Memory for to-be-performed tasks versus memory for performed tasks

Women outperform men in remembering to remember

The study of gender differences in prospective memory (i.e., remembering to remember) has received modest attention in the literature. The few reported studies investigating either subjective or objective evaluations of prospective memory have shown inconsistent data. In this study, we aimed to verify the presence of gender differences during the performance of an objective prospective memory test by considering the weight of specific variables such as length of delay, type of response, and type of cue. We submitted a sample of 100 healthy Italian participants (50 men and 50 women) to a test expressly developed to assess prospective memory: The Memory for Intentions Screening Test. Women performed better than men in remembering to do an event-based task (i.e., prompted by an external event) and when the task required a physical response modality. We discuss the behavioural differences that emerged by considering the possible role of sociological, biological, neuroanatomical, and methodological variables.

A goal-based mechanism for delayed motor intention: considerations from motor skills, tool use and action memory

Thinking about our behaviors for a future recall like playing a piano sonata during the next weekend (i.e., delayed motor intention) should engage at some level sensorimotor-based representations. Theoretically, such representations can be stored through both an action- and a goal-based mechanism. An action-based mechanism is related to the specific motor sequence of fingers like the key presses on the piano, and a goal-based mechanism is related to the musical tones generated by the key presses. From these considerations, the present article tries to explore whether the cognitive nature of delayed motor intention is more based on an action or goal mechanism. We reviewed empirical evidence and theoretical accounts of different domains such as motor skills, tool use, and action memory supporting the idea that such delayed motor intentions are rather represented through a goal-based mechanism. The specific role of this goal-based mechanism is to envision the future in an implementation-neutral mode to flexibly and efficiently retrieve an adapted action to environmental constraints. This goal-based account offers an interesting alternative to reshape the classical models about the representations of delayed motor intention. We also discuss how this account can be applied to practical activities in daily life situations.

Embodied Grounding of Memory: Toward the Effects of Motor Execution on Memory consolidation

Behavioural and neuroscientific research has provided evidence for a strong functional link between the neural motor system and lexical–semantic processing of action-related language. It remains unclear, however, whether the impact of motor actions is restricted to online language comprehension or whether sensorimotor codes are also important in the formation and consolidation of persisting memory representations of the word's referents. The current study now demonstrates that recognition performance for action words is modulated by motor actions performed during the retention interval. Specifically, participants were required to learn words denoting objects that were associated with either a pressing or a twisting action (e.g., piano, screwdriver) and words that were not associated to actions. During a 6–8-minute retention phase, participants performed an intervening task that required the execution of pressing or twisting responses. A subsequent recognition task revealed a better memory for words that denoted objects for which the functional use was congruent with the action performed during the retention interval (e.g., pepper mill–twisting action, doorbell–pressing action) than for words that denoted objects for which the functional use was incongruent. In further experiments, we were able to generalize this effect of selective memory enhancement of words by performing congruent motor actions to an implicit perceptual (Experiment 2) and implicit semantic memory test (Experiment 3). Our findings suggest that a reactivation of motor codes affects the process of memory consolidation and emphasizes therefore the important role of sensorimotor codes in establishing enduring semantic representations.

Sensory-based mechanism for delayed motor intention

Prospective motor learning (PML) can be defined as learning an action to be performed in the future. The privileged retrieval mechanism behind this delayed motor performance remains unknown. From a motor control and learning perspective, we may conceive of two forms of retrieval: a stimulus- and an intention-based control. Retrieval from intention-based control is based on the anticipation of intended sensory effects related to an action in order to select and control the appropriate motor procedure (i.e., the ideomotor mechanism). In contrast, in a stimulus-based control a connection between stimuli-features and their related action-features is stored in the memory and serves as the retrieval mechanism. In this view, action retrieval from external stimuli is based on the detection of events in the environment to perform the intended behaviour (i.e., the sensorimotor mechanism). In this study, we report an advantage in the action retrieval for participants who use an intention-based mode of control in comparison to a stimulus-based control. Furthermore, a control task reveals that the intention-based advantage is specific to PML. Our findings show that PML is benefited by mental anticipation of a sensory effect that is efficiently processed through an ideomotor mechanism to fulfil delayed motor intentions.

