Hesperus is Phosphorus, Indeed

Tobias Hansson Wahlberg argues in a recent article that the truth of “Hesperus is Phosphorus” depends on the assumption that the endurance theory of persistence is true. I argue that the premise Wahlberg’s conclusion is based upon leads to absurd consequences, therefore, nothing recommends it. As a consequence, “Hesperus is Phosphorus” has to be true, if it is true, regardless of which theory of persistence one is committed to.     

Strategies for written additions in adults

Studies about strategies used by adults to solve multi-digit written additions are very scarce. However, as advocated here, the specificity and characteristics of written calculations are of undeniable interest. The originality of our approach lies in part in the presentation of two-digit addition problems on a graphics tablet, which allowed us to precisely follow and analyse individuals’ solving process. Not only classic solution times and accuracy measures were recorded but also initiation times and starting positions of the calculations. Our results show that adults largely prefer the fixed columnar strategy taught at school rather than more flexible mental strategies. Moreover, the columnar strategy is executed faster and as accurately as other strategies, which suggests that individuals’ choice is usually well adapted. This result contradicts past educational intuitions that the use of rigid algorithms might be detrimental to performance. We also demonstrate that a minority of adults can modulate their strategy choice as a function of the characteristics of the problems. Tie problems and additions without carry were indeed solved less frequently through the columnar strategy than non-tie problems and additions with a carry. We conclude that the working memory demand of the arithmetic operation influences strategy selection in written problem-solving.     

“Not performing worse but feeling older !” the negative effect of the induction of a negative aging stereotype

The present research investigated the effect of the induction of a negative stereotype on older adults’ performance during an endurance task, and how this stereotype influenced older adults’ subjective age. Thirty-four old women were randomly assigned to one of the two conditions: a negative stereotype condition and a nullified-stereotype condition. They performed an endurance task consisting of maintaining 30% of their maximal strength, as long as possible. Then, they answered a questionnaire including subjective age measurement. Contrary to expectations, the induction of the negative stereotype did not influence participants’ endurance performance. However, participants in the negative stereotype condition felt older than participants in the nullified-stereotype condition. As subjective age is relevant to late-life health outcomes, such as walking speed or mortality risk, it seems necessary to implement some strategies to decrease the negative effect of the negative stereotype on subjective age.     

Focusing attention on circular pedaling reduces movement economy in cycling

Previous research has shown that focus of attention affects movement economy in endurance tasks. This experimental study was designed to take a closer look at how focusing attention on special characteristics of endurance cycling actions can influence metabolic energy costs. Twenty-five trained cyclists completed 4 × 6 min time trials at submaximal intensity on a cycling ergometer. For each of the four time trials, they were instructed to adopt a different focus of attention: (1) circular pedaling, (2) force production of quad muscles, (3) head position, (4) stimuli in a cycling video. The order of conditions was counterbalanced. The main dependent measure was movement economy (i.e., oxygen consumption at a given workload). The results show that a focus on the circular pedaling action leads to reduced economy than a focus on the video (p = 0.001). Focusing on smooth and circular pedaling includes a continuous monitoring of the cycling action, which could disturb the rhythmical nature of movement execution, thereby leading to detriments in movement economy.     

负荷越大，转换更难-来自数字大小交替比较的证据

工作记忆与认知灵活性是执行功能的两个核心成分,但两者之间的关系并不清晰。本研究在一个数字大小交替比较任务中操纵工作记忆负荷,考察转换代价在不同记忆负荷下的差异。结果显示与非转换条件相比,转换条件下的反应时更长,正确率更低。另外,高记忆负荷下的转换代价显著高于低记忆负荷下的转换代价。这些结果表明工作记忆负荷越大,转换越难,代价越大。     

La pratique répétée du Trail Making Test réduit les différences liées à l’âge sur la performance à ce test

Age-related impairment in executive functioning has been found to explain partially the decrease of cognitive performance with aging. However, the practice of an executