Reference dependence in iterative choices

Valuation of goods often proceeds from a series of hypothetical pairwise choices. We examine reference dependence on the outcome of such evaluations in a large-scale study in which respondents make a series of choices between areas that differ on cost of living and the quality of lakes and rivers. We uncover three substantial reference effects. First, we find that respondents’ choices are altered by being told the national value of water quality. For these people, consistent with prospect theory, changes in water quality below the 65% referenced national standard are treated as losses and given more weight while identical changes above 65% are treated as gains and given less weight. Second, we find that the sequence of iterative choices matters in a surprising way. The iterations proceed by encouraging switching either by degrading the chosen alternative or improving the item chosen. We show that improving the item not chosen produces the greatest switching, a result consistent with prospect theory, but only if the item changed in the iteration becomes the reference alternative. Finally, we find a strong starting reference effect. That is, we show that the trade-off in the first choice reflected in the change in cost of living divided by the change in water quality has a substantial impact on the final valuation. We assess the relative impact of these three reference effects and suggest ways of dealing with them for valuation of non-market goods.     

Effect of negative emotion on visual attention: Automatic capture by fear‐related stimuli1

Abstract: In this study, we examined the effect of threatening pictures (e.g., snakes and spiders) on control of spatial attention using a probe detection task. In addition to attentional capture by the threatening stimuli (Unpredictable task), the effects of affective valence of the pictures on the voluntary control of attention were explored (Predictable task). Results showed that reaction time (RT) was facilitated to the probe that appeared at the location of threatening stimuli when it occurred in the right visual field (but not in the left visual field), indicating that attention was captured automatically, at least in this visual field. However, when participants were able to predict the probe location, the attentional gains increased similarly for all the conditions (composed of visual field by picture type combinations) relative to those of Unpredictable task, with no indication of deferred deployment of attention to threatening stimuli. The results of this study suggested that the emotional valence, particularly negative valence, affected the automatic control of attention. This effect differed between the two visual fields in which emotional stimuli occurred.     

What we know now that we didn’t know then: reply to critics of <Emphasis Type="Italic">The Age of Meaning</Emphasis>

Author’s response to critical essays by Brian Weatherson, Alex Byrne, and Stephen Yablo on Philosophical Analysis in the Twentieth Century, Volume 2 The Age of Meaning     

Response inhibition in motor and oculomotor conflict tasks: Different mechanisms,different dynamics?

Previous research has shown that the appearance of task-irrelevant abrupt onsets influences saccadic eye movements during visual search and may slow down manual reactions to target stimuli. Analysis of reaction time distributions in the present study offers evidence suggesting that top-down inhibition processes actively suppress oculomotor or motor responses elicited by a salient distractor, in order to resolve the conflict that arises when reflex-like and deliberate responses are in opposition. Twenty-six participants carried out a variation of the oculomotor capture task. They were instructed to respond with either a saccade toward or with a button press at the side of the hemifield in which a target color singleton appeared. A distractor stimulus could appear either in the same or in the opposite hemifield. Delta plots revealed competition between reflex-like and deliberate response activation, and highlighted selective inhibition of automatic responses: While participants generally responded more slowly in incongruent compared to congruent situations, this effect diminished and even reversed in the slowest speed quantiles. These effects were present in both the oculomotor and motor response-mode conditions.     

一种自上而下加工的注意选择新机制:视觉标记

视觉标记是国外新近提出的有关注意选择机制的一种假设。该假设认为,在任务目标预先设定的条件下视觉系统是通过抑制旧刺激所处的位置来实现对新刺激的优先选择。本文主要介绍了视觉标记研究的经典实验范式、视觉标记理论的行为实验依据和脑成像实验依据,还概述了三种质疑视觉标记理论的观点。最后对视觉标记的未来研究做了展望。     

