Episodic storage and retrieval in visuo-spatial tasks: evidence of indirect retrieval

Episodic storage contends that the relevant target and irrelevant distractor features of a display are processed and then stored together within the boundaries of an episode, and are linked in this way. Accordingly, the selective and “direct” retrieval of either a stored target or distractor should result in the “indirect” and unintended retrieval of the other stimulus. In the present investigation, interest focused upon spatial tasks and the “indirect” retrieval of prime distractor processing. The novel findings obtained supported the existence of the “indirect” retrieval of prime distractor processing in visuo-spatial tasks and, to a lesser extent, of the stored prime target event, consistent with identity tasks (i.e. bi-directional episodically-based retrieval). Clearly, more is retrieved than is presented (Hintzman, D. L. (1984). MINERVA 2: A simulation model of human memory. Behavior Research Methods, Instruments, & Computers, 16, 96–101. doi:10.3758/BF03202365), as an episodic storage structure would predict.     

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

Schatz, T.R., Spranger, T. & Knopf, M. (2010). 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. Scandinavian Journal of Psychology 51, 465–472. 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.     

Manipulating the temporal locus and content of mind-wandering

The human brain has a tendency to drift into the realm of internally-generated thoughts that are unbound by space and time. The term mind-wandering (MW) is often used describe such thoughts when they are perceptually decoupled. Evidence suggests that exposure to forward and backward illusory motion skews the temporal orientation of MW thoughts to either the future or past respectively. However, little is known about the impact of this manipulation on other features of MW. Here, using a novel experimental paradigm, we first confirmed that our illusory motion method facilitated the generation of MW thoughts congruent with the direction of motion. We then conducted content analyses which revealed that goal orientation and temporal distance were also significantly affected by the direction of illusory motion. We conclude that illusory motion may be an effective means of assaying MW and could help to elucidate this ubiquitous, and likely critical, component of cognition.     

Neuroimaging the sleeping brain: Insight on memory functioning in infants and toddlers

Episodic memory, or the ability to remember past events with specific detail, is central to the human experience and is related to learning and adaptive functioning in a variety of domains. In typically developing children, episodic memory emerges during infancy and improves during early childhood and beyond. Developmental processes within the hippocampus are hypothesized to be primarily responsible for both the early emergence and persistence of episodic memory in late infancy and early childhood. However, these hypotheses are based on non-human models. In-vivo investigations in early human development of hippocampal processes have been significantly limited by methodological challenges in acquiring neuroimaging data, particularly task-related functional neuroimaging data, from infants and toddlers. Recent studies in adults have shown neural activity in the brain regions supporting episodic memory during slow-wave sleep using functional magnetic resonance imaging (fMRI), and fMRI has been increasingly utilized in infancy and early childhood to address other research questions. We review initial evidence and present preliminary data showing the promise of this approach for examining hippocampal contribution to how infants and toddlers remember individual events, and their association with information about the context in which the event occurred. Overall, our review, integrated with the presentation of some preliminary data provides insight on leveraging sleep to gain new perspectives on early memory functioning.     

Parallel interactive retrieval of item and associative information from event memory

Memory contains information about individual events (items) and combinations of events (associations). Despite the fundamental importance of this distinction, it remains unclear exactly how these two kinds of information are stored and whether different processes are used to retrieve them. We use both model-independent qualitative properties of response dynamics and quantitative modeling of individuals to address these issues. Item and associative information are not independent and they are retrieved concurrently via interacting processes. During retrieval, matching item and associative information mutually facilitate one another to yield an amplified holistic signal. Modeling of individuals suggests that this kind of facilitation between item and associative retrieval is a ubiquitous feature of human memory.