Hsin-I Liao

On the generality of the contingent orienting hypothesis.

The contingent-orienting hypothesis states that attentional capture by a task-irrelevant stimulus is contingent on whether that stimulus shares a feature property that is critical to the task at hand [Folk, C. L., Remington, R. W., & Johnston, J. C. (1992). Involuntary covert orienting is contingent on attentional control settings. Journal of Experimental Psychology: Human Perception and Performance, 18, 1030-1044]. Studies supporting this hypothesis have mostly used set size four displays throughout the experiment and thus constrict its ecological validity, since conclusions drawn from experiments using fixed set-size displays may not be generalized to other conditions with different set sizes. We used a spatial cueing paradigm in which a non-informative onset or color cue preceded an onset or a color target, and manipulated set size as a within- or between-subject factor. In four experiments, the original finding of Folk et al. (1992) was replicated only when a fixed set size (four) was used throughout. When both set-size four and eight were used in an experiment, stimulus-driven capture by onset in search of a color target was found even for set-size four displays. These results raise doubts as to the generality of the contingent-orienting hypothesis and help to delineate the boundary conditions on this hypothesis.

Novelty vs. Familiarity Principles in Preference Decisions: Task-Context of Past Experience Matters

Our preferences are shaped by past experience in many ways, but a systematic understanding of the factors is yet to be achieved. For example, studies of the mere exposure effect show that experience with an item leads to increased liking (familiarity preference), but the exact opposite tendency is found in other studies utilizing dishabituation (novelty preference). Recently, it has been found that image category affects whether familiarity or novelty preference emerges from repeated stimulus exposure (Park et al., 2010). Faces elicited familiarity preference, but natural scenes elicited novelty preference. In their task, preference judgments were made throughout all exposures, raising the question of whether the task-context during exposure was involved. We adapt their paradigm, testing if passive exposure or objective judgment task-contexts lead to different results. Results showed that after passive viewing, familiar faces were preferred, but no preference bias in either direction was found with natural scenes, or with geometric figures (control). After exposure during the objective judgment task, familiar faces were preferred, novel natural scenes were preferred, and no preference bias was found with geometric figures. The overall results replicate the segregation of preference biases across object categories and suggest that the preference for familiar faces and novel natural scenes are modulated by task-context memory at different processing levels or selection involvement. Possible underlying mechanisms of the two types of preferences are discussed.

Interaction between stimulus-driven orienting and top-down modulation in attentional capture

The issue whether attentional capture is determined by top-down factors or can be stimulus-driven remains unsolved. To examine this, we used a spatial cueing paradigm with set size four and eight in which a color target is preceded by an uninformative cue (color or onset) that either matches or does not match the target-defining feature. The critical manipulation lies in adding no-cue trials to make the subsequent first with-cue trial unexpected, which reveals the stimulus-driven component. For the onset cue, the first-trial analysis indicated attentional capture at set size four and eight, whereas results from the average data indicated attentional capture at set size eight but not at set size four. For the color cue, attentional capture was found in the average data but not in the first trial, regardless of set size. These results can be explained by the interactive processing of early stimulus-driven activation followed by top-down modulation.

On the generality of the displaywide contingent orienting hypothesis: Can a visual onset capture attention without top-down control settings for displaywide onset?

The contingent orienting hypothesis (Folk, Remington, & Johnston, 1992) states that attentional capture is contingent on top-down control settings induced by task demands. Past studies supporting this hypothesis have identified three kinds of top-down control settings: for target-specific features, for the strategy to search for a singleton, and for visual features in the target display as a whole. Previously, we have found stimulus-driven capture by onset that was not contingent on the first two kinds of settings (Yeh & Liao, 2008). The current study aims to test the third kind: the displaywide contingent orienting hypothesis (Gibson & Kelsey, 1998). Specifically, we ask whether an onset stimulus can still capture attention in the spatial cueing paradigm when attentional control settings for the displaywide onset of the target are excluded by making all letters in the target display emerge from placeholders. Results show that a preceding uninformative onset cue still captured attention to its location in a stimulus-driven fashion, whereas a color cue captured attention only when it was contingent on the setting for displaywide color. These results raise doubts as to the generality of the displaywide contingent orienting hypothesis and help delineate the boundary conditions on this hypothesis.

Capturing attention is not that simple: Different mechanisms for stimulus-driven and contingent capture

Attentional orienting can be involuntarily directed to task-irrelevant stimuli, but it remains unsolved whether such attentional capture is contingent on top-down settings or could be purely stimulus-driven. We propose that attentional capture depends on the stimulus property because transient and static features are processed differently; thus, they might be modulated differently by top-down controls. To test this hybrid account, we adopted a spatial cuing paradigm in which a noninformative onset or color cue preceded an onset or color target with various stimulus onset asynchronies (SOAs). Results showed that the onset cue captured attention regardless of target type at short—but not long—SOAs. In contrast, the color cue captured attention at short and long SOAs, but only with a color target. The overall pattern of results corroborates our hypothesis, suggesting that different mechanisms are at work for stimulus-driven capture (by onset) and contingent capture (by color). Stimulus-driven capture elicits reflexive involuntary orienting, and contingent capture elicits voluntary feature-based enhancement.

