Nudge and bias in subjective ratings? The role of icon sets in determining ratings of icon characteristics.

Subjective ratings have been central to the evaluation of icon characteristics. The current study examined biases in ratings in relation to the context in which icons are presented. Context was manipulated between participants, with some groups rating icon sets with limited variability, and others rating icon sets with wide variability. It was predicted that the context created by the icon set would influence participants' ratings; when the range of icons was limited, this would create bias given participants' expectation that a full range of icon values was being presented. Six key icon characteristics were rated, which were visual (visual complexity, appeal), affective (valence, feelings), and semantic (concreteness, semantic distance). Some icon characteristics were susceptible to rating bias while others were not. Where subjective judgements were being made of visual icon characteristics (appeal/complexity) and highly concrete icons which were very pictorial, there was clear evidence of substantial bias in ratings. The same susceptibility to bias was not evident when ratings relied solely on learned semantic associations or were associated with the emotional attributions made to icons. The dynamic nature of the ratings bias was demonstrated when the rating context was changed without participants' knowledge. When participants rated further blocks of icons providing a different range of the to-be-rated characteristic, this resulted in rapid and dramatic changes in rating behaviour. These findings demonstrate the need for representative sampling of icon characteristics to avoid ratings bias. Practically, this is important when determining the usability of newly designed icon sets in order to avoid over-valuing or under-valuing of key characteristics.

Aesthetic appeal influences visual search performance.

Aesthetic appeal of a visual image can influence performance in time-critical tasks, even if it is irrelevant to the task. This series of experiments examined whether aesthetic appeal can act as an object attribute that guides visual search. If appeal enhances the salience of the targets pre-attentively, then appealing icons would lead to more efficient searches than unappealing targets and, conversely, appeal of distractors would reduce search efficiency. Three experiments (N = 112) examined how aesthetic appeal influences performance in a classic visual search task. In each experiment, participants completed 320 visual search trials, with icons varying in rated aesthetic appeal and either visual complexity (Experiments 1 and 2) of concreteness (Experiment 3) among two, four, eight, or 11 distractor icons. While target appeal did not influence search efficiency it sped up search times in all three experiments: appealing targets led to faster response time (RT) than unappealing targets across all experiments, and compared to neutral distractors, appealing distractors slowed search RT down. These findings are the first to show that an object's aesthetic appeal influences visual search performance.

Mood moderates the effect of aesthetic appeal on performance.

Aesthetically appealing stimuli can improve performance in demanding target localisation tasks compared to unappealing stimuli. Two search-and-localisation experiments were carried out to examine the possible underlying mechanism mediating the effects of appeal on performance. Participants (N = 95) were put in a positive or negative mood prior to carrying out a visual target localisation task with appealing and unappealing targets. In both experiments, positive mood initially led to faster localisation of appealing compared to unappealing stimuli, while an advantage for appealing over unappealing stimuli emerged over time in negative mood participants. The findings are compatible with the idea that appealing stimuli may be inherently rewarding, with aesthetic appeal overcoming the detrimental effects of negative mood on performance.

The relative contribution of shape and colour to object memory.

The current studies examined the relative contribution of shape and colour in object representations in memory. A great deal of evidence points to the significance of shape in object recognition, with the role of colour being instrumental under certain circumstances. A key but yet unanswered question concerns the contribution of colour relative to shape in mediating retrieval of object representations from memory. Two experiments (N=80) used a new method to probe episodic memory for objects and revealed the relative contribution of colour and shape in recognition memory. Participants viewed pictures of objects from different categories, presented one at a time. During a practice phase, participants performed yes/no recognition with some of the studied objects and their distractors. Unpractised objects shared shape only (Rp-Shape), colour only (Rp-Colour), shape and colour (Rp-Both), or neither shape nor colour (Rp-Neither), with the practised objects. Interference effects in memory between practised and unpractised items were revealed in the forgetting of related unpractised items - retrieval-induced forgetting. Retrieval-induced forgetting was consistently significant for Rp-Shape and Rp-Colour objects. These findings provide converging evidence that colour is an automatically encoded object property, and present new evidence that both shape and colour act simultaneously and effectively to drive retrieval of objects from long-term memory.

Surface diagnosticity predicts the high-level representation of regular and irregular object shape in human vision.

The human visual system has an extraordinary capacity to compute three-dimensional (3D) shape structure for both geometrically regular and irregular objects. The goal of this study was to shed new light on the underlying representational structures that support this ability. Observers (N = 85) completed two complementary perceptual tasks. Experiment 1 involved whole-part matching of image parts to whole geometrically regular and irregular novel object shapes. Image parts comprised either regions of edge contour, volumetric parts, or surfaces. Performance was better for irregular than for regular objects and interacted with part type: volumes yielded better matching performance than surfaces for regular but not for irregular objects. The basis for this effect was further explored in Experiment 2, which used implicit part-whole repetition priming. Here, we orthogonally manipulated shape regularity and a new factor of surface diagnosticity (how predictive a single surface is of object identity). The results showed that surface diagnosticity, not object shape regularity, determined the differential processing of volumes and surfaces. Regardless of shape regularity, objects with low surface diagnosticity were better primed by volumes than by surfaces. In contrast, objects with high surface diagnosticity showed the opposite pattern. These findings are the first to show that surface diagnosticity plays a fundamental role in object recognition. We propose that surface-based shape primitives-rather than volumetric parts-underlie the derivation of 3D object shape in human vision.

