The influence of action on episodic memory: A virtual reality study

A range of empirical findings suggest that active learning is important for memory. However, few studies have focused on the mechanisms underlying this enactment effect in episodic memory using complex environments. Research using virtual reality has yielded inconsistent results. We postulated that the effect of action depends on the degree of interaction with the environment and freedom in the planning of an itinerary. To test these hypotheses, we disentangled the interaction and planning components of action to investigate whether each enhances factual and spatial memory. Seventy-two participants (36 male and 36 female) explored a virtual town in one of three experimental conditions: (a) a passive condition where participants were immersed as passenger of the car (no interaction, no planning); (b) a planning-only condition (the subject chose the itinerary but did not drive the car); (c) an interaction-only condition (the subject drove the car but the itinerary was fixed). We found that itinerary choice and motor control both enhanced spatial memory, while factual memory was impaired by online motor control. The role of action in memory is discussed.     

Age and active navigation effects on episodic memory: A virtual reality study

We investigated the navigation‐related age effects on learning, proactive interference semantic clustering, recognition hits, and false recognitions in a naturalistic situation using a virtual apartment‐based task. We also examined the neuropsychological correlates (executive functioning [EF] and episodic memory) of navigation‐related age effects on memory. Younger and older adults either actively navigated or passively followed the computer‐guided tour of an apartment. The results indicated that active navigation increased recognition hits compared with passive navigation, but it did not influence other memory measures (learning, proactive interference, and semantic clustering) to a similar extent in either age group. Furthermore, active navigation helped to reduce false recognitions in younger adults but increased those made by older adults. This differential effect of active navigation for younger and older adults was accounted for by EF score. Like for the subject‐performed task effects, the effects from the navigation manipulation were well accounted for by item‐specific/relational processing distinction, and they were also consistent with a source monitoring deficit in older adults.     

The impact of state and dispositional mindfulness on prospective memory: A virtual reality study

Prospective memory (PM) consists of remembering to perform an action that was previously planned. The recovery and execution of these actions require attentional resources. Mindfulness, as a state or a dispositional trait, has been associated with better attentional abilities while mind wandering is linked with attentional failures. In this study, we investigated the impact of mindfulness on PM. Eighty participants learned 15 cue-action associations. They were, then, asked to recall the actions at certain moments (time-based items) or places (event-based items) during a walk in a virtual town. Before the PM task, participants were randomly assigned to a mindfulness or mind wandering (control condition) session. Dispositional mindfulness was measured via the Five Facets Mindfulness Questionnaire (FFMQ). Although considered as two opposite states, we did not report any difference between the two groups on PM abilities. Nevertheless, the natural tendency to describe one's own sensations (the Describing facet of the FFMQ) predicted time-based performance in both groups. We discuss different hypotheses to explain this finding in light of recent findings on the impact of mind wandering on future oriented cognition. Our main observation is a positive link between the Describing facet and time-based PM performances. We propose that this link could be due to the common association of this mindfulness facets and PM with attentional and interoceptive abilities. Additional studies are needed to explore this hypothesis.     

A study of retrieval processes in action memory for school-aged children: the impact of recall period and difficulty on action memory

ABSTRACT

Research in action memory for adults has shown that enacted encoding is not only retrieved more frequently but is also faster in comparison to verbal encoding. The aim of this study was to investigate retrieval processes in terms of recall period and recall difficulty for different encoding conditions in school-aged children (8-, 10-, 12-, 14-years old). The participants studied verbal tasks, subject-performed tasks and experimenter-performed tasks, and received immediate and final free-recall tests. The results revealed that older children not only outperformed younger children in terms of accuracy but also outpaced them in all recall periods. Moreover, recalls of subject-performed tasks and experimenter-performed tasks were better and faster compared with verbal encoding on both types of recall test, by increasing throughout the recall periods. These results are discussed in terms of memory strategies and information processing methods. Pedagogic implications for the use of action memory in children's learning are also considered.     

