Cognitive control in number processing: evidence from the unit-decade compatibility effect

In this study we evaluated whether the reverse compatibility effect observed when participants compare two-digit Spanish number words might be modulated as a function of the percentage of filler trials (within-decade comparisons). The participants performed a comparison task with two-digit Spanish number words while the unit–decade compatibility in between decade comparison trials was manipulated. We biased the relevance of units by increasing the intra/inter decade comparison ratio (20%, 50%, and 70%). The compatibility effect shifted from reverse to regular depending on the unit relevance which indicates that the relative emphasis on the unit processing in two-digit number word can be modulated by the stimulus list. These results are discussed in terms of cognitive control in number processing.     

Relative - not absolute - judgments of credibility affect susceptibility to misinformation conveyed during discussion

People remember different details about the same events, and when they discuss events they exchange new – and misleading – information. Discussion can change memory, especially when the source of new information is highly credible. But we do not know whether the effects of credibility are based on absolute judgments – judging a source's credibility independently from our own credibility – or relative judgments – judging a source's credibility only in relation to our own credibility. We addressed this question by manipulating subjects' expectations, leading them to believe that they either had the same, higher or lower “visual acuity” than their partner while they watched a movie together. To create ample opportunities for the pairs to mention misleading details to one another, each member unknowingly saw a different version of the movie. The pairs then discussed some of the critical differences, but not others. Later, everyone took an independent recognition test. Subjects' susceptibility to misinformation depended on their own credibility relative to their partner's, supporting the idea that susceptibility to misinformation depends on relative differences in credibility.     

Task switching and serial memory: looking into the nature of switches and tasks

Task switching research has so far focused on the impact of switching task-sets between two-choice classification tasks that require little or no memory load. Empirical work is lacking however to determine whether the switching cost can be extended to other cognitive activities and to different types of switches. In the present study, switching between the content – verbal to spatial – of the tasks was contrasted with switching cognitive processes — categorization to serial memory. Our pattern of results revealed the absence of local and general switch costs on serial memory tasks, while substantial costs were observed with two-choice judgement tasks. Such a finding challenges the widely accepted assumption that task alternation comes with a considerable cost in performance regardless of the cognitive tasks undertaken. Our results are discussed in context of the predominant models of task switching.     

Gender differences in adult word learning

In prior work, women were found to outperform men on short-term verbal memory tasks. The goal of the present work was to examine whether gender differences on short-term memory tasks are tied to the involvement of long-term memory in the learning process. In Experiment 1, men and women were compared on their ability to remember phonologically-familiar novel words and phonologically-unfamiliar novel words. Learning of phonologically-familiar novel words (but not of phonologically-unfamiliar novel words) can be supported by long-term phonological knowledge. Results revealed that women outperformed men on phonologically-familiar novel words, but not on phonologically-unfamiliar novel words. In Experiment 2, we replicated Experiment 1 using a within-subjects design, and confirmed gender differences on phonologically-familiar, but not on phonologically-unfamiliar stimuli. These findings are interpreted to suggest that women are more likely than men to recruit native-language phonological knowledge during novel word-learning.     

The time course of face matching for featural and relational image manipulations

It was found recently that horizontal and vertical relationships of facial features are differently vulnerable to inversion (Goffaux & Rossion, 2007). When faces are upside down manipulations of vertical relations are difficult to detect, while only moderate performance deficits are found for manipulations of horizontal relations, or when features differ. We replicate the findings of Goffaux and Rossion, and record the temporal courses of face matching performance and the effects of inversion. For vertical relations and featural changes inversion effects arise immediately, starting with the first 50 ms of processing. For horizontal relations inversion effects are absent at brief timings, but arise later, after about 200 ms. The final magnitudes of inversion effects are different in all three conditions, reaching 23.4% for vertical displacement, 10.7% for feature replacement, and 5.8% for horizontal displacement. Our results underline the special status of horizontal in contrast to vertical feature relations, and indicate that local and global configural information is handled in parallel by specific routines, as proposed recently (Senunkova & Barton, 2008).     

Does temporal preparation increase the rate of sensory information accumulation?

Recent studies showed that temporal preparation, i.e., the ability to prepare for an upcoming stimulus, improves perceptual processing. The mechanisms underlying this benefit are still controversial. Based upon the theoretical framework of accumulation models, it has been proposed that the accumulation of sensory stimulus information begins earlier when participants are temporally prepared than when they are unprepared. Alternatively, however, temporal preparation might also affect the accumulation rate of sensory information. In the present study, we examined these possibilities. Specifically, in three experiments, we manipulated participants' decision criterion. This manipulation should interact with any experimental manipulation affecting the rate of information processing, but produce additive effects with any manipulation affecting the onset of information accumulation rather than its rate. We obtained additive effects on RT, irrespective of whether the decision criterion was manipulated by increasing catch trial proportion or nogo trial proportion. These results suggest that temporal preparation improves perceptual processing by operating on the onset of sensory information accumulation rather than the rate of sensory information accumulation.     