What makes icons appealing? The role of processing fluency in predicting icon appeal in different task contexts.

Although icons appear on almost all interfaces, there is a paucity of research examining the determinants of icon appeal. The experiments reported here examined the icon characteristics determining appeal and the extent to which processing fluency - the subjective ease with which individuals process information - was used as a heuristic to guide appeal evaluations. Participants searched for, and identified, icons in displays. The initial appeal of icons was held constant while ease of processing was manipulated by systematically varying the complexity and familiarity of the icons presented and the type of task participants were asked to carry out. Processing fluency reliably influenced users' appeal ratings and appeared to be based on users' unconscious awareness of the ease with which they carried out experimental tasks.

The role of surface-based representations of shape in visual object recognition.

This study contrasted the role of surfaces and volumetric shape primitives in three-dimensional object recognition. Observers (N = 50) matched subsets of closed contour fragments, surfaces, or volumetric parts to whole novel objects during a whole-part matching task. Three factors were further manipulated: part viewpoint (either same or different between component parts and whole objects), surface occlusion (comparison parts contained either visible surfaces only, or a surface that was fully or partially occluded in the whole object), and target-distractor similarity. Similarity was varied in terms of systematic variation in nonaccidental (NAP) or metric (MP) properties of individual parts. Analysis of sensitivity (d') showed a whole-part matching advantage for surface-based parts and volumes over closed contour fragments--but no benefit for volumetric parts over surfaces. We also found a performance cost in matching volumetric parts to wholes when the volumes showed surfaces that were occluded in the whole object. The same pattern was found for both same and different viewpoints, and regardless of target-distractor similarity. These findings challenge models in which recognition is mediated by volumetric part-based shape representations. Instead, we argue that the results are consistent with a surface-based model of high-level shape representation for recognition.

When the going gets tough the beautiful get going: aesthetic appeal facilitates task performance.

The current studies examined the effect of aesthetic appeal on performance. According to one hypothesis, appeal would lead to overall decrements or enhancements in performance [e.g. Sonderegger & Sauer, (Applied Ergonomics, 41, 403-410, 2010)]. Alternatively, appeal might influence performance only in problem situations, such as when the task is difficult [e.g. Norman, (2004)]. The predictions of these hypotheses were examined in the context of an icon search-and-localisation task. Icons were used because they are well-defined stimuli and pervasive to modern everyday life. When search was made difficult using visually complex stimuli (Experiment 1), or abstract and unfamiliar stimuli (Experiment 2), icons that were appealing were found more quickly than their unappealing counterparts. These findings show that in a low-level visual processing task, with demand characteristics related to appeal eliminated, appeal can influence performance, especially under duress.

The fickle nature of similarity change as a result of categorization.

Several researchers have reported that learning a particular categorization leads to compatible changes in the similarity structure of the categorized stimuli. The purpose of this study is to examine whether different category structures may lead to greater or less corresponding similarity change. We created six category structures and examined changes in similarity within categories or between categories, as a result of categorization, in between-participant conditions. The best supported hypothesis was that the ease of learning a categorization affects change in within-categories similarity, so that greater (within-categories) similarity change was observed for category structures that were harder to learn.

The representation of response effector and response location in episodic memory for newly acquired actions: evidence from retrieval-induced forgetting.

Information retrieval can cause forgetting for related but non-retrieved information. Such retrieval-induced forgetting (RIF) has been previously found for semantically and episodically related information. The current study used RIF to examine whether response effector and location are encoded explicitly in action memory. Participants learned unique touchscreen responses to ten novel objects. Correct actions to each object involved left-hand or right-hand pushing of one of four possible object buttons. After learning, participants practiced two of the ten object-specific sequences. Unpracticed actions could share hand only, button only, both hand and button, or neither hand nor button, with the practiced actions. Subsequent testing showed significant RIF (in retrieval accuracy and speed measures) for actions that shared hand only, button only, or both hand and button with the practiced action. The results have implications for understanding the representations mediating episodic action memory, and for the potential of RIF as a tool for elucidating feature-based representations in this and other domains.

Informational affordances: evidence of acquired perception-action sequences for information extraction.

Visual objects can automatically prime actions allowing efficient interaction with them. The present study examined whether object perception can automatically prime actions leading to efficient information extraction. Participants in Experiment 1 learned to rotate a cube in a specific way with the end goal of efficiently revealing object-identifying information. In Experiments 2 and 3, the end goal of obtaining object-identifying information was removed, but the stimulus-response associations were preserved. Only object views associated with actions learned in the context of obtaining identifying information caused response interference and benefits in a subsequent test phase where the object was irrelevant. These results demonstrate the existence of informational affordances: perception-action sequences acquired with the goal of information extraction that are automatically primed during later exposure to the object. Perceptual priming of actions for efficient information extraction is an important component of expert performance and its use of action systems to optimally deal with the world.

