Friendship similarity during early adolescence: gender and racial patterns.

We studied the relationship of reciprocity, gender, and racial composition (Caucasian, African American, cross-race) of adolescent friendship dyads to similarity and proximity in 136 young adolescents. We found that adolescents selected friends who were of the same gender and race and that female dyads were more similar than male dyads on verbal achievement and several personality dimensions. Caucasian dyads were more similar than African American dyads on verbal achievement, mental alertness, and dominance. African American adolescents had more contact with their best friends outside school, whereas Caucasian adolescent friends had more in-school contact. African American students had fewer reciprocal relationships than the Caucasian students. Cross-race friendships were less reciprocal than same-race friendships. Race and gender were important in determining friendship patterns. Similarity and proximity were more important than reciprocity in understanding early adolescent friendships.     

The rolling totals method of computing sums,sums of squares,and sums of cross-products

The rolling totals method of computing sums, sums of squares, and sums of cross-products appears to have several advantages over usual methods, in that it saves time and requires less equipment. Only an IBM sorter and a tabulator equipped with Card Cycle Total Transfer Device are used. The method provides an immediate independent visual check on the accuracy of the sums of cross-products of each successive variable as it is run. Since controlling is done by sorting, the necessity for re-wiring after each run on the tabulator is eliminated. The wiring, illustrated by a diagram, is simple and straightforward.ABITIBI POWER AND PAPER COMPANY     

The City Infant Faces Database: A validated set of infant facial expressions

Adults need to be able to process infants’ emotional expressions accurately to respond appropriately and care for infants. However, research on processing of the emotional expressions of infant faces is hampered by the lack of validated stimuli. Although many sets of photographs of adult faces are available to researchers, there are no corresponding sets of photographs of infant faces. We therefore developed and validated a database of infant faces, which is available via e-mail request. Parents were recruited via social media and asked to send photographs of their infant (0–12 months of age) showing positive, negative, and neutral facial expressions. A total of 195 infant faces were obtained and validated. To validate the images, student midwives and nurses (n = 53) and members of the general public (n = 18) rated each image with respect to its facial expression, intensity of expression, clarity of expression, genuineness of expression, and valence. On the basis of these ratings, a total of 154 images with rating agreements of at least 75% were included in the final database. These comprise 60 photographs of positive infant faces, 54 photographs of negative infant faces, and 40 photographs of neutral infant faces. The images have high criterion validity and good test–retest reliability. This database is therefore a useful and valid tool for researchers.     

A mechanistic account of the mirror effect for word frequency: a computational model of remember-know judgments in a continuous recognition paradigm

A theoretical account of the mirror effect for word frequency and of dissociations in the pattern of responding Remember vs. Know (R vs. K) for low- and high-frequency words was tested both empirically and computationally by comparing predicted with observed data theory in 3 experiments. The SAC (Source of Activation Confusion) theory of memory makes the novel prediction of more K responses for high- than for low-frequency words, for both old and new items. Two experiments used a continuous presentation and judgment paradigm that presented words up to 10 times. The computer simulation closely modeled the pattern of results, fitting new Know and Remember patterns of responding at each level of experimental presentation and for both levels of word frequency for each participant. Experiment 3 required list discrimination after each R response (Group 1) or after an R or K response (Group 2). List accuracy was better following R responses. All experiments were modeled using the same parameter values.     

“If I didn’t write it,why would I remember it?” Effects of encoding,attention, and practice on accurate and false memory

In two experiments involving recall and recognition, we manipulated encoding strategies, attention, and practice in the Deese, Roediger, and McDermott false memory procedure. During the study of auditory word lists, participants listened to the words, wrote the words, wrote the second letter of the words, or counted backward by threes and wrote numbers in time with the words. The results from both experiments showed that, relative to the full-attention hear word condition, the divided-attention write number condition impaired accurate memory, but not false memory. In contrast, the focused-attention write word and write second letter conditions were comparable to the hear word condition in producing accurate memory, yet they were better at reducing false memory. But even after multiple study-test trials, people still falsely recalled or recognized words that they had never written during study. These results are consistent with predictions generated from fuzzy trace theory and the activation/monitoring framework.     

People don't exercise because they can't think of reasons to exercise: an examination of causal reasoning within the Transtheoretical Model

This study compared the accessibility of the pros (advantages) and cons (disadvantages) of exercise in a group of non-exercisers and regular exercisers, using the Transtheoretical Model of behaviour change as a theoretical framework. Pre-contemplators (n?=?18), and maintainers (n?=?25), were asked to generate a list of 'advantages to taking part in exercise' (pro reasons), and a list of 'disadvantages to taking part in exercise' (con reasons). The time to generate their first item was recorded as well as the total number of items generated within 60?s. The results showed that pre-contemplators provided more con reasons relative to pro reasons; and maintainers provided more pro reasons relative to con reasons for exercise. Pre-contemplators were also quicker to provide their first con reason, relative to their first pro reason, but there was no difference in pro and con latencies in the maintainers. It was concluded that one reason pre-contemplation individuals do not participate in regular exercise may be because they cannot think of reasons to exercise.     

Reported sleep: needed minus obtained sleep, family resemblance, and age

For a normal population from 13 to 89 yr. of age there was a correlation of .02 between age and sleep obtained, -.07 between age and sleep needed, and -.33 (p less than .01) between age and sleep needed minus sleep obtained. Also, significant family resemblance was found for all three of the above sleep variables.