On the representation of intentions: do personally relevant consequences determine activation?

The intention-superiority effect describes shorter latencies for reactions to stimuli intended for future enactment, relative to stimuli associated with no enactment or canceled enactment. Previous attempts to demonstrate an intention-superiority effect for other types of tasks--for instance, observing the experimenter executing actions--have not yielded an intention-superiority effect. A reason for this could be that the typical enactment task was associated with a higher degree of personal relevance than were other laboratory-based tasks and that task importance or its consequences heighten the accessibility of intention-relevant materials. In two experiments, we demonstrate an intention-superiority effect for different types of tasks (e.g., monitoring a video clip) when task realization has personally relevant consequences in terms of a performance evaluation. In contrast, we found no intention-superiority effect when future enactment had no personally relevant consequences for participants. These findings imply that the intention-superiority effect is not restricted to actions but occurs generally for relevant plans.

Is there a memory profit after repeated learning of subject-performed actions? Comparing direct and long-term memory performance level as a function of age

The present two studies investigated the possibility for improvement and maintenance of episodic memory in young and older adults. In a first study, the performance-enhancing effect of two separate as well as combined learning devices, enactive encoding and repeated learning, was tested. With a time lag of one week, four different series of 30 action phrases were encoded either verbally or by enacting them symbolically. Memory was assessed in four immediate free recall tests. In a second study, the maintenance of the memory profit was tested in an unexpected fifth session half a year later. As expected, there was a steady improvement of memory performance as a function of repeated learning in study one. This holds true regardless of age. In addition, enactive encoding led to a better memory performance than verbal encoding in both age groups. Moreover, younger adults outperformed the elderly regardless of type of encoding. The combination of the two learning devices was not efficient enough to eliminate aging effects in episodic memory. However, memory flexibility is demonstrated also in the elderly. In the long-term follow-up, maintenance of learning and memory could be found in all participant groups.

Gesturing makes memories that last

When people are asked to perform actions, they remember those actions better than if they are asked to talk about the same actions. But when people talk, they often gesture with their hands, thus adding an action component to talking. The question we asked in this study was whether producing gesture along with speech makes the information encoded in that speech more memorable than it would have been without gesture. We found that gesturing during encoding led to better recall, even when the amount of speech produced during encoding was controlled. Gesturing during encoding improved recall whether the speaker chose to gesture spontaneously or was instructed to gesture. Thus, gesturing during encoding seems to function like action in facilitating memory.

Memory for everyday actions in schizophrenia

In healthy people, enacting actions by manipulating objects improves memory compared to verbal encoding of the description of the same actions. We used this paradigm to test memory for actions in 40 stable schizophrenia participants and 24 healthy volunteers. Three encoding conditions were used and consisted of action sentences that were: 1) self-performed by the participants, 2) performed by an experimenter (observed), or 3) encoded verbally. Memory for those actions was tested in two formats. First a cued-recall task with the object as a retrieval cue was administered. Secondly source recognition was examined by asking the participants to decide in which of the three conditions each action was encoded. On cued-recall, schizophrenia participants largely benefited from self-enacting actions, reaching performance levels comparable to that of the healthy volunteers. On the source recognition test however, they showed a substantial impairment. The present study thus indicates that people with schizophrenia can benefit from the enactment effect. However, the fact that their performance was reduced considerably during source recognition relative to healthy volunteers suggests that the beneficial effect provided by enactment was mostly implicit.

Limits on the role of retrieval cues in memory for actions: enactment effects in the absence of object cues in the environment

Verb-object phrases (open the umbrella, knock on the table) are usually remembered better if they have been enacted during study (also called subject-performed tasks) than if they have merely been learned verbally (verbal tasks). This enactment effect is particularly pronounced for phrases for which the objects (table) are present as cues in the study and test contexts. In previous studies with retrieval cues for some phrases, the enactment effect in free recall for the other phrases has been surprisingly small or even nonexistent. The present study tested whether the often replicated enactment effect in free recall can be found if none of the phrases contains context cues. In Experiment 1, we tested, and corroborated, the suppression hypothesis: The enactment effect for a given type of phrase (marker phrases) is modified by the presence or absence of cues for the other phrases in the list (experimental phrases). Experiments 2 and 3 replicated the enactment effect for phrases without cues. Experiment 2 also showed that the presence of cues either at study or at test is sufficient for obtaining a suppression effect, and Experiment 3 showed that the enactment effect may disappear altogether if retrieval cues are very salient.

Motor brain regions are involved in the encoding of delayed intentions: a fMRI study

In studies of prospective memory, recall of the content of delayed intentions is normally excellent, probably because they contain actions that have to be enacted at a later time. Action words encoded for later enactment are more accessible from memory than those encoded for later verbal report [Freeman, J.E., and Ellis, J.A. 2003a. The representation of delayed intentions: A prospective subject-performed task? Journal of Experimental Psychology: Learning, Memory, and Cognition, 29, 976-992.]. As this higher assessibility is lost when the intended actions have to be enacted during encoding, or when a motor interference task is introduced concurrent to intention encoding, Freeman and Ellis suggested that the advantage of to-be-enacted actions is due to additional preparatory motor operations during encoding. Accordingly, in a fMRI study with 10 healthy young participants, we investigated whether motor brain regions are differentially activated during verbal encoding of actions for later enactment with the right hand in contrast to verbal encoding of actions for later verbal report. We included an additional condition of verbal encoding of abstract verbs for later verbal report to investigate whether the semantic motor information inherent in action verbs in contrast to abstract verbs activates motor brain regions different from those involved in the verbal encoding of actions for later enactment. Differential activation for the verbal encoding of to-be-enacted actions in contrast to to-be-reported actions was found in brain regions known to be involved in covert motor preparation for hand movements, i.e. the postcentral gyrus, the precuneus, the dorsal and ventral premotor cortex, the posterior middle temporal gyrus and the inferior parietal lobule. There was no overlap between these brain regions and those differentially activated during the verbal encoding of actions in contrast to abstract verbs for later verbal report. Consequently, the results of this fMRI study suggest the presence of preparatory motor operations during the encoding of delayed intentions requiring a future motor response, which cannot be attributed to semantic information inherent to action verbs.

Memory and action: an experimental study on normal subjects and schizophrenic patients

Psychologists have shown that recall of sentences describing previously performed actions is enhanced compared to recall of heard-only action-phrases (enactment effect). One interpretation of this effect argues that subjects benefit from a multi-modal encoding where movement plays a major role. In line with this motor account, it is conceivable that the beneficial effect of enactment might rely, at least in part, on procedural learning, thus tapping more directly implicit memory functions. Neuropsychological observations support this hypothesis, as shown by the fact that the enactment effect is quite insensitive to perturbations affecting declarative memories. i.e. Alzheimer disease. Memory for subject performed tasks in patients with Korsakoff syndrome. The present study attempts to evaluate whether pure motor activity is sufficient to guarantee the described memory facilitation or alternatively, whether first-person experience in carrying out the action (i.e. true enactment) would be required. To this purpose, in a first experiment on healthy subjects, we tested whether sentence meaning and content of the executed action should match in order to produce facilitation in recall of enacted action-phrases. In a second experiment, we explored whether the enactment effect is present in patients suffering from psychiatric disorders supposed to spare procedural memory but to alter action awareness (e.g. schizophrenia). We show that better recall for action phrases is found only when the motor component is a true enactment of verbal material. Moreover, this effect is nearly lost in schizophrenia. This latter result, on the one hand, queries the automatic/implicit nature of the enactment effect and supports the role of the experience of having performed the action in the first-person. On the other hand, it questions the nature of the memory impairments detected in schizophrenia.