The retrieval of sentences from memory: A speed-accuracy study

A speed-accuracy tradeoff method was used to study the retrieval dynamics for recognition memory of parts of sentences. All sentences contained a subject, verb, object, location, and time. Recognition accuracy increased from chance at a processing time of about 0.5 sec to asymptotic accuracy at about 3 sec. The asymptotic accuracy levels for subject-verb, subject-object or verb-object recognition probes exceeded those of pair probes containing times or locations. This result suggests that the former may be more closely associated in semantic memory. The only difference among speed-accuracy curves was in asymptotic accuracy. The chance intercept and the rate of increase in accuracy were similar for all pair probes. A second finding was that the speed-accuracy curves for triple probes (e.g., subject-verb-object) were virtually identical to those of the comparable pair probes. These results appear to contradict a serial search hypothesis for the access of information from semantic memory. They support a parallel, direct-access hypothesis.     

Critical processes in serial short-term memory: A developmental study

Two experiments are described which were designed to test the possible involvement of two operations in developmental auditory serial short-term memory (SSTM), namely rehearsal proficiency and item identification. The experiments provided mainly negative support for the notion that these operations are critical in developmental SSTM. As an alternative, the possibility that developmental differences in SSTM might have their origins in the processing of speech sound patterns was discussed.     

Using a virtual reality system to study balance and walking in a virtual outdoor environment: a pilot study.

Falls and fall-related injuries are a major problem for elderly persons. Most falls occur during walking and turning, and the risk of falling increases when attention is diverted to something besides walking. It is often difficult to standardize methods for testing balance and fall tendency in a clinically relevant setting. We describe the development of a system using a virtual environment (VE) to assess how attention demanding and unexpected events influence a person's capacity to control balance and movement. The hardware in the system consists of a head-mounted display (HMD), a magnetic tracker system, and two SGI computers. The software consists of the image generation of the VE and the management and visualization of motion tracking data. In a preliminary pilot study eight subjects (age 23-80) participated. Each subject walked on a normal floor and was visually presented a familiar outdoor environment in the HMD. They were exposed to different unexpected events, such as a virtual snowfall and tilting of the VE. Disturbances of balance and walking patterns such as changes in speed, stride length and balance reactions like slipping were observed. Two subjects experienced symptoms of cyber sickness with a SSQ score above 25 points. Walking with sensors only did not affect walking time, but in VE the subjects generally walked more slowly. Virtual tilting of the environment had an impact on balance performance during walking. This effect was not observed while the test subjects were walking in a virtual snowfall. The model needs further development but may hold a potential for clinical use.     

A vasopressin metabolite produces qualitatively different effects on memory retrieval depending on the accessibility of the memory

A vasopressin metabolite, AVP4-9, was injected 1 h prior to retention tests at 1, 6, 11, and 16 days after learning to test the hypothesis that the peptide exerts qualitatively different effects on memory retrieval depending on the accessibility of the memory. The findings provided strong support for this hypothesis: At a retention interval associated with excellent recall in control animals, pretest administration of AVP4-9 (3.0 micrograms/kg) significantly impaired memory, while this same treatment significantly improved recall at an interval associated with poor retention in controls. At retention tests associated with intermediate recall in controls, retrieval was not significantly affected by the peptide treatment. This pattern of results indicates that the peptide treatment is interacting with endogenous changes that correspond to the accessibility of the memory.     

Why and how to use virtual reality to study human social interaction: The challenges of exploring a new research landscape

As virtual reality (VR) technology and systems become more commercially available and accessible, more and more psychologists are starting to integrate VR as part of their methods. This approach offers major advantages in experimental control, reproducibility, and ecological validity, but also has limitations and hidden pitfalls which may distract the novice user. This study aimed to guide the psychologist into the novel world of VR, reviewing available instrumentation and mapping the landscape of possible systems. We use examples of state-of-the-art research to describe challenges which research is now solving, including embodiment, uncanny valley, simulation sickness, presence, ethics, and experimental design. Finally, we propose that the biggest challenge for the field would be to build a fully interactive virtual human who can pass a VR Turing test – and that this could only be achieved if psychologists, VR technologists, and AI researchers work together.     

