Fluent event processing involves segmenting streaming sensory information into discrete units. Adults and childrenselectively attend to these meaningful moments within event streams, which predicts later memory. In natural environments,however, uninterrupted attention is unlikely. Consequently, some information is missed, including event boundary information.To what extent does missing information alter the attentional dynamics of processing, specifically viewers’ ability to targetremaining boundaries with enhanced attention? Adults advanced at their own pace through slideshows of unfolding activity.Slides were systematically deleted to enable comparison of viewers’ attentional dynamics when specific content was presentversus absent. Average dwelling per slide increased with missing content. However, the attentional dynamics of processingwere unaltered; attention to boundaries displayed comparable enhancement regardless of missing content. Attention modulationduring processing of relatively familiar events appears to be highly robust to missing information. What occurs with more novelevents is an interesting question for future research.

A fundamental aspect of everyday processing involves identifying discrete events within continuously unfoldingsensory experience. However, the processes enabling determination of event boundaries remain poorly understood. Recently,inconsistent conclusions have emerged regarding attentional processes associated with detection of event boundaries. Use ofthe Dwell-Time Paradigm has indicated enhanced attention at event boundaries (e.g., Hard, Recchia, & Tversky, 2011), whereasevidence from the Rapid Serial Visual Presentation paradigm (e.g., Huff, Papenmeier, & Zacks, 2012) indicates impairment.We employed a change-detection procedure similar to the RSVP, except that the change to be detected was uniform across theentire visual field, rather than varying with respect to the viewer’s spatial locus of attention. Changes occurred either at eventboundaries or mid-stream within event segments. With spatial locus of attention rendered irrelevant, participants displayedsignificantly faster reaction time to changes coinciding with event boundaries, implying that viewers selectively target eventboundaries with heightened attention.

Human activity generates dynamic, multi-modal sensorystreams. Effectively processing this complex flow ofinformation on-the-fly is essential if one is to remember andrespond to others’ action, anticipate what they might do next,and learn how to perform new actions. Selectively attending toinformation-rich regions of activity seems key to fluentprocessing. However, what counts as information-rich likelydepends on numerous factors including relevance to the causalstructure of the activity, local opportunity for repeated viewing,and processing goals of the observer. We explored theinfluence of these factors on observers’ attention to a dynamic,novel activity sequence. A performance context elicitednuanced differences in processing in contrast to a remembercontext. Specifically, individuals given a perform contexttuned in to causally distinct regions of the action stream andfine-level event details. These findings provide altogether newinformation regarding how processing rapidly reorganizesaround novel activity and responds to the processing task athand.

Fluent event processing appears to critically involveselectively attending to information-rich junctures withincontinuously unfolding sensory streams (e.g., Newtson, 1973).What counts as information-rich would seem to depend on avariety of factors, however, including the novelty/familiarityof such events, as well as local opportunity for repeatedviewings. Using Hard, Recchia, & Tversky’s “Dwell-timeParadigm,” we investigated the extent to which viewers’attention to unfolding activity streams is affected bynovelty/familiarity and a second viewing. Viewers’ dwelltimes were recorded as they advanced twice each through threeslideshows varying in familiarity but equated on otherdimensions. Dwell time patterns revealed reorganization on anumber of fronts: a) familiarity elicited decreased dwellingoverall, b) dwell-time patterns changed systematically onsecond viewing, and c) familiarity modulated the specificnature of change associated with repeated viewing. Thesefindings illuminate reorganization in attention as actioninformation is first encountered and then quickly incorporatedto guide event processing.

How might ADHD symptomatology influence adults’ ability to process and recall the actions of others? Universityundergraduates observed a woman packing a suitcase by advancing through a self-paced slide show of still images extractedfrom a digital video, and were then asked to recall as many actions as possible. Results showed that lower self-reported retro-spective ADHD symptomatology was associated with a) longer overall dwelling on images from the slideshow, r(91) = -.315,p=.002, and b) recall of more actions r(85) = -.237, p=01. Further, exploratory analyses indicated that ADHD symptomatologymodulated the specific linkage between dwell time patterns and stronger recall: Attention to fine-grain details within activityimproved recall for those reporting higher ADHD symptomatology; those reporting lower ADHD symptomatology displayedstronger recall when prioritizing attention at a more coarse-grain level, F(1,83) = 4.19, p=.04. These findings offer suggestivenovel evidence that ADHD has implications for event processing.