Connectivity among semantic associates: an fMRI study of semantic priming

Semantic priming refers to a reduction in the reaction time to identify or make a judgment about a stimulus that has been immediately preceded by a semantically related word or picture and is thought to result from a partial overlap in the semantic associates of the two words. A semantic priming lexical decision task using spoken words was presented in event-related fMRI and behavioral paradigms. Word pairs varied in terms of semantic relatedness and the connectivity between associates. Thirteen right-handed subjects underwent fMRI imaging and 10 additional subjects were tested in a behavioral version of the semantic priming task. It was hypothesized priming would be greatest, reaction time fastest, and cortical activation reduced the most for related word pairs of high connectivity, followed by related word pairs of low connectivity, and then by unrelated word pairs. Behavioral and fMRI results confirmed these predictions. fMRI activity located primarily in bilateral posterior superior and middle temporal regions showed modulation by connectivity and relatedness. The results suggest that these regions are involved in semantic processing.     

Reward magnitude effects on temporal discrimination

Changes in reward magnitude or value have been reported to produce effects on timing behavior, which have been attributed to changes in the speed of an internal pacemaker in some instances and to attentional factors in other cases. The present experiments therefore aimed to clarify the effects of reward magnitude on timing processes. In Experiment 1, rats were trained to discriminate a short (2 s) vs. a long (8 s) signal followed by testing with intermediate durations. Then, the reward on short or long trials was increased from 1 to 4 pellets in separate groups. Experiment 2 measured the effect of different reward magnitudes associated with the short vs. long signals throughout training. Finally, Experiment 3 controlled for satiety effects during the reward magnitude manipulation phase. A general flattening of the psychophysical function was evident in all three experiments, suggesting that unequal reward magnitudes may disrupt attention to duration.     

The effect of mindfulness meditation on time perception

Research has increasingly focussed on the benefits of meditation in everyday life and performance. Mindfulness in particular improves attention, working memory capacity, and reading comprehension. Given its emphasis on moment-to-moment awareness, we hypothesised that mindfulness meditation would alter time perception. Using a within-subjects design, participants carried out a temporal bisection task, where several probe durations are compared to “short” and “long” standards. Following this, participants either listened to an audiobook or a meditation that focussed on the movement of breath in the body. Finally, participants completed the temporal bisection task for a second time. The control group showed no change after the listening task. However, meditation led to a relative overestimation of durations. Within an internal clock framework, a change in attentional resources can produce longer perceived durations. This meditative effect has wider implications for the use of mindfulness as an everyday practice and a basis for clinical treatment.     

The Mechanisms of Space‐Time Association: Comparing Motor and Perceptual Contributions in Time Reproduction

The spatial‐temporal association indicates that time is represented spatially along a left‐to‐right line. It is unclear whether the spatial‐temporal association is mainly related to a perceptual or a motor component. In addition, the spatial‐temporal association is not consistently found using a time reproduction task. Our rationale for this finding is that, classically, a non‐lateralized button for performing the task has been used. Using two lateralized response buttons, the aim of the study was to find a spatial‐temporal association in a time reproduction task. To account for the perceptual component, reference and target stimuli were presented in different spaces through four experiments. In all experiments, a Spatial‐Temporal Association of Response Codes (STEARC) effect was found and this effect was not modulated by the spatial position of both reference and target stimuli. The results suggested that the spatial‐temporal association was mainly derived from the spatial information provided by response buttons, reflecting a motor but not visuospatial influence.     

Strategies for spatial organization in adults and children

People have a tendency to organize space by extracting meaningful shapes from the configuration of elements. However, research on spatial correspondence in children suggests that when configural processing is difficult, individuation of elements may be critical. To begin to address the distinction between the use of configurations and individuation, and changes associated with age, we relied upon perceptual grouping and manipulated the colour of the displays—promoting either extraction of configural information (monochromatic) or individuation of elements (multicoloured). In a layout reproduction task (Experiments 1 and 2), children showed a robust advantage for multicoloured arrays, whereas adults showed an attenuated advantage for monochromatic displays. Visual discrimination in adults (Experiment 3) revealed that the influence of the display type occurs at the level of perception. Taken together, these results suggest that there are (at least) two routes to establishing spatial correspondence in arrays of elements, with differential dependence over development.     

Scene layout from ground contact,occlusion, and motion parallax

An important factor in determining perceived scene layout is optical contact between objects and the ground surface (“ground contact”). The relation between ground contact and occlusion was investigated in four experiments with stationary and motion parallax scenes containing a pole that occluded or was occluded by one or more cylinders. Some judgements were inconsistent with occlusion in stationary scenes, but judgements were consistent with occlusion in motion parallax scenes. When the range of object positions consistent with occlusion did not include the positions specified by ground contract or by motion parallax, the ground contact and motion parallax information still had a quantitative effect on the perceived position of the object within the range consistent with occlusion. These results demonstrate a cooperative interaction between ground contact, occlusion, and motion parallax in determining perceived layout in 3-D scenes.     