Physical effort biases the perceived pleasantness of neutral faces: A virtual reality study

The role of affective responses to effort in the regulation of physical activity behavior is widely accepted. Yet, to investigate these affective responses during physical activity, most studies used direct self-reported measures that are prone to biases (e.g., social desirability, ability to introspect). To reduce these biases, we used an indirect measure (i.e., an affect misattribution procedure) that assessed the implicit affective valence elicited by physical effort in 42 healthy young adults. Specifically, participants rated the pleasantness of neutral human faces presented in a virtual environment while cycling at different intensities. We used this rating as an indicator of implicit affective valence. Results showed that higher perceived effort was associated with lower pleasantness ratings of neutral faces, with this effect only emerging at moderate-to-high levels of perceived effort. Further analyses showed that higher actual effort was also associated with lower pleasantness ratings of neutral faces. Overall, these findings suggest that higher levels of perceived effort are associated with decreased affective valence during physical activity. Finally, this study presents a new indirect measure of affective valence during physical activity.     

The role of two types of outcome on storage and retrieval processes in memory

Two experiments are reported which demonstrate the typical finding of better performance on responses given positive outcomes as compared to performance on resiponses given negative and neutral outcomes. These effects of reinforcement are studied in more detail in the context of storage and retrieval processes. “Right” or “wrong” and monetary gain or loss were used as outcomes in the experiments. Both these types of outcome were found to have similar effects on storage, while the former tended to affect retrieval more than the latter outcomes did. The results clearly reject the notion that an outcome is stored along with the response to facilitate retrieval. A prerequisite for such a facilitation is a presentation of cues for retrieval at the time of test.     

A family study of memory processes and their relations to cognitive test scores

Members of 118 families (456 individuals) who had been tested on several measures of cognitive ability were retested on the same battery in order to determine test-retest reliability. They then were administered the Wechsler Adult Intelligence Scale and tests of visual memory, auditory memory, and figure memory, as well as other measures not discussed herein. Intercorrelations of memory tasks were low to moderate. Factor analysis resulted in a four factor solution. The different factors appeared to represent auditory sequential memory (Factor I); visual memory, as measured psychometrically (Factor II); visual memory, as measured experimentally (Factor III); and figure memory (Factor IV). A second order factor analysis yielded two factors, one consisting of basically psychometric measures of memory and the other of measures of memory obtained in the experimental psychological tradition. Memory measures generally showed low to moderate positive correlations with scores on the cognitive test battery. Significant spouse correlations were found for 3 of the 11 measures of memory. Significant midparent-midchild regressions were found for 9 of the 11 memory measures.     

The study of locomotor pointing in virtual reality: The validation of a test set-up

The goal of this experiment was to validate an experimental set-up for studying locomotor pointing. The specific and also original element of this set-up was the interactive nature of virtual reality and movement production. This interaction was achieved through the coupling of a treadmill and a Silicon Graphics system. This latter system generated on a screen (3 × 2.3 m) an environmental array that moved according to the action produced by subjects on a treadmill. The task was to place either foot on a spatial target that appeared on the floor in front of the subject’s displacement trajectory. We analyzed the step length patterns of subjects approaching these targets, along with the current target-subject relationship. The results are in agreement with aperception-action coupling type of control mechanism that operates continuously as the subject approaches the desired target. Apparently, these findings mirror observations of real-life locomotion, indicating that the present set-up provides a valid and useful tool for examining human locomotion.     

