Long-term memory for movie details: selective decay for verbal information at one week.

Mnemonic representations of complex events are multidimensional, incorporating information about objects and characters, their interactions and their spatial-temporal context. The present study investigated the degree to which detailed verbal information (i.e., dialogues), as well as semantic and spatiotemporal (i.e., "what", "where", and "when") elements of episodic memories for movies, are forgotten over the course of a week. Moreover, we tested whether the amount of dimension-specific forgetting differed as a function of the participant's age. In a mixed design, younger and middle-aged participants were asked to watch a ∼90 min movie and provide yes/no answers to detailed questions about different dimensions of the presented material after 1, 3 days, and 1 week. The results indicate that memory decay mainly affects the verbal dimension, both in terms of response accuracy and confidence. Instead, detailed information about objects/characters' features and spatiotemporal context seems to be relatively preserved, despite a general decrease in response confidence. Furthermore, younger adults were in general more accurate and confident than middle-aged participants, although, again, the verbal dimension exhibited a significant age-related difference. We propose that this selective forgetting depends on the progressive advantage of visual compared to auditory/verbal information in memory for complex events.

Effects of a narrative template on memory for the time of movie scenes: automatic reshaping is independent of consolidation.

Memory for time is influenced by reconstructive processes, but the underlying mechanisms remain unclear. The present study investigated whether the effect of schematic prior knowledge on temporal memory for movie scenes, produced by the incomplete presentation (cut) of the movie at encoding, is modulated by cut position, retention interval, and task repetition. In a timeline positioning task, participants were asked to indicate when short video clips extracted from a previously encoded movie occurred on a horizontal timeline that represented the video duration. In line with previous findings, removing the final part of the movie resulted in a systematic underestimation of clips' position as a function of their proximity to the missing part. Further experiments demonstrate that the direction of this automatic effect depends on which part of the movie is deleted from the encoding session, consistent with the inferential structure of the schema, and does not depend on consolidation nor reconsolidation processes, at least within the present experimental conditions. We propose that the observed bias depends on the automatic influence of reconstructive processes on judgments about the time of occurrence, based on prior schematic knowledge.

Travel in the Physical and Mental Space: A Behavioral Assessment of the Phylogenetic Continuity Hypothesis Between Egocentric Navigation and Episodic Memory.

Based on the neuro-functional association between navigation in the physical and the mental space at the level of the hippocampal-entorhinal system, Buzsáki and Moser (2013) have hypothesized a phylogenetic continuity between spatial navigation and declarative memory functions. According to this proposal, mechanisms of episodic and semantic memory would have evolved from mechanisms of self-based and map-based navigation in the physical space, respectively. Using classic versions of path integration and item recognition tasks in human subjects, we have recently described a correlation and a predictive relationship between abilities in egocentric navigation and episodic memory. Here we aim at confirming and extending this association to the dynamic component of sequential updating in the physical (egocentric navigation) and mental (episodic memory) space, and at investigating the relationship of these self-centered abilities with semantic memory. To this aim, we developed three new experimental tasks in which the dynamic component of updating information is particularly emphasized in the spatial, the temporal, and the semantic domain. The contribution of visual short-term memory to the three tasks was also controlled by including an additional task. The results confirmed the existence of a direct and predictive relationship between self-based spatial navigation and episodic memory. We also found a significant association between egocentric navigation and semantic memory, but this relationship was explained by short-term memory abilities and was mediated by episodic memory functions. Our results support the hypothesis of an evolutionary link between mechanisms that allow spatial navigation in the physical space and time travel in the mental space.

Reconstructive nature of temporal memory for movie scenes.

Remembering when events took place is a key component of episodic memory. Using a sensitive behavioral measure, the present study investigates whether spontaneous event segmentation and script-based prior knowledge affect memory for the time of movie scenes. In three experiments, different groups of participants were asked to indicate when short video clips extracted from a previously encoded movie occurred on a horizontal timeline that represented the video duration. When participants encoded the entire movie, they were more precise at judging the temporal occurrence of clips extracted from the beginning and the end of the film compared to its middle part, but also at judging clips that were closer to event boundaries. Removing the final part of the movie from the encoding session resulted in a systematic bias in memory for time. Specifically, participants increasingly underestimated the time of occurrence of the video clips as a function of their proximity to the missing part of the movie. An additional experiment indicated that such an underestimation effect generalizes to different audio-visual material and does not necessarily reflect poor temporal memory. By showing that memories are moved in time to make room for missing information, the present study demonstrates that narrative time can be adapted to fit a standard template regardless of what has been effectively encoded, in line with reconstructive theories of memory.

Influence of time-of-day on joint Navon effect.

The shared attention theory suggests that people devote greater cognitive resources to those features co-attended simultaneously with others, determining better performance in several types of tasks. When co-actors performed a go/no-go Navon task attending different features of target letters, the performance was impaired, reflecting a joint Navon effect (the representation of a co-actor's attentional focus made it more difficult to select and apply one's own focus of attention), probably due to asynchronous co-attention with a decrease in cognitive resources involved. Researches in chronobiology and chronopsychology demonstrated that not only selective attention (involved in a Navon task), but also cognitive resources have a daily fluctuations, mainly paralleling the circadian rhythm of body temperature (i.e. increasing values from the morning to evening with a subsequent decline in the night). The study was conducted to assess whether the presence of joint attention, as measured by the joint Navon effect, was influenced by the time-of-day. Sixteen pairs of participants sitting next to each other were required to respond to the identity letters in a go/no-go Navon task twice: in the morning (09:00-10:00) and early afternoon (13:00-14:00). The results showed a joint Navon effect in the morning session only, suggesting that joint attention was affected by the time-of-day effect on cognitive resources.

Synchrony effect on joint attention.

Research on joint attention has demonstrated that individuals are sensitive to a coactor's attentional relation to jointly attended stimuli. Within a chronobiological approach, a study was conducted to assess whether the presence of joint attention, as measured by the joint Navon effect, was influenced by the synchrony effect. Pairs of participants sitting next to each other were required to respond to the identity letters in a go/no-go Navon task. The joint Navon task was performed by morning, intermediate and evening types (81 pairs) at different times of day (09:00-10:00; 13:00-14:00; 17:00-18:00). The joint Navon effect on task performance was highlighted at the optimal time of day (in the morning for morning types, in the early afternoon for intermediate types and in the evening for evening types), but it disappeared or decreased at the non-optimal time of day, with the exception of evening types. The results demonstrated that joint attention was affected by the synchrony effect.