Perceiving, remembering, and communicating structure in events

Detecting neural state transitions underlying event segmentation

Segmenting perceptual experience into meaningful events is a key cognitive process that helps us make sense of what is happening around us in the moment, as well as helping us recall past events. Nevertheless, little is known about the underlying neural mechanisms of the event segmentation process. Recent work has suggested that event segmentation can be linked to regional changes in neural activity patterns. Accurate methods for identifying such activity changes are important to allow further investigation of the neural basis of event segmentation and its link to the temporal processing hierarchy of the brain. In this study, we introduce a new set of elegant and simple methods to study these mechanisms. We introduce a method for identifying the boundaries between neural states in a brain area and a complementary one for identifying the number of neural states. Furthermore, we present the results of a comprehensive set of simulations and analyses of empirical fMRI data to provide guidelines for reliable estimation of neural states and show that our proposed methods outperform the current state-of-the-art in the literature. This methodological innovation will allow researchers to make headway in investigating the neural basis of event segmentation and information processing during naturalistic stimulation.

Influences of domain knowledge on segmentation and memory

Much research has shown that experts possess superior memory in their domain of expertise. This memory benefit has been proposed to be the result of various encoding mechanisms, such as chunking and differentiation. Another potential encoding mechanism that is associated with memory is event segmentation, which is the process by which people parse continuous information into meaningful, discrete units. Previous research has found evidence that segmentation, to some extent, is affected by top-down processing. To date, few studies have investigated the influence of expertise on segmentation, and questions about expertise, segmentation ability, and their impact on memory remain. The goal of the current study was to investigate the influence of expertise on segmentation and memory ability for two different domains: basketball and Overwatch. Participants with high and low knowledge for basketball and with low knowledge for Overwatch viewed and segmented videos at coarse and fine grains, then completed memory tests. Differences in segmentation ability and memory were present between experts and control novices, specifically for the basketball videos; however, experts' segmentation only predicted memory for activities for which knowledge was lacking. Overall, this research suggests that experts' superior memory is not due to their segmentation ability and contributes to a growing body of literature showing evidence supporting conceptual effects on segmentation.

Tea With Milk? A Hierarchical Generative Framework of Sequential Event Comprehension

To make sense of the world around us, we must be able to segment a continual stream of sensory inputs into discrete events. In this review, I propose that in order to comprehend events, we engage hierarchical generative models that "reverse engineer" the intentions of other agents as they produce sequential action in real time. By generating probabilistic predictions for upcoming events, generative models ensure that we are able to keep up with the rapid pace at which perceptual inputs unfold. By tracking our certainty about other agents' goals and the magnitude of prediction errors at multiple temporal scales, generative models enable us to detect event boundaries by inferring when a goal has changed. Moreover, by adapting flexibly to the broader dynamics of the environment and our own comprehension goals, generative models allow us to optimally allocate limited resources. Finally, I argue that we use generative models not only to comprehend events but also to produce events (carry out goal-relevant sequential action) and to continually learn about new events from our surroundings. Taken together, this hierarchical generative framework provides new insights into how the human brain processes events so effortlessly while highlighting the fundamental links between event comprehension, production, and learning.

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.

Context-dependent memory effects in two immersive virtual reality environments: On Mars and underwater

The context-dependent memory effect, in which memory for an item is better when the retrieval context matches the original learning context, has proved to be difficult to reproduce in a laboratory setting. In an effort to identify a set of features that generate a robust context-dependent memory effect, we developed a paradigm in virtual reality using two semantically distinct virtual contexts: underwater and Mars environments, each with a separate body of knowledge (schema) associated with it. We show that items are better recalled when retrieved in the same context as the study context; we also show that the size of the effect is larger for items deemed context-relevant at encoding, suggesting that context-dependent memory effects may depend on items being integrated into an active schema.

Attention in naïve psychology

In everyday life, mentalizing is nested in a rich context of cognitive faculties and background information that potentially contribute to its success. Yet, we know little about these modulating effects. Here we propose that humans develop a naïve psychological model of attention (featured as a goal-dependent, intentional relation to the environment) and use this to fine-tune their mentalizing attempts, presuming that the way people represent their environment is influenced by the cognitive priorities (attention) their current intentions create. The attention model provides an opportunity to tailor mental state inferences to the temporary features of the agent whose mind is in the focus of mentalizing. The ability to trace attention is an exceptionally powerful aid for mindreading. Knowledge about the partner's attention provides background information, however being grounded in his current intentions, attention has direct relevance to the ongoing interaction. Furthermore, due to its causal connection to intentions, the output of the attention model remains valid for a prolonged but predictable amount of time: till the evoking intention is in place. The naïve attention model theory is offered as a novel theory on social attention that both incorporates existing evidence and identifies new directions in research.