The effects of total sleep deprivation on recognition memory processes: A study of event-related potential

This study examined the memorization of information after a night of normal sleep and total sleep deprivation (TSD) by means of event-related potentials (ERPs). We expected a disfacilitatory effect of TSD on memory processing. Eighteen subjects were tested twice in a counterbalanced fashion. During the study session, subjects were presented with unfamiliar face stimuli and asked to memorize them for a subsequent memory test. At the test session, the subjects were presented with the studied faces intermixed with “new” faces and asked to indicate the previously presented stimuli. The N100 was used as a covariate to control for the differences in level of vigilance between the two sessions. Sleep deprivation decreased subjects’ ability to discriminate new from previously studied stimuli and decreased the peak amplitude of the early component (N200) to the decrement of performance. In addition, following TSD the amplitude of the late frontal component (LFC), which is thought to reflect contextual processing, was decreased in covariance with the N100 vigilance component. The amplitude of the late posterior component (LPC/P600) was also reduced but was unrelated to the vigilance component of the ERP. Based on prior studies, this LPC reduction can be interpreted to indicate a decrease in information retrieved after TSD. In summary, a night of TSD decreased the amplitude of the ERPs associated with complex episodic memory task stimuli, affected the frontal cortex during episodic retrieval, and prevented the elaboration process. Furthermore, there was an inability to discriminate what is and what is not in memory, possibly due to less local processing of details.     

A cognitive footprint in archival data: Generalizing the dilution effect from laboratory to field settings

This paper delineates a bridging strategy for generalizing a theoretical proposition about human judgment from laboratory to field settings. This strategy encompasses experimental and archival methods, emphasizing each method’s complementary rather than competitive advantage. Basic experiments that use generic tasks and settings, and novice subjects, contribute empirical tests that maximize internal validity. Given a target area in the “real world” for generalizing the proposition, applied experiments that use tasks and settings with greater mundane realism, and professional subjects from the target area, contribute replicating tests that balance internal and external validity. As a complement to experimentation, archival research adds value by testing observable implications of the proposition in field settings. We relate the bridging strategy to judgment research on the dilution effect (i.e., the presence of nondiagnostic cues, when processed with diagnostic cues, causes judges to under-weigh the diagnostic cues) in psychology and applied areas. Finally, we contribute an archival data analysis that uncovers indirect evidence, or a cognitive footprint, of the dilution effect in a professional judgment setting where social and economic mechanisms potentially discipline systematic error.     

The role of mediators in memory retrieval as a function of practice: controlled mediation to direct access

The role of prior knowledge in retrieval of Spanish-English vocabulary pairs learned using keyword mediators was examined in 4 experiments. Retrieval was tested immediately after learning and after 1-week and 1-month no-practice intervals (Experiment 1), after moderate retrieval practice (Experiment 2), and after extended retrieval practice (Experiments 3 and 4). Using accuracy, latency, and verbal report data, a detailed account of memory retrieval processes was developed. Initial retrieval is an explicit mediation process that involves retrieving keyword mediators into working memory and using them as retrieval cues to access the English equivalents of the Spanish words. After extended vocabulary retrieval practice, this sequential mediation process qualitatively changed to a direct retrieval process in which the English equivalent was accessed in a single working memory step. However, direct retrieval was still influenced by a covert mediation process.     

Memory trace stabilization leads to large-scale changes in the retrieval network: a functional MRI study on associative memory

Spaced learning with time to consolidate leads to more stabile memory traces. However, little is known about the neural correlates of trace stabilization, especially in humans. The present fMRI study contrasted retrieval activity of two well-learned sets of face-location associations, one learned in a massed style and tested on the day of learning (i.e., labile condition) and another learned in a spaced scheme over the course of one week (i.e., stabilized condition). Both sets of associations were retrieved equally well, but the retrieval of stabilized association was faster and accompanied by large-scale changes in the network supporting retrieval. Cued recall of stabilized as compared with labile associations was accompanied by increased activity in the precuneus, the ventromedial prefrontal cortex, the bilateral temporal pole, and left temporo–parietal junction. Conversely, memory representational areas such as the fusiform gyrus for faces and the posterior parietal cortex for locations did not change their activity with stabilization. The changes in activation in the precuneus, which also showed increased connectivity with the fusiform area, are likely to be related to the spatial nature of our task. The activation increase in the ventromedial prefrontal cortex, on the other hand, might reflect a general function in stabilized memory retrieval. This area might succeed the hippocampus in linking distributed neocortical representations.