Do wild raccoons (Procyon lotor) use tools?

Animal Cognition - Being able to make and use tools was once considered to be an evolutionary hallmark of our species, but has since been documented in other animals. However, for reasons that...     

Outcomes of hemisphericity questionnaires correlate with unilateral dichotic deafness

Using the Dichotic Deafness Test, 145 university workers were separated into dichotic deafness and hearing groups based on minor ear responses to dichotic consonant-vowel stimuli. They were also separated into putative right and left brain-oriented groups by Zenhausern's Preference Questionnaire. Interestingly, members of the dichotically hearing group chose mainly right brain-oriented answers and vice versa. A correlation coefficient twice that obtained for Zenhausern's Preference Questionnaire resulted when subject groups separated by the novel Polarity Questionnaire were compared to Dichotic Deafness Test groups. Only 30% of Preference Questionnaire items, versus 90% of Polarity Questionnaire items, were significantly correlated with Dichotic Deafness Test groups. This is the first report of hemisphericity-type questionnaires showing significant correlations with a biophysical measure of brain laterality.     

MMPI-A scores and high points of male juvenile delinquents: scales 4, 5, and 6 as markers of juvenile delinquency

The Minnesota Multiphasic Personality Inventory-Adolescent (MMPI-A) clinical, supplementary, and content scale score patterns for 655 male delinquents were examined. Low scores on Scale 5 (Masculinity/Femininity) were found to be the most frequent deviation, followed by elevations on Scales 6 (Paranoia) and 4 (Psychopathic Deviate). This is consistent with previous research, although the importance of Scale 5 deviations has been little noted because of the traditional focus on scale elevations only. Classification analysis indicated that a combination of MMPI-A scales discriminated between this delinquent sample and the normative sample, with a sensitivity of 90%-95% and a specificity of 80%-85%. This level of sensitivity was maintained in a replication sample (N = 473).     

Keeping track: the function of the current state buffer

The Current State Buffer has been proposed to account for our ability to keep track of significant stimuli in our immediate environment. The three experiments reported here were designed to test the independence of the Current State Buffer from the established components of Working Memory. Pre-schoolers were used in order to minimize the possible interference of other memory structures and complex strategies on the part of the subjects, thus allowing a cleaner test of the hypotheses. In the experiments, 180 pre-schoolers watched an Emu glove puppet tidy away toys into receptacles (the 'Tidy Emu Paradigm'), such that the number of pairings just exceeded their capacity for recall of the locations of toys in receptacles. We take this task to be a prototypical visuospatial Working Memory task. In the Object condition of Experiment 1, a Teddy was an object and was tidied away with the other toys. In the Character condition the Teddy was an animated character who interacted with the children and then went to sleep in one of the receptacles. Where Teddy was a character, all children remembered his location even though they had not been asked to; when he was an object only half of the children were correct despite explicit instructions to remember. More crucially, the location of the other toys was better recalled for children in the Character condition than those in the Object condition. These data are taken as evidence for the independence of the Current State Buffer from the Visuospatial Sketchpad. Other explanations, such as a von Restorff effect, are considered, and Experiments 2 and 3 test and reject these as possibilities.     

Large individual differences in minor ear output during dichotic listening

Using dichotic consonant-vowel (CV) stimuli, 150 highly educated adults were segregated into two groups. In the high-output group (n = 63), the mean number of CV syllables reported by the minor ear was more than half that of the major ear, while for the low-output group (n = 87), it was less than one-fourth. The low minor ear performance of the latter group immediately disappeared when CV syllables were separated by 90 ms. These subjects (44 male, 43 females) were unaware of their temporary minor ear incapacities. Although the mechanism and brain laterality significance of this phenomenon remain to be clarified, preliminary research indicates that members of each of these two groups have other differences in common.     

Pulling smarties out of a bag: a Headed Records analysis of children's recall of their own past beliefs.

The work reported provides an information processing account of young children's performance on the Smarties task (Perner, J., Leekam, S.R., & Wimmer, H. 1987, Three-year-olds' difficulty with false belief: the case for a conceptual deficit. British Journal of Developmental Psychology, 5, 125-137). In this task, a 3-year-old is shown a Smarties tube and asked about the supposed contents. The true contents, pencils, is then revealed, and the majority of 3-year-olds cannot recall their initial belief that the tube contained Smarties. The theoretical analysis, based on the Headed Records framework (Morton, J., Hammersley, R.J., & Bekerian, D.A. 1985, Headed records: a model for memory and its failures, Cognition, 20, 1-23), focuses on the computational conditions that are required to resolve the Smarties task; on the possible limitations in the developing memory system that may lead to a computational breakdown; and on ways of bypassing such limitations to ensure correct resolution. The design, motivated by this analysis, is a variation on Perner's Smarties task. Instead of revealing the tube's contents immediately after establishing the child's beliefs about it, these contents were then transferred to a bag and a (false) belief about the bag's contents established. Only then were the true contents of the bag revealed. The same procedure (different contents) was carried out a week later. As predicted children's performance was better (a) in the 'tube' condition; and (b) on the second test. Consistent with the proposed analysis, the data show that when the computational demands imposed by the original task are reduced, young children can and do remember what they had thought about the contents of the tube even after its true contents are revealed.