Target detection and discrimination in pop-out visual search with two targets.

To successfully interact with objects in complex and crowded environments, we often perform visual search to detect or identify a relevant target (or targets) among distractors. Previous studies have reported a redundancy gain when two targets instead of one are presented in a simple target detection task. However, research is scant about the role of multiple targets in target discrimination tasks, especially in the context of visual search. Here, we address this question and investigate its underlying mechanisms in a pop-out search paradigm. In Experiment 1, we directly compared visual search performance for one or two targets for detection or discrimination tasks. We found that two targets led to a redundancy gain for detection, whereas it led to a redundancy cost for discrimination. To understand the basis for the redundancy cost observed in discrimination tasks for multiple targets, we further investigated the role of perceptual grouping (Experiment 2) and stimulus-response feature compatibility (Experiment 3). We determined that the strength of perceptual grouping among homogenous distractors was attenuated when two targets were present compared with one. We also found that response compatibility between two targets contributed more to the redundancy cost compared with perceptual compatibility. Taken together, our results show how pop-out search involving two targets is modulated by the level of feature processing, perceptual grouping, and compatibility of perceptual and response features.

Time perception in film is modulated by sensory modality and arousal.

Considerable research has shown that the perception of time can be distorted subjectively, but little empirical work has examined what factors affect time perception in film, a naturalistic multimodal stimulus. Here, we explore the effect of sensory modality, arousal, and valence on how participants estimate durations in film. Using behavioral ratings combined with pupillometry in a within-participants design, we analyzed responses to and duration estimates of film clips in three experimental conditions: audiovisual (containing music and sound effects), visual (without music and sound effects), and auditory (music and sound effects without a visual scene). Participants viewed clips from little-known nature documentaries, fiction, animation, and experimental films. They were asked to judge clip duration and to report subjective arousal and valence, as their pupil sizes were recorded. Data were analyzed using linear mixed-effects models. Results reveal duration estimates varied between experimental conditions. Clip durations were judged to be shorter than actual durations in all three conditions, with visual-only clips perceived as longer (i.e., less distorted in time) than auditory-only and audiovisual clips. High levels of Composite Arousal (an average of self-reported arousal and pupil size changes) were correlated with longer (more accurate) estimates of duration, particularly in the audiovisual modality. This effect may reflect stimulus complexity or greater cognitive engagement. Increased ratings of valence were correlated with longer estimates of duration. The use of naturalistic, complex stimuli such as film can enhance our understanding of the psychology of time perception.

Transsaccadic integration of visual information is predictive, attention-based, and spatially precise.

Eye movements produce shifts in the positions of objects in the retinal image, but observers are able to integrate these shifting retinal images into a coherent representation of visual space. This ability is thought to be mediated by attention-dependent saccade-related neural activity that is used by the visual system to anticipate the retinal consequences of impending eye movements. Previous investigations of the perceptual consequences of this predictive activity typically infer attentional allocation using indirect measures such as accuracy or reaction time. Here, we investigated the perceptual consequences of saccades using an objective measure of attentional allocation, reverse correlation. Human observers executed a saccade while monitoring a flickering target object flanked by flickering distractors and reported whether the average luminance of the target was lighter or darker than the background. Successful task performance required subjects to integrate visual information across the saccade. A reverse correlation analysis yielded a spatiotemporal "psychophysical kernel" characterizing how different parts of the stimulus contributed to the luminance decision throughout each trial. Just before the saccade, observers integrated luminance information from a distractor located at the post-saccadic retinal position of the target, indicating a predictive perceptual updating of the target. Observers did not integrate information from distractors placed in alternative locations, even when they were nearer to the target object. We also observed simultaneous predictive perceptual updating for two spatially distinct targets. These findings suggest both that shifting neural representations mediate the coherent representation of visual space, and that these shifts have significant consequences for transsaccadic perception.

A Combined Alcohol and Smoking Cue-Reactivity Paradigm in People Who Drink Heavily and Smoke Cigarettes: Preliminary Findings.

AIMS: Previous studies have shown that there may be an underlying mechanism that is common for co-use of alcohol and tobacco and it has been shown that treatment for alcohol use disorder can increase rates of smoking cessation. The primary aim of this study was to assess a novel methodological approach to test a simultaneous behavioral alcohol-smoking cue reactivity (CR) paradigm in people who drink alcohol and smoke cigarettes. METHODS: This was a human laboratory study that utilized a novel laboratory procedure with individuals who drink heavily (≥15 drinks/week for men; ≥8 drinks/week for women) and smoke (>5 cigarettes/day). Participants completed a CR in a bar laboratory and an eye-tracking (ET) session using their preferred alcohol beverage, cigarettes brand and water. RESULTS: In both the CR and ET session, there was a difference in time spent interacting with alcohol and cigarettes as compared to water (P's < 0.001), but no difference in time spent interacting between alcohol and cigarettes (P > 0.05). In the CR sessions, craving for cigarettes was significantly greater than craving for alcohol (P < 0.001), however, only time spent with alcohol, but not with cigarettes, was correlated with craving for both alcohol and cigarettes (P < 0.05). CONCLUSION: This study showed that it is feasible to use simultaneous cues during a CR procedure in a bar laboratory paradigm. The attention bias measured in the integrated alcohol-cigarettes ET procedure predicted participants' decision making in the CR. This novel methodological approach revealed that in people who drink heavily and smoke, alcohol cues may affect craving for both alcohol and cigarettes.