Time monitoring and executive functioning in children and adults

This study examined time-based prospective memory performance in relation to individual and developmental differences in executive functioning. School-age children and young adults completed six experimental tasks that tapped three basic components of executive functioning: inhibition, updating, and mental shifting. Monitoring performance was examined in a time-based prospective memory task in which participants indicated the passing of time every 5min while watching a movie. Separate analyses of the executive functioning data yielded a two-factor solution for both age groups, with the updating and inhibition tasks constituting a common factor and the shifting tasks constituting a separate factor. Both children and adults showed accelerating monitoring functions with low rates of clock checking during the early phase of each 5-min interval. However, compared with adults, children needed more clock checks for obtaining the same level of response accuracy. Executive functioning had selective effects on time-based prospective memory performance. In both children and adults, monitoring performance was related to the inhibition and updating components, but not to the shifting component, of executive functioning. We conclude that difficulties in temporary maintenance and updating of working memory contents may create discontinuities in sense of time, leading to an increased reliance on external cues for time keeping.     

Short-term memory for time in children and adults: A behavioral study and a model

This experiment investigated the effect of the short-term retention of duration on temporal discrimination in 5- and 8-year-olds, as well as in adults, by using an episodic temporal generalization task. In each age group, the participants' task was to compare two successive durations (a standard and a comparison duration) separated by a retention interval of 500ms, 5s, or 10s, with the order of presentation of these two durations being counterbalanced. The results revealed a shortening effect for the first presented stimulus in all of the age groups, although this was greater in the younger children, thereby indicating the presence of a negative time-order error. Furthermore, introducing a retention delay between the two durations did not produce a shortening effect but instead flattened the generalization gradient, especially in the younger children. However, this flattening of the generalization gradient with the retention delay was more marked between 500ms and 5s than between 5s and 10s. Thus, retaining the first duration in short-term memory during a task requiring the comparison of two successive durations reduced temporal discrimination accuracy and did so to a greater extent in the younger children.     

Positive and negative associations underlying ambivalent attitudes

In two studies, we compared the strength of positive and negative associations of ambivalent attitudes to those of nonambivalent attitudes. In Study 1, results from an implicit association task showed that, in contrast to nonambivalent attitudes, ambivalent attitudes were characterized by strong positive and negative associations. In Study 2 responses to ambivalent attitude objects were faster following a positive as well as following a negative prime, compared to a non-word prime, whereas for neutral attitude objects prime type did not influence response times. Results provide direct evidence for the assumption that both positive and negative associations of ambivalent attitudes are relatively strong. Implications for attitude strength and attitude structure are discussed.     

Effects of decision-phase time constraints on emotion-based learning in the Iowa Gambling Task

Research employing the Iowa Gambling Task (IGT) has frequently shown that learning is impaired in various clinical populations. However, precisely what constitutes "unimpaired" control group learning remains unclear. In order to understand some of the possible factors underlying variability in control group IGT performance, the present study sought to manipulate features of the task to intentionally disrupt learning. Specifically, the present study investigated the effects of time constraints on emotion-based learning during automated administration of the IGT. For two groups of participants, a time-constraint of either 2-s or 4-s was implemented during the critical decision making period, while a control group received no time constraint. We also evaluated participants' subjective experience after every block of 20 trials. Results demonstrated that the 2-s group differed significantly from the control group. Subjective experience measures revealed rapid development of awareness of the advantageous and disadvantageous decks among all three groups. Overall, our findings demonstrate, for the first time, the effects of decision-phase time constraints on emotion-based learning and indicate that the IGT reward/punishment schedules are to some extent cognitively penetrable.     

Optokinetic stimulation affects temporal estimation in healthy humans

The representation of time and space are closely linked in the cognitive system. Optokinetic stimulation modulates spatial attention in healthy subjects and patients with spatial neglect. In order to evaluate whether optokinetic stimulation could influence time perception, a group of healthy subjects performed "time-comparison" tasks of sub- and supra-second intervals before and after leftward or rightward optokinetic stimulation. Subjective time perception was biased by the direction of optokinetic stimulation. Rightward optokinetic stimulation induced an overestimation of time perception compared with baseline and leftward optokinetic stimulation. These results indicate a directional bias in time perception induced by manipulation of spatial attention and could argue for a mental linear representation of time intervals.     

