Optimising Repeated Exposure: Determining Optimal Stimulus Shape for Introducing a Novel Vegetable among Children

Although it is well evident that a healthy diet rich in fruit and vegetables could prevent a number of major chronic diseases, national and international guidelines concerning their intake are not being reached by a large percentage of the population, including children. Thus, it is of interest to investigate how the consumption of this food group by children could be increased. The aim of this study was to examine the impact of serving style on the consumption of a raw snack vegetable (daikon) and the influence of its exposure on liking and intake of the vegetable. A group of 185 children 3–5 years old participated in the study. Two kindergartens served as intervention groups, while the third was assigned to be the control group of the study (n = 50). The intervention groups were repeatedly exposed to one of three different serving styles of daikon: sticks (n = 42), triangles (n = 46) or grated (n = 47), and they were all visited 7 times during the exposure period, on the same frequency (twice per week). Familiarity and liking of the target vegetable, daikon, and six other vegetables (cucumber, celery, celeriac, broccoli, cauliflower and beetroot) were measured at baseline, post-intervention and two follow up sessions (3- and 6-month) to investigate the likelihood of generalisation effects. Intake of daikon was measured at all control sessions and exposures. Moreover, children were asked to rank their favourite serving style of daikon and beetroot, among triangle, stick and grated, towards understanding the influence of shape on the efficacy of the exposure. The results revealed significant changes between liking and intake of daikon for the groups of triangles and sticks and the control group (p < 0.05). The group that received grated daikon did not show significant differences in liking and at intake levels during the exposures but performed well in the long-term. Throughout the exposure period, intake levels followed an overall increasing pattern, with all the groups to demonstrate a decrease of their intake at the last session, which was not found significant for the triangle group. Mere exposure was efficient towards increasing liking and intake of the novel vegetable with all the shapes to deliver positive results, but based on this study no particular serving style can be recommended.

Location-independent feature binding in visual working memory for sequentially presented objects

Spatial location is believed to have a privileged role in binding features held in visual working memory. Supporting this view, Pertzov and Husain (Attention, Perception, & Psychophysics, 76(7), 1914–1924, 2014) reported that recall of bindings between visual features was selectively impaired when items were presented sequentially at the same location compared to sequentially at different locations. We replicated their experiment, but additionally tested whether the observed impairment could be explained by perceptual interference during encoding. Participants viewed four oriented bars in highly discriminable colors presented sequentially either at the same or different locations, and after a brief delay were cued with one color to reproduce the associated orientation. When we used the same timing as the original study, we reproduced its key finding of impaired binding memory in the same-location condition. Critically, however, this effect was significantly modulated by the duration of the inter-stimulus interval, and disappeared if memoranda were presented with longer delays between them. In a second experiment, we tested whether the effect generalized to other visual features, namely reporting of colors cued by stimulus shape. While we found performance deficits in the same-location condition, these did not selectively affect binding memory. We argue that the observed effects are best explained by encoding interference, and that memory for feature binding is not necessarily impaired when memoranda share the same location.

4D Printed Shape Memory Polymer Composite Structures for Deployable Small Spacecrafts

Four dimensional (4D) printing is the convergence of three dimensional (3D) printing, which is an emerging additive manufacturing technology for smart materials. 4D printing is referred to the capability of changing the shape, property, or functionality of a 3D printed structure under a particular external stimulus. This paper presents the structural performance, shape memory behavior and photothermal effect of 4D printed pristine shape memory polymer (SMP) and it’s composite (SMPC) with multi-walled carbon nanotubes (MWCNTs). Both materials have demonstrated the ability to retain a temporary shape and then recover their original. It is revealed that the incorporation of MWCNTs into the SMP matrix has enhanced the light stimulus shape recovery capabilities. Light stimulus shape transformation of 4D printed SMPC is advantageous for space engineering applications as light can be focused onto a particular area at a long distance. Subsequently, a model 4D printed deployable boom, which is applicable for small spacecrafts is presented. The shape fixity and recovery behaviors of the proposed boom have been investigated. Notably, the model boom structure has demonstrated ∼86 % shape recovery ratio. The proposed innovative approach of additive manufacturing based deployable composite structures will shape up the future space technologies.

Thermal reception in the Mexican Lance-head rattlesnake, Crotalus polystictus

The sensory systems of Boidae and Crotalinae snakes detect subtle differences of thermal infrared energy. The complexity of this ability involves neurophysiological mechanisms with interspecific differences in the anatomy of thermoreceptor organs and functionally in thermal detection ranges and thermal thresholds, with ecological correlations that influence the thermo-reception. However, little is known about the information these snakes obtain and use from infrared radiation. We analyzed the behavioral response of adult Mexican Lance-head Rattlesnakes (Crotalus polystictus) to static thermal stimuli, evaluating the influence of distance from the snake of the thermal stimuli, and its lizard-like or mouse-like shape. The results reveal that C. polystictus is able to detect static thermal stimuli located from 20 to 200 cm away. Head movements and tongue-flicks were the most frequently performed behaviors, which suggests they are behaviors that can facilitate the detection of subtle differences in temperature of static stimuli. In addition, we suggest that stimulus shape and temperature are important in the timing of head orientation and frequency of tongue-flicks. We discuss the possible methodological and sensory implications of this behavioral response in C. polystictus.

