Positive contrast obtained in reacquisition following interpolation of nonreinforced or partially reinforced trials

Two experiments investigated the effects of shifting from either nonreinforcement or partial reinforcement (PRF) to continuous reinforcement conditions (CRF). In the first experiment, three groups of rats were given food reinforcement under CRF conditions in a runway followed by regular extinction trials (RE), extinction trials where Ss were delayed for 30 sec before entering the empty goal box (DE), or CRF trials where Ss were delayed for 30 sec before entering the baited goal box (DF). Then all Ss were run on the delayed reinforcement condition (DF). In the final delayed reinforcement condition, group DE ran significantly faster than group DF, reflecting positive contrast. In the second experiment, four groups of rats were trained in a runway to receive either 4% or 18% sucrose reinforcers under either PRF or CRF conditions. Then all Ss were transferred to a Skinner box and bar presses were continuously reinforced, with each S continuing to receive the same sucrose concentration as before. The former PRF Ss, regardless of the reinforcer, bar pressed at a significantly higher rate in the Skinner box than the former CRF Ss. The evidence seemed to favor the view that the effectiveness of a reinforcer is not an absolute, unchanging quantity but rather depends on the historical context in which the reinforcer occurs.     

Simple actions influence pop-out search

Recent research has revealed that a simple action (pressing a computer key) produced in response to a visual object prioritizes features of that object in subsequent visual search. The effects of simple action, however, have only been studied with search displays that required serial search. Here we explored whether simple actions have an effect when the target in visual search is always a salient singleton. Participants viewed a coloured shape at the beginning of each trial, and sometimes they acted (pressed the space bar) in response to it. In the subsequent search task, after acting (but not after viewing), the previously-seen colour affected search performance even though the target was always a salient singleton and the colour was uninformative. The results reveal that prior action can interact with bottom-up salience during search. Implications for our understanding of both visual search and repetition priming are discussed.     

Is gaze behaviour in a laboratory context similar to that in real-life? A study in bicyclists

Numerous laboratory-based studies recorded eye movements in participants with varying expertise when watching video projections in the lab. Although research in the lab offers the advantage of internal validity, reliability and ethical considerations, ecological validity is often questionable. Therefore the current study compared visual search in 13 adult cyclists, when cycling a real bicycle path and while watching a film clip of the same road. Dwell time towards five Areas of Interest (AOIs) is analysed. Dwell time (%) in the lab and real-life was comparable only for the low quality bicycle path. Both in real-life and the lab, gaze is predominantly driven towards the road. Since gaze behaviour in the lab and real-life tends to be comparable with increasing task-complexity (road quality), it is concluded that under certain task constraints laboratory experiments making use of video clips might provide valuable information regarding gaze behaviour in real-life.     

Visual search for emotional expressions: Effect of stimulus set on anger and happiness superiority

Prior reports of preferential detection of emotional expressions in visual search have yielded inconsistent results, even for face stimuli that avoid obvious expression-related perceptual confounds. The current study investigated inconsistent reports of anger and happiness superiority effects using face stimuli drawn from the same database. Experiment 1 excluded procedural differences as a potential factor, replicating a happiness superiority effect in a procedure that previously yielded an anger superiority effect. Experiments 2a and 2b confirmed that image colour or poser gender did not account for prior inconsistent findings. Experiments 3a and 3b identified stimulus set as the critical variable, revealing happiness or anger superiority effects for two partially overlapping sets of face stimuli. The current results highlight the critical role of stimulus selection for the observation of happiness or anger superiority effects in visual search even for face stimuli that avoid obvious expression related perceptual confounds and are drawn from a single database.     

Probabilistic Inferences Under Emotional Stress: How Arousal Affects Decision Processes

Many models of decision making neglect emotional states that could affect individuals' cognitive processes. The present work explores the effect of emotional stress on people's cognitive processes when making probabilistic inferences. Two contrasting hypotheses are tested against one another: the uncertainty‐reduction and attention‐narrowing hypotheses of how emotional stress affects decision making. In the experimental study, emotional stress was induced through the use of highly aversive pictures immediately before each decision. Emotional state was assessed by both subjective (state anxiety, arousal, and pleasantness ratings) and objective (skin conductance) measures. The results show that emotional stress impacts decision making; in particular, emotionally aroused participants seem to have focused on the most important information and selected simpler decision strategies relative to participants in a control condition. The results are in line with the attention‐narrowing hypothesis and suggest that emotional stress can impact decision making through limited predecisional information search and the selection of simpler decision strategies. Copyright © 2015 John Wiley & Sons, Ltd.     

不同背景下不同频率闪烁的突显工效研究

本实验对黑、白背景下高频、中频、低频三种闪烁的突显工效进行了比较研究。实验结果表明：闪烁作为突显类型可以提高视觉搜索的绩效,而且,在闪烁的频率较高时（２７Ｈｚ以上）,这种闪烁的突显工效更为明显。视觉材料的呈现背景对闪烁突显视觉搜索绩效没有明显的影响,但在白背景下采用闪烁效果较好。     

不规则几何图形识别的取样首视点研究

用实验方法对不规则几何图形的取样首视点进行研究。作业任务有认同与匹配二种,显示条件有良好与不良二种,显示方式有旋转与不旋转二种,绩效指标用反应时与错误指数二项。结果表明：首视点的分布是非均匀的,落在轮廓部位的概率最大,落在中央或某条特定边的概率极小。首视点分布的均匀度与作业难度有关,在作业难度较大的情况下,首视点分布趋于集中。多数情况下,首视点的置位对作业绩效的影响不大。