Culture influences how people divide continuous sensory experience into events

Everyday experience is divided into meaningful events as a part of human perception. Current accounts of this process, known as event segmentation, focus on how characteristics of the experience (e.g., situation changes) influence segmentation. However, characteristics of the viewers themselves have been largely neglected. We test whether one such viewer characteristic, their cultural background, impacts online event segmentation. Culture could impact event segmentation (1) by emphasizing different aspects of experiences as being important for comprehension, memory, and communication, and (2) by providing different exemplars of how everyday activities are performed, which objects are likely to be used, and how scenes are laid out. Indian and US viewers (N = 152) identified events in everyday activities (e.g., making coffee) recorded in Indian and US settings. Consistent with their cultural preference for analytical processing, US viewers segmented the activities into more events than did Indian viewers. Furthermore, event boundaries identified by US viewers were more strongly associated with visual changes, whereas boundaries identified by Indian viewers were more strongly associated with goal changes. There was no evidence that familiarity with an activity impacted segmentation. Thus, culture impacts event perception by altering the types of information people prioritize when dividing experience into meaningful events.

The Witness-Aimed First Account (WAFA): A new technique for interviewing autistic witnesses and victims

LAY ABSTRACT

Autistic people may be more likely to be interviewed by police as a victim/witness, yet they experience social communication difficulties alongside specific memory difficulties that can impact their ability to recall information from memory. Police interviewing techniques do not take account of these differences, and so are often ineffective. We developed a new technique for interviewing autistic witnesses, referred to a Witness-Aimed First Account, which was designed to better support differences in the way that autistic witnesses process information in memory. The Witness-Aimed First Account technique encourages witnesses to first segment the witnessed event into discrete, parameter-bound event topics, which are then displayed on post-it notes while the witness goes onto freely recall as much information as they can from within each parameter-bound topic in turn. Since witnessed events are rarely cohesive stories with a logical chain of events, we also explored autistic and non-autistic witnesses' recall when the events were witnessed in a random (nonsensical) order. Thirty-three autistic and 30 typically developing participants were interviewed about their memory for two videos depicting criminal events. Clip segments of one video were 'scrambled', disrupting the event's narrative structure; the other video was watched intact. Although both autistic and non-autistic witnesses recalled fewer details with less accuracy from the scrambled video, Witness-Aimed First Account interviews resulted in more detailed and accurate recall from both autistic and non-autistic witnesses, for both scrambled and unscrambled videos. The Witness-Aimed First Account technique may be a useful tool to improve witnesses' accounts within a legally appropriate, non-leading framework.

Differential effects of direct and cross examination on mock jurors' perceptions and memory in cases of child sexual abuse

When children testify in cases of child sexual abuse (CSA), they often provide minimal responses to attorneys' questions. Thus, how attorneys ask questions may be particularly influential in shaping jurors' perceptions and memory for case details. This study examined mock jurors' perceptions after reading an excerpt of a CSA trial transcript. Participants' memory of the excerpt was tested after a two-day delay. We examined how reading a direct or cross-examination excerpt that included either high or low temporal structure impacted participants' perceptions, verdict decisions and memory reports. We found that participants who read a direct examination excerpt rated the child witness as more credible, were more likely to convict the defendant and had more accurate memory reports than those who read a cross-examination excerpt, regardless of temporal structure. Suggestions for improving jurors' comprehension and recall of child statements presented as evidence in CSA cases are discussed.

Neural dynamics of grip and goal integration during the processing of others' actions with objects: An ERP study

Recent behavioural evidence suggests that when processing others’ actions, motor acts and goal-related information both contribute to action recognition. Yet the neuronal mechanisms underlying the dynamic integration of the two action dimensions remain unclear. This study aims to elucidate the ERP components underlying the processing and integration of grip and goal-related information. The electrophysiological activity of 28 adults was recorded during the processing of object-directed action photographs (e.g., writing with pencil) containing either grip violations (e.g. upright pencil grasped with atypical-grip), goal violations (e.g., upside-down pencil grasped with typical-grip), both grip and goal violations (e.g., upside-down pencil grasped with atypical-grip), or no violations. Participants judged whether actions were overall typical or not according to object typical use. Brain activity was sensitive to the congruency between grip and goal information on the N400, reflecting the semantic integration between the two dimensions. On earlier components, brain activity was affected by grip and goal typicality independently. Critically, goal typicality but not grip typicality affected brain activity on the N300, supporting an earlier role of goal-related representations in action recognition. Findings provide new insights on the neural temporal dynamics of the integration of motor acts and goal-related information during the processing of others’ actions.

