A test of object permanence in a new-world monkey species,cotton top tamarins (<Emphasis Type="Italic">Saguinus oedipus</Emphasis>)

Cotton top tamarins were tested in visible and invisible displacement tasks in a method similar to that used elsewhere to test squirrel monkeys and orangutans. All subjects performed at levels significantly above chance on visible (n=8) and invisible (n=7) displacements, wherein the tasks included tests of the perseverance error, tests of memory in double and triple displacements, and "catch" trials that tested for the use of the experimenter's hand as a cue for the correct cup. Performance on all nine tasks was significantly higher than chance level selection of cups, and tasks using visible displacements generated more accurate performance than tasks using invisible displacements. Performance was not accounted for by a practice effect based on exposure to successive tasks. Results suggest that tamarins possess stage 6 object permanence capabilities, and that in a situation involving brief exposure to tasks and foraging opportunities, tracking objects' movements and responding more flexibly are abilities expressed readily by the tamarins. Electronic Publication     

Cognition and affective style: Individual differences in brain electrical activity during spatial and verbal tasks

Relations between brain electrical activity and performance on two cognitive tasks were examined in a normal population selected to be high on self-reported measures of Positive or Negative Affectivity. Twenty-five right-handed women, from an original pool of 308 college undergraduates, were the participants. EEG was recorded during baseline and during psychometrically matched spatial and verbal tasks. As predicted, participants who were high in Positive Affectivity performed equally well on the verbal and spatial tasks, while participants who were high in Negative Affectivity had spatial scores that were lower than their verbal scores. There were no group differences in baseline EEG. Both groups exhibited left central activation (i.e., alpha suppression) during the verbal and spatial tasks. When EEG data were analyzed separately for the group high in Positive Affectivity, there was evidence of parietal activation for the spatial task relative to the verbal task. The EEG data for the group high in Negative Affectivity had comparable EEG power values during verbal and spatial tasks at parietal scalp locations. These data suggest that, within a selected normal population, differences in affective style may interact with cognitive performance and with the brain electrical activity associated with that performance.     

The role of the executive system in visuo-spatial memory functioning

Participants were presented with a spatial sequence in which between 4 and 10 cells were highlighted. On each trial list length was unknown to the participant who was required to serially recall the last four cells. Processing of longer lists is assumed to call upon the executive system, which is thought to be involved in updating the contents of the short-term visuo-spatial store. Study 1 revealed that loading the executive system with concurrent random letter generation impaired performance on the spatial task especially recall of the early serial positions. However, contrary to expectation the degree of impairment was no greater on the longer lists, where it had been assumed that updating would be occurring. Study 2 confirmed this finding and demonstrated that relative to sequences of known length, under conditions of uncertainty when the list length was unknown, spatial recall was impaired even on short sequences. The present results support the growing consensus, which is suggestive of closer links between visuo-spatial and executive processes. However, it remains unclear whether or not updating is actually occurring on the longer sequences, and if it is, what specific executive processes are involved.     

Preattentive bias for snake words in snake phobia?

Stroop interference and skin conductance responses (SCRs) for words related to snakes, spiders, flowers, and mushrooms were studied in a group of women (n=40) with snake phobia who were randomised to a stress or no-stress condition. The 21 low-stress snake phobics showed Stroop interference for unmasked (but not for masked) snake words, compared with 21 age- and sex-matched controls. Stroop interference was not significantly different between high-stress and low-stress snake phobics. No support for stronger SCRs for masked snake words was found in snake phobics in a lexical decision task with masked presentations of the same words. The lack of a masked Stroop interference in snake phobics suggests a possible difference in cognitive-emotional mechanisms underlying specific phobia vs. other anxiety disorders that deserves further investigation.     

Effects of task difficulty and type of contingency on students' allocation of responding to math worksheets

This study investigated students' allocation of responding as a function of task difficulty and type of reinforcement contingency (i.e., accuracy based or time based). Four regular education fourth-grade students were presented with two identical stacks of easy and then difficult math worksheets using a reversal design. Regardless of condition, completing problems from each stack of worksheets was reinforced according to a different contingency; one required correct completion of math problems (accuracy based) and one required on-task behavior (time based). Results suggested that 3 of the 4 students preferred the accuracy-based contingency when given easy material and the time-based contingency when given difficult material. One student allocated more responding to the accuracy-based contingency when given easy problems but did not show a clear preference for either contingency with difficult problems. The implications of these findings for designing reinforcement-based programs for tasks of varying difficulty are discussed.     

