Development of sensitivity to information for impending collision

Infants were tested in three experiments to study the development of sensitivity to information for impending collision and to investigate the hypothesis that postural changes of very young infants in response to an approaching object are of a tracking rather than of a defensive nature. Experiment 1 involved the presentation of three types of shadow projection displays, specifying (1) collision, (2) noncollision, and (3) a nonexpanding rising contour, to infants from 1 to 9 months of age. Avoidance of collision appears to be absent in 1- to 2-month-olds, begins to develop in 4- to 6-month-olds, and is present in 8- to 9-month-old infants. In Experiment 2, 1- to 2-month-old infants were presented with optical expansion patterns which specified collision and noncollision. The top contour of these displays stayed at eye level. No significant difference was observed between reaction to the collision and the noncollision displays, suggesting that the young infants were tracking the displays and not attempting to avoid collision. Experiment 3 was designed to determine whether an approaching real object might elicit an avoidance response in infants not sensitive to an optical display specifying collision. No evidence of avoidance behavior was observed in the 1- to 2-month-olds; however, avoidance, as indexed by blinking, does appear to be present at 4 months of age.     

Neural correlates of transformational apparent motion

Transformational apparent motion (TAM) arises when a shape that is abruptly flashed on and off next to a static shape of similar color or texture appears as a protrusion that extends and retracts smoothly from the static object. Here we report that the strength of the TAM percept can be predicted from the waveform of visual evoked potentials (VEPs) measured while observers rated their percepts. The VEPs at pattern onset and offset are maximally symmetric when the static inducer and the flashing patches of the display are of the same contrast. VEP symmetry is affected by how the two patches can be matched as a single surface and may reflect the relative contribution of different motion and object detection systems in visual cortex.     

Diverse knowledges and competing interests: An essay on socio-technical problem-solving

Solving complex socio-technical problems, this paper claims, involves diverse knowledges (cognitive diversity), competing interests (social diversity), and pragmatism. To explain this view, this paper first explores two different cases: Canadian pulp and paper mill pollution and siting nuclear reactors in seismically sensitive areas of California. Solving such socio-technically complex problems involves cognitive diversity as well as social diversity and pragmatism. Cognitive diversity requires one to not only recognize relevant knowledges but also to assess their validity. Finally, it is suggested, integrating the resultant set of diverse relevant and valid knowledges determines the parameters of the solution space for the problem. The author is a Professor of Philosophy at The University of Sudbury, Ontario, Canada.     

Late maturation of visual hyperacuity

We used a visual evoked–potential measure to study the development of two components of pattern vision, vernier acuity and grating acuity, in humans from early infancy through adolescence. These two visual functions develop at similar rates and have nearly the same absolute values between 1 month and 6 years of age. After age 6, grating acuity is constant at the adult level, but vernier acuity continues to improve, becoming a hyperacuity. Vernier acuity reaches asymptotic levels around age 14 years. These results suggest that adultlike vernier hyperacuity is not limited by spatial resolution or sensitivity of small receptive fields, but rather that the limitation is imposed by higher–level processing. Sensitivity, connections in visual cortical areas, or both therefore retain plasticity throughout childhood and into adolescence.     

Emotion understanding,pictorial representations of friendship and reciprocity in school-aged children

This study examined the relationship between emotional understanding, friendship representation and reciprocity in school-aged children. Two hundred and fifty-one Caucasian 6-year-old children (111 males and 140 females) took part in the study. The Test of Emotion Comprehension (TEC) and the Pictorial Assessment of Interpersonal Relationships (PAIR) were used. Children having a reciprocal friendship and children having a unilateral friendship with a child named as their “best friend” were compared on the emotional understanding task and on their pictorial representations of friendship. Multilevel analyses indicated that friendship status effects were not influenced by classroom-level differences. Results showed that children with reciprocal friendships drew themselves as more similar to and more cohesive with their best friends, and they showed better understanding of emotions, than children having a unilateral friendship. Finally, the implications of these findings for theoretical and empirical research development on friendship are discussed.     

Lexical and sublexical cortical tuning for print revealed by Steady-State Visual Evoked Potentials (SSVEPs) in early readers

There are multiple levels of processing relevant to reading that vary in their visual, sublexical, and lexical orthographic processing demands. Segregating distinct cortical sources for each of these levels has been challenging in EEG studies of early readers. To address this challenge, we applied recent advances in analyzing high-density EEG using Steady-State Visual Evoked Potentials (SSVEPs) via data-driven Reliable Components Analysis (RCA) in a group of early readers spanning from kindergarten to second grade. Three controlled stimulus contrasts—familiar words versus unfamiliar pseudofonts, familiar words versus pseudowords, and pseudowords versus nonwords—were used to isolate coarse print tuning, lexical processing, and sublexical orthography-related processing, respectively. First, three overlapping yet distinct neural sources—left vOT, dorsal parietal, and primary visual cortex were revealed underlying coarse print tuning. Second, we segregated distinct cortical sources for the other two levels of processing: lexical fine tuning over occipito-temporal/parietal regions; sublexical orthographic fine tuning over left occipital regions. Finally, exploratory group analyses based on children's reading fluency suggested that coarse print tuning emerges early even in children with limited reading knowledge, while sublexical and higher-level lexical processing emerge only in children with sufficient reading knowledge.

Research Highlights

• Cognitive processes underlying coarse print tuning, sublexical, and lexical fine tuning were examined in beginning readers.
• Three overlapping yet distinct neural sources—left ventral occipito-temporal (vOT), left temporo-parietal, and primary visual cortex—were revealed underlying coarse print tuning.
• Responses to sublexical orthographic fine tuning were found over left occipital regions, while responses to higher-level linguistic fine tuning were found over occipito-temporal/parietal regions.
• Exploratory group analyses suggested that coarse print tuning emerges in children with limited reading knowledge, while sublexical and higher-level linguistic fine tuning effects emerge in children with sufficient reading knowledge.