Age and sex as factors influencing spontaneous exploration and object investigation by preadult rats (Rattus norvegicus).

This study examined developmental and sex differences in the exploratory and investigatory behaviors of Long-Evans rats (Rattus norvegicus). Littermate sextuplets were divided into sex-matched groups (at 30, 60, and 90 days of age) and were individually videotaped on 2 consecutive nights in an arena that contained stimulus objects. Multiple measures of locomotor exploration and object investigation increased significantly with age but were not influenced by sex. Older rats entered more quickly, were more active, spent more time in the arena, and spent more time investigating inanimate stimulus objects than did younger rats. Sex did not significantly affect most measures of open-field behavior; however, the data suggest that the sexes may begin to diverge by 90 days. These results suggest that preadult rats of both sexes are equipped early in development with similar strategies and repertoires for exploration and investigation.     

Doing as if: The histrionic self-presentation style

The histrionic self-presentation style is introduced as a concept that describes specific individual differences in self-presentation, namely, performing explicit As-If-behaviors in everyday interactions. The As-If-Scale (AIS), a trait measure of histrionic self-presentation, shows good internal consistency and test–retest reliability as well as convergent and discriminant validity in several samples. Construct validation involved determining relations between the AIS and the Big Five, histrionic role concepts, motives, competencies, humor and ambivalence. Furthermore, the AIS yielded incremental validity in predicting behaviors related to histrionic self-presentation over and above the self-monitoring construct. The possible impact of the histrionic style for research on self-presentation and other fields is discussed. It is argued that histrionic phenomena are pervasive within many facets of our western culture and therefore deserve further examination.     

Identifying topic sentencehood

Four experiments were conducted to assess two models of topic sentencehood identification: the derived model and the free model. According to the derived model, topic sentences are identified in the context of the paragraph and in terms of how well each sentence in the paragraph captures the paragraph's theme. In contrast, according to the free model, topic sentences can be identified on the basis of sentential features without reference to other sentences in the paragraph (i.e., without context). The results of the experiments suggest that human raters can identify topic sentences both with and without the context of the other sentences in the paragraph. Another goal of this study was to develop computational measures that approximated each of these models. When computational versions were assessed, the results for the free model were promising; however, the derived model results were poor. These results collectively imply that humans' identification of topic sentences in context may rely more heavily on sentential features than on the relationships between sentences in a paragraph.     

Local rather than global processing of visual arrays in numerosity discrimination by pigeons (Columba livia)

A series of experiments investigated which stimulus properties pigeons use when they discriminate pairs of visual arrays that differ in numerosity. Transfer tests with novel stimuli confirmed that the birds’ choices were based on relative differences in numerosity. However, pigeons differed from other species in the non-numerical cues that affected their choices. In human and non-human primates, numerical discrimination is often influenced by continuous variables such as surface area or overall stimulus brightness. Pigeons showed little evidence of using those cues, even when summed area and brightness had been correlated with numerosity differences and reward outcome. But when array-element sizes were asymmetrically distributed across numerosities, the birds readily utilized information about item sizes as an additional discriminative cue. These novel results are discussed in relation to pigeons’ tendency to focus on local, rather than global dimensions when they process other non-numerical complex visual stimuli. The findings suggest there may be inter-specific differences in the type of perceptual information that provides the input stage for mechanisms underlying numerical processing. Electronic supplementary material  The online version of this article (doi:) contains supplementary material, which is available to authorized users.     

Hindsight bias after receiving self-relevant health risk information: a motivational perspective

The phenomenon of hindsight bias was explored in the context of self-relevant health risk information. Participants in a community screening estimated their cholesterol level (foresight measure) before receiving positive or negative feedback based on their actual cholesterol level. Hindsight estimations were then assessed twice: once immediately after the feedback, and again several weeks later. While the unexpected positive feedback group showed no systematic recall bias, hindsight estimations of individuals receiving unexpectedly negative feedback showed a dynamic change over time. Immediately after the feedback, participants' recollection of their expected cholesterol level were shifted towards their actual cholesterol level (hindsight bias). In contrast, several weeks later, foresight estimations were recalled as less accurate than they had been (reversed hindsight bias). These data might reflect a change of the motivational focus from "hot affect" and fear control, which occur immediately after receiving negative feedback, to danger control, which occurs some time after the feedback, as proposed by the dual process model.     

Performance-based measures in autism: implications for diagnosis, early detection, and identification of cognitive profiles

Provides a critical review of performance-based assessment measures in autism. Currently, performance-based measures of autism are being explored in two domains: structured play sessions and cognitive-neuropsychological assessments. Structured play sessions are designed to elicit the behavioral symptoms associated with autism to provide a consistent and valid means of early detection and diagnosis of autism across different evaluators and settings. These structured play sessions provide a supplement to diagnostic instruments based on parental report. Cognitive-neuropsychological tasks have been used to identify possible underlying cognitive impairments in autism including executive function, theory of mind, selective attention, and abstraction. Currently, cognitive tasks are useful in treatment planning but are inappropriate for diagnostic purposes. Important goals for the future will be to integrate parent-report diagnostic interviews and structured play observations and to identify a profile of cognitive impairments that are specific to pervasive developmental disorders that can be incorporated into diagnostic protocols.     

Defining Elemental Imitation Mechanisms: A Comparison of Cognitive and Motor-Spatial Imitation Learning Across Object- and Computer-Based Tasks

During the first 5 years of life, the versatility, breadth, and fidelity with which children imitate change dramatically. Currently, there is no model to explain what underlies such significant changes. To that end, the present study examined whether task-independent but domain-specific—elemental—imitation mechanism explains performance across imitation tasks or domains. Preschool-age children (n = 156) were tested on 4 imitation tasks, 2 object-based (animal, puzzle box) and 2 computer-based (cognitive, motor-spatial). All tasks involved 3 serial actions. The animal task involved making an animal face, and the puzzle box task involved manipulating a box to retrieve a reward. The cognitive task involved responding to 3 different pictures in a specific picture order, and the motor-spatial task involved responding to 3 identical pictures in a specific spatial order. A principal component analysis including performance on all 4 tasks produced 2 components: “cognitive imitation” (cognitive and animal tasks) and “motor-spatial imitation” (motor-spatial and puzzle box tasks). Regression analyses replicated these results. These findings provide preliminary support for the hypothesis that underlying performance across these different tasks involves multiple—elemental—imitation mechanisms for learning and copying domain-specific information across tasks.     

The “New Big Five” from a personalistic point of view

McAdams and Pals (2006) “New Big Five” principles are contrasted with William Stern's conception of the person. It is criticized that the intra-individual organization of the person is not adequately addressed in the “New Big Five” approach: McAdams and Pals are shifting the issue of the idiosyncratic organization of the person to the level of a more or less coherent life narrative. The person tells or constructs a narrative, the person, however, is not the narrative.It is therefore suggested to complement and enrich the “New Big Five” with the three primary characteristics of the person as proposed by William Stern: unitas multiplex, purposefulness and individuality. In addition, Stern's concept of introception is suggested as a more integrated view of how the external world is internalized within the person. In concluding, the significance of Stern's critical personalism for an integrative science of personality in the 21^st century is highlighted.