Differential effects of knowledge and aging on the encoding and retrieval of everyday activities

We deconstruct continuous streams of action into smaller, meaningful events. Research has shown that the ability to segment continuous activity into such events and remember their contents declines with age; however, knowledge improves with age. We investigated how young and older adults use knowledge to more efficiently encode and later remember information from everyday events by having participants view a series of self-paced slideshows depicting everyday activities. For some activities, older adults produce more normative scripts than do young adults (older adult activities) and for other activities, young adults produce more normative scripts than do older adults (young adult activities). Overall, participants viewed event boundaries longer than within events (i.e., the event boundary advantage) replicating prior research (e.g., Hard, Recchia, & Tversky, 2011). Importantly, older adults demonstrated the boundary advantage for the older adult activities but not the young adult activities, and they also had better recognition memory for the older adult activities than the young adult activities. We also found that the magnitude of a participant's boundary advantage was associated with better memory, but only for the less knowledgeable activities. Results indicate that older adults use their intact knowledge to better encode and remember everyday activities, but that knowledge and event segmentation may have independent influences on event memory.

Enumeration in time is irresistibly event-based

One of the most fundamental questions that can be asked about any process concerns the underlying units over which it operates. And this is true not just for artificial processes (such as functions in a computer program that only take specific kinds of arguments) but for mental processes. Over what units does the process of enumeration operate? Recent work has demonstrated that in visuospatial arrays, these units are often irresistibly discrete objects. When enumerating the number of discs in a display, for example, observers underestimate to a greater degree when the discs are spatially segmented (e.g., by connecting pairs of discs with lines): you try to enumerate discs, but your mind can't help enumerating dumbbells. This phenomenon has previously been limited to static displays, but of course our experience of the world is inherently dynamic. Is enumeration in time similarly based on discrete events? To find out, we had observers enumerate the number of notes in quick musical sequences. Observers underestimated to a greater degree when the notes were temporally segmented (into discrete musical phrases, based on pitch-range shifts), even while carefully controlling for both duration and the overall range and heterogeneity of pitches. Observers tried to enumerate notes, but their minds couldn't help enumerating musical phrases - since those are the events they experienced. These results thus demonstrate how discrete events are prominent in our mental lives, and how the units that constitute discrete events are not entirely under our conscious, intentional control.

What effort is required in retrieving self-defining memories? Specific autonomic responses for integrative and non-integrative memories

Self-defining memories (SDM) are autobiographical memories associated with the construction and maintenance of identity, and which play a core role in establishing and achieving goals in life. The aim of this study was to evaluate the effort required in retrieving SDM as reflected by physiological activity. We examined the neurovegetative responses associated with three dimensions of SDM: specificity, integrative meaning and emotional valence. Electrodermal activity (skin conductance response frequency, phasic driver) and the high frequency component of heart rate variability (HF-HRV) were recorded during the retrieval of SDM in 36 healthy participants to assess the activation of the sympathetic and parasympathetic systems, respectively. SDM were characterized by three independent investigators with satisfactory inter-rater reliability. Linear mixed effects analyses showed that only the integrative meaning dimension led to a main effect on electrodermal activity. In addition, an interaction effect showed that the retrieval of non-integrative and specific memories was associated with a higher level of electrodermal activity than the retrieval of integrative specific memories. No effects were obtained regarding the HRV indicators. The higher activation of the sympathetic nervous system associated with the retrieval of non-integrative SDM suggests that the ability to derive meaning from personal experiences plays a regulatory role and is a fundamental component in personal adjustment.

In a Temporally Segmented Experience Hippocampal Neurons Represent Temporally Drifting Context But Not Discrete Segments

There is widespread agreement that episodic memory is organized into a timeline of past experiences. Recent work suggests that the hippocampus may parse the flow of experience into discrete episodes separated by event boundaries. A complementary body of work suggests that context changes gradually as experience unfolds. We recorded from hippocampal neurons as male Long-Evans rats performed 6 blocks of an object discrimination task in sets of 15 trials. Each block was separated by removal from the testing chamber for a delay to enable segmentation. The reward contingency reversed from one block to the next to incentivize segmentation. We expected animals to hold two distinct, recurring representations of context to match the two distinct rule contingencies. Instead, we found that overtrained rats began each block neither above nor below chance but by guessing randomly. While many units had clear firing fields selective to the conjunction of objects in places, a significant population also reflected a continuously drifting code both within block and across blocks. Despite clear boundaries between blocks, we saw no neural evidence for event segmentation in this experiment. Rather, the hippocampal ensemble drifted continuously across time. This continuous drift in the neural representation was consistent with the lack of segmentation observed in behavior.SIGNIFICANCE STATEMENT The neuroscience literature yet to reach consensus on how the hippocampus supports the organization of events across time in episodic memory. Initial studies reported stable hippocampal maps segmented by remapping events. However, it remains unclear whether segmentation is an artifact of cue responsivity. Recently, research has shown that the hippocampal code exhibits continuous drift. Drift may represent a continually evolving context; however, it is unclear whether this is an artifact of changing experiences. We recorded dCA1 in rats performing an object discrimination task designed to segment time. Overtrained rats could not anticipate upcoming context switches but used context boundaries to their advantage. Hippocampal ensembles showed neither evidence of alternating between stable contexts nor sensitivity to boundaries, but showed robust temporal drift.

