The role of perceptual load in inattentional blindness

Perceptual load theory offers a resolution to the long-standing early vs. late selection debate over whether task-irrelevant stimuli are perceived, suggesting that irrelevant perception depends upon the perceptual load of task-relevant processing. However, previous evidence for this theory has relied on RTs and neuroimaging. Here we tested the effects of load on conscious perception using the "inattentional blindness" paradigm. As predicted by load theory, awareness of a task-irrelevant stimulus was significantly reduced by higher perceptual load (with increased numbers of search items, or a harder discrimination vs. detection task). These results demonstrate that conscious perception of task-irrelevant stimuli critically depends upon the level of task-relevant perceptual load rather than intentions or expectations, thus enhancing the resolution to the early vs. late selection debate offered by the perceptual load theory.     

Identification from CCTV: Assessing police super‐recogniser ability to spot faces in a crowd and susceptibility to change blindness

Police worldwide regularly review closed‐circuit television (CCTV) evidence in investigations. This research found that London police experts who work in a full‐time “Super‐Recogniser Unit” and front line police identifiers regularly making suspect identifications from CCTV possessed superior unfamiliar face recognition ability and, with higher levels of confidence, outperformed controls at locating actors in a bespoke Spot the Face in a Crowd Test. Police were also less susceptible to change blindness errors and possessed higher levels of conscientiousness and lower levels of neuroticism and openness. Controls who took part in Spot the Face in a Crowd Test actor familiarisation training outperformed untrained controls, suggesting this exercise might enhance identification of persons of interest in real investigations. This research supports an accumulating body of evidence demonstrating that international police forces may benefit from deploying officers with superior face recognition ability to roles such as CCTV review, as these officers may be the most likely to identify persons of interest.     

Perceptual load does not modulate auditory distractor processing

In vision, it is well established that the perceptual load of a relevant task determines the extent to which irrelevant distractors are processed. Much less research has addressed the effects of perceptual load within hearing. Here, we provide an extensive test using two different perceptual load manipulations, measuring distractor processing through response competition and awareness report. Across four experiments, we consistently failed to find support for the role of perceptual load in auditory selective attention. We therefore propose that the auditory system – although able to selectively focus processing on a relevant stream of sounds – is likely to have surplus capacity to process auditory information from other streams, regardless of the perceptual load in the attended stream. This accords well with the notion of the auditory modality acting as an ‘early-warning’ system as detection of changes in the auditory scene is crucial even when the perceptual demands of the relevant task are high.     

Release of inattentional blindness by high working memory load: elucidating the relationship between working memory and selective attention

An unexpected stimulus often remains unnoticed if attention is focused elsewhere. This inattentional blindness has been shown to be increased under conditions of high memory load. Here we show that increasing working memory load can also have the opposite effect of reducing inattentional blindness (i.e., improving stimulus detection) if stimulus detection is competing for attention with a concurrent visual task. Participants were required to judge which of two lines was the longer while holding in working memory either one digit (low load) or six digits (high load). An unexpected visual stimulus was presented once alongside the line judgment task. Detection of the unexpected stimulus was significantly improved under conditions of higher working memory load. This improvement in performance prompts the striking conclusion that an effect of cognitive load is to increase attentional spread, thereby enhancing our ability to detect perceptual stimuli to which we would normally be inattentionally blind under less taxing cognitive conditions. We discuss the implications of these findings for our understanding of the relationship between working memory and selective attention.     

不同注意条件下的知觉启动及其机制

采用快速命名方法探讨不同注意条件下的知觉启动效应及其机制。实验中呈现一系列颜色词,要求被试分别完成集中和分散注意任务,然后进行词命名和再认测验。在词命名任务中．实验1包括旧词、重组颜色词和新词,而在实验2中重组颜色词改为新颜色词。结果表明,在实验1中,只有在集中注意条件下,被试对旧词的命名时间明显短于重组颜色词．即表现出知觉启动效应。而在实验2的两种注意条件下,被试对旧词的命名时间均明显短于新颜色词。这提示,在不同注意条件下的学习会影响其后的颜色知觉启动,并且与词和颜色的联结捆绑有关。     

Sustained attention can create an (illusory) experience of seeing dynamic change

Recent studies speculated that two types of change detection exist, one involving the experience of seeing dynamic change (change over brief interval), the other involving detecting a completed change (change over long interval), with only the former requiring sustained attention. To examine this supposition, a flicker change detection task was conducted in which the spatial location of objects was manipulated (shift, no-shift). In shift conditions, changed image display appeared in different locations than they did in the original display. The time interval separating images was manipulated (200 or 1000 ms). Results showed that a shift led to poor change detection only in the short interval condition. The performance decline by the image shift was not attenuated even when participants knew beforehand whether or not a shift would occur. Results indicate that sustained attention, which is sustained for a brief time, is related to the experience of seeing dynamic change.     

