Interrupting infants’ persisting object representations: an object‐based limit?

Making sense of the visual world requires keeping track of objects as the same persisting individuals over time and occlusion. Here we implement a new paradigm using 10-month-old infants to explore the processes and representations that support this ability in two ways. First, we demonstrate that persisting object representations can be maintained over brief interruptions from additional independent events - just as a memory of a traffic scene may be maintained through a brief glance in the rearview mirror. Second, we demonstrate that this ability is nevertheless subject to an object-based limit: if an interrupting event involves enough objects (carefully controlling for overall salience), then it will impair the maintenance of other persisting object representations even though it is an independent event. These experiments demonstrate how object representations can be studied via their 'interruptibility', and the results are consistent with the idea that infants' persisting object representations are constructed and maintained by capacity-limited mid-level 'object-files'.     

The persistence of object file representations

Coherent visual experience of dynamic scenes requires not only that the visual system segment scenes into component objects but that these object representations persist, so that an object can be identified as the same object from an earlier time. Object files (OFs) are visual representations thought to mediate such abilities: OFs lie between lower level sensory processing and higher level recognition, and they track salient objects over time and motion. OFs have traditionally been studied via object-specific preview benefits (OSPBs), in which discriminations of an object's features are speeded when an earlier preview of those features occurred on the same object, as opposed to on a different object, beyond general displaywide priming. Despite its popularity, many fundamental aspects of the OF framework remain unexplored. For example, although OFs are thought to be involved primarily in online visual processing, we do not know how long such representations persist; previous studies found OSPBs for up to 1500 msec but did not test for longer durations. We explored this issue using a modified object reviewing paradigm and found that robust OSPBs persist for more than five times longer than has previously been tested-for at least 8 sec, and possibly for much longer. Object files may be the "glue" that makes visual experience coherent not just in online moment-by-moment processing, but on the scale of seconds that characterizes our everyday perceptual experiences. These findings also bear on research in infant cognition, where OFs are thought to explain infants' abilities to track and enumerate small sets of objects over longer durations.     

Social risk and protective factors for suicide attempts in low income African American men and women

A case-control study was conducted to examine a broad array of potential social risk and protective factors for suicide attempt among 200 African American men and women receiving care at a large, public, urban hospital. Specifically, we examined the effect of the following potential risk factors for suicide attempt: life hassles, partner abuse, partner dissatisfaction, and racist events; as well as the following potential protective factors: effectiveness of obtaining resources, social embeddedness, and social support. Using logistic regression, suicide attempter status was predicted by two independently significant social variables: one risk factor (life hassles) and one protective factor (social support). Male versus female suicide attempters were not distinguished by the social variables. These findings, which support the utility of an ecological conceptualization of risk and protective factors for suicide attempt, help to clarify the independently significant social environment risk and protective factors for suicide attempts among economically disadvantaged African Americans in particular. Research on both risk factors and protective factors provide a basis for culturally competent interventions aimed at reducing both the risk of future suicide attempts and completions.     

How is spatial context learning integrated over signal versus noise? A primacy effect in contextual cueing

Over repeated exposure to particular visual search displays, subjects are able to implicitly extract regularities that then make search more efficient-a phenomenon known as contextual cueing. Here we explore how the learning involved in contextual cueing is formed, maintained, and updated over experience. During an initial training phase, a group of signal first subjects searched through a series of predictive displays (where distractor locations were perfectly correlated with the target location), followed with no overt break by a series of unpredictive displays (where repeated contexts were uncorrelated with target locations). A second noise first group of subjects encountered the unpredictive displays followed by the predictive displays. Despite the fact that both groups had the same overall exposure to signal and noise, only the signal first group demonstrated subsequent contextual cueing. This primacy effect indicates that initial experience can result in hypotheses about regularities in displays-or the lack thereof-which then become resistant to updating. The absence of regularities in early stages of training even blocked observers from learning predictive regularities later on.     

Object files can be purely episodic

Our ability to track an object as the same persisting entity over time and motion may primarily rely on spatiotemporal representations which encode some, but not all, of an object's features. Previous researchers using the 'object reviewing' paradigm have demonstrated that such representations can store featural information of well-learned stimuli such as letters and words at a highly abstract level. However, it is unknown whether these representations can also store purely episodic information (i.e. information obtained from a single, novel encounter) that does not correspond to pre-existing type-representations in long-term memory. Here, in an object-reviewing experiment with novel face images as stimuli, observers still produced reliable object-specific preview benefits in dynamic displays: a preview of a novel face on a specific object speeded the recognition of that particular face at a later point when it appeared again on the same object compared to when it reappeared on a different object (beyond display-wide priming), even when all objects moved to new positions in the intervening delay. This case study demonstrates that the mid-level visual representations which keep track of persisting identity over time--e.g. 'object files', in one popular framework can store not only abstract types from long-term memory, but also specific tokens from online visual experience.     

