Adaptation to continuous perturbation of balance: progressive reduction of postural muscle activity with invariant or increasing oscillations of the center of mass depending on perturbation frequency and vision conditions

We investigated the adaptation of balancing behavior during a continuous, predictable perturbation of stance consisting of 3-min backward and forward horizontal sinusoidal oscillations of the support base. Two visual conditions (eyes-open, EO; eyes-closed, EC) and two oscillation frequencies (LF, 0.2 Hz; HF, 0.6 Hz) were used. Center of Mass (CoM) and Center of Pressure (CoP) oscillations and EMG of Soleus (Sol) and Tibialis Anterior (TA) were recorded. The time course of each variable was estimated through an exponential model. An adaptation index allowed comparison of the degree of adaptation of different variables. Muscle activity pattern was initially prominent under the more challenging conditions (HF, EC and EO; LF, EC) and diminished progressively to reach a steady state. At HF, the behavior of CoM and CoP was almost invariant. The time-constant of EMG adaptation was shorter for TA than for Sol. With EC, the adaptation index showed a larger decay in the TA than Sol activity at the end of the balancing trial, pointing to a different role of the two muscles in the adaptation process. At LF, CoM and CoP oscillations increased during the balancing trial to match the platform translations. This occurred regardless of the different EMG patterns under EO and EC. Contrary to CoM and CoP, the adaptation of the muscle activities had a similar time-course at both HF and LF, in spite of the two frequencies implying a different number of oscillation cycles. During adaptation, under critical balancing conditions (HF), postural muscle activity is tuned to that sufficient for keeping CoM within narrow limits. On the contrary, at LF, when vision permits, a similar decreasing pattern of muscle activity parallels a progressive increase in CoM oscillation amplitude, and the adaptive balancing behavior shifts from the initially reactive behavior to one of passive riding the platform. Adaptive balance control would rely on on-line computation of risk of falling and sensory inflow, while minimizing balance challenge and muscle effort. The results from this study contribute to the understanding of plasticity of the balance control mechanisms under posture-challenging conditions.     

The valence of sex:Automatic affective associations in erotophilia and erotophobia

Sexual stimuli may elicit positive and negative emotions that can impact sexual thoughts, responses, and behavior. To date, most research on affect and sexuality has focused on conscious processes and affective states. Less is known about how automatic and trait-level affective processes influence our reactions to sexual stimuli. This study used a priming task with backward masking and a trait measure of erotophobia-erotophilia - the tendency to respond to sex on a negative-to-positive continuum - to improve our understanding of the role of automatic and affective processes in response to sexual stimuli. Erotophilic individuals demonstrated automatic associations between sexual primes and positively-valenced targets, whereas erotophobic individuals classified negatively-valenced targets faster regardless of whether primes were sexual or neutral. The findings suggest that the valence of sexual stimuli can be processed automatically and is associated with trait-level affective responses to sex. Implications for research on risky sexual behavior and sexual dysfunction are discussed.     

Learning diphone-based segmentation

This paper reconsiders the diphone-based word segmentation model of Cairns, Shillcock, Chater, and Levy (1997) and Hockema (2006), previously thought to be unlearnable. A statistically principled learning model is developed using Bayes' theorem and reasonable assumptions about infants' implicit knowledge. The ability to recover phrase-medial word boundaries is tested using phonetic corpora derived from spontaneous interactions with children and adults. The (unsupervised and semi-supervised) learning models are shown to exhibit several crucial properties. First, only a small amount of language exposure is required to achieve the model's ceiling performance, equivalent to between 1 day and 1 month of caregiver input. Second, the models are robust to variation, both in the free parameter and the input representation. Finally, both the learning and baseline models exhibit undersegmentation, argued to have significant ramifications for speech processing as a whole.     

Towards a Vygotskyan cognitive robotics: The role of language as a cognitive tool

Cognitive Robotics can be defined as the study of cognitive phenomena by their modeling in physical artifacts such as robots. This is a very lively and fascinating field which has already given fundamental contributions to our understanding of natural cognition. Nonetheless, robotics has to date addressed mainly very basic, low-level cognitive phenomena like sensory-motor coordination, perception, and navigation, and it is not clear how the current approach might scale up to explain high-level human cognition. In this paper we argue that a promising way to do that is to merge current ideas and methods of ‘embodied cognition’ with the Russian tradition of theoretical psychology which views language not only as a communication system but also as a cognitive tool, that is by developing a Vygotskyan cognitive robotics. We substantiate this idea by discussing several domains in which language can improve basic cognitive abilities and permit the development of high-level cognition: learning, categorization, abstraction, memory, voluntary control, and mental life.     

The mediating effects of time structure on the relationships between time management behaviour,job satisfaction,and psychological well‐being

This article examined the relationship between time structure and Macan's process model of time management. This study proposed that time structure—‘appraisal of effective time usage’—would be a more parsimonious mediator than perceived control over time in the relationship between time management behaviours and outcome variables, such as job satisfaction and psychological well‐being. Alternative structure models were compared using a sample of 111 university students. Model 1 tested Macan's process model of time management with perceived control over time as the mediator. Model 2 replaced perceived control over time by the construct of time structure. Model 3 examined the possibility of perceived control over time and time structure as being parallel mediators of the relationships between time management and outcomes. Results of this study showed that Model 1 and Model 2 fitted the data equally well. On the other hand, the mediated effects were small and partial in both models. This pattern of results calls for reassessment of the process model.     