知觉负载、注意定势与选择性注意

本研究采用Eriksen Flanker（侧抑制）范式,将当前任务区分为高、低知觉负载两种条件．并系统操纵边缘视野干扰项与中央靶子的不同加工层次关系,从而考察注意选择的知觉负载理论。实验一发现,高知觉负载情况下没有任何flanker冲突效应,而低知觉负载情况下既有知觉层次和反应层次的冲突效应,也有一致条件下的促进效应。实验二增加了一致条件试次的比例,从而操纵自上而下的注意定势,发现高、低知觉负载情况下都存在知觉冲突效应和一致条件下的促进效应。这些发现表明,对任务无关信息的加工既受到任务相关信息的知觉负载和剩余加工资源的分配的影响,也受到自上而下注意定势的影响;自下而上和自上而下过程相互作用,共同决定加工资源的分配和注意选择的认知阶段。     

Detection of a change in photorealism1

The perceived degree of photorealism is interpreted as reflecting the artificialness or naturalness of images. Natural images (real‐scene photographs) are images with high degrees of naturalness, while artificial images (e.g., paintings) are images with low degrees of naturalness. Alternatively, natural images are images with low degrees of artificialness, while artificial images are images with high degrees of artificialness. We attempted to disambiguate these two interpretations of the perception of photorealism by using a change‐blindness paradigm. Participants observed an image sequence showing a gradual transformation from a natural image to an artificial image or vice versa, and reported changes they noticed. More participants reported noticing changes in photorealism for the natural‐to‐artificial transformations than for the opposite transformations. This asymmetry indicates that disappearing naturalness was detected more readily than emerging naturalness, or alternatively, emerging artificialness was detected more readily than disappearing artificialness. The results for the control conditions showed that the emergence of visual information was detected more readily than the disappearance. These results suggest that the perception of photorealism should be considered as the perception of artificialness.     

Sugar ingestion and dichotic listening: Increased perceptual capacity is more than motivation

Participants ingested a sugar drink or a sugar-free drink and then engaged in a pair of dichotic listening tasks. Tasks presented category labels then played a series of word pairs, one in the left ear and one in the right. Participants attempted to identify pairs containing a target category member. Target category words were homonyms. For example, arms appeared as a target in the “body parts” category. Nontargets that played along with targets were related to a category-appropriate version of the target (e.g., sleeves), a category-inappropriate version (e.g., weapons), or were unrelated to either version of the target (e.g., plant). Hence, an effect of nontarget type on number of targets missed was evidence that participants processed nontargets for meaning. In the divided attention task, participants monitored both ears. In the focused attention task, participants monitored the left ear. Half the participants in each group had the divided attention task before the focused attention task; the other half had the focused attention task before the divided attention task. We set task lengths to about 12 min so working on the first task would give sufficient time for metabolizing sugar from the drink before the start of the second task. Nontarget word type significantly affected targets missed in both tasks. Drink type affected performance in the divided attention task only after sufficient time for converting sugar into blood glucose. The result supports an energy model for the effect of sugar ingestion on perceptual tasks rather than a motivational model.     