The role of character goals and changes in body position in the processing of events in visual narratives

BACKGROUND

A growing body of research is beginning to understand how people comprehend sequential visual narratives. However, previous work has used materials that primarily rely on visual information (i.e., they contain minimal language information). The current work seeks to address how visual and linguistic information streams are coordinated in sequential image comprehension. In experiment 1, participants viewed picture stories and engaged in an event segmentation task. The extent to which critical points in the narrative depicted situational continuity of character goals and continuity in bodily position was manipulated. The likelihood of perceiving an event boundary and viewing latencies at critical locations were measured. Experiment 1 was replicated in the second experiment, without the segmentation task. That is, participants read the picture stories without deciding where the event boundaries occurred.

RESULTS

Experiment 1 indicated that changes in character goals were associated with an increased likelihood of segmenting at the critical point, but changes in bodily position were not. A follow-up analysis, however, revealed that over the course of the entire story, changes in body position were a significant predictor of event segmentation. Viewing time, however, was affected by both goal and body position shifts. Experiment 2 corroborated the finding that viewing time was affected by changes in goals and body positions.

CONCLUSION

The current study shows that changes in body position influence a viewer's perception of event structure and event processing. This fits into a growing body of research that attempts to understand how consumers of multimodal media coordinate multiple information streams. The current study underscores the need for the systematic study of the visual, perceptual, and comprehension processes that occur during visual narrative understanding.

Linguistic Information in Auditory Dynamic Events Contributes to the Detection of Fine, Not Coarse Event Boundaries

Human observers (comprehenders) segment dynamic information into discrete events. That is, although there is continuous sensory information, comprehenders perceive boundaries between two meaningful units of information. In narrative comprehension, comprehenders use linguistic, non-linguistic , and physical cues for this event boundary perception. Yet, it is an open question - both from a theoretical and an empirical perspective - how linguistic and non-linguistic cues contribute to this process. The current study explores how linguistic cues contribute to the participants' ability to segment continuous auditory information into discrete, hierarchically structured events. Native speakers of German and non-native speakers, who neither spoke nor understood German, segmented a German audio drama into coarse and fine events. Whereas native participants could make use of linguistic, non-linguistic, and physical cues for segmentation, non-native participants could only use non-linguistic and physical cues. We analyzed segmentation behavior in terms of the ability to identify coarse and fine event boundaries and the resulting hierarchical structure. Non-native listeners identified almost identical coarse event boundaries as native listeners, but missed some of the fine event boundaries identified by the native listeners. Interestingly, hierarchical event perception (as measured by hierarchical alignment and enclosure) was comparable for native and non-native participants. In summary, linguistic cues contributed particularly to the identification of certain fine event boundaries. The results are discussed with regard to the current theories of event cognition.

Does semantic knowledge influence event segmentation and recall of text?

Knowledge benefits episodic memory, particularly when provided before encoding (Anderson & Pichert in Journal of Verbal Learning and Verbal Behavior, 17(1), 1-12, 1978; Bransford & Johnson in Journal of Verbal Learning and Verbal Behavior, 11(6), 717-726, 1972). These benefits can occur through several encoding mechanisms, one of which may be event segmentation. Event segmentation is one's ability to parse information into meaningful units as an activity unfolds. The current experiment evaluated whether two top-down manipulations-providing context or perspective taking-influence the segmentation and memory of text. For the ambiguous texts in Experiment 1, half the participants received context in the form of a title, whereas the other half received no context. For the text in Experiment 2, half the participants read from the perspective of a burglar and the other half read from the perspective of a home buyer. In both experiments, participants read the passages, recalled the information, and then segmented the passages into meaningful units. Consistent with previous findings, participants who received context recalled more information compared with those who received no context, and participants in one perspective were more likely to recall information relevant to their perspective. Most importantly, we found that context and perspective facilitated more normative segmentation; however, the differences were small and suggest that effects of top-down processing on the segmentation of text may be modest at best. Thus, event segmentation processes that operate during text comprehension are influenced by semantic knowledge but may be more heavily driven by other factors (e.g., perceptual cues).