Time in language: event duration in language comprehension

This work investigates how we process and represent event duration in on-line language comprehension. Specifically, it examines how events of different duration are processed and what type of knowledge underlies their representations. Studies 1–4 examined verbs and phrases in different contexts. They showed that durative events took longer to process than non-durative events and that the duration attributed to the stimulus events correlated with on-line processing times. Studies 5 and 6 indicated that durative events occur in semantically more diverse contexts and elicit semantically more diverse associations than non-durative events. Semantic and contextual diversity also correlated with attributed durations and processing times. Results indicate that (a) event-specific durations are computed on-line from multiple unfolding cues, (b) processing cost and duration representations emerge from semantic and contextual diversity reflecting our experience, and (c) key components of duration representations may be situation-specific knowledge of causal and contingency relations between events.     

Inference making and linking both require thinking: Spontaneous trait inference and spontaneous trait transference both rely on working memory capacity

Past research suggests that spontaneous trait inference (STI) and spontaneous trait transference (STT) may reflect different cognitive processes, the former being inferential and the latter associational. The present research was designed to explore whether either or both of these processes involve thinking that occupies cognitive capacity. Four studies suggest that reductions in available cognitive capacity reduce both STI and STT effects, both on measures of savings in relearning (which reflect the strength of trait associations with a person) and on trait ratings measures (which reflect the strength of trait inferences made about a person). Similar results were obtained using an individual difference measure of cognitive capacity. Although these results suggest that STI and STT are similar, in that both exhibit interference from reductions in cognitive capacity, other results, such as halo effects in trait ratings, support previous assertions that their underlying processes are distinct.     

Predicting sights from sounds: 6-month-olds' intermodal numerical abilities

Although the psychophysics of infants’ nonsymbolic number representations have been well studied, less is known about other characteristics of the approximate number system (ANS) in young children. Here three experiments explored the extent to which the ANS yields abstract representations by testing infants’ ability to transfer approximate number representations across sensory modalities. These experiments showed that 6-month-olds matched the approximate number of sounds they heard to the approximate number of sights they saw, looking longer at visual arrays that numerically mismatched a previously heard auditory sequence. This looking preference was observed when sights and sounds mismatched by 1:3 and 1:2 ratios but not by a 2:3 ratio. These findings suggest that infants can compare numerical information obtained in different modalities using representations stored in memory. Furthermore, the acuity of 6-month-olds’ comparisons of intermodal numerical sequences appears to parallel that of their comparisons of unimodal sequences.     

Find the picture of eight turtles: a link between children's counting and their knowledge of number word semantics

An essential part of understanding number words (e.g., eight) is understanding that all number words refer to the dimension of experience we call numerosity. Knowledge of this general principle may be separable from knowledge of individual number word meanings. That is, children may learn the meanings of at least a few individual number words before realizing that all number words refer to numerosity. Alternatively, knowledge of this general principle may form relatively early and proceed to guide and constrain the acquisition of individual number word meanings. The current article describes two experiments in which 116 children (2½- to 4-year-olds) were given a Word Extension task as well as a standard Give-N task. Results show that only children who understood the cardinality principle of counting successfully extended number words from one set to another based on numerosity—with evidence that a developing understanding of this concept emerges as children approach the cardinality principle induction. These findings support the view that children do not use a broad understanding of number words to initially connect number words to numerosity but rather make this connection around the time that they figure out the cardinality principle of counting.     

Pre‐outcome regret: Widespread and overlooked

Many real‐life decisions (e.g. promises, plans and agreements) involve a time interval between when the decision is made and the main outcome is revealed. Nearly all regret studies focus on anticipated or experienced post‐outcome regret. We argue that regret is also frequently experienced in the pre‐outcome period, and that this ‘pre‐outcome regret’ has other sources than regret experienced after the outcome is known. Regret experienced in the pre‐outcome period has an important function post‐outcome regret (usually) cannot have, namely to motivate the decision maker to reconsider the ongoing decision process and reverse the initial decision. Pre‐outcome regret should for these reasons be distinguished from post‐outcome regret, and studied separately. In two scenario studies, participants were asked to imagine their regret after agreeing to perform an inconvenient task. In both, more regret was reported before than after the event, even when they had imagined a ‘worst case’ outcome. In the third study, participants described a difficult choice from their own life. Again, regret was perceived as higher in the pre‐outcome period than afterwards. In a fourth study, participants reported regret ‘online’ during an economic game (a version of the ultimatum game). They regretted their decisions more before than after they knew the outcome. We conclude that experienced pre‐outcome regret is often stronger than post‐outcome regret, and typically increases during the pre‐outcome period. We suspect that the absence of JDM studies of pre‐outcome regret is a legacy of the dominant gambling metaphor within decision research. Copyright © 2010 John Wiley & Sons, Ltd.