Generalization peak shift in rats under conditions of positive reinforcement and avoidance

Rats were trained to discriminate between two click frequencies. One frequency was associated with either variable-interval food reinforcement (Experiment 1) or free-operant avoidance (Experiment 2). The other frequency was associated with the absence of food in Experiment 1 and the absence of shock in Experiment 2. On a click frequency generalization test, the rats in both experiments showed positive peak shift with the shape of the relative gradients being very similar. This is the first reported instance of peak shift in rats when responding was maintained by an avoidance contingency. Nondifferentially trained controls showed that this shift was due exclusively to associative processes, with nonassociative stimulus factors in themselves apparently making no contribution to increased rates at particular stimulus values. These results show the comparability of appetitive and aversive control and support the position that gradient differences do not result from approach versus avoidance per se.     

Line-orientation generalization following signalled-reinforcer training

Three naive and three nonnaive pigeons key pecked for food on a multiple variable-interval 1-minute variable-interval 1-minute schedule with a black zero-degree vertical line on a white surround associated with one component and a black line shifted 30 degrees to the right (+30 degree) associated with the other component. Subsequently, a signalled-reinforcer procedure was introduced in the +30 degree component, i.e., whenever the reinforcer was available for the next response, the key changed to blank white. Following this training, the original unsignalled-reinforcer condition was re-instated. Line orientation generalization tests were given at the end of signalled-reinforcer training and after the second unsignalled-reinforcer condition. The signalled-reinforcer procedure reduced response rate in the +30-degree component in all subjects but facilitated responding during the zero-degree component (behavioral contrast) for two of the naive subjects only. However, average generalization gradients following signalled-reinforcer training indicated peak shift in two subjects and area shift in all five subjects that completed the experiment. There was no apparent relation between contrast and peak shift or degree of area shift. The data were interpreted as supporting the notion that the signalled-reinforcer procedure segments a variable-interval schedule into extinction and fixed ratio 1 segments.     

The allocation of time to temporally defined behaviors: responding during stimulus generalization.

In one stimulus condition, reinforcement depended on rats holding a lever for a duration having both minimum and maximum boundaries. During a second light intensity, reinforcement was not available for some rats; for others, reinforcement depended on a second response duration requirement. Generalization test stimuli controlled the same response durations found during training, and the amount of time allocated to a given response duration depended on the proximity of the test stimulus to the training stimulus which controlled that particular duration. The results indicated that a gradient of stimulus control does not reflect an underlying continuous change in responding, but is a result of the mixing of responses previously controlled by stimuli present during conditioning.     

Effects of unintentional coordination on attentional load

The goal of this study was to evaluate the impact of unintentional (spontaneous) coordination on high attentional visual load. More precisely, we wondered whether such coordination could free up some attentional resources and help improve performance in other more demanding attentional tasks. An experiment was performed in which participant attentional allocation was challenged by performing three tasks simultaneously while simultaneously being induced to unintentional entrain to an environmental rhythm. The first task was an interception task associated with a Stroop test to increase their attentional load. The second task was a reaction time test to alarms in different modalities (auditory, visual and bimodal) which was used to assess participant attentional load. The third task was a motor task in which participants were asked to swing their legs at a preferred frequency. The interface background brightness intensity was either synchronized in real time using a bidirectional coupling to participant leg movement or the background brightness was not changing at all. Our results on the reaction time task demonstrated that participants exhibited better reaction times for alarms in the bimodal condition than in the auditory condition and lastly for the visual condition. Also, participants exhibited a lower reaction time to alarms when the background brightness was synchronizing with their leg regardless the alarm modality. Overall, our study suggests a beneficial effect of unintentional environmental coordination on attentional resource allocation and highlights the importance of bidirectionality in interaction.     