Scientific reasoning in a real‐world context: The effect of prior belief and outcome on children's hypothesis‐testing strategies

The impact of event outcome and prior belief on scientific reasoning was investigated within a real‐world oral health context. Participants (N= 144; ranging from 3 to 11 years) were given hypothesis‐testing tasks and asked to explain their answers. Participants were presented with information that was either consistent or inconsistent with their own beliefs. Each task consisted of scenarios in which the outcome was either good or bad oral health. When the information was belief consistent and the outcome was good, or when the information was belief inconsistent and the outcome was bad, children were more likely to choose scientifically appropriate tests of the stated hypothesis (i.e. manipulate only one variable). Evidence‐based explanations were associated with scientifically appropriate choices in the good‐outcome, belief‐inconsistent scenario and the belief‐consistent, bad‐outcome scenario. Participants' performance on these tasks is explained by considering the plausibility of causal variables. A control of variables strategy was used to test hypotheses in cases in which the evidence was consistent with participants' beliefs and knowledge of causal mechanisms. In contrast, when the evidence was inconsistent with participants' beliefs, children chose to manipulate behaviours likely to lead to a positive health outcome. These findings demonstrate that context and prior knowledge interact to play an important role in children's scientific reasoning.     

Disability as a test of justice in a globalising world

This paper shows how most modern theories of justice could require or at least condone international aid aimed at alleviating the ill effects of disability. Seen from the general viewpoint of liberal egalitarianism, this is moderately encouraging, since according to the creed people in bad positions should be aided, and disability tends to put people in such positions. The actual responses of many theories, including John Rawls's famous view of justice, remain, however, unclear. Communitarian, liberal egalitarian, and luck egalitarian thinkers alike have to consider their attitude towards cosmopolitan ideals before they can extend their theories across national borders. The only view of justice that automatically rejects the obligation of international aid based on disability is libertarianism. This is significant for two reasons. Libertarianism is arguably the economic doctrine of globalisation; and its moral appeal to voluntary charity draws attention to the foundations of voluntary corporate social responsibility. Is the latter a prompt for greater or lesser social and political responsibility in global matters?     

External source monitoring in a real‐life event: developmental changes in ability to identify source persons

The present study investigated young children's and adults' external source‐monitoring abilities with respect to facial identification accuracy for complex live events. Five‐ to 6‐ year‐olds and adults watched a magic show in which three different female magicians (i.e. source persons) performed three different kinds of magic tricks each. After approximately 1 month, the participants were asked to recognize what kinds of magic tricks had been performed, to make face identifications as to which magician had performed those magic tricks and to recognize those magicians' attributes. Results showed that both young children and adults had more difficulty with identifying source persons than recognizing them in a real‐life event in which a number of persons appeared. Especially for young children, low credibility was shown not only for the source memories but also for the recognition memories of the source person attributes. Copyright © 2007 John Wiley & Sons, Ltd.     

Creating coherence in real‐life decision processes: Reasons,differentiation and consolidation

Svenson, O. & Jakobsson, M. (2009). Creating coherence in real‐life decision processes: Reasons, differentiation and consolidation. Scandinavian Journal of Psychology, 51, 93–102. Differentiation and Consolidation Theory describes human decision making as a process in which attractiveness values are restructured in order to reach a decision and support the decision made. Here, the theory was developed to include reasons pro and con alternatives and tested on students making decisions between two university psychotherapy training programs (cognitive‐behavioral and psychodynamic therapy). Before and also after the decision, the attractiveness of the chosen alternative was upgraded and the non‐chosen alternative downgraded. Different measures of evaluations of an alternative, such as “best” or “worse” converged over time until shortly after the decision. The number of reasons pro and con alternatives give a more complete picture than attractiveness and increased from the first to the last session. The reasons supporting the chosen alternative increased in strength, but reasons against the non‐chosen alternative decreased. In informal comments participants reported that the study also served as a decision aid.     

Attentional distractor interference may be diminished by concurrent working memory load in normal participants and traumatic brain injury patients

A reduction in congruency effects under working memory (WM) load has been previously described using different attentional paradigms (e.g.,  and ). One hypothesis is that different types of WM load have different effects on attentional selection, depending on whether a specific memory load demands resources in common with target or distractor processing. In particular, if information in WM is related to the distractors in the selective attention task, there is a reduction in distraction (Kim et al., 2005). However, although previous results seem to point to a decrease in interference under high WM load conditions (Kim et al., 2005), the lack of a neutral baseline for the congruency effects makes it difficult to differentiate between a decrease in interference or in facilitation. In the present work we included neutral trials in the task introduced by Kim et al. (2005) and tested normal participants and traumatic brain injury patients. Results support a reduction in the processing of distractors under WM load, at least for incongruent trials in both groups. Theoretical as well as applied implications are discussed.     