Event memory uniquely predicts memory for large-scale space

When a person explores a new environment, they begin to construct a spatial representation of it. Doing so is important for navigating and remaining oriented. How does one's ability to learn a new environment relate to one's ability to remember experiences in that environment? Here, 208 adults experienced a first-person videotaped route, and then completed a spatial map construction task. They also took tests of general cognitive abilities (working memory, laboratory episodic memory, processing speed, general knowledge) and of memory for familiar, everyday activities (event memory). Regression analyses revealed that event memory (memory for everyday events and their temporal structure), laboratory episodic memory (memory for words and pictures) and gender were unique predictors of spatial memory. These results implicate the processing of temporal structure and organization as an important cognitive ability in large-scale spatial-memory-from-route experience. Accounting for the temporal structure of people's experience while learning the layout of novel spaces may improve interventions for addressing navigation problems.

Can Young Children Ignore Irrelevant Events, or Subevents, During Verb Learning?

Children learning a verb may benefit from hearing it across situations (e.g., Behrend, 1995; Childers, 2011; Fisher et al, 1994; Pinker, 1989). At the same time, in everyday contexts, situations in which a verb is heard will be interrupted by distracting events. Using Structural Alignment theory as a framework (e.g., Gentner & Namy, 2006), Study 1 asks whether children can learn a verb when irrelevant, interleaved events are present. Two½- and 3½-year-old children saw dynamic events and were randomly assigned to one of three experimental conditions (differing in orders of events), or one of two control conditions. They extended the verbs in the experimental conditions, and not the control conditions. Three ½-year-olds were more successful than 2½-year-olds, though the younger children could extend verbs. A more difficult task is segmenting dynamic action into subevents that could be relevant for a verb (e.g., finding "chopping" in a cooking scene). In Study 2, 2½-, 3½- and 4½-year-old children were assigned to experimental conditions in which relevant events flowed into irrelevant events (or vice versa), or to a control. Two½-year-olds failed to extend the verbs at test, differing from the older children; children in experimental conditions extended the verbs while children in the control condition did not. Altogether, these results show children can ignore irrelevant events (and subevents), and extend new verbs by 3½ years. Results are important to understand learning in everyday contexts in which verbs are heard in varied situations over time.

How language and event recall can shape memory for time

How do we represent the duration of past events that we have conceptualized through language? Prior research suggests that memory for duration depends on the segmental structure perceived at encoding. However, it remains unclear why duration memory displays characteristic distortions and whether language-mediated encoding can further distort duration memory. Here we examine these questions and specifically ask whether the amount of event information recalled relative to the stimulus duration explains temporal distortions. In several studies, participants first studied animated stimuli described by phrases implying either fast or slow motion (e.g., a mule vs car going up a road). They then mentally reproduced the stimuli from memory (as if replaying them in their minds) and verbally recalled them. We manipulated the amount of stimulus study and the type of recall cue (visual vs linguistic) to assess the role of language and information recalled on the length of mental reproductions. Results indicated that the density of the information recalled (number of details recalled per second) explained temporal distortions: higher density events were lengthened and lower density events were shortened. Moreover, language additionally lengthened or shortened duration reproductions when phrases cued the task, suggesting that episodic details and verbal conceptual features were combined during recollection rather than encoding. These results suggest that the density of the details recalled and language-mediated recollection shape memory for event duration. We argue that temporal memory distortions stem from event encoding and retrieval mechanisms. Implications of these findings for theories of time, memory and language are discussed.

Shared neural and cognitive mechanisms in action and language: The multiscale information transfer framework

This review compares how humans process action and language sequences produced by other humans. On the one hand, we identify commonalities between action and language processing in terms of cognitive mechanisms (e.g., perceptual segmentation, predictive processing, integration across multiple temporal scales), neural resources (e.g., the left inferior frontal cortex), and processing algorithms (e.g., comprehension based on changes in signal entropy). On the other hand, drawing on sign language with its particularly strong motor component, we also highlight what differentiates (both oral and signed) linguistic communication from nonlinguistic action sequences. We propose the multiscale information transfer framework (MSIT) as a way of integrating these insights and highlight directions into which future empirical research inspired by the MSIT framework might fruitfully evolve. This article is categorized under: Psychology > Language Linguistics > Language in Mind and Brain Psychology > Motor Skill and Performance Psychology > Prediction.