Directing visual attention by subliminal cues

Unconscious attention shift has been proven to be automatic, effortless, and unresisting; however, whether it is applicable to images of complex scene remains to be verified. We propose a novel method for directing human visual attention by flashing a short-duration visual stimulus before presenting the image. This method directs viewers visual attention to an arbitrary location in the image without engaging the viewers awareness. Unlike previous studies using simple stimuli (e.g. simple geometric figures, image of uniform color, or artificial white-noise), we use complex color images for guiding unconscious visual attention in real-world. To our best knowledge, this is the first study demonstrating that short-duration cues presented at arbitrary locations can attract human visual attention in a complex scene. The proposed method is useful for applications that require efficient and unresisting attention shift to the target image area.

Dynamic Preference Formation via Gaze and Memory

Publisher Summary This chapter discusses how preference decision-making is a dynamic process spreading over several seconds. During the process, active inspection itself contributes to preference decision formation. It remains unclear how memory affects gaze/orienting and further affects preference. For novelty preference, gaze is biased towards novel pictures initially and later towards a chosen picture with shallower accumulation. However, for familiarity preference, the gaze bias towards a chosen picture grows with the steeper accumulation. The initial gaze predicts the preference decision in different object categories through different processes, which interacts with choice types. The preference decision in natural scenes can be predicted by initial gaze location. Considering that the initial gaze is biased toward novel natural scenes. This initial gaze bias may trigger the positive loop of gaze and preference and then lead to a final novelty preference decision. Preference decision-making is a dynamic process spreading over several seconds. During the process, active inspection itself contributes to preference decision formation.

Local Dimming of Liquid Crystal Display Using Visual Attention Prediction Model

Local dimming of the LED backlight is a popular technique for saving the power of a liquid crystal display. This paper presents a novel approach that improves the performance of conventional local dimming algorithms by incorporating a visual attention prediction model in the backlight dimming process. The approach saves the energy of the liquid crystal display and, in the mean time, maintains the perceptual image quality. This is achieved by preserving the backlight luminance of the image areas that attract human attention while reducing that of the other image areas. Experimental results are provided to show the effectiveness of the proposed approach.

Happy Faces Are Preferred Regardless of Familiarity—Sad Faces Are Preferred Only When Familiar

Familiarity leads to preference (e.g., the mere exposure effect), yet it remains unknown whether it is objective familiarity, that is, repetitive exposure, or subjective familiarity that contributes to preference. In addition, it is unexplored whether and how different emotions influence familiarity-related preference. The authors investigated whether happy or sad faces are preferred or perceived as more familiar and whether this subjective familiarity judgment correlates with preference for different emotional faces. An emotional face--happy or sad--was paired with a neutral face, and participants rated the relative preference and familiarity of each of the paired faces. For preference judgment, happy faces were preferred and sad faces were less preferred, compared with neutral faces. For familiarity judgment, happy faces did not show any bias, but sad faces were perceived as less familiar than neutral faces. Item-by-item correlational analyses show preference for sad faces--but not happy faces--positively correlate with familiarity. These results suggest a direct link between positive emotion and preference, and argue at least partly against a common cause for familiarity and preference. Instead, facial expression of different emotional valence modulates the link between familiarity and preference.

Involuntary Orienting Caused by Salient Stimuli Outside Focal Attention: Comparison of Two Paradigms

A peripheral red distractor hampers central target identification when the target is defined by red (Folk, Leber, & Egeth, 2002). On the other hand, a peripheral onset distractor fails to affect task performance when the target location is pre-cued by a 100%-valid central cue (Theeuwes, 1991; Yantis & Jonides, 1990). Different paradigms were used in these two sets of studies (RSVP in the former and spatial cueing in the later studies) and this may affect the deployment of attention and the results differently. We asked the participants to search for a red target as in Folk et al. (2002) and compared attentional capture by red distractor (i.e., contingent on the target-defining feature) and onset distractor (i.e., not contingent on the target-defining feature), using the RSVP paradigm (Experiment 1) and the spatial cueing paradigm (Experiment 2 and 3). Results showed that, regardless of which paradigm is used, attentional capture occurs only by the red distractor but not by the onset distractor, suggesting that the different results obtained in previous studies were not caused by different paradigms used. Outside focal attention a salient stimulus that is contingent on the target-defining feature has the highest possibility to capture attention.