Is the link between forebrain size and feeding innovations caused by confounding variables? A study of Australian and North American birds

The short notes of ornithology journals feature new and unusual feeding behaviours, which, when systematically collated, could provide a quantitative estimate of behavioural flexibility in different bird groups. Previous studies suggest that taxonomic variation in the frequency of new behaviours (innovations) is correlated with variation in relative forebrain size. Recent work on primates shows, however, that observer bias can affect innovation frequency. We assess this possibility in birds via three estimates in North America and Australia: the number of full-length papers in academic journals, the frequency of photographs in birding magazines and a questionnaire on reporting bias given to ornithologists at a meeting. We also look at sampling effects due to single journal sources by doing a split-half analysis of our North American database (The Wilson Bulletin vs. six other journals) and adding three new Australian journals to the one we had used previously. In multiple regressions that also included species number per taxon, none of the potential biases could account for the correlation between forebrain size and innovation frequency. Species number was the best predictor of full-length paper frequency, which was the best predictor of photograph numbers. Ornithologists are not preferentially interested in innovative, large-brained taxa, suggesting that the correlation between innovations and neural substrate size is not a spurious effect of the biases examined here. Accepted after revision: 27 July 2001 Electronic Publication     

Item to decision mapping in rapid response learning

Repeated classification of a visually presented stimulus rapidly leads to a form of response learning that bypasses the original evaluation in favor of a more efficient response mechanism. In two experiments, we examined the level of input and output representations that make up this form of learning. In Experiment 1, alterations in the finger mapping of the output response had no effect on the expression of response learning, demonstrating that a classification decision, not motor output, is associated with repeated items. In Experiments 2A and 2B, we tested whether response learning would transfer across different visual exemplars of a studied item. There was no evidence of transfer to different visual exemplars, even when these exemplars were judged to be highly visually similar. Taken together, these results indicate that response learning consists of the formation of an association between a specific visual representation and a classification decision.     

The effect of divided attention on false memory depends on how memory is tested

In three experiments, we investigated the effects of divided attention on false memory, using the Deese/Roediger-McDermott (DRM) paradigm. In Experiments 1 and 2, participants studied six DRM lists with full attention and six in one of two divided-attention conditions (random number generation or digit monitoring). Both divided-attention conditions increased false recall of related words (Experiment 1) but reduced false recognition (Experiment 2). These results were confirmed in Experiment 3, in which the type of secondary task was manipulated within groups. We argue that the increase in false recall with divided attention reflects a change in participants' response criterion, whereas the decrease in false recognition occurs because the secondary tasks prevent participants from generating associates of the words presented at study.     

Cognitive imitation in typically-developing 3- and 4-year olds and individuals with autism

Individuals diagnosed with autism suffer from numerous social, affective and linguistic impairments. It has also been suggested that they have a global imitation deficit. That hypothesis, however, is compromised by the fact that individuals with autism suffer from various motor impairments. Here we describe an experiment on cognitive imitation, a type of imitation that doesn’t require motor learning. Nine male autistic subjects and 20 typically-developing 3- and 4-year olds were trained to respond, in a prescribed order, to different lists of photographs that were displayed simultaneously on a touch-sensitive monitor. Because the position of the photographs varied randomly from trial to trial, sequences could not be learned by motor imitation. In three different imitation treatments, including a ghost control, autistic subjects learned new sequences more rapidly after observing a model execute those sequences than when they had to learn new sequences entirely by trial and error. Moreover, the performance of autistic subjects did not significantly differ from the performance of typically-developing controls. The result of this and other studies suggests that individuals with autism suffer from a specific novel motor imitation deficit.     

"If you want me to treat you like an adult, start acting like one!" Comparing the criteria that emerging adults and their parents have for adulthood.

