disorder. Suggestions for improving the methodological quality and statistical reporting of studies of this topic are made.     

On the role of beliefs in observational flavor conditioning

In previous research (Baeyens, Vansteenwegen et al., 1996) we demonstrated that when observers consume a series of CS+ and CS−flavored drinks while simultaneously watching a videotaped model who synchronically drinks identical drinks and facially expresses his evaluation (dislike to CS+, neutral to CS−) of the liquids, the observers acquire a dislike for CS+ flavored relative to CS−flavored drinks. The aim of the present experiments was to test some predictions derived from a “direct conditioning” theory of such observational flavor learning. Using the same observational flavor conditioning procedure, we investigated (Exp. 1) the effect of manipulating the observers’ belief concerning the relationship between the drinks that they and the model were consuming (same/different/no information). Observational flavor conditioning was obtained when observers were led to believe that they were drinking the same drinks as the model did, and when they were not informed about this relationship, but not when told to be drinking different drinks. At the same time, however, the observers were not able to correctly identify the source of the model’s expression of dislike: They showed no CS-US contingency-awareness. Whereas the former finding suggests the causal involvement of conscious beliefs and cognitive inference processes in observational learning, the latter is more in line with the idea that the model’s facial expressions may act like a US’ which is automatically associated with the paired flavor CS+, without any involvement of conscious beliefs or cognitive inferences. These two crucial findings were replicated in Exp. 2. Also, we obtained evidence in this study that the belief manipulation affected learning through its influence on the observers’ attention for the model’s facial evaluative expressions. These results can be integrated either by a cognitive theory allowing the beliefs on which the inferences are based to be of an implicit nature, or by a “direct conditioning” theory that conceives of the US’ as an interpreted event, rather than as a mechanistically and invariantly acting physical entity.     

Observational Learning in Pigeons: The effects of Model Proficiency on Observer Performance

Observational learning of a successive visual discrimination problem by pigeons was studied using conspecifics as models performing at proficient or at nonproficient levels. During the observational period, observers were confined without response opportunity and were subsequently trained in the model's discriminative task. Significantly better performance in subsequent learning was found for observers of nonproficient models. In contrast, no significant differences in learning of the visual discrimination task were found between pigeons that observed proficient models and pigeons that had undergone only confinement in the observation apparatus or those trained without prior observation or confinement experience. The apparent paradox of less proficient models producing better learners may be related to the consequences of observing additional negative-stimulus responding per se or to observation of models' behavior changing from less proficient to more proficient with consequent improvement in reinforcement opportunity.     

Four-year-old children's visual attention in direct and observational learning

The study was designed to compare direct learning (learning by performing) with observational learning (learning by observing) on a memory task that assessed 4-year-old children's selective attention. 17 pairs of kindergarteners of the same sex (aged 3 yr., 8 mo. to 4 yr., 4 mo.) participated in a central-incidental memory task. Data from a retention test indicated that the performers' mean central learning score was higher than their mean incidental score, while the observers showed no difference between their central and incidental learning scores, performers had a higher mean central learning score than observers. On the other hand, the frequency of the subjects' overt visual attention to the task in their learning phase was also counted. Both observers and performers showed high frequency of visual attention.     

The role of response selection in sequence learning

We investigated the role of response selection in sequence learning in the serial reaction time (SRT) task, by manipulating stimulus–response compatibility. Under conditions in which other types of learning, like perceptual, response-based, and response-effect learning, were unaffected, sequence learning was better with an incompatible than with a compatible stimulus–response mapping. Stimulus discriminability, on the other hand, had no influence on the amount of sequence learning. This indicates that the compatibility effects cannot be accounted for by a different level of task difficulty. Relating our results to the dimensional overlap model (Kornblum, Hasbroucq, & Osman, 1990), which assumes that incompatible stimulus–response mappings require more controlled response selection than do compatible stimulus–response mapping, we suggest that sequence learning in the SRT task is particularly effective when response selection occurs in a controlled way.     

The role of response selection in sequence learning

We investigated the role of response selection in sequence learning in the serial reaction time (SRT) task, by manipulating stimulus-response compatibility. Under conditions in which other types of learning, like perceptual, response-based, and response-effect learning, were unaffected, sequence learning was better with an incompatible than with a compatible stimulus-response mapping. Stimulus discriminability, on the other hand, had no influence on the amount of sequence learning. This indicates that the compatibility effects cannot be accounted for by a different level of task difficulty. Relating our results to the dimensional overlap model (Kornblum, Hasbroucq, & Osman, 1990), which assumes that incompatible stimulus-response mappings require more controlled response selection than do compatible stimulus-response mapping, we suggest that sequence learning in the SRT task is particularly effective when response selection occurs in a controlled way.     

