精神运动警觉性任务在不同知觉负荷下的疲劳状态监测

精神疲劳是由于长时间的认知活动引起的一种疲劳形式,不同任务水平可能造成不同的疲劳状态。本研究采用双任务范式,利用精神运动警觉性任务(Psychomotor Vigilance Task,PVT)的不同指标,考察了不同任务水平下的视觉搜索任务引起的不同精神疲劳状态。结果发现:PVT任务的最快10%反应时指标与自评疲劳程度结果一致,随着任务持续时间的增加而增加,最快10%反应时能够反映不同任务水平条件下的疲劳状态变化。注意忽视频次指标能够反映简单任务条件下的疲劳状态变化。平均反应时指标的时间主效应和任务主效应都显著,可能是反映精神疲劳状态和任务负荷情况的综合指标。PVT任务的最慢10%反应时指标,仅仅存在显著的任务效应,可能主要体现了任务负荷状态的变化。这些结果表明,PVT任务各指标能够反映不同任务水平引起的疲劳状态的不同变化,是研究和监测不同状态下精神疲劳程度较好的任务选择。     

You detect while I search: examining visual search efficiency in a joint search task

Numerous factors impact attentional allocation, with behaviour being strongly influenced by the interaction between individual intent and our visual environment. Traditionally, visual search efficiency has been studied under solo search conditions. Here, we propose a novel joint search paradigm where one individual controls the visual input available to another individual via a gaze contingent window (e.g., Participant 1 controls the window with their eye movements and Participant 2 – in an adjoining room – sees only stimuli that Participant 1 is fixating and responds to the target accordingly). Pairs of participants completed three blocks of a detection task that required them to: (1) search and detect the target individually, (2) search the display while their partner performed the detection task, or (3) detect while their partner searched. Search was most accurate when the person detecting was doing so for the second time while the person controlling the visual input was doing so for the first time, even when compared to participants with advanced solo or joint task experience (Experiments 2 and 3). Through surrendering control of one’s search strategy, we posit that there is a benefit of a reduced working memory load for the detector resulting in more accurate search. This paradigm creates a counterintuitive speed/accuracy trade-off which combines the heightened ability that comes from task experience (discrimination task) with the slower performance times associated with a novel task (the initial search) to create a potentially more efficient method of visual search.     

Working memory capacity predicts search accuracy for novel as well as repeated targets

Visual search behaviour is guided by mental representations of targets that direct attention toward relevant features in the environment. Electrophysiological data suggests these target templates are maintained by visual working memory during search for novel targets and rapidly transfer to long term memory with target repetition. If this account is correct, an individual’s working memory capacity should be more predictive of search performance for novel targets than repeated targets. Across six experiments, we tested this hypothesis using both single (Experiments 5 and 6) and multiple (Experiments 1–4) target search tasks with three different types of stimuli (real world objects, letters, and triple conjunction shapes). Each target set was repeated for six consecutive trials. In addition, we estimated visual working memory capacity using a change detection working memory task. Overall, working memory capacity did not predict response time or efficiency in the visual search task. However, working memory capacity was equally predictive of search accuracy for both novel and repeated targets. These results suggest that working memory requirements do not substantially differ between novel and repeated target search, and working memory capacity may continue to play an important role in the encoding or maintenance of target representations after they are presumed to be in long term memory.     

LIFE ON THE ISLAND

Walker Percy was both a medical doctor and a serious Catholic—a scientist and a religious believer. He thought, however, that science had become hegemonic in the twentieth century and that it was incapable of answering the most fundamental needs of human beings. He thus leveled a critique of the scientific method and its shortcomings in failing to address the individual person over against the group. In response to these shortcomings Percy postulates a religious understanding of human life, one in which man's life is understood as a pilgrimage or a search. The person who searches may not find the “object” of his search during his earthly life, but it is likely that he will come to a better understanding of himself by means of it.     