Being the agent: Memory for action events

Whoever paid the bill at the restaurant last night, will clearly remember doing it. Independently from the type of action, it is a common experience that being the agent provides a special strength to our memories. Even if it is generally agreed that personal memories (episodic memory) rely on separate neural substrates with respect to general knowledge (semantic memory), little is known on the nature of the link between memory and the sense of agency. In the present paper, we review results from two experiments investigating the effects of agency on both explicit and implicit memory traces. Performance of normal subjects is compared to that of schizophrenic patients in order to explore the role of awareness of action on memory. It is proposed that reliable first-person information is necessary to create a stable and coherent motor memory trace.

Gains and losses in action memory

Enacting action phrases (SPT for subject-performed task) produces better free recall than only learning the phrases verbally (VT for verbal task). A widespread explanation of the enactment effect is based on the distinction between item-specific and relational information. There is widespread agreement that the main reason is the excellent item-specific encoding by enactment. However, there is little direct evidence in the case of free recall. The role of relational information is less clear. We suggest that content-based relational encoding is better in VTs than in SPTs. In three experiments, in which multiple free recall testing used item gains and losses as indices of item-specific and content-based relational encoding, respectively, these assumptions were confirmed. Consistently more gains (indexing better item-specific encoding) and more losses (indexing poorer relational encoding) were observed in SPTs than in VTs (Experiments 1 and 2). Furthermore, it was demonstrated that the content-based relational information underlying losses is not identical with order-relational information (Experiment 2). In Experiment 3, it was shown that an item-specific orienting task for VTs produced an equivalent number of item gains and losses as did the SPT condition.

Effects of encoding style, expectation of retrieval mode, and retrieval style on memory for action phrases

The purpose of this study was to examine the effects of encoding style, expectation of retrieval mode, and retrieval style on memory for action phrases using the recall test and the source-monitoring test. In Exp. 1, the subjects were asked to memorize action phrases with a variety of encoding styles (verbal, performance, imaging), expectation of retrieval mode (to-be-remembered, to-be-performed, to-be-forgotten), and retrieval style (verbal, enacted). Analysis showed that memory for action phrases was affected by processes of encoding, i.e., type of encoding and expectation of retrieval at encoding, rather than retrieval. Also, action phrases, which were either acted out, or in which performance was imaged, or where enacting was expected later at the encoding phase, were recalled better. These results were replicated in Exp. 2, in which subjects were asked to identify the source of memories at the time of the recall test. However, results of the source-monitoring test in Exp. 1 which required, following the recall test, that participants recall as many of the test-expectation condition of action phrases as possible, showed that source memory for phrases enacted at encoding was weaker than for those in which performance was imaged or expected later but not enacted at encoding. Since, in Exp. 2, source memory for enacted items at encoding was maintained at a relatively high level, it is suggested that source memory for enacted action phrases at encoding might decay rapidly. In addition, a robust directed forgetting effect was observed in verbal and imaging encoding but not in performance encoding.

Investigating the encoding and retrieval of intentions with event-related potentials

Strong evidence exists in the literature that remembering to complete intentions involves executive processing subserved by the frontal lobes. Event-related potentials were measured during the encoding of actions with the intention to perform versus more neutral material about which there was no such intentionality. Event-related potentials were also measured in a two-alternative discrimination task requiring identification of the to-be-performed actions and to-be-memorized actions. The results suggest that formation and retrieval of intentions differs from encoding and retrieval of similar material committed to memory. Additionally, the results suggest that right frontal areas may play an important role in the formation of prospective actions and that intentions are kept active in memory by processing mediated by the left frontal pole.