Thermal reception in the Mexican Lance-head rattlesnake, Crotalus polystictus

The sensory systems of Boidae and Crotalinae snakes detect subtle differences of thermal infrared energy. The complexity of this ability involves neurophysiological mechanisms with interspecific differences in the anatomy of thermoreceptor organs and functionally in thermal detection ranges and thermal thresholds, with ecological correlations that influence the thermo-reception. However, little is known about the information these snakes obtain and use from infrared radiation. We analyzed the behavioral response of adult Mexican Lance-head Rattlesnakes (Crotalus polystictus) to static thermal stimuli, evaluating the influence of distance from the snake of the thermal stimuli, and its lizard-like or mouse-like shape. The results reveal that C. polystictus is able to detect static thermal stimuli located from 20 to 200 cm away. Head movements and tongue-flicks were the most frequently performed behaviors, which suggests they are behaviors that can facilitate the detection of subtle differences in temperature of static stimuli. In addition, we suggest that stimulus shape and temperature are important in the timing of head orientation and frequency of tongue-flicks. We discuss the possible methodological and sensory implications of this behavioral response in C. polystictus.

Practice improves peri-saccadic shape judgment but does not diminish target mislocalization

Visual sensitivity is markedly reduced during an eye movement. Peri-saccadic vision is also characterized by a mislocalization of the briefly presented stimulus closer to the saccadic target. These features are commonly viewed as obligatory elements of peri-saccadic vision. However, practice improves performance in many perceptual tasks performed at threshold conditions. We wondered if this could also be the case with peri-saccadic perception. To test this, we used a paradigm in which subjects reported the orientation (or location) of an ellipse briefly presented during a saccade. Practice on peri-saccadic orientation discrimination led to long-lasting gains in that task but did not alter the classical mislocalization of the visual stimulus. Shape discrimination gains were largely generalized to other untrained conditions when the same stimuli were used (discrimination during a saccade in the opposite direction or at a different stimulus location than previously trained). However, performance dropped to baseline level when participants shifted to a novel Vernier discrimination task under identical saccade conditions. Furthermore, practice on the location task did not induce better stimulus localization or discrimination. These results suggest that the limited visual information available during a saccade may be better used with practice, possibly by focusing attention on the specific target features or a better readout of the available information. Saccadic mislocalization, by contrast, is robust and resistant to top-down modulations, suggesting that it involves an automatic process triggered by the upcoming execution of a saccade (e.g., an efference copy signal).

Mirroring and beyond: coupled dynamics as a generalized framework for modelling social interactions

When people observe one another, behavioural alignment can be detected at many levels, from the physical to the mental. Likewise, when people process the same highly complex stimulus sequences, such as films and stories, alignment is detected in the elicited brain activity. In early sensory areas, shared neural patterns are coupled to the low-level properties of the stimulus (shape, motion, volume, etc.), while in high-order brain areas, shared neural patterns are coupled to high-levels aspects of the stimulus, such as meaning. Successful social interactions require such alignments (both behavioural and neural), as communication cannot occur without shared understanding. However, we need to go beyond simple, symmetric (mirror) alignment once we start interacting. Interactions are dynamic processes, which involve continuous mutual adaptation, development of complementary behaviour and division of labour such as leader–follower roles. Here, we argue that interacting individuals are dynamically coupled rather than simply aligned. This broader framework for understanding interactions can encompass both processes by which behaviour and brain activity mirror each other (neural alignment), and situations in which behaviour and brain activity in one participant are coupled (but not mirrored) to the dynamics in the other participant. To apply these more sophisticated accounts of social interactions to the study of the underlying neural processes we need to develop new experimental paradigms and novel methods of data analysis

PFC Neurons Reflect Categorical Decisions about Ambiguous Stimuli

We examined whether PFC neuron activity reflects categorical decisions in monkeys categorizing ambiguous stimuli. A morphing system was used to systematically vary stimulus shape and precisely define category boundaries. Ambiguous stimuli were centered on a category boundary, that is, they were a mix of 50% of two prototypes and therefore had no category information, so monkeys guessed at their category membership. We found that the monkeys' trial-by-trial decision about the category membership of an ambiguous image was reflected in PFC activity. Activity to the same ambiguous image differed significantly, depending on which category the monkey had assigned it to. This effect only occurred when that scheme was behaviorally relevant. These indicate that PFC activity reflects categorical decisions.