Preschool language and visuospatial skills respectively predict multiplication and addition/subtraction skills in middle school children

A converging body of evidence from neuroimaging, behavioral, and neuropsychology studies suggests that different arithmetic operations rely on distinct neuro-cognitive processes: while addition and subtraction may rely more on visuospatial reasoning, multiplication would depend more on verbal abilities. In this paper, we tested this hypothesis in a longitudinal study measuring language and visuospatial skills in 358 preschoolers, and testing their mental calculation skills at the beginning of middle school. Language skills at 5.5 years significantly predicted multiplication, but not addition nor subtraction scores at 11.5 years. Conversely, early visuospatial skills predicted addition and subtraction, but not multiplication scores. These results provide strong support for the existence of a double dissociation in mental arithmetic operations, and demonstrate the existence of long-lasting links between language/visuospatial skills and specific calculation abilities.     

A tribute to Howard Rachlin and his two-parameter discounting model: Reliable and flexible model fitting

Delay discounting reflects the rate at which a reward loses its subjective value as a function of delay to that reward. Many models have been proposed to measure delay discounting, and many comparisons have been made among these models. We highlight the two-parameter delay discounting model popularized by Howard Rachlin by demonstrating two key practical features of the Rachlin model. The first feature is flexibility; the Rachlin model fits empirical discounting data closely. Second, when compared with other available two-parameter discounting models, the Rachlin model has the advantage that unique best estimates for parameters are easy to obtain across a wide variety of potential discounting patterns. We focus this work on this second feature in the context of maximum likelihood, showing the relative ease with which the Rachlin model can be utilized compared with the extreme care that must be used with other models for discounting data, focusing on two illustrative cases that pass checks for data validity. Both of these features are demonstrated via a reanalysis of discounting data the authors have previously used for model selection purposes.     

Human–Grey parrot (Psittacus erithacus) reciprocity: a follow-up study

In a previous study (Péron et al. in Anim Cogn, doi:10.1007/s10071-012.05640, 2012), Grey parrots, working in dyads, took turns choosing one of four differently coloured cups with differing outcomes: empty (null, non-rewarding), selfish (keeping reward for oneself), share (sharing a divisible reward), or giving (donating reward to other). When the dyads involved three humans with different specific intentions (selfish, giving, or copying the bird’s behaviour), birds’ responses only tended towards consistency with human behaviour. Our dominant bird was willing to share a reward with a human who was willing to give up her reward, was selfish with the selfish human, and tended towards sharing with the copycat human; our subordinate bird tended slightly towards increased sharing with the generous human and selfishness with the selfish human, but did not clearly mirror the behaviour of the copycat. We theorized that the birds’ inability to understand the copycat condition fully—that they could potentially maximize reward by choosing to share—was a consequence of their viewing the copycat’s behaviour as erratic compared with the consistently selfish or giving humans and thus not realizing that they were indeed being mirrored. We suggested that copycat trials subsequently be performed as a separate experiment, without being contrasted with trials in which humans acted consistently, in order to determine if results might have differed. We have now performed that experiment, and shown that at least one Grey parrot—our dominant—responded in a manner suggesting that he deduced the appropriate contingencies.     

Managers' Tradeoffs Between Equality and Efficiency: Preferences and Emotional Responses

In a survey questionnaire, 81 Swedish managers working in the private and public sectors were presented with scenarios in which a manager chose among inefficient (i.e., economically worse) alternatives, implying equal rewards to subordinates; and efficient (i.e., economically better) alternatives, implying unequal rewards. The managers also rated 26 different emotion words, describing their responses to the inequality of rewards in the scenarios. The results showed stronger outward‐directed and inward‐directed negative emotions, and weaker inward‐directed positive emotions when the inequality of rewards increased. Furthermore, negative emotions were found to mediate the choices among efficient and inefficient alternatives.     

Late reaction times identify MCI

A group of 172 mild cognitive impairment (MCI) patients and 79 healthy control participants (HC) were tested on simple reaction time (SRT). There was a significant difference between MCI and HC in mean SRT. The test could be partitioned into five segments of 16 trials each, but RT's were not always available for each partition. However, scores from each segment for 166 MCI and 41 of the HC's were available. These data showed that a significant interaction between RT‐partition and diagnostic category was the main source of the difference between groups. The interaction indicated that MCI patients performed at about the same level as HC in the initial three of the five segments of the test, but were significantly impaired during the last two segments of the 80 trials. The results were interpreted as impaired sustained attention among a large part of the MCI group, and the study shows the importance of taking into account all avaliable data resulting from this type of test.     

Is the principle of minimization of secondary moments validated during various fingertip force production conditions?

During the application of fingertip forces with simultaneous flexion of the four fingers, namely index, middle, ring, and little fingers, a stable force sharing among fingers is adopted. Several studies have hypothesized that this stable force sharing is established to minimize unnecessary rotational moments (different from the main flexion moments). This principle labeled "minimization of secondary moments" is presented in the literature as a principle used by the central nervous system to solve musculoskeletal redundancy. However, this principle has only been tested with one solicited degree of freedom and in one finger posture. Our study tests this principle with various degrees of freedom solicited as secondary moments and in two different finger postures. Participants (n=6) were asked to apply a downward vertical force using their four fingers with the forearm placed in two different configurations: a "horizontal" condition (involving flexion/extension and pronation/supination at the wrist joint) and a "vertical" condition (involving flexion/extension and radial/ulnar deviation at the wrist joint). Additionally, two finger postures were tested in each forearm configuration: in the first, the distal inter-phalangeal joints (DIP) were extended and the proximal inter-phalangeal joints (PIP) highly flexed. In the second finger posture, both DIP and PIP joints were flexed. The resultant four-finger force and the relative involvement of each finger in the resultant four-finger force (force sharing) were analyzed. Results showed that the finger postures did not influence the finger force sharing, showing that the minimization of the secondary moment principle was stable among the finger joint angle configurations. Nonetheless, the relative involvement of each finger was dependent on the secondary degree of freedom solicited (pronation/supination vs. radial/ulnar). The modifications of the finger force sharing between the "horizontal" and "vertical" conditions were in accordance with the principle of minimization of the secondary moments.     

Physicians' understanding of patients' personal representations of their diabetes: accuracy and association with self-care

The degree of accuracy with which physicians understand their patients' views may be of central importance for promoting self-care in the majority of chronic illnesses and in type 2 diabetes in particular. The objectives of this study were to measure the accuracy of the general practitioners' understanding of the patients' views and relate it to health behavioural outcomes in patients with non-complicated type 2 diabetes. The participants in this cross-sectional study consisted of 14 clinicians and 78 of their patients from Paris, France. The predictors were levels of accuracy in understanding the patients' views derived from the illness perception questionnaire-revised (IPQ-R). The outcomes were patient-reported self-care measures. In regression models controlling for clinical and personal variables, higher accuracy on chronicity beliefs was associated with an improved diet and increased blood glucose self-testing and higher accuracy in identifying treatment control beliefs was associated with better dietary self-care. Accuracy was higher with regard to beliefs about causes, treatment control and consequences. These results suggest that accuracy may impact self-care in specific domains of illness perception but not others. The results may help identify useful avenues of communication training designed for professionals.