Although plants are essentially sessile in nature, these organisms are very much in tune with their environment and are capable of a variety of movements. This may come as a surprise to many non-botanists, but not to Charles Darwin, who reported that plants do produce movements. Following Darwin’s specific interest on climbing plants, this paper will focus on the attachment mechanisms by the tendrils. We draw attention to an unsolved problem in available literature: whether during the approach phase the tendrils of climbing plants consider the structure of the support they intend to grasp and plan the movement accordingly ahead of time. Here we report the first empirical evidence that this might be the case. The three-dimensional (3D) kinematic analysis of a climbing plant (Pisum sativum L.) demonstrates that the plant not only perceives the support, but it scales the kinematics of tendrils’ aperture according to its thickness. When the same support is represented in two-dimensions (2D), and thus unclimbable, there is no evidence for such scaling. In these circumstances the tendrils’ kinematics resemble those observed for the condition in which no support was offered. We discuss these data in light of the evidence suggesting that plants are equipped with sensory mechanisms able to provide the necessary information to plan and control a movement.

It may be simpler to consider well-being to be a unidimensional construct, as hypothesized, for example, by the Oxford Happiness Questionnaire (Hills & Argyle, 2002) or by the single-item measures proposed in several contexts (

Speed-accuracy trade-off (SAT) is the tendency for decision speed to covary with decision accuracy. SAT is an inescapable property of aimed movements being present in a wide range of species, from insects to primates. An aspect that remains unsolved is whether SAT extends to plants' movement. Here, we tested this possibility by examining the swaying in circles of the tips of shoots exhibited by climbing plants (Pisum sativum L.) as they approach to grasp a potential support. In particular, by means of three-dimensional kinematical analysis, we investigated whether climbing plants scale movement velocity as a function of the difficulty to coil a support. Results showed that plants are able to process the properties of the support before contact and, similarly to animal species, strategically modulate movement velocity according to task difficulty.

A rapid response to a threatening face in a crowd is important to successfully interact in social environments. Visual search tasks have been employed to determine whether there is a processing advantage for detecting an angry face in a crowd, compared to a happy face. The empirical findings supporting the ''anger superiority effect'' (ASE), however, have been criticized on the basis of possible lowlevel visual confounds and because of the limited ecological validity of the stimuli. Moreover, a ''happiness superiority effect'' is usually found with more realistic stimuli. In the present study, we tested the ASE by using dynamic (and static) images of realistic human faces, with validated emotional expressions having similar intensities, after controlling the bottom-up visual saliency and the amount of image motion. In five experiments, we found strong evidence for an ASE when using dynamic displays of facial expressions, but not when the emotions were expressed by static face images.Keywords: Anger superiority effect; Dynamic faces; Face-in-the-crowd effect; Face perception; Emotion.Evolutionary arguments may lead us to expect that threatening faces are detected more efficiently among a crowd of distractor faces than nonthreatening faces. Because facial threat provides a particularly potent social Please address all correspondence to Corrado Caudek, Department of Neuroscience, Psychology, Pharmacology, and Child's Health (NEUROFARBA), University of Florence, Via di San Salvi 12, Complesso di San Salvi, Padiglione 26, 50135 Firenze, Italy. E-mail: corrado.caudek@unifi.it These findings suggest that the ASE might be mediated by mechanisms that are summoned only in part (or not at all) by stimuli lacking the typical dynamic characteristics of facial emotion in natural settings.

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