A systematic overview of methods,their limitations,and their opportunities to investigate inattentional blindness

During the past two decades, the interest in investigating the phenomenon of inattentional blindness strongly increased and resulted in a fraying of paradigms investigating this specific failure of awareness. We reviewed 129 full‐text articles containing 219 experiments for their design and methods to create awareness for the growing variety of inattentional blindness paradigms. Also, we promote a deliberate use of future paradigms (proposedly based on their functionality and representativeness) to improve the transferability of research findings to the real world. In general, we argue that paradigms should be well‐chosen based on the respective purpose, as the concept of inattentional blindness represents most likely several subtypes with different underlying mechanisms rather than a single phenomenon. Finally, we propose to include expectancy as a continuous variable into the definition of inattentional blindness rather than using it as an exclusion criterion.     

Inferior parietal lobule involved in representation of “what” in a delayed-action Libet task

Intentional motor action is typically characterized by the decision about the timing, and the selection of the action variant, known as the “what” component. We compared free action selection with instructed action, where the movement type was externally cued, in order to investigate the action selection and action representation in a Libet’s task. Temporal and spatial locus of these processes was examined using the combination of high-density electroencephalography, topographic analysis of variance, and source reconstruction. Instructed action, engaging representation of the response movement, was associated with distinct negativity at the parietal and centro-parietal channels starting around 750 ms before the movement, which has a source particularly in the bilateral inferior parietal lobule. This suggests that in delayed-action tasks, the process of action representation in the inferior parietal lobule may play an important part in the larger parieto-frontal activity responsible for movement selection.     

Influence of vestibular signals on bodily self-consciousness: Different sensory weighting strategies based on visual dependency

Previous studies showed that the vestibular system is crucial for multisensory integration, however, its contribution to bodily self-consciousness more specifically on full-body illusions is not well understood. Thus, the current study examined the role of visuo-vestibular conflict on a full-body illusion (FBI) experiment that was induced during a supine body position. In a mixed design experiment, 56 participants underwent through a full-body illusion protocol. During the experiment, half of the participants received synchronous visuo-tactile stimulation, and the other half received asynchronous visuo-tactile stimulation, while their physical body was lying in a supine position, but the virtual body was standing. Additionally, the contribution of individual sensory weighting strategies was investigated via the Rod and Frame task (RFT), which was applied both before (pre-FBI standing and pre-FBI supine) and after the full-body illusion (post-FBI supine) protocol. Subjective reports of the participants confirmed previous findings suggesting that there was a significant increase in ownership over a virtual body during synchronous visuo-tactile stimulation. Additionally, further categorization of participants based on their visual dependency (by RFT) showed that those participants who rely more on visual information (visual field dependents) perceived the full-body illusion more strongly than non-visual field dependents during the synchronous visuo-tactile stimulation condition. Further analysis provided not only a quantitative demonstration of full-body illusion but also revealed changes in perceived self-orientation based on their field dependency. Altogether, findings of the current study make further contributions to our understanding of the vestibular system and brought new insight for individual sensory weighting strategies during a full-body illusion.     

Do not interrupt me if it makes me feel something – Study of the effect of the pleasantness of interruptions on performance

IntroductionInterruptions are mostly related to negative outcomes and researchers already found that the complexity or the length of interruptions modulate their deleterious effect on performance. However, none of them investigated the effect of the pleasantness of interruptions.ObjectiveThe objective of the study is to evaluate the impact of the pleasantness on both the correct completion of the interrupting task and the time required to resume the primary task.MethodWe designed a realistic email searching primary task during which 46 participants were either not interrupted or interrupted by a simple math addition task during which a positive or a negative picture was progressively revealed. We then asked participants how pleasant they found the interrupting task and investigated the effects of perceived pleasantness both on the interrupting task and on resuming the primary task.ResultsResults showed that performance on the interrupting task was worst and the time to resume the primary task was longer when participants found the task very pleasant or very unpleasant. Performance in both tasks was the best when participants gave intermediate pleasantness judgments. The findings were independent of the valence and arousal of the pictures used to manipulate task pleasantness.ConclusionThese results are discussed in light of empirical studies assessing the deleterious effects of emotions on cognition, and practical implications are proposed.     

工作记忆中的部分线索效应:任务呈现方式的影响

以往研究主要在长时记忆中考察部分线索效应,很少关注工作记忆中的部分线索效应及其作用机制。本研究采用项目再认任务,考察了工作记忆中提供部分学习项目作为提取线索,对存储在工作记忆中的已有表征的影响。结果发现：有、无部分线索试次分组呈现时,相较于无部分线索条件,有部分线索条件下再认正确率和d'降低,β升高,反应时间延长;有、无部分线索试次随机混合呈现时,有部分线索条件下再认正确率降低,β升高,但反应时间并无显著延长。结果表明：工作记忆中部分线索的提供降低了目标项目的表征强度;研究结果可用提取抑制假说解释,但工作记忆中部分线索的作用可能受注意资源有限性制约。