How can a stereotype inconsistency bias be encouraged in communication?

This study aimed to investigate what conditions can lead to a bias for communicating stereotype inconsistent (SI) information, relative to stereotype consistent (SC) information. Sixty‐three undergraduate university students (22 males, 41 females; M_age = 21.25) read a story about an Arab man who exhibited characteristics consistent and inconsistent with the stereotype of Arab men. The story was transmitted through 21 three‐person communication chains; each participant rewrote the story from memory for the next person in the chain to read, with only the first participant in each chain reading the original story. As hypothesized, when a surprising category conjunction was formed by pairing the primary stereotype (Arab men) with a secondary stereotype of a contradictory nature (kindergarten teachers), SC information was circulated less than SI information. This was also the case when a causal explanation was provided that accounted for the unexpected SI information. Findings indicate the potential of techniques that elicit cognitive elaboration of SI information to encourage an SI bias in communication, and show promise for exploring ways to reduce the impact of negative stereotypical information in the long term.     

Temporal coordination between performing musicians

Many common behaviours require people to coordinate the timing of their actions with the timing of others' actions. We examined whether representations of musicians' actions are activated in coperformers with whom they must coordinate their actions in time and whether coperformers simulate each other's actions using their own motor systems during temporal coordination. Pianists performed right-hand melodies along with simple or complex left-hand accompaniments produced by themselves or by another pianist. Individual performers' preferred performance rates were measured in solo performance of the right-hand melody. The complexity of the left-hand accompaniment influenced the temporal grouping structure of the right-hand melody in the same way when it was performed by the self or by the duet partner, providing some support for the action corepresentation hypothesis. In contrast, accompaniment complexity had little influence on temporal coordination measures (asynchronies and cross-correlations between parts). Temporal coordination measures were influenced by a priori similarities between partners' preferred rates; partners who had similar preferred rates in solo performance were better synchronized and showed mutual adaptation to each other's timing during duet performances. These findings extend previous findings of action corepresentation and action simulation to a task that requires precise temporal coordination of independent yet simultaneous actions.     

An analysis of confusion errors in many-to-one matching with temporal and nontemporal samples

In experiment 1, pigeons were trained to match temporal (2, 8, and 10 s of houselight) and location (feeder light, left key, center key illumination) samples to color comparison stimuli. Red choices were correct following the 2-s and feeder light, orange choices were correct following the 8-s and center key, and green choices were correct following the 10-s and left key. Samples that were harder to discriminate (8- vs 10-s, and left vs center key) were mapped onto comparisons that were easy to discriminate (orange vs green), while samples that were easier to discriminate (2- vs 8-s, and feeder light vs left key) were mapped onto comparisons that were hard to discriminate(red vs orange). The pattern of errors for temporal and location samples indicated that these samples were not represented by a common code even though they were associated with the same comparison stimuli. In experiment 2, the same pigeons were trained with visual samples in which samples that were hard to discriminate (triangle vs circle) were mapped onto comparisons that were easy to discriminate (orange vs green), while samples that were easy to discriminate(plus vs triangle) were mapped onto comparisons that were hard to discriminate (red vs orange). Following acquisition of the visual discrimination, the temporal samples were re-introduced and many-to-one training was continued. During delay testing, the pattern of errors for temporal and visual samples was equivalent and consistent with the hypothesis that visual samples were being coded in terms of the duration appropriate for the temporal sample with which it shared a common comparison response. Data from no-sample test sessions ruled out a simple response bias explanation of the data. The properties of common codes for temporal and nontemporal events can be somewhat flexible and more complicated than previously envisaged. Received: 21 January 1998 / Accepted after revision: 5 April 1998     

Élaboration et validation du Test d’Orientation Temporelle (TOT)

Temporal orientation is an essential data of the human psyche that modulates how we relied to the times of life. This survey describes the creation of a psychometric measure of temporal orientation in young French adults. Starting with the observation that temporal orientation is difficult for youngsters, a team of psychologists developed a preliminary version of the instrument. The psychometric validity of the test has been analyzed. The data have been collected on 507 high school students and academic students in the region of Nantes. An exploratory factorial analysis shows four dimensions: “short-term”, “immediately”, “anticipation” and “long-term”. The internal consistency is generally satisfactory and the measure of convergence confirms the external validity. The weak interrelationships between dimensions indicate distinct psychological constructs. A validated version composed of 30 items of the Temporal Orientation Test (TOT) is proposed.