Tau and Kappa effects in physical space: the case of audition

The organization of spatio-temporal information in an auditory memory task was studied in two experiments. Stimuli consisted of four different configurations of eight sequentially presented beeps. In two configurations, the stimuli were space-time congruent, with (constant or variable) inter-stimulus distances corresponding to (constant or variable) inter-stimulus time intervals. In the other two configurations, the stimuli were space-time incongruent, with (constant or variable) inter-stimulus distances not corresponding to (variable or constant) inter-stimulus time intervals. After a learning phase consisting of 20 presentations of the target configuration, participants reproduced the spatial (Experiment 1) or temporal (Experiment 2) characteristics of the target 60 times in succession without re-examining the target configuration. Accuracy (with respect to the target) and variability (between responses) were found to evolve independently. In the incongruent space-time conditions, effects of variable inter-stimulus time intervals or distances on the reproduction of, respectively, constant distances (Tau effect) or constant time intervals (Kappa effect) were observed, while the reverse was not the case. Thus, dimensional interference occurred when the dimension to be ignored was variable. The results are discussed in the light of the distinction between properties of the stabilized mental image and the process of stabilization.     

A real-time phoneme counting algorithm and application for speech rate monitoring

Adults who stutter can learn to control and improve their speech fluency by modifying their speaking rate. Existing speech therapy technologies can assist this practice by monitoring speaking rate and providing feedback to the patient, but cannot provide an accurate, quantitative measurement of speaking rate. Moreover, most technologies are too complex and costly to be used for home practice. We developed an algorithm and a smartphone application that monitor a patient’s speaking rate in real time and provide user-friendly feedback to both patient and therapist. Our speaking rate computation is performed by a phoneme counting algorithm which implements spectral transition measure extraction to estimate phoneme boundaries. The algorithm is implemented in real time in a mobile application that presents its results in a user-friendly interface. The application incorporates two modes: one provides the patient with visual feedback of his/her speech rate for self-practice and another provides the speech therapist with recordings, speech rate analysis and tools to manage the patient’s practice. The algorithm’s phoneme counting accuracy was validated on ten healthy subjects who read a paragraph at slow, normal and fast paces, and was compared to manual counting of speech experts. Test-retest and intra-counter reliability were assessed. Preliminary results indicate differences of −4% to 11% between automatic and human phoneme counting. Differences were largest for slow speech. The application can thus provide reliable, user-friendly, real-time feedback for speaking rate control practice.     

Time perception and time perspective differences between adolescents and adults

The present experiment aimed to investigate the differences in time perception and time perspective between subjects representing two developmental stages, namely adolescence and middle adulthood. Twenty Chinese adolescents aged 15–25 and twenty Chinese adults aged 35–55 participated in the study. A time discrimination task and a time reproduction task were implemented to measure the accuracy of their time perception. The Zimbardo Time Perspective Inventory (Short-Form) was adopted to assess their time orientation. It was found that adolescents performed better than adults in both the time discrimination task and the time reproduction task. Adolescents were able to differentiate different time intervals with greater accuracy and reproduce the target duration more precisely. For the time reproduction task, it was also found that adults tended to overestimate the duration of the target stimuli while adolescents were more likely to underestimate it. As regards time perspective, adults were more future-oriented than adolescents, whereas adolescents were more present-oriented than adults. No significant relationship was found between time perspective and time perception.     

Driving next to automated vehicle platoons: How do short time headways influence non-platoon drivers’ longitudinal control?

Advanced driver assistance systems (ADAS) are taking over an increasing part of the driving task and are supporting the introduction of semi- and fully automated vehicles. As a consequence, a mixed traffic situation is developing where vehicles equipped with automated systems taking over the lateral and longitudinal control of the vehicle will interact with unequipped vehicles (UV) that are not fitted with such automated systems. Different forms of automation are emerging and it appears that regardless of which form is going to become popular on our roads, there is a consensus developing that it will be accompanied by a reduction in time headway (THW). The present simulator study examined whether a ‘contagion’ effect from the short THW held in platoons on the UV drivers would occur. Thirty participants were asked to follow a lead vehicle (LV) on a simulated motorway in three different traffic conditions: surrounding traffic including (1) platoons with short following distance (THW = 0.3 s), (2) large following distance (THW = 1.4 s) or (3) no platoons at all. Participants adapted their driving behaviour by displaying a significant shorter average and minimum THW while driving next to a platoon holding short THWs as when THW was large. They also spent more time keeping a THW below a safety threshold of 1 s. There was no carryover effect from one platoon condition to the other, which can be interpreted as an effect that is not lasting in time. The results of this study point out the importance of examining possibly negative behavioural effects of mixed traffic on UV drivers.