Luna-Rodriguez, Aquiles

Attention can be directed to the global or local level of a visual stimulus (i.e., Navon figure). Previous studies yielded reliable trial-to-trial level switch costs (i.e., worse performance when responding to the other level than on a previous trial), even though level cueing effects indicated anticipatory deployment of attention to the upcoming target level. To investigate the interplay of attentional preparation and persistence, we applied a probe trial method assumed to ensure a high degree of preparation for the upcoming target level and minimizing stimulus-specific proactive interference. Mirroring previous findings obtained in the domain of spatial attention, we found evidence for anticipatory attentional focusing on global/local target levels but not for persistence of the attentional set adopted on the previous trial. In a second experiment, we prevented preparation for upcoming attentional demands (in both global-local and spatial attention tasks). This resulted in the modulation of performance (in critical probe trials) by the attentional demands of the predecessor trial. Together, our findings demonstrate sensitivity of the probe trial method for attentional persistence and raise the possibility that such persistence can be completely eliminated by sufficiently strong preparation for the attentional demands of the following trial.

Public attitude toward Unmanned Aerial Vehicles (UAVs) has been extensively researched, frequently using surveys or experimental settings involving sound/noise. In this study, we present an experiment using visual stimuli, exploring not only the acceptance of UAVs as such but also of their interactions with different environments. The stimuli were pictures of quadcopters, either white or orange, with medical or commercial markings. For comparison, pictures of helicopters with the same four variations and a goose were also used. These pictures were superimposed over three types of backgrounds: urban, industrial, and rural. Twenty-four student participants took part in this study, each responding to 81 stimuli with Likert scale ratings for the acceptance and beauty of the stimuli after responding to objects that were used as a manipulation check. Reaction times for all responses were recorded. Afterward, participants completed a survey designed to identify the reasons for their judgments regarding acceptance. Our results deliver a complex view of the acceptance of UAVs. For example, the usage of the UAV had the largest impact on acceptance, with medical usage having the highest acceptance rating. Commercial usage was more accepted in industrial areas, and UAVs were more accepted than helicopters. The survey showed a heterogeneous variety and relevance of reasons for the acceptance ratings. On average, usefulness, traffic relief, reduction of privacy, and acceptance by society were indicated as the most relevant factors affecting the acceptance ratings. In general, our study suggests that the less considered visual factors of drones (salience in our study) can be expected to influence the acceptance of UAVs in addition to the noise factor. Most importantly, the physical characteristics of UAVs alone are insufficient to predict their acceptance. The purposes for which UAVs are used (that might be visually recognizable) and the environment in which they are operated play an important role in shaping public attitudes towards this new technology.

Response conflict evoked by a distractor stimulus object in interference tasks is associated with longer reaction times and a pronounced ERP component referred to as the fronto‐central N2. Increasing the proportion congruency (PC, i.e., the proportion of trials in which target and distractor are associated with the same response) is assumed to enhance distractor‐evoked conflict via defocusing of attention. Findings concerning the effect of the PC on the N2 in Eriksen flanker task experiments have been inconsistent, however, lending little support to the notion that the N2 reflects a conflict monitoring process. Here, we analyze the N2 in a temporal flanker task, in which the distractor stimuli, presented in advance of the target, elicit pronounced activation of the associated responses (as inferred from the lateralized readiness potential) when the PC is high. Consistent with result pattern obtained in other tasks involving successive presentation of the distractor and the target, conflict trials in a high‐PC condition evoked a particularly large N2. These findings accord with the assumption that the N2 reflects either conflict monitoring or conflict‐induced regulatory measures (i.e., reactive control). In light of the discrepancy of results obtained under conditions of simultaneous and successive distractor–target presentation, we speculate that the N2 is pronounced in situations that offer strong hints for classifying dominating response activation as incorrect, possibly reflecting particular control to counter this activation. Additional properties of the temporal flanker task, related to ERP investigations, are discussed.

The congruency sequence effect (CSE) describes the performance difference of congruent trials (in which target and distractor stimuli are associated with the same response) compared to incongruent trials (in which target and distractor stimuli are associated with different responses) as a function of the preceding congruency level (congruent trials relative to incongruent trials). The CSE is commonly interpreted as a measure of conflict-induced attentional adjustment. Although previous research has made substantial progress aiming at controlling for alternative explanations of the CSE, both task-specific and fundamental confounds have remained. In the current study, we used a temporal flanker task, in which two stimuli (i.e., distractor and target) are presented in rapid succession, and extended previous demonstrations of a CSE in flanker tasks by deconfounding target-distractor congruency from perceptual similarity. Using a four-choice task, we could also control for the reversal of distractor-response priming after incongruent trials (which is only feasible in two-choice tasks). Furthermore, we controlled for all confounds based on the sequence (i.e., repetition versus alternation) of the congruency level – such as feature sequence effects, distractor-response contingency switch costs, or temporal learning – by probing the allocation of attention to the points in time of presentation of the first and the second stimulus of a trial. This was achieved by intermixing trials of a temporal search task. The performance accuracy results in this task were consistent with a stronger attentional bias in favor of the target stimulus’ temporal position after incongruent than after congruent trials.

Performance in task switching experiments is worse when the current stimulus is associated with different responses in the two tasks (i.e., incongruent condition) than when it is associated with the same response (i.e., congruent condition). This congruency effect reflects some sort of application of the irrelevant task's stimulus-response translation rules. Manipulating the recency and the proportion of congruent and incongruent trials results in a modulation of the congruency effect (i.e., Congruency Sequence Effect, CSE, and Proportion Congruency Effect, PCE, respectively), suggesting attentional adjustment of processing weights. Here, we investigated the impact of task switching practice on the congruency effect and the modulation thereof by (a) re-analyzing the data of a task switching experiment involving six consecutive sessions and (b) conducting a novel four-session experiment in which the proportions of congruent and incongruent trials were manipulated. Although practice appeared to reduce the reaction times overall and the task switch costs (i.e., slower reaction times after task switches than after task repetitions) to an asymptotic level, the congruency effect as well as its modulations remained remarkably constant. These findings thus do not provide evidence that conflict effects between tasks and attentional adjustment are affected by task switching practice.

Electrophysiological recording in a temporal flanker task (i.e., distractors preceding the targets) has demonstrated that distractor processing is adjusted to the overall utility of the distractors. Under high utility, that is, distractors are predictive of the target/response, distractors immediately activate the corresponding response (as indicated by the lateralized readiness potential, LRP). This activation has been shown to be markedly postponed when the target predictably occurs delayed. To investigate the occurrence and time course of distractor-related response activation under conditions of unpredictable target onset, we randomly varied the stimulus-onset asynchrony (SOA) between distractors and targets and recorded the distractor-evoked LRP. When the distractor utility was high, an LRP occurred shortly after distractor presentation. In case of a long SOA the time course of this LRP was characterized by a drop back to baseline and a subsequent re-activation that reached a substantial level before target onset. These results suggest that distractor processing is characterized by sophisticated adjustments to experienced utility and temporal constraints of the task as well as by further control processes that regulate premature response activation. © 2019, Springer-Verlag GmbH Germany, part of Springer Nature.