It takes me back: The mnemonic time-travel effect

Given the links between motion and temporal thinking, it is surprising that no studies have examined the possibility that transporting participants back mentally towards the time of encoding could improve memory. Six experiments investigated whether backward motion would promote recall relative to forward motion or no-motion conditions. Participants saw a video of a staged crime (Experiments 1, 3 and 5), a word list (Experiments 2 and 4) or a set of pictures (Experiment 6). Then, they walked forward or backwards (Experiments 1 and 2), watched a forward- or backward-directed optic flow-inducing video (Experiments 3 and 4) or imagined walking forward or backwards (Experiments 5 and 6). Finally, they answered questions about the video or recalled words or pictures. The results demonstrated for the first time that motion-induced past-directed mental time travel improved mnemonic performance for different types of information. We briefly discuss theoretical and practical implications of this "mnemonic time-travel effect".

Examining memory for ritualized gesture in complex causal sequences

Humans have created and maintained an exponentially large and sophisticated behavioral corpus over evolutionary time. In no small part this was achieved due to our tendency to imitate behaviours rather than to emulate outcomes. This tendency, however, can lead to inefficiency and redundancy in our behavioral repertoires. Drawing on evidence from multiple fields of psychology, we propose two novel competing hypotheses. The 'catalyst hypothesis' suggests that low (but not high) proportions of ritualized gesture in instrumental action sequences will improve subsequent recall of the entire action sequence (without itself enhancing the instrumental utility of the sequence). Conversely, the 'cost hypothesis' suggests that increasing proportions of ritualized gesture will impair recall, due to the introduction of cognitive load. The null hypothesis states that ritualized gestures are neither beneficial nor costly. In a pre-registered experiment, we presented participants with multiple versions of two complicated 2-min action sequences in which we varied the proportion of ritualized gesture. We then quantified the influence ritualized gesture had on recall for individuals gestures, overall outcomes, and described detail. We found clear evidence that high proportions of ritualized gestures impair recall for individual gestures and overall success, and weak evidence that low proportions increase overall success. At present, we may reject the null, but cannot rule out either of our competing hypotheses. We discuss potential implications for cultural evolution, and generate competing predictions that allow for adjudication between Ritual Modes theory (Whitehouse, 2004) and the 'Cognitive Resource Depletion' account of Religious Interaction (Schjoedt et al., 2013). All files (including data and syntax) are freely available at https://osf.io/spz68/.

Event segmentation and the temporal compression of experience in episodic memory

Recent studies suggest that episodic memory represents the continuous flow of information that constitutes daily life events in a temporally compressed form, but the nature and determinants of this compression mechanism remain unclear. In the present study, we used wearable camera technology to investigate whether the temporal compression of experience in episodic memory depends on event segmentation. Participants experienced a series of events during a walk on a university campus and were later asked to mentally replay these events. The temporal compression of events in memory and grain size of event segmentation were estimated based on records of participants' experience taken by the camera. The results showed that the temporal compression of events in memory (i.e., the density of recalled moments of experience per unit of time of the actual event duration) closely corresponded to the grain size of event segmentation. Specifically, grain sizes of event segmentation and temporal compression rates were four to five times lower when remembering events that involved goal-directed actions compared to other kinds of events (e.g., spatial displacements). Furthermore, temporal compression rates in memory were significantly predicted by the grain size of event segmentation and event boundaries were more than five times more likely to be remembered than other parts of events. Together, these results provide new insights into the mechanism of temporal compression of events in episodic memory.

The role of perspective in event segmentation

People divide their ongoing experience into meaningful events. This process, event segmentation, is strongly associated with visual input: when visual features change, people are more likely to segment. However, the nature of this relationship is unclear. Segmentation could be bound to specific visual features, such as actor posture. Or, it could be based on changes in the activity that are correlated with visual features. This study distinguished between these two possibilities by examining whether segmentation varies across first- and third-person perspectives. In two experiments, observers identified meaningful events in videos of actors performing everyday activities, such as eating breakfast or doing laundry. Each activity was simultaneously recorded from a first-person perspective and a third-person perspective. These videos presented identical activities but differed in their visual features. If segmentation is tightly bound to visual features then observers should identify different events in first- and third-person videos. In addition, the relationship between segmentation and visual features should remain unchanged. Neither prediction was supported. Though participants sometimes identified more events in first-person videos, the events they identified were mostly indistinguishable from those identified for third-person videos. In addition, the relationship between the video's visual features and segmentation changed across perspectives, further demonstrating a partial dissociation between segmentation and visual input. Event segmentation appears to be robust to large variations in sensory information as long as the content remains the same. Segmentation mechanisms appear to flexibly use sensory information to identify the structure of the underlying activity.