Beauty or function? How different mass customization toolkits affect customers' process enjoyment

Although it is widely acknowledged that mass customization (MC) increases both company and customer value, the research has neglected the possible effects of different MC toolkits on customer responses. In this study, we investigate the influence of different MC toolkits on customers' process enjoyment by manipulating the extent to which those toolkits allow customers to customize a product's functional attributes (functional MC toolkits), aesthetic attributes (aesthetic MC toolkits), or both (supreme toolkits). In addition, we examine the moderating effect of customers' ability to customize. The results of two experimental studies show that regardless of their ability to customize, customers' process enjoyment is higher with an aesthetic MC toolkit than with a functional MC toolkit. For customers with a high ability to customize, process enjoyment with a supreme toolkit is higher than process enjoyment with an aesthetic toolkit, whereas no differences exist for customers with a low ability to customize. This research contributes significantly to the existing literature on mass customization and provides managers with insights on how to more effectively develop and implement MC toolkits. Copyright © 2015 John Wiley & Sons, Ltd.     

Self-affirmation moderates effects of unrealistic optimism and pessimism on reactions to tailored risk feedback

We examined whether self-affirmation would facilitate intentions to engage in colorectal cancer (CRC) screening among individuals who were off-schedule for CRC screening and who were categorised as unrealistically optimistic, realistic or unrealistically pessimistic about their CRC risk. All participants received tailored risk feedback; in addition, one group received threatening social comparison information regarding their risk factors, a second received this information after a self-affirmation exercise and a third was a no-treatment control. When participants were unrealistically optimistic about their CRC risk (determined by comparing their perceived comparative risk to calculations from a risk algorithm), they expressed greater interest in screening if they were self-affirmed (relative to controls). Non-affirmed unrealistic optimists expressed lower interest relative to controls, suggesting that they were responding defensively. Realistic participants and unrealistically pessimistic participants who were self-affirmed expressed relatively less interest in CRC screening, suggesting that self-affirmation can be helpful or hurtful depending on the accuracy of one's risk perceptions.     

Attenuated Change Blindness for Exogenously Attended Items in a Flicker Paradigm

When two scenes are alternately displayed, separated by a mask, even large, repeated changes between the scenes often go unnoticed for surprisingly long durations. Change blindness of this sort is attenuated at “centres of interest” in the scenes, however, supporting a theory of change blindness in which attention is necessary to perceive such changes (Rensink, O'Regan, & Clark, 1997). Problems with this measure of attentional selection - via verbally described “centres of interest” - are discussed, including worries about describability and explanatory impotence. Other forms of attentional selection, not subject to these problems, are employed in a “flicker” experiment to test the attention-based theory of change detection. Attenuated change blindness is observed at attended items when attentional selection is realized via involuntary exogenous capture of visual attention - to late-onset items and colour singletons - even when these manipulations are uncorrelated with the loci of the changes, and are thus irrelevant to the change detection task. These demonstrations ground the attention-based theory of change blindness in a type of attentional selection which is understood more rigorously than are “centres of interest”. At the same time, these results have important implications concerning the nature of exogenous attentional capture.     

Are objects required for object-files? Roles of segmentation and spatiotemporal continuity in computing object persistence

Two central tasks of visual processing are (1) to segment undifferentiated retinal images into discrete objects, and (2) to represent those objects as the same persisting individuals over time and motion. Here we explore the interaction of these two types of processing in the context of object files—mid-level visual representations that “stick” to moving objects on the basis of spatiotemporal properties. Object files can be revealed by object-specific preview benefits (OSPBs), wherein a “preview” of information on a moving object speeds the recognition of that information at a later point when it appears again on the same object (compared to when it reappears on a different moving object), beyond display-wide priming. Here we explore the degree of segmentation required to establish object files in the first place. Surprisingly, we find that no explicit segmentation is required until after the previews disappear, when using purely motion-defined objects (consisting of random elements on a random background). Moreover, OSPBs are observed in such displays even after moderate (but not long) delays between the offset of the preview information and the onset of the motion. These effects indicate that object files can be established without initial static segmentation cues, so long as there is spatiotemporal continuity between the previews and the eventual appearance of the objects. We also find that top-down strategies can sometimes mimic OSPBs, but that these strategies can be eliminated by novel manipulations. We discuss how these results alter our understanding of the nature of object files, and also why researchers must take care to distinguish “true OSPBs” from “illusory OSPBs”.     

The role of eye fixations in concentration and amplification effects during multiple object tracking

When tracking spatially extended objects in a multiple object tracking task, attention is preferentially directed to the centres of those objects (attentional concentration), and this effect becomes more pronounced as object length increases (attentional amplification). However, it is unclear whether these effects depend on differences in attentional allocation or differences in eye fixations. We addressed this question by measuring eye fixations in a dual-task paradigm that required participants to track spatially extended objects, while simultaneously detecting probes that appeared at the centres or near the endpoints of objects. Consistent with previous research, we observed concentration and amplification effects: Probes at the centres of objects were detected more readily than those near their endpoints, and this difference increased with object length. Critically, attentional concentration was observed when probes were equated for distance from fixation during free viewing, and concentration and amplification were observed without eye movements during strict fixation. We conclude that these effects reflect the prioritization of covert attention to particular spatial regions within extended objects, and we discuss the role of eye fixations during multiple object tracking.