Design-Effects in Prospective and Retrospective Memory for Actions

There is ample evidence that memory for action phrases such as “open the bottle” is better in subject-performed tasks (SPTs), i.e., if the participants perform the actions, than in verbal tasks (VTs), if they only read the phrases or listen to them. It is less clear whether also the sole intention to perform the actions later, i.e., a prospective memory task (PT), improves memory compared with VTs. Inconsistent findings have been reported for within-subjects and between-subjects designs. The present study attempts to clarify the situation. In three experiments, better recall for SPTs than for PTs and for PTs than for VTs were observed if mixed lists were used. If pure lists were used, there was a PT effect but no SPT over PT advantage. The findings were discussed from the perspective of item-specific and relational information.

Memory organization of action events and its relationship to memory performance

Previous research yielded inconsistent results regarding the memory organization of self-performed actions. The authors propose that task performance changes the very basis of memory organization. Enactment during study and test (Experiment 1) yielded stronger enactive clustering (based on motor-movement similarities), whereas verbal encoding yielded stronger conceptual clustering (based on semantic-episodic similarities). Enactment enhanced memory quantity and memory accuracy. Both measures increased with enactive clustering under self-performance instructions but with conceptual clustering under verbal instructions. Enactment only during study (Experiment 2) or only during testing (Experiment 3) also enhanced enactive clustering. It is proposed that different conditions affect the relative salience of different types of memory organization and their relative contribution to recall.

Did I do that? An ERP study of memory for performed and planned actions

Memory for performed and planned actions was measured on source recognition and source recall tests. Event-related potentials (ERPs) were recorded during the source recognition test to index brain activity during output monitoring. Source identification of performed actions was superior to planned actions and more performed actions were recalled, thereby replicating the enactment effect. Examination of recall errors revealed that more planned than performed actions were omitted. In addition, intrusions and source misattributions were equally likely when recalling planned actions, whereas more misattributions were observed when performed actions were recalled. The ERP data indicated that brain activity elicited by performed actions differed from planned and new actions. Furthermore, activity in the left and right frontal lobes appeared to differ for performed and planned actions indicating that performed actions were evaluated with more heuristic decision processes than both planned and new items. The temporal onset of the frontal ERP differences also suggests that heuristic decision processes begin earlier than systematic processes.

Effects of enactment by professional actors at encoding and retrieval

This experiment investigated memory benefits similar to those found with subject-performed tasks (SPTs) but under widely differing circumstances. Almost all SPT research has shown that as long as enactment takes place at encoding, mode of recall (enactment vs. verbal recall) is immaterial. Using professional actors, the experimenters had previously shown (Noice & Noice, 1999) that movement that was not semantically congruent with the accompanying material produced enhanced recall at retrieval compared to a non-moving condition, a result that did not appear to be due to the fact that retrieval conditions closely resembled encoding conditions. Experiment 1 of the present study replicated and extended this finding, demonstrating that the effect can be found after a delay of five months with actors of varying age and experience, and that the enhancement is not dependent on physical context. Experiment 2 demonstrated that, even with purely verbal retrieval of material that had been equated for memorability, dialogue originally performed when the participants had been engaged in movement from place to place was better recalled than dialogue originally performed when the participants had remained in one location. Taken together, these results indicate that movement at retrieval is not necessary for the nonliteral enactment effect to occur, but that such movement can aid recall compared to a purely verbal mode of report.

The role of enactment in prospective remembering

This study investigated, in a laboratory setting, whether prospective memory (remembering to perform intended actions in the future) would be improved by self-enactment of the to-be-remembered tasks. The subjects, 45 university students, were asked to remember later to perform five tasks that they initially enacted themselves, watched the experimenter perform, or had described to them. These tasks were to be performed, ostensibly in preparation for the next subject, at the end of 30 min of filler activity, which was presented as the experimental task. Surprisingly, self-enactment produced the poorest prospective remembering. Speculative explanations are offered in terms of both metacognitive expectations about memory and output-monitoring deficiencies.