Visualizing the temporal dynamics of spatial information processing responsible for the Simon effect and its amplification by inhibition of return

Research has shown that the Simon effect is larger for targets suffering from inhibition of return (IOR). We used speed–accuracy trade-off (SAT) methodology to explore the temporal dynamics underlying this interaction. In Experiment 1, a new method for sorting the data was used to reveal a monotonic decay in the impact of task-irrelevant location information that is responsible for the Simon effect. In Experiment 2, we show that IOR delays both task-relevant identity and task-irrelevant location codes; a relatively longer delay for location than identity codes accounts for the effect of IOR on the Simon effect. When location information was made task-relevant in Experiment 3, IOR delayed the accumulation of this information by about the same amount as when location was irrelevant. The results suggest that IOR, therefore, has a greater effect on location than identity information.     

Linguistic correlates of asymmetric motor symptom severity in Parkinson’s Disease

Asymmetric motor severity is common in Parkinson’s Disease (PD) and provides a method for examining the neurobiologic mechanisms underlying cognitive and linguistic deficits associated with the disorder. In the present research, PD participants (N = 31) were assessed in terms of the asymmetry of their motor symptoms. Interviews with the participants were analyzed with the Linguistic Inquiry and Word Count (LIWC) program. Three measures of linguistic complexity – the proportion of verbs, proportion of function words, and sentence length – were found to be affected by symptom asymmetry. Greater left-side motor severity (and hence greater right-hemisphere dysfunction) was associated with the production of significantly fewer verbs, function words, and shorter sentences. Hence, the production of linguistic complexity in a natural language context was associated with relatively greater right hemisphere involvement. The potential neurobiological mechanisms underlying this effect are discussed.     

Effects of loss aversion on post-decision wagering: Implications for measures of awareness

Wagering contingent on a previous decision, or post-decision wagering, has recently been proposed to measure conscious awareness. Whilst intuitively appealing, it remains unclear whether economic context interacts with subjective confidence and how such interactions might impact on the measurement of awareness. Here we propose a signal detection model which predicts that advantageous wagers placed on the identity of preceding stimuli are affected by loss aversion, despite stimulus visibility remaining constant. This pattern of predicted results was evident in a psychophysical task where we independently manipulated perceptual and economic factors. Changes in wagering behaviour induced by changes in wager size were largely driven by changes in criterion, consistent with the model. However, for near-threshold stimuli, a reduction in wagering efficiency was also evident, consistent with an apparent but potentially illusory decrease in awareness of the stimulus. These findings challenge an assertion that post-decision wagering provides a direct index of subjective awareness.     

Imagining Reproduction in Science and History

Reproduction is at the core of many aspects of human existence. It is intrinsic in our biology and in the broad social constructs in which we all reside. The introduction to this special issue is designed to reflect on some of the differences between the humanities/arts and the sciences on the subject of Reproduction now and in the past. The intellectual/cultural distance between humanists and reproductive biologists is vast, yet communication between the Two Cultures has much to offer in guiding future research, pedagogy, and social policy. The challenges to communication include differences in methodology, professional protocols, specialization, and the increasing speed with which reproductive technology advances. The solutions require a new kind of student who can learn and adapt the approaches from both sides of the disciplinary divide to create new ways of understanding how our current and future concepts of reproduction may be informed by the past. This co-authored introduction reviews the range of interests represented in the essays and represents first steps of a dialogue between a humanist and a reproductive biologist who chart some of the possibilities on what the future of the subject might hold.     

The role of the dorsal CA1 and ventral CA1 in memory for the temporal order of a sequence of odors

Memory for the temporal order of a sequence of odors was assessed in male rats. A sequence of five odors mixed in sand was presented in digging cups one at a time to each rat in a sequence that varied on each trial. A reward was buried in each cup. Following the fifth odor, two of the previous five odors were presented simultaneously and the rat needed to choose the odor that occurred earliest in the sequence to receive a reward. Temporal separations of 1, 2, or 3 were used which represented the number of odors that occurred between the two odors in the sequence. Once pre-operative criterion was reached, rats received a control, dorsal CA1 (dCA1), or ventral CA1 (vCA1) lesion and were retested on the task. On post-operative trials, only the vCA1 group was impaired relative to both control and dCA1 groups. All groups of rats could discriminate between the odors. The data suggest that the vCA1, but not dorsal CA1, is involved in separating sensory events (odors) in time so that one odor can be remembered separate from another odor.     