Learning by observation and learning by doing in Down and Williams syndromes

New skills may be learned by active experience (experiential learning or learning by doing) or by observation of others’ experience (learning by observation). In general, learning by observation reduces the time and the attempts needed to learn complex actions and behaviors. The present research aimed to compare learning by observation and learning by doing in two clinical populations with different etiology of intellectual disability (ID), as individuals with Down syndrome (DS) and individuals with Williams syndrome (WS), with the hypothesis that specific profiles of learning may be found in each syndrome. To this end, we used a mixture of new and existing data to compare the performances of 24 individuals with DS, 24 individuals with WS and 24 typically developing children on computerized tasks of learning by observation or learning by doing. The main result was that the two groups with ID exhibited distinct patterns of learning by observation. Thus, individuals with DS were impaired in reproducing the previously observed visuo‐motor sequence, while they were as efficient as TD children in the experiential learning task. On the other hand, individuals with WS benefited from the observational training while they were severely impaired in detecting the visuo‐motor sequence in the experiential learning task (when presented first). The present findings reinforce the syndrome‐specific hypothesis and the view of ID as a variety of conditions in which some cognitive functions are more disrupted than others because of the differences in genetic profile and brain morphology and functionality. These findings have important implications for clinicians, who should take into account the genetic etiology of ID in developing learning programs for treatment and education.     

Learning complex sequences: no role for observation?

Two experiments examined performance in a sequence learning task. Participants were trained on a repeating sequence which was presented as a visual display and learning was measured via the increase in reaction time to respond to a new sequence. Some participants made a response to each stimulus while others merely observed the sequence. In Experiment 1 participants responding to the display via a keypress showed learning, but those merely observing did not. Five possible reasons for the failure to find observational learning were considered and the Experiment 2 attempted to resolve these. This second experiment confirmed the findings of Experiment 1 in a non-spatial sequence display using a cover story which encouraged attention to the display but not rule-search strategies. The results are discussed in relation to applied and theoretical aspects of implicit learning. Received: 20 December 1999 / Accepted: 16 March 2000     

Implicit motor sequence learning is not represented purely in response locations

This study employed a novel variant of the serial reaction time task, focused on sequencing one element of movement—direction. During the task a repeated pattern of alternating directions (right–left–right, etc.) was embedded in the stimuli, and there was no series of response locations. Responses were made via two effector systems: single-finger responding (necessitates lateral arm movements between response keys), and four-fingered responding (4 individual fingers on 4 individual keys; requires no lateral arm movement). The sequence of directions was only learned by participants who performed lateral movements during training, indicating that learning was contingent on the particular motor effector used. Participants with low levels of sequence awareness displayed the same pattern of results.     

What matters in implicit task sequence learning: perceptual stimulus features, task sets, or correlated streams of information?

Implicit task sequence learning may be attributed to learning the order of perceptual stimulus features associated with the task sequence, learning a series of automatic task set activations, or learning an integrated sequence that derives from 2 correlated streams of information. In the present study, our purpose was to distinguish among these 3 possibilities. In 4 separate experiments, we replicated and extended a previous study by Heuer, Schmidtke, and Kleinsorge (2001). The presence or absence of a sequence of tasks, as well as that of a sequence of different task-to-response mappings, was manipulated independently within experiments. Evidence of implicit sequence learning was found only when correlated sequences of tasks and mappings were present. No sequence learning effects were found when only a single task sequence or a single mapping sequence was present, even when the structure of the single sequence was identical to the structure of the integrated sequence of task-mapping combinations. These results suggest that implicit task sequence learning is not dependent on either perceptual learning of stimulus features or automatic task-set activation per se. Rather, it appears to be driven by correlated streams of information.     

Verbal Implicit Sequence Learning in Persons Who Stutter and Persons With Parkinson's Disease

The authors investigated the integrity of implicit learning systems in 14 persons with Parkinson's disease (PPD), 14 persons who stutter (PWS), and 14 control participants. In a 120-min session participants completed a verbal serial reaction time task, naming aloud 4 syllables in response to 4 visual stimuli. Unbeknownst to participants, the syllables formed a repeating 8-item sequence. PWS and PPD demonstrated slower reaction times for early but not late learning trials relative to controls reflecting delays but not deficiencies in general learning. PPD also demonstrated less accuracy in general learning relative to controls. All groups demonstrated similar limited explicit sequence knowledge. Both PWS and PPD demonstrated significantly less implicit sequence learning relative to controls, suggesting that stuttering may be associated with compromised functional integrity of the cortico-striato-thalamo-cortical loop.     

Automatic and intentional activation of task sets.

Four experiments examined automatic and intentional activation of task sets in a switching paradigm. Experiment 1 demonstrated incidental task sequence learning that was not accompanied by verbalizable task sequence knowledge. This learning did not affect task shift cost and may be attributed to automatic task-set activation. In Experiment 2, both shift cost and learning effect increased when the response-cue interval was short, indicating the influence of residual, persisting activation of the preceding task set. In Experiment 3, learning disappeared with a long cue-stimulus interval (CSI), which resulted in a strong preparation effect. This preparation, however, reduced reaction time level but was not specific to task shifts. Finally, Experiment 4 showed that a within-subject C