非期望刺激的生态意义信息对无意视盲的影响:情绪效价和精细程度的作用

采用Most(2000)的持续动态的实验范式,以圆圈、抽象面孔和真实面孔为非期望刺激,研究其生态意义信息对无意视盲的影响。研究发现:(1)相对于正性面孔和中性面孔,被试对负性面孔作为非期望刺激时的觉察率更高;而对正性面孔和中性面孔作为非期望刺激时的觉察率无显著性差异;(2)相对于圆圈,抽象面孔和真实面孔作为非期望刺激的觉察率更高,而抽象面孔与真实面孔作为非期望刺激时的觉察率均无显著性差异。结果表明,负性的、精细的非期望刺激的无意视盲率更低,即生态意义信息强的非期望刺激更易捕获注意。     

Multi-segmental thoracic spine kinematics measured dynamically in the young and elderly during flexion

In contrast to the cervical and lumbar region, the normal kinematics of the thoracic spine have not been thoroughly investigated. The aim of this study was to characterize normal multi-segmental continuous motion of the whole thoracolumbar spine, during a flexion maneuver, in young and elderly subjects. Forty-two healthy volunteers were analyzed: 21 young (age = 27.00 ± 3.96) and 21 elderly (age = 70.1 ± 3.85). Spinal motion was recorded with a motion-capture system and analyzed using a 3rd order polynomial function to approximate spinal curvature throughout the motion sequence. The average motion profiles of the two age groups were characterized. Flexion timing of the thoracic region of the spine, as compared to the lumbar spine and hips, was found to be different in the two age groups (p = 0.011): a delayed/sequential motion type was observed in most of the young, whereas mostly a simultaneous motion pattern was observed in the elderly subjects. A similar trend was observed in flexion of the lower thoracic segments (p = 0.017). Differences between age groups were also found for regional and segmental displacements and velocities. The reported characterization of the thoracic spine kinematics may in the future support identification of abnormal movement or be used to improve biomechanical models of the spine.     

Which kind of attention is captured by cues with the relative target colour?

Most theories of visual search maintain that attention is selectively tuned to the attributes of the search target (e.g., orange). Conversely, according to the relational account, attention is biased to the relative feature of the target (e.g., redder). However, previous studies that supported the relational account mainly measured mean response times. Hence, the results might not reflect early, perceptual mechanisms (e.g., signal enhancement) but later, decision-based mechanisms (channel selection). The current study tested the relational account against feature-specific theories in a spatial cueing task, in which the targets were backward-masked, and target identification accuracy was measured. The first experiment corroborated earlier results, demonstrating that relational effects are due to signal enhancement. In the second experiment, we chose highly discriminable colours along the blue–red continuum, and obtained results that were more consistent with broad feature-specific rather than relational tuning. The implications of these findings for current theories of attention are discussed.     

Attentional capture within and between objects

The present study addressed the question whether attentional capture by abrupt onsets is affected by object-like properties of the stimulus field. Observers searched for a target circle at one of four ends of two solid rectangles. In the focused attention condition the location of the upcoming target was cued by means of a central arrowhead, whereas in the divided attention condition, the target location was not cued. Irrelevant abrupt onsets could appear either within the attended or within the non-attended object. The results showed that in the focused attention condition, onsets ceased to capture attention irrespective of whether the onset appeared within an attended object or within a non-attended object.     

Cognitive control and counterproductive oculomotor capture by reward-related stimuli

Two experiments investigated the extent to which value-modulated oculomotor capture is subject to top-down control. In these experiments, participants were never required to look at the reward-related stimuli; indeed, doing so was directly counterproductive because it caused omission of the reward that would otherwise have been obtained. In Experiment 1, participants were explicitly informed of this omission contingency. Nevertheless, they still showed counterproductive oculomotor capture by reward-related stimuli, suggesting that this effect is relatively immune to cognitive control. Experiment 2 more directly tested whether this capture is controllable by comparing the performance of participants who either had or had not been explicitly informed of the omission contingency. There was no evidence that value-modulated oculomotor capture differed between the two conditions, providing further evidence that this effect proceeds independently of cognitive control. Taken together, the results of the present research provide strong evidence for the automaticity and cognitive impenetrability of value-modulated attentional capture.