Principles of Temporal Processing Across the Cortical Hierarchy

The world is richly structured on multiple spatiotemporal scales. In order to represent spatial structure, many machine-learning models repeat a set of basic operations at each layer of a hierarchical architecture. These iterated spatial operations - including pooling, normalization and pattern completion - enable these systems to recognize and predict spatial structure, while robust to changes in the spatial scale, contrast and noisiness of the input signal. Because our brains also process temporal information that is rich and occurs across multiple time scales, might the brain employ an analogous set of operations for temporal information processing? Here we define a candidate set of temporal operations, and we review evidence that they are implemented in the mammalian cerebral cortex in a hierarchical manner. We conclude that multiple consecutive stages of cortical processing can be understood to perform temporal pooling, temporal normalization and temporal pattern completion.

Children's Use of Morphological Cues in Real-Time Event Representation

The present study investigated whether and how fast young children can use information encoded in morphological markers during real-time event representation. Using the visual world paradigm, we tested 35 adults, 34 5-year-olds and 33 3-year-olds. The results showed that the adults, the 5-year-olds and the 3-year-olds all exhibited eye gaze patterns that reflected a rapid use of morphological cues during real-time event representation. There was no difference in the time course of the eye gaze patterns of the 5-year-olds and those of the adults, indicating that 5-year-old children already have adult-like processing abilities and they can use morphological cues as effectively as adults during real-time event representation. However, a 400 ms delay was observed in the eye gaze patterns by the 3-year-olds as compared to the 5-year-olds and the adults. We proposed that the observed difference might reflect a difference in the general cognitive processing abilities between the three age groups. Due to the immature cognitive processing abilities of 3-year-olds, it took longer for them to progress their eye movements to the target pictures as compared to older children and adults.

Constructing Experience: Event Models from Perception to Action

Mental representations of everyday experience are rich, structured, and multimodal. In this article we consider the adaptive pressures that led to human construction of such representations, arguing that structured event representations enable cognitive systems to more effectively predict the trajectory of naturalistic everyday activity. We propose an account of how cortical systems and the hippocampus (HPC) interact to construct, maintain, and update event representations. This analysis throws light on recent research on story comprehension, event segmentation, episodic memory, and action planning. It also suggests how the growing science base can be deployed to diagnose impairments in event perception and memory, and to improve memory for everyday events.

The Psychology of Rituals: An Integrative Review and Process-Based Framework

Traditionally, ritual has been studied from broad sociocultural perspectives, with little consideration of the psychological processes at play. Recently, however, psychologists have begun turning their attention to the study of ritual, uncovering the causal mechanisms driving this universal aspect of human behavior. With growing interest in the psychology of ritual, this article provides an organizing framework to understand recent empirical work from social psychology, cognitive science, anthropology, behavioral economics, and neuroscience. Our framework focuses on three primary regulatory functions of rituals: regulation of (a) emotions, (b) performance goal states, and (c) social connection. We examine the possible mechanisms underlying each function by considering the bottom-up processes that emerge from the physical features of rituals and top-down processes that emerge from the psychological meaning of rituals. Our framework, by appreciating the value of psychological theory, generates novel predictions and enriches our understanding of ritual and human behavior more broadly.

Discovering Event Structure in Continuous Narrative Perception and Memory

During realistic, continuous perception, humans automatically segment experiences into discrete events. Using a novel model of cortical event dynamics, we investigate how cortical structures generate event representations during narrative perception and how these events are stored to and retrieved from memory. Our data-driven approach allows us to detect event boundaries as shifts between stable patterns of brain activity without relying on stimulus annotations and reveals a nested hierarchy from short events in sensory regions to long events in high-order areas (including angular gyrus and posterior medial cortex), which represent abstract, multimodal situation models. High-order event boundaries are coupled to increases in hippocampal activity, which predict pattern reinstatement during later free recall. These areas also show evidence of anticipatory reinstatement as subjects listen to a familiar narrative. Based on these results, we propose that brain activity is naturally structured into nested events, which form the basis of long-term memory representations.

Not so secret agents: Event-related potentials to semantic roles in visual event comprehension

Research across domains has suggested that agents, the doers of actions, have a processing advantage over patients, the receivers of actions. We hypothesized that agents as "event builders" for discrete actions (e.g., throwing a ball, punching) build on cues embedded in their preparatory postures (e.g., reaching back an arm to throw or punch) that lead to (predictable) culminating actions, and that these cues afford frontloading of event structure processing. To test this hypothesis, we compared event-related brain potentials (ERPs) to averbal comic panels depicting preparatory agents (ex. reaching back an arm to punch) that cued specific actions with those to non-preparatory agents (ex. arm to the side) and patients that did not cue any specific actions. We also compared subsequent completed action panels (ex. agent punching patient) across conditions, where we expected an inverse pattern of ERPs indexing the differential costs of processing completed actions asa function of preparatory cues. Preparatory agents evoked a greater frontal positivity (600-900ms) relative to non-preparatory agents and patients, while subsequent completed actions panels following non-preparatory agents elicited a smaller frontal positivity (600-900ms). These results suggest that preparatory (vs. non-) postures may differentially impact the processing of agents and subsequent actions in real time.