Temporal-range estimation of multiple objects: evidence for an early bottleneck

When making parallel time-to-contact (TTC) estimates of two approaching objects, the two respective TTC estimates interfere with one another in an asymmetric fashion. The TTC of the later-arriving object is systematically overestimated, while the estimated TTC for the first-arriving object is as accurate as in a condition presenting only a single object. This asymmetric interference points to a processing bottleneck that could be due to early (e.g., during the estimation of the TTC from the optic flow) or late (e.g., during the timing of the response or the motor execution) constraints in the TTC estimation process. We used a Sperling-like prediction-motion task to differentiate between these two possibilities. Participants produced an absolute estimate of the TTC of only one of two objects approaching a target line. The target object to which the response was to be made was indicated by an auditory cue that occurred either at motion-onset or at the instant at which the two objects disappeared from the screen (occlusion-onset). The cue at motion-onset should disengage visual processing of the irrelevant stimulus. The cue at occlusion-onset, in contrast, requires visual processing of both relevant and irrelevant stimulus until occlusion. A single-object condition was introduced as a control condition. Results show symmetric interference in the motion-onset condition. In the occlusion-onset condition however, the results were congruent with asymmetric interference. Thus, the processing bottleneck in TTC estimation is originating at the earlier stages.     

Attention control and the antisaccade task: a response time distribution analysis

In three experiments response time (RT) differences between correct prosaccade and antisaccade trials were examined via distribution analyses by fitting an ex-Gaussian function to individual RT distributions. Experiment 1 demonstrated that antisaccades are slower than prosaccades and this difference is due to both a shift in the overall distribution as well as a lengthening of the tail of the distribution. Experiment 2 demonstrated that manipulating foreperiod duration led to changes in both accuracy and RT for antisaccades but not prosaccades. Furthermore, the change in RT for antisaccades resulted in a lengthening in the tail of the distribution but not a shift in the distribution. Finally, Experiment 3 demonstrated that with sufficient practice performance on antisaccades was equated with performance on prosaccades in terms of both accuracy and RT. An examination of the RT distributions suggested that practice led to parallel changes in both the mean of the distribution and the tail of the antisaccade distribution. These results are interpreted within a two-factor theory of attention control that suggests that performance on antisaccades is driven by both competition resolution and goal-maintenance abilities.     

Attention and suppression affect tactile perception in reach-to-grasp movements

Reaching with the hand is characterized by a decrease in sensitivity to tactile stimuli presented to the moving hand. Here, we investigated whether tactile suppression can be canceled by attentional orienting. In a first experiment, participants performed a dual-task involving a goal-directed movement paired with the speeded detection of a tactile pulse. The pulse was either delivered to the moving or stationary hand, during movement preparation, execution, or the post-movement phase. Furthermore, stimulation was delivered with equal probability to either hand, or with a higher probability to either the moving or resting hand. The results highlighted faster RTs under conditions of higher probability of stimulation delivery to both moving and resting hands, thus indicating an attentional effect. For the motor preparation period, RTs were faster only at the resting hand under conditions where tactile stimulation was more likely to be delivered there. In a second experiment, a non-speeded perceptual task was used as a secondary task and tactile discrimination thresholds were recorded. Tactile stimulation was delivered concomitantly at both index fingers either in the movement preparation period (both before and after the selection of the movement effector had taken place), in the motor execution period, or, in a control condition, in the time-window of motor execution, but the movement of the hand was restrained. In the preparation period, tactile thresholds were comparable for the two timings of stimulation delivery; i.e., before and after the selection of the movement effector had taken place. These results therefore suggest that shortly prior to, and during, the execution of goal-directed movements, a combined facilitatory and inhibitory influence acts on tactile perception.     

Relative salience affects the process of detecting changes in orientation and luminance

This study tests the effect of relative saliency on perceptual comparison and decision processes in the context of change detection in which distinct visual mechanisms process two features (e.g., luminance and orientation). Townsend and Nozawa's (1995) systems factorial technology was used to investigate the process architecture and stopping rule when deciding whether luminance or orientation of a Gabor patch had changed. Experiment 1 found individual differences in decision strategies when we did not control relative saliency. One group of participants adopted co-active processing, and the other group adopted serial self-terminating processing to detect the change signals. When Experiment 2 eliminated the relative saliency, all but one observer adopted parallel processing and followed a self-terminating rule. These results support the relative saliency hypothesis and highlight the fact that observers adopt different change-detection strategies for two features, especially when relative saliency exists between the two feature dimensions.