The purpose of this study was (a) to identify the criteria parents of emerging adults consider necessary and important for their children to achieve adulthood, (b) to compare parents' criteria for adulthood with the criteria espoused by emerging adults, and (c) to examine how these criteria might differ on the basis of gender of the parent and gender of the child. Participants included 392 unmarried college students, ages 18-25, and at least 1 of their parents (271 fathers, 319 mothers). Results revealed that (a) as did their children, most parents did not yet view their children as adults, (b) there was disagreement between children and their parents in the emphasis they placed on various criteria for adulthood, (c) mothers and fathers did not always agree on the importance of various criteria, and (d) the gender of both the parent and the child played a role in the criteria parents deemed important for adulthood. Taken together, the findings suggest that parents and children view the transition to adulthood differently, which might have implications for the parent-child relationship during this period of development.     

Prevalence of poor psychological morbidity following a minor road traffic accident (RTA): The clinical implications of a prospective longitudinal study

Few Road Traffic Accident (RTA) victims have their psychological needs attended to in hospital or afterwards. We conducted a small-scale preliminary investigation exclusively focussing on the prevalence of poor psychological morbidity following minor road traffic accidents (RTAs). Participants (N?=?50) completed assessments one-month after their minor RTA and (N?=?39) at 4-months follow-up. The identification of clinically significant anxiety, depression and post traumatic stress disorder (PTSD) in this minor RTA sample supports both evidence reported elsewhere and our specific predictions. Seven (14%) participants at baseline and five (12.8%) at follow-up met diagnostic criteria for PTSD. The clinical implications for identifying and meeting the psychological needs of minor RTA victims are discussed in the context of cognitive behavioural conceptualizations of mental disorder.     

Dissociative tendencies and memory performance on directed-forgetting tasks

The current article presents two studies that aimed to replicate DePrince and Freyd's (2001, 2004) studies demonstrating that high and low dissociators differentially recall neutral and trauma words under conditions of varying cognitive load. We did not find this effect. This lack of replication was apparent for both free recall and word recognition memory and in both studies. In effect, we found little evidence to support betrayal trauma theory, yet observed increased memory fallibility, as demonstrated by lower general recall and (in one study) commission errors, in high dissociators.     

Better the DVL you know: acronyms reveal the contribution of familiarity to single-word reading

Current theories of reading are divided between dual-route accounts, which propose that separable processes subserve word recognition for orthographically regular and irregular strings, and connectionist models, which propose a single mechanism mapping form to meaning. These theories make distinct predictions about the processing of acronyms, which can be orthographically illegal and yet familiar, as compared with the processing of pseudowords, which are regular but unfamiliar. This study examined whether acronyms are processed like pseudowords and words. Event-related potentials (ERPs) were recorded as subjects viewed familiar and unfamiliar acronyms, words, pseudowords, illegal strings, and--as the targets of the substantive behavioral task--proper names. Familiar acronyms elicited repetition effects on the N400 component, a functionally specific index of semantic activation processes; repetition effects for familiar acronyms were similar in magnitude, timing, and scalp distribution to those for words and pseudowords. The similarity of the brain response to familiar--but--illegal and unfamiliar--but--legal classes of stimuli is inconsistent with predictions of dual-route models of reading.     

Satisfactions and Regrets of Midlife Parents: A Qualitative Analysis

The study examined the satisfactions and regrets of midlife parents at a specific family life-cycle milestone, their child’s graduation from high school. The purpose was to compare mothers’ and fathers’ appraisals of the gains and losses associated with this developmental transition and turning point in their parenting roles. A total of 260 parents (147 mothers; 113 fathers) who had a child graduating from high school responded in writing to open-ended questions regarding their satisfactions and regrets at this stage of their lives. Responses were coded to identify themes salient to these parents. Results indicate that both mothers and fathers are aware of both the gains and losses at this time in their family life cycle, but they differed in how they expect to be affected by the transition. Mothers’ responses suggest that they are anticipating and planning for the transition. Fathers’ responses suggest they are less aware of the personal implications of this family transition and are less prepared for its emotional impact.