Attachment avoidance and the cultural fit hypothesis: A cross-cultural investigation

This study examined the impact of attachment avoidance on relationship outcomes. A "cultural fit" hypothesis, which states that individual differences in personality should be associated with relationship problems if they encourage patterns of behavior that are incongruent with cultural norms, was investigated. It was hypothesized that attachment avoidance, a style of relationship in which emotional distance and independence are emphasized, would be more strongly associated with relationship problems in more collectivist societies (Hong Kong and Mexico) than in a more individualist one (the United States), given the greater emphasis placed on closeness and harmony in relationships in collectivist cultures. As predicted, associations between avoidant attachment and relationship problems were stronger in Hong Kong and Mexico than in the United States.     

Durability,Negative Impact,and Neuropsychological Predictors of Tic Suppression in Children with Chronic Tic Disorder

Chronic tic disorders are characterized by involuntary motor and vocal tics, which are influenced by contextual factors. Recent research has shown that (a) children can suppress tics for brief periods of time, (b) suppression is enhanced when programmed reinforcement is provided for tic-free intervals, and (c) short periods of suppression do not result in a paradoxical "rebound" in tic frequency when active suppression has ceased. The current study extended existing research in three important ways. First, we examined whether tic suppression ability decreased as suppression duration increased from 5 to 25 to 40 min. Second, we examined post-suppression tic frequency to test whether longer periods of suppression were more likely to be associated with a rebound effect. Finally, we explored neuropsychological predictors of tic suppression. Thirteen children with Tourette syndrome or a chronic tic disorder completed the study. Results showed that (a) tic suppression was sustained for all of the suppression durations, (b) rebound effects were not observed following any of the suppression durations, and (c) ability to suppress was correlated with omission, but not commission errors on a continuous performance task. Implications of these findings are discussed.     

Peer tutoring to prevent firearm play acquisition, generalization, and long-term maintenance of safety skills

Hundreds of accidental injuries and deaths to children occur annually in the United States as a result of firearm play. Behavioral skills training (BST) and in situ training have been found to be effective in teaching children the skills to use if they find a firearm, but training requires substantial time and effort. The current study examined the use of peers as tutors as a potential way to decrease the time and resources needed to teach these safety skills to youngsters. Peer trainers conducted BST and in situ training with other children. Children taught by the peer trainers acquired the safety skills and demonstrated them in naturalistic situations in which the skills were needed. Furthermore, all of the peer trainers acquired and maintained the skills. These results support the use of peer tutoring for teaching safety skills to other children.     

The effect of gaze on gaze direction while looking at art

In highly controlled cuing experiments, conspecific gaze direction has powerful effects on an observer’s attention. We explored the generality of this effect by using paintings in which the gaze direction of a key character had been carefully manipulated. Our observers looked at these paintings in one of three instructional states (neutral, social, or spatial) while we monitored their eye movements. Overt orienting was much less influenced by the critical gaze direction than what the cuing literature might suggest: An analysis of the direction of saccades following the first fixation of the critical gaze showed that observers were weakly biased to orient in the direction of the gaze. Over longer periods of viewing, however, this effect disappeared for all but the social condition. This restriction of gaze as an attentional cue to a social context is consistent with the idea that the evolution of gaze direction detection is rooted in social communication. The picture stimuli from this experiment can be downloaded from the Psychonomic Society’s Archive of Norms, Stimuli, and Data, www.psychonomic.org/archive.     

Human topological task adapted for rats: Spatial information processes of the parietal cortex

Human research has shown that lesions of the parietal cortex disrupt spatial information processing, specifically topological information. Similar findings have been found in non-humans. It has been difficult to determine homologies between human and non-human mnemonic mechanisms for spatial information processing because methodologies and neuropathology differ. The first objective of the present study was to adapt a previously established human task for rats. The second objective was to better characterize the role of parietal cortex (PC) and dorsal hippocampus (dHPC) for topological spatial information processing. Rats had to distinguish whether a ball inside a ring or a ball outside a ring was the correct, rewarded object. After rats reached criterion on the task (>95%) they were randomly assigned to a lesion group (control, PC, and dHPC). Animals were then re-tested. Post-surgery data show that controls were 94% correct on average, dHPC rats were 89% correct on average, and PC rats were 56% correct on average. The results from the present study suggest that the parietal cortex, but not the dHPC processes topological spatial information. The present data are the first to support comparable topological spatial information processes of the parietal cortex in humans and rats.