The Impact of Affective States and Affective Shifts on Creative Ideation and Evaluation

This study aims to examine the impact of affective states and affective shifts on ideation and evaluation of creativity. Affects were induced by a two‐stage imagination procedure of recalling autobiographical experiences. Three periods of divergent thinking were measured to represent the participants’ creative ideation at different times. Creative evaluation was measured by estimating the originality of each response provided by the participants. The results indicate that (a) during the initial period of ideation, groups with positive affect obtain better creative ideation than the groups with neutral or negative affect. (b) The ideation in positive affect groups gradually decreases over time, while the ideation in negative affect groups gradually increases over time. (c) During the evaluation of originality, groups with negative affect have a higher proportion of over‐estimates and a lower proportion of under‐estimates than groups with positive affect. The viewpoints of cognitive tuning theory, which posit that the affective state influences creativity, are supported.     

Dispositional mindfulness and the wandering mind: Implications for attentional control in older adults

Age-related cognitive decline brings decreases in functional status. Dispositional mindfulness, the tendency towards present-moment attention, is hypothesized to correspond with enhanced attention, whereas mind-wandering may be detrimental to cognition. The relationships among mindfulness, task-related and task-unrelated thought, and attentional control performance on Go/No-Go and Continuous Performance tasks were examined in older adults. Dispositional mindfulness was negatively associated with task-unrelated thought and was positively associated with reactive control, but not proactive control or Go/No-Go performance. Although mind-wandering was not directly associated with performance, task-unrelated thought mediated the mindfulness-proactive control relation. Fewer task-unrelated thoughts were associated with lower proactive control. Interestingly, this effect was moderated by working memory such that it was present for those with low-average, but not high, working memory. This study highlights the importance of dispositional mindfulness and mind-wandering propensity in accounting for individual differences in attentional control in older adults, providing important targets for future cognitive remediation interventions.     

The attentional blink is attenuated for objects of expertise

Perceptual expertise with a specific domain of stimuli has been shown to afford numerous benefits to information processing performance. Previous work has suggested that face perception, a domain of perceptual expertise for many, is less susceptible to one of the most robust examples of information processing limits, namely the attentional blink. Here we extend this finding to non-face objects of expertise, supporting an expertise-related account of this benefit. Further, the attenuation of the attentional blink phenomenon was correlated with expertise at an individual level, whereby greater expertise with cars yielded a smaller attentional blink for these stimuli. These results support previous work suggesting that extensive experience with a class of objects, such as in the case of perceptual experts, can reduce the consequence of inherent limitations in human information processing. Possible mechanistic accounts of how experience may circumvent processing limitations are discussed.     

目标状态与时间信息在情境模型加工中的作用

采用移动窗口和记录探测句阅读时间的实时阅读技术, 对情境模型中目标状态与时间信息的关系进行了探索。运用重复测量的实验设计进行了三个实验, 实验发现(1)在顺序发生的事件结构中, 未达成目标作为持续追踪的焦点, 使得时间转换增大的条件下, 也不会对信息的整合产生影响; 而对时间距离的表征不仅起到了提高速度的作用, 而且也没有产生时间距离的远近效应。(2)同样是在顺序语篇中, 无目标和目标达成条件下, 随着时间转换的增大, 则出现了时间转换的大小效应, 也出现了时间距离的远近效应。(3)在回溯事件的建构中, 读者把回溯事件表征为时间距离的背景信息, 目标促进了信息的整合。     

Mindfulness meditation and reduced emotional interference on a cognitive task

The effect of mindfulness meditation (MM) on attentional control in emotional contexts was examined. In Study 1, MM practitioners (N = 28) categorized tones presented 1 or 4 s following the onset of affective pictures. Reaction times (RTs) to tones for affective minus neutral pictures provided an index of emotional interference. Participants with more MM experience showed less interference from affective pictures and reported higher mindfulness and psychological well-being. Study 2 was a controlled, randomized experimental study in which participants (N = 82) received MM training, relaxation meditation (RM) training, or no intervention (waiting-list control; WLC). Behavioral, self-report, and psychophysiological measures were administered before and after a 7-week intervention period. Although both MM and RM resulted in smaller skin conductance responses to unpleasant pictures and increased well-being, reductions in emotional interference from unpleasant pictures were specific to MM. These findings indicate that MM attenuates prolonged reactivity to emotional stimuli.