More Eagerness,More Suffering from Search Bias: Accuracy Incentives and Need for Cognition Exacerbate the Detrimental Effects of Excessive Searching in Finding Romantic Partners Online

The systematic use of Web search tools to browse and evaluate recommendations is widespread. Such tools may be crucial for users to truly benefit from the enormous selection of options available online. However, a recent study demonstrated that a greater number of search options triggered excessive searching and led to inferior decisions (i.e., the more‐means‐worse effect; Wu & Chiou, 2009 ). Given that individuals who are motivated to make accurate choices (the accuracy incentive) tend to engage in broader and more exhaustive searches, Experiment 1 examined how the accuracy incentive influenced the search process. The findings indicated that the accuracy incentive led to excessive searching and poorer choices. Moreover, the search ratio, an indicator of excessive searching, mediated the negative effect of the accuracy incentive on choice quality. Experiment 2 investigated the role of the need for cognition (NFC) in the more‐means‐worse effect. High‐NFC participants demonstrated an increased tendency toward excessive searching and exhibited poorer selectivity than did low‐NFC participants. The current research indicated that the accuracy incentive of online searchers may serve as a determinant of excessive searching and that online searchers characterized by high NFC may be more vulnerable to the negative effects of excessive searching. Copyright © 2015 John Wiley & Sons, Ltd.     

Eye See What You Are Saying: Testing Conversational Influences on the Information Gleaned from Home‐Loan Disclosure Forms

The federal government mandates the use of home‐loan disclosure forms to facilitate understanding of offered loans, enable comparison shopping, and prevent predatory lending. Predatory lending persists, however, and scant research has examined how salespeople might undermine the effectiveness of these forms. Three eye‐tracking studies (a laboratory simulation and two controlled experiments) investigated how conversational norms affect the information consumers can glean from these forms. Study 1 was a laboratory simulation that recreated in the laboratory; the effects that previous literature suggested is likely happening in the field, namely, that following or violating conversational norms affects the information that consumers can glean from home‐loan disclosure forms and the home‐loan decisions they make. Studies 2 and 3 were controlled experiments that isolated the possible factors responsible for the observed biases in the information gleaned from these forms. The results suggest that attentional biases are largely responsible for the effects of conversation on the information consumers get and that perceived importance plays little to no role. Policy implications and how eye‐tracking technology can be employed to improve decision‐making are considered. Copyright © 2015 John Wiley & Sons, Ltd.     

Revisiting the looking at nothing phenomenon: Visual and semantic biases in memory search

When visual stimuli remain present during search, people spend more time fixating objects that are semantically or visually related to the target instruction than looking at unrelated objects. Are these semantic and visual biases also observable when participants search within memory? We removed the visual display prior to search while continuously measuring eye movements towards locations previously occupied by objects. The target absent trials contained objects that were either visually or semantically related to the target instruction. When the overall mean proportion of fixation time was considered, we found biases towards the location previously occupied by the target, but failed to find biases towards visually or semantically related objects. However, in two experiments the pattern of biases towards the target over time provided a reliable predictor for biases towards the visually and semantically related objects. We therefore conclude that visual and semantic representations alone can guide eye movements in memory search, but that orienting biases are weak when the stimuli are no longer present.     

Selective scanpath repetition during memory-guided visual search

Visual search efficiency improves with repetition of a search display, yet the mechanisms behind these processing gains remain unclear. According to Scanpath Theory, memory retrieval is mediated by repetition of the pattern of eye movements or “scanpath” elicited during stimulus encoding. Using this framework, we tested the prediction that scanpath recapitulation reflects relational memory guidance during repeated search events. Younger and older subjects were instructed to find changing targets within flickering naturalistic scenes. Search efficiency (search time, number of fixations, fixation duration) and scanpath similarity (repetition) were compared across age groups for novel (V1) and repeated (V2) search events. Younger adults outperformed older adults on all efficiency measures at both V1 and V2, while the search time benefit for repeated viewing (V1–V2) did not differ by age. Fixation-binned scanpath similarity analyses revealed repetition of initial and final (but not middle) V1 fixations at V2, with older adults repeating more initial V1 fixations than young adults. In young adults only, early scanpath similarity correlated negatively with search time at test, indicating increased efficiency, whereas the similarity of V2 fixations to middle V1 fixations predicted poor search performance. We conclude that scanpath compression mediates increased search efficiency by selectively recapitulating encoding fixations that provide goal-relevant input. Extending Scanpath Theory, results suggest that scanpath repetition varies as a function of time and memory integrity.     

La création d’animaux chimères porteurs d’organes humains

Generate a human organ in an animal in order to elaborate a stock of available organs for transplantation… This is not the scenario of a science fiction movie but the result of the hard work of some researchers convinced of the feasibility of this major innovation. If the interest of this discovery is undeniable, it generates also many ethical and legal questions.