Encoding richness of self-generated elaboration and spacing effects on incidental memory

The present study investigated encoding variability in self-generated elaboration on incidental memory as a function of the type of presentation which was either massed or spaced. The subjects generated different answers to a "why" question for the first and the second presentations of a target sentence in a self-generated elaboration condition. In an experimenter-provided elaboration condition they then rated the appropriateness of the different answers provided by the experimenter for the first and second presentations. This procedure was followed by two free recall tests, one of which was immediate and the other delayed. A self-generated elaboration effect was observed in both the spaced and the massed presentations. These results indicated that the self-generated elaboration effect was facilitated, even in the massed presentation because the different answers to the first and the second presentations led to a richer encoding of each target.     

Kanizsa's shrinkage illusion produced by a misapplied 3-D corrective mechanism

In order to include the monocular areas from the left and the right eye in the cyclopean view, the visual system displaces the occluded elements which would result in a horizontal elongation of the shape but does not occur thanks to a correction mechanism which preserves the shape. We hypothesised that this mechanism causes Kanizsa's amodal shrinkage illusion (the apparent elongation of a partially occluded square) when it is incorrectly applied by the visual system to a two-dimensional stimulus. Four experiments tested this hypothesis: (i) one-eyed observers were less susceptible to the illusion than people with normal binocular vision because, for them, the correction for shape is unnecessary; (ii) the illusion was stronger with binocular than with monocular vision since binocularity induces the visual system to correct for the shape distortion; (iii) the illusion diminished when the stimulus was rotated 90 degrees given that displacement and compression are not required for vertical occlusion; (iv) the magnitude of the illusion was a function of the width of the occluder because, as previous research has shown, the edges of a partially occluded square are less displaced the farther they are from the edges of the occluder. The data from the four experiments support our hypothesis even though no condition was able to eliminate the illusion; other possible causes are discussed.     

Involvement of IP3 receptors in LTP and LTD induction in guinea pig hippocampal CA1 neurons

The role of inositol 1, 4, 5-trisphosphate receptors (IP3Rs) in long-term potentiation (LTP) and long-term depression (LTD) was studied in CA1 neurons in guinea pig hippocampal slices. In standard solution, short tetanic stimulation consisting of 15 pulses at 100 Hz induced LTP, while three short trains of low-frequency stimulation (LFS; 200 pulses at 1 Hz) at 18-min intervals or one long train of LFS (1000 pulses at 1 Hz) induced stable LTD in both the slope of the field EPSP (S-EPSP) and the amplitude of the population spike (A-PS). Bath application of 2-aminoethoxydiphenyl borate (2-APB), an IP3R antagonist, or of alpha-methyl-4-carboxyphenylglycine (MCPG), a wide-spectrum metabotropic glutamate receptor antagonist, during weak tetanic stimulation significantly increased the magnitude of the LTP in both the S-EPSP and A-PS. Three short trains of LFS or one long train of LFS delivered in the presence of 2-APB or MCPG did not induce LTD, but elicited LTP. Based on these results, we conclude that, in hippocampal CA1 neurons, IP3Rs play an important role in synaptic plasticity by attenuating LTP and facilitating LTD.     

Multidimensional unfolding analyses of ranking data for groups

One probabilistic version of Coombs' unfolding model called the MMUR (Marginalization model for the Multidimensional Unfolding analysis of Ranking data) is extended to treat ranking data for groups. One favorable feature of the model is that it can both take into consideration individual differences without estimating the subject parameters and capture the differences between the groups in a systematic manner. Another advantage lies in the fact that one can see the group differences in the geometrical point configuration, since the model shows how the ideal points of the groups differ from each other in space. Four applications are provided which demonstrate that the model is useful for clarifying systematic differences in this type of data.     

Tactile pattern recognition by graphic display: Importance of 3-D information for haptic perception of familiar objects

Haptic recognition of familiar objects by the early blind, the late blind, and the sighted was investigated with two-dimensional (2-D) and three-dimensional (3-D) stimuli produced by small tactor-pins. The 2-D stimulus was an outline of an object that was depicted by raising tactor-pins to 1.5 mm. The 3-D stimulus was a relief that was produced by raising the tactors up to 10 mm, corresponding to the height of the object. Mean recognition times for correct answers to the 3-D stimuli were faster than those for the 2-D stimuli, in all three subject groups. No statistically significant differences in percentage of correct responses between the 2-D and the 3-D stimuli were found for the late-blind and sighted groups, but the early-blind group demonstrated a significant difference. In addition, the haptic legibility for the quality of depiction of the object, without regard to whether or not the stimulus was understood, was measured. The haptic legibility of the 3-D stimuli was significantly higher than that of the 2-D stimuli for all the groups. These results suggest that 3-D presentation seems to promise a way to overcome the limitations of 2-D graphic display.     

The stereoscopic views of Wheatstone and Brewster

Summary The study of stereopsis, made possible by the invention of the stereoscope, freed binocular vision from the yoke of monocular phenomena. Wheatstone used this freedom to determine the factors involved in the perception of size and distance, and interpreted them within a cognitive framework. He devised an adjustable stereoscope which allowed him to apply the systematic experimental procedures of physics to the phenomena of depth perception. Brewster, by contrast, tried to force the newly discovered binocular phenomena back into the mould of monocular vision, using the lever of visible direction. His interpretations of visual phenomena, be they monocular or binocular, could be reduced to the two fundamental laws of visible direction and distinct vision. While Wheatstone's cognitive approach influenced Helmholtz, and thereby modern cognitive theorists. Brewster's interpretations, based as they were in analyses of the retinal projection, find an echo in modern direct theorists.     

The subjective size of visual stimuli affects the perceived duration of their presentation

The perception of time spent looking at a stimulus is lengthened or shortened when its physical attributes, such as area, differ from those of a comparison stimulus. We measured the perceived presentation duration of a visual object whose apparent area was altered by the Ebbinghaus illusion while its physical size remained invariant, so that a central circle surrounded by larger inducers appeared smaller than a same-size central circle surrounded by smaller inducers. The results showed that the perceived duration of presentation for apparently larger circles was longer than that of apparently smaller circles, although the actual area remained invariant across all circles. We concluded that the time perception process receives input from later visual processing.     

"Robovie, you'll have to go into the closet now": children's social and moral relationships with a humanoid robot

Children will increasingly come of age with personified robots and potentially form social and even moral relationships with them. What will such relationships look like? To address this question, 90 children (9-, 12-, and 15-year-olds) initially interacted with a humanoid robot, Robovie, in 15-min sessions. Each session ended when an experimenter interrupted Robovie's turn at a game and, against Robovie's stated objections, put Robovie into a closet. Each child was then engaged in a 50-min structural-developmental interview. Results showed that during the interaction sessions, all of the children engaged in physical and verbal social behaviors with Robovie. The interview data showed that the majority of children believed that Robovie had mental states (e.g., was intelligent and had feelings) and was a social being (e.g., could be a friend, offer comfort, and be trusted with secrets). In terms of Robovie's moral standing, children believed that Robovie deserved fair treatment and should not be harmed psychologically but did not believe that Robovie was entitled to its own liberty (Robovie could be bought and sold) or civil rights (in terms of voting rights and deserving compensation for work performed). Developmentally, while more than half the 15-year-olds conceptualized Robovie as a mental, social, and partly moral other, they did so to a lesser degree than the 9- and 12-year-olds. Discussion focuses on how (a) children's social and moral relationships with future personified robots may well be substantial and meaningful and (b) personified robots of the future may emerge as a unique ontological category.     

Context-dependent olfactory learning monitored by activities of salivary neurons in cockroaches

Context-dependent discrimination learning, a sophisticated form of nonelemental associative learning, has been found in many animals, including insects. The major purpose of this research is to establish a method for monitoring this form of nonelemental learning in rigidly restrained insects for investigation of underlying neural mechanisms. We report context-dependent olfactory learning (occasion-setting problem solving) of salivation, which can be monitored as activity changes of salivary neurons in immobilized cockroaches, Periplaneta americana. A group of cockroaches was trained to associate peppermint odor (conditioned stimulus, CS) with sucrose solution reward (unconditioned stimulus, US) while vanilla odor was presented alone without pairing with the US under a flickering light condition (1.0 Hz) and also trained to associate vanilla odor with sucrose reward while peppermint odor was presented alone under a steady light condition. After training, the responses of salivary neurons to the rewarded peppermint odor were significantly greater than those to the unrewarded vanilla odor under steady illumination and those to the rewarded vanilla odor was significantly greater than those to the unrewarded peppermint odor in the presence of flickering light. Similar context-dependent responses were observed in another group of cockroaches trained with the opposite stimulus arrangement. This study demonstrates context-dependent olfactory learning of salivation for the first time in any vertebrate and invertebrate species, which can be monitored by activity changes of salivary neurons in restrained cockroaches.