Successes and failures in producing attentional object-based cueing effects.

Over 30 years of research using Posner's spatial cueing paradigm has shown that selective attention operates on representations of spatial locations, leading to space-based theories of attention. Manipulations of stimuli and methods have shown this paradigm to be sensitive to several types of object-based representations-providing evidence for theories incorporating object-based attentional selection. This paper critically evaluates the evidence demanding object-based explanations that go beyond positing spatial representations alone, with an emphasis on identifying and interpreting successes and failures in obtaining object-based cueing effects. This overview of current evidence is used to generate hypotheses regarding critical factors in the emergence and influence of object representations-their generation, strength, and maintenance-in the modulation of object-based facilitatory and inhibitory cueing effects.

How does attention spread across objects oriented in depth?

Previous evidence suggests that attention can operate on object-based representations. It is not known whether these representations encode depth information and whether object depth, if encoded, is in viewer- or object-centered coordinates. To examine these questions, we employed a spatial cuing paradigm in which one corner of a 3-D object was exogenously cued with 75% validity. By rotating the object in depth, we can determine whether validity effects are modulated by 2-D or 3-D cue-target distance and whether validity effects depend on the position of the viewer relative to the object. When the image of a 3-D object was present (Experiments 1A and 1B), validity effects were not modulated by changes in 2-D cue-target distance, and shifting attention toward the viewer led to smaller validity effects than did shifting attention away from the viewer. When there was no object in the display (Experiments 2A and 2B), validity effects increased linearly as a function of 2-D cue-target distance. These results demonstrate that attention spreads across representations of perceived objects that encode depth information and that the object's orientation in depth is encoded in viewer-centered coordinates.

Surface but not volumetric part structure mediates three-dimensional shape representation: evidence from part-whole priming.

The decomposition of three-dimensional (3-D) objects into shape primitives consisting of geometric volumes is a key proposal of some theories of object recognition. It implicitly assumes that recognition involves volumetric completion--the derivation of a three-dimensional structure that comprises inferred shape properties, such as surfaces, that are not directly visible due to self-occlusion. The goal of this study was to test this claim. In Experiment 1 participants memorized novel objects and then discriminated these from previously unseen objects. Targets were preceded by primes containing a subset of object surfaces that either matched those visible in the whole objects or that could only be inferred through volumetric completion. The results showed performance benefits through priming from visible surfaces but not from inferred surfaces. In Experiment 2, we found equivalent priming for part-primes containing two visible surfaces from the same volumetric part and for primes containing one surface from each of two volumes. These results challenge the view that 3-D object recognition is mediated by shape primitives comprising geometric volumes. Instead, the results support an alternative model that proposes that 3-D shapes are represented as a non-volumetric surface-based structural description.

Structure-based modulation of inhibition of return is triggered by object-internal but not occluding shape features.

When attention is oriented to an object it is inhibited from returning to the same object following a short delay. This inhibition-of-return (IOR) effect is modulated by an edge discontinuity presented between cue and target--an effect referred to as structure-based modulation of IOR. Here we examined two alternative accounts for the structure-based modulation effect. On one account the modulation is caused by the presence of any intervening feature between cue and target. On another account the modulation is caused by edge-bounded (i.e., closed) regions of space, on which space-based selection mechanisms operate. We presented cues and targets on unsegmented and internally or externally segmented rectangles to examine the two alternative accounts for the effect. Contrary to the predictions of the two alternative accounts, structure-based modulation of IOR was found with the internally but not with the externally segmented displays. This supports our hypothesis that object-based IOR arises from perceptually complete and internally structured object representations.

The structure of three-dimensional object representations in human vision: evidence from whole-part matching.

This article examines how the human visual system represents the shapes of 3-dimensional (3D) objects. One long-standing hypothesis is that object shapes are represented in terms of volumetric component parts and their spatial configuration. This hypothesis is examined in 3 experiments using a whole-part matching paradigm in which participants match object parts to whole novel 3D object shapes. Experiments 1 and 2, consistent with volumetric image segmentation, show that whole-part matching is faster for volumetric component parts than for either open or closed nonvolumetric regions of edge contour. However, the results of Experiment 3 show that an equivalent advantage is found for bounded regions of edge contour that correspond to object surfaces. The results are interpreted in terms of a surface-based model of 3D shape representation, which proposes edge-bounded 2-dimensional polygons as basic primitives of surface shape.

The modulation of inhibition of return by object-internal structure: implications for theories of object-based attentional selection.

Recently, Vecera, Behrmann, and McGoldrick (2000), using a divided-attention task, reported that targets are detected more accurately when they occur on the same structural part of an object, suggesting that attention can be directed toward object-internal features. We present converging evidence using the object-based inhibition of return (IOR) paradigm as an implicit measure of selection. The results show that IOR is attenuated when cues and targets appear on the same part of an object relative to when they are separated by a part boundary. These findings suggest that object-based mechanisms of selection can operate over shape representations that make explicit information about object-internal structure.