A high-loaded hemisphere successfully ignores distractors

We used a response competition paradigm to investigate whether a distractor is effectively rejected under conditions where it is projected to a highly-loaded hemisphere. In two experiments we asked right-handed participants to identify a target among five task-relevant letters while they ignored a distractor. We manipulated both the distractor visual-field (low-load/high-load) and the compatibility of the target and the distractor. In the low-loaded visual-field, we presented a distractor with one task-relevant stimulus to one visual-field and the remaining task-relevant stimuli to the opposite visual-field. In the high-loaded visual-field, we presented a distractor and task-relevant stimuli in reverse. In Experiment 1 (left/right), we found a compatibility effect for the low-loaded, but not for the high-loaded visual-field. In Experiment 2, this modulation of the compatibility effect did not appear when the upper/lower visual-field was manipulated. These findings demonstrate that a distractor is successfully ignored when it is presented to a highly-loaded hemisphere.     

Ethnicity and adolescent substance use

This study focuses on diverse ethnic differences among adolescent substance use, utilizing selected items from the Substance Abuse Subtle Screening Inventory-Adolescent version (SASSI-A). Data were gathered from a large-scale, cross-sequential study of adolescents during the 1993-1996 school years. Exploratory analyses were conducted for 3,711 students on the basis of their responses to a self-administered survey. Results indicated significant ethnic and gender differences for specific SASSI-A items and factor scores, with Hawaiian, "Other," and Caucasian students reporting higher scores than Japanese students and greater scores for female than male students. These findings suggest the need to develop culturally sensitive substance use prevention and treatment strategies that should also take gender differences into consideration for adolescents in Hawai'i.     

Differences in State-Trait Anxiety Inventory scores for ethnically diverse adolescents in Hawaii

This study examined the association between anxiety and 5 predictor variables: ethnicity (Caucasian, Native Hawaiian/part Hawaiian, Japanese, other), gender, grade level (9-12th), main wage earners' educational level, and State-Trait Anxiety Inventory (STAI; C. D. Spielberger, R. L. Gorsuch, & R. E. Lushene, 1970) factors for a diverse group of students. Hawaiian students were found to have significantly higher levels of anxiety than Japanese students; however, ethnicity was not a significant predictor when gender, grade level, and main wage earners' education were statistically held constant. An interaction between ethnicity and STAI factor scores indicated an atypical pattern for Caucasians. Female students scored significantly higher than male students, and main wage earners' education predicted amount of anxiety. In general, these 2 associations remained significant when ethnicity and grade level were held constant. An interaction between gender and STAI factor scores indicated that the difference between female and male students was relatively larger for positively (as opposed to negatively) worded State items and for negatively (as opposed to positively) worded Trait items. Overall, the findings suggested that apparent ethnic differences in anxiety levels may be due to causal variables related to other sociodemographic variables. Factor scores in the form of positively versus negatively worded items should be considered an important variable; using only a global STAI composite as a measure of anxiety will mask the differential effects of the STAI factor scores. Further research is needed to determine the generalizability of these findings to other groups and to provide knowledge on direct causal variables that may account for a greater percentage of variance.     

Exploring children’s face-space: A multidimensional scaling analysis of the mental representation of facial identity

We explored differences in the mental representation of facial identity between 8-year-olds and adults. The 8-year-olds and adults made similarity judgments of a homogeneous set of faces (individual hair cues removed) using an “odd-man-out” paradigm. Multidimensional scaling (MDS) analyses were performed to represent perceived similarity of faces in a multidimensional space. Five dimensions accounted optimally for the judgments of both children and adults, with similar local clustering of faces. However, the fit of the MDS solutions was better for adults, in part because children’s responses were more variable. More children relied predominantly on a single dimension, namely eye color, whereas adults appeared to use multiple dimensions for each judgment. The pattern of findings suggests that children’s mental representation of faces has a structure similar to that of adults but that children’s judgments are influenced less consistently by that overall structure.     

Fitting the child's mind to the world: adaptive norm-based coding of facial identity in 8-year-olds

In adults, facial identity is coded by opponent processes relative to an average face or norm, as evidenced by the face identity aftereffect: adapting to a face biases perception towards the opposite identity, so that a previously neutral face (e.g. the average) resembles the identity of the computationally opposite face. We investigated whether children as young as 8 use adaptive norm-based coding to represent faces, a question of interest because 8-year-olds are less accurate than adults at recognizing faces and do not show the adult neural markers of face expertise. We found comparable face identity aftereffects in 8-year-olds and adults: perception of identity in both groups shifted in the direction predicted by norm-based coding. This finding suggests that, by 8 years of age, the adaptive computational mechanisms used to code facial identity are like those of adults and hence that children's immaturities in face processing arise from another source.     

In-situ high-voltage electron microscopy observations of reactions between molten Zn and Fe

Reactions between molten Zn and Fe have been observed directly by means of an in-situ heating experiment in a high-voltage electron microscope. In order to suppress evaporation of Zn during the in-situ heating experiment the specimen was coated with a plasma-polymerized hydrocarbon film. Mechanisms for the formation of Fe-Zn intermetallic compounds are discussed and it is concluded that all the models proposed so far are of doubtful validity.     

Effects of laterality and pitch height of an auditory accessory stimulus on horizontal response selection: The Simon effect and the SMARC effect

In the present article, we investigated the effects of pitch height and the presented ear (laterality) of an auditory stimulus, irrelevant to the ongoing visual task, on horizontal response selection. Performance was better when the response and the stimulated ear spatially corresponded (Simon effect), and when the spatial—musical association of response codes (SMARC) correspondence was maintained—that is, right (left) response with a high-pitched (low-pitched) tone. These findings reveal an automatic activation of spatially and musically associated responses by task-irrelevant auditory accessory stimuli. Pitch height is strong enough to influence the horizontal responses despite modality differences with task target.     

Visual and auditory accessory stimulus offset and the Simon effect

We investigated the effect on the right and left responses of the disappearance of a task-irrelevant stimulus located on the right or left side. Participants pressed a right or left response key on the basis of the color of a centrally located visual target. Visual (Experiment 1) or auditory (Experiment 2) task-irrelevant accessory stimuli appeared or disappeared at locations to the right or left of the central target. In Experiment 1, responses were faster when onset or offset of the visual accessory stimulus was spatially congruent with the response. In Experiment 2, responses were again faster when onset of the auditory accessory stimulus and the response were on the same side. However, responses were slightly slower when offset of the auditory accessory stimulus and the response were on the same side than when they were on opposite sides. These findings indicate that transient change information is crucial for a visual Simon effect, whereas sustained stimulation from an ongoing stimulus also contributes to an auditory Simon effect.