Stereotypes and attribution processes in a multi‐ethnic Italian province

In South Tyrol, a multi‐ethnic Italian province (Italians, Germans, Ladins) with an autonomous statute, the intergroup attributions expressed by members of the Italian group were examined (relationship: Italians vs. Germans). It was found that, while the stereotypes are more favourable to the ingroup, the attributions are more favourable to the outgroup. The implications of these results for South Tyrol and community relations are discussed. Copyright © 1999 John Wiley & Sons, Ltd.     

The interaction of state and trait aspects of self-focused attention affects genital, but not subjective, sexual arousal in sexually functional women

In this study we investigated the effects of state and trait aspects of self-focused attention on genital and subjective sexual arousal of sexually functional, healthy women during presentation of audiovisual erotic stimuli. Psychophysiological sexual response was measured as vaginal pulse amplitude using a vaginal photoplethysmograph. Experiential aspects of sexual arousal were measured both during stimulus presentation and retrospectively after stimulus offset. Trait level of sexual self-focus was measured with the Sexual Self-Consciousness Scale. State self-focus was induced by switching on a TV camera that pointed at the participant's face and upper torso. A manipulation check revealed that both groups experienced equally elevated levels of self-focused attention of their physical appearance. Induction of state self-focus per se did not affect genital responses, but an interaction effect of self-focus and participants' level of trait sexual self-focus was revealed. Compared with women with low scores on this trait, women with high scores exhibited smaller genital responses when state self-focus was induced. Both groups did not differ when no self-focus was induced. Increase of state self-focus did not affect subjective sexual arousal, but participants with a high level of trait sexual self-focus reported stronger subjective arousal, compared with those with low trait level. The results were discussed with reference to previous work in this field. Some implications for treatment of sexual arousal disorder were discussed.     

Implicit learning for probable changes in a visual change detection task

Previous research demonstrates that implicitly learned probability information can guide visual attention. We examined whether the probability of an object changing can be implicitly learned and then used to improve change detection performance. In a series of six experiments, participants completed 120–130 training change detection trials. In four of the experiments the object that changed color was the same shape (trained shape) on every trial. Participants were not explicitly aware of this change probability manipulation and change detection performance was not improved for the trained shape versus untrained shapes. In two of the experiments, the object that changed color was always in the same general location (trained location). Although participants were not explicitly aware of the change probability, implicit knowledge of it did improve change detection performance in the trained location. These results indicate that improved change detection performance through implicitly learned change probability occurs for location but not shape.     

Early Positive Information Impacts Final Evaluations: No Deliberation‐Without‐Attention Effect and a Test of a Dynamic Judgment Model

Evaluation judgments were affected by information order and not by subsequent unconscious versus conscious deliberation. In three experiments, we examined the influence of early positive information on final evaluations of four objects. Based on a task analysis, we predicted primacy effects in judgments in a sequential data acquisition task. Thinking periods following presentation were used to manipulate conscious or unconscious processing. In all three studies, we found no effects of thinking manipulations but instead found reliable order effects. We developed and tested an online judgment model on the basis of the belief updating model of Hogarth and Einhorn. The model accounted for large proportion of the individual level variability, and model comparison tests supported the presence of a primacy effect. Copyright © 2013 John Wiley & Sons, Ltd.     

Pigeons (<Emphasis Type="Italic">Columba livia</Emphasis>) show change blindness in a color-change detection task

Change blindness is a phenomenon whereby changes to a stimulus are more likely go unnoticed under certain circumstances. Pigeons learned a change detection task, in which they observed sequential stimulus displays consisting of individual colors back-projected onto three response keys. The color of one response key changed during each sequence and pecks to the key that displayed the change were reinforced. Pigeons showed a change blindness effect, in that change detection accuracy was worse when there was an inter-stimulus interval interrupting the transition between consecutive stimulus displays. Birds successfully transferred to stimulus displays involving novel colors, indicating that pigeons learned a general change detection rule. Furthermore, analysis of responses to specific color combinations showed that pigeons could detect changes involving both spectral and non-spectral colors and that accuracy was better for changes involving greater differences in wavelength. These results build upon previous investigations of change blindness in both humans and pigeons and suggest that change blindness may be a general consequence of selective visual attention relevant to multiple species and stimulus dimensions.