Representation of two geometric features of the environment in the domestic chick (<Emphasis Type="Italic">Gallus gallus</Emphasis>)

We report experiments based on a novel test in domestic chicks (Gallus gallus), designed to examine the encoding of two different geometric features of an enclosed environment: relative lengths of the walls and amplitude of the corners. Chicks were trained to search for a food reward located in one corner of a parallelogram-shaped enclosure. Between trials, chicks were passively disoriented and the enclosure was rotated, making reorientation possible only on the basis of the internal spatial structure of the enclosure. In order to reorient, chicks could rely on two sources of information: the relative lengths of the walls of the enclosure (associated to their left-right sense order) and the angles subtended by walls at corners. Chicks learned the task choosing equally often the reinforced corner and its rotational equivalent. Results of tests carried out in novel enclosures, the shapes of which were chosen ad hoc (1) to induce reorientation based only on the ratio of walls lengths plus sense (rectangular enclosure), or (2) to induce reorientation based only on corner angles (rhombus-shaped enclosure), suggested that chicks encoded both features of the environment. In a third test, in which chicks faced a conflict between these geometric features (mirror parallelogram-shaped enclosure), reorientation seemed to depend on the salience of corner angles. These results shed light on the elements of the environmental geometry which control spatial reorientation, and broaden the knowledge on the geometric representation of space in animals.     

Representing others' actions: just like one's own?

Previous research has shown that observing others' actions can affect individual performance of the same actions. In the present study, we developed a new paradigm to investigate whether and how complementary actions at the disposal of another agent are represented and influence one's own actions. A spatial compatibility task was distributed among two people so that each participant took care of one of two responses. The identical task was performed alone and alongside another participant. There was a spatial compatibility effect in the group setting only. It was similar to the effect obtained when one person took care of both responses. This result suggests that one's own actions and others' actions are represented in a functionally equivalent way.     

Syntactic priming of relative clause attachments: persistence of structural configuration in sentence production

Three sentence completion experiments will be reported in which participants had to generate German equivalents of "the servant of the actress who..." (NP-of-NP-RC) constructions. Target fragments (which were unconstrained as to whether the relative pronoun permitted high or low attachment) were preceded by constrained prime fragments, which were either structurally congruent with the targets (Experiments 1 and 2) or structurally incongruent with the targets (anaphoric adverbial clauses rather than relative clauses (RCs), Experiment 3). While the first two experiments established reliable repetition of RC attachments between primes and targets, Experiment 3 failed to obtain a significant priming effect, indicating that RC attachment priming is dependent on a syntactic overlap between primes and targets. The results suggest a tendency of language producers to retain hierarchical syntactic relations over consecutive trials. Current models of syntactic priming in production do not offer an explanatory mechanism for this kind of observation as they presently stand.     

Developmental dyslexia in different languages: language-specific or universal?

Most of the research on developmental dyslexia comes from English-speaking countries. However, there is accumulating evidence that learning to read English is harder than learning to read other European orthographies (Seymour, Aro, & Erskine, 2003). These findings therefore suggest the need to determine whether the main English findings concerning dyslexia can be generalized to other European orthographies, all of which have less irregular spelling-to-sound correspondences than English. To do this, we conducted a study with German- and English-speaking children (n=149) in which we investigated a number of theoretically important marker effects of the reading process. The results clearly show that the similarities between dyslexic readers using different orthographies are far bigger than their differences. That is, dyslexics in both countries exhibit a reading speed deficit, a nonword reading deficit that is greater than their word reading deficit, and an extremely slow and serial phonological decoding mechanism. These problems were of similar size across orthographies and persisted even with respect to younger readers that were at the same reading level. Both groups showed that they could process larger orthographic units. However, the use of this information to supplement grapheme-phoneme decoding was not fully efficient for the English dyslexics.     

The effect of grammatical gender and semantic context on lexical access in Italian using a timed word-naming paradigm

The effects of sentence context and grammatical gender on lexical access were investigated in Italian using a timed word-naming paradigm. Large main effects of both sentence context and the gender of the article were observed; the interaction between gender and semantics was significant over subjects. Strong facilitation by both gender and semantics was observed, relative to a neutral-control baseline condition. Results are compared with (1) a prior study with the same design, using a picture-naming paradigm, except that objects described by written words were replaced by pictures (Bentrovato, Devescovi, D'Amico, & Bates, 1999); (2) a separate norming study of timed word reading in a list format, using the same stimuli (D'Amico, Devescovi, & Bates, 2001); and (3) a prior study of German comparing word and picture naming in short, semantically neutral phrases (Jacobsen, 1999). Differences in methodology and in findings between the Italian word naming and the German word naming are compared and discussed. Findings of the present study are interpreted in support of interactive-activation models in which different sources of information are combined on-line to predict, anticipate, or preactivate lexical targets.     