Distinct hippocampal-cortical memory representations for experiences associated with movement versus immobility

While ongoing experience proceeds continuously, memories of past experience are often recalled as episodes with defined beginnings and ends. The neural mechanisms that lead to the formation of discrete episodes from the stream of neural activity patterns representing ongoing experience are unknown. To investigate these mechanisms, we recorded neural activity in the rat hippocampus and prefrontal cortex, structures critical for memory processes. We show that during spatial navigation, hippocampal CA1 place cells maintain a continuous spatial representation across different states of motion (movement and immobility). In contrast, during sharp-wave ripples (SWRs), when representations of experience are transiently reactivated from memory, movement- and immobility-associated activity patterns are most often reactivated separately. Concurrently, distinct hippocampal reactivations of movement- or immobility-associated representations are accompanied by distinct modulation patterns in prefrontal cortex. These findings demonstrate a continuous representation of ongoing experience can be separated into independently reactivated memory representations.

Memory for temporally dynamic scenes

Recognition memory was investigated for individual frames extracted from temporally continuous, visually rich film segments of 5–15 min. Participants viewed a short clip from a film in either a coherent or a jumbled order, followed by a recognition test of studied frames. Foils came either from an earlier or a later part of the film (Experiment 1) or from deleted segments selected from random cuts of varying duration (0.5 to 30 s) within the film itself (Experiment 2). When the foils came from an earlier or later part of the film (Experiment 1), recognition was excellent, with the hit rate far exceeding the false-alarm rate (.78 vs. 18). In Experiment 2, recognition was far worse, with the hit rate (.76) exceeding the false-alarm rate only for foils drawn from the longest cuts (15 and 30 s) and matching the false-alarm rate for the 5 s segments. When the foils were drawn from the briefest cuts (0.5 and 1.0 s), the false-alarm rate exceeded the hit rate. Unexpectedly, jumbling had no effect on recognition in either experiment. These results are consistent with the view that memory for complex visually temporal events is excellent, with the integrity unperturbed by disruption of the global structure of the visual stream. Disruption of memory was observed only when foils were drawn from embedded segments of duration less than 5 s, an outcome consistent with the view that memory at these shortest durations are consolidated with expectations drawn from the previous stream.

Gesture as representational action: A paper about function

A great deal of attention has recently been paid to gesture and its effects on thinking and learning. It is well established that the hand movements that accompany speech are an integral part of communication, ubiquitous across cultures, and a unique feature of human behavior. In an attempt to understand this intriguing phenomenon, researchers have focused on pinpointing the mechanisms that underlie gesture production. One proposal--that gesture arises from simulated action (Hostetter & Alibali Psychonomic Bulletin & Review, 15, 495-514, 2008)--has opened up discussions about action, gesture, and the relation between the two. However, there is another side to understanding a phenomenon and that is to understand its function. A phenomenon's function is its purpose rather than its precipitating cause--the why rather than the how. This paper sets forth a theoretical framework for exploring why gesture serves the functions that it does, and reviews where the current literature fits, and fails to fit, this proposal. Our framework proposes that whether or not gesture is simulated action in terms of its mechanism--it is clearly not reducible to action in terms of its function. Most notably, because gestures are abstracted representations and are not actions tied to particular events and objects, they can play a powerful role in thinking and learning beyond the particular, specifically, in supporting generalization and transfer of knowledge.

Event perception: Translations and applications

Event segmentation is the parsing of ongoing activity into meaningful events. Segmenting in a normative fashion-identifying event boundaries similar to others' boundaries-is associated with better memory for and better performance of naturalistic actions. Given this, a reasonable hypothesis is that interventions that improve memory and attention for everyday events could lead to improvement in domains that are important for independent living, particularly in older populations. Event segmentation and memory measures may also be effective diagnostic tools for estimating people's ability to carry out tasks of daily living. Such measures preserve the rich, naturalistic character of everyday activity, but are easy to quantify in a laboratory or clinical setting. Therefore, event segmentation and memory measures may be a useful proxy for clinicians to assess everyday functioning in patient populations and an appropriate target for interventions aimed at improving everyday memory and tasks of daily living.