Responding for sucrose and wheel-running reinforcement: effects of sucrose concentration and wheel-running reinforcer duration

Six male albino rats were placed in running wheels and exposed to a fixed-interval 30-s schedule of lever pressing that produced either a drop of sucrose solution or the opportunity to run for a fixed duration as reinforcers. Each reinforcer type was signaled by a different stimulus. In Experiment 1, the duration of running was held constant at 15 s while the concentration of sucrose solution was varied across values of 0, 2.5. 5, 10, and 15%. As concentration decreased, postreinforcement pause duration increased and local rates decreased in the presence of the stimulus signaling sucrose. Consequently, the difference between responding in the presence of stimuli signaling wheel-running and sucrose reinforcers diminished, and at 2.5%, response functions for the two reinforcers were similar. In Experiment 2, the concentration of sucrose solution was held constant at 15% while the duration of the opportunity to run was first varied across values of 15, 45, and 90 s then subsequently across values of 5, 10, and 15 s. As run duration increased, postreinforcement pause duration in the presence of the wheel-running stimulus increased and local rates increased then decreased. In summary, inhibitory aftereffects of previous reinforcers occurred when both sucrose concentration and run duration varied; changes in responding were attributable to changes in the excitatory value of the stimuli signaling the two reinforcers.     

The unification of mind: Integration of hemispheric semantic processing

Seventy-six participants performed a visual half-field lexical decision task at two different stimulus onset asynchronies (50 or 750 ms). Word targets were primed either by a highly associated word (e.g., CLEAN-DIRTY), a weakly associated word (e.g., CLEAN-TIDY), or an unrelated word (e.g., CLEAN-FAMILY) projected to either the same or opposite visual field (VF) as the target. In the short SOA, RVF-left hemisphere primes resulted in high associate priming regardless of target location (ipsilateral or contralateral to the prime) whereas LVF-right hemisphere primes produced both high and low associate priming across both target location conditions. In the long SOA condition, contralateral priming patterns converged, demonstrating only high associate priming in both VF locations. The results of this study demonstrate the critical role of interhemispheric transfer in semantic processing and indicate a need to elaborate current models of semantic processing.     

Familial handedness and spatial ability: a study with Chinese students aged 14-24

This study tested Annett's right-shift theory on spatial ability with two samples from China. The Vandenberg Mental Rotation Test (MRT), Edinburgh Handedness Inventory, and Family Handedness Questionnaire were administered to 266 high school students and 297 undergraduates. We found very few r++ or r-- among Chinese students. Most Chinese are either moderately right-handed or ambidextrous. Consistent with Casey's finding, we found using different methods to classify handedness leads to different conclusions. However, we did not find the effect of familial handedness that Casey found. Visual strategy is related to success on the MRT but handedness is not.     

Repetition effects for words and nonwords as indexed by event-related fMRI: a preliminary study

We have previously shown differential effects of stimulus familiarity on the repetition-related responses in right fusiform cortex to both faces and symbols. Repetition of familiar stimuli produced a response decrease, whereas repetition of unfamiliar stimuli produced a response increase. In the present experiment, we used words and nonwords as the familiar and unfamiliar stimuli respectively. In this case, the only fusiform region showing the familiarity-by-repetition interaction was in anterior left fusiform. This left-lateralisation of the fusiform interaction is consistent with our hypothesis that these repetition-related effects occur in the same regions responsible for perceptual recognition of familiar stimuli.     

Beyond the Obvious: Chronic Vividness of Imagery and the Use of Information in Decision Making

The authors investigate two competing hypotheses about how chronic vividness of imagery interacts with the vividness and salience of information in decision making. Results from four studies, covering a variety of decision domains, indicate that chronic imagery vividness rarely amplifies the effects of vivid and salient information. Imagery vividness may, in fact, attenuate the effects of vivid and salient information. This is because, relative to nonvivid imagers, vivid imagers rely less on information that appears obvious and rely more on information that seems less obvious. This tendency is so robust that vividness of imagery may amplify the effects of vivid information only when this information is the only information available in the decision field. The findings seem to reflect vivid imagers' tendency to totally immerse themselves in a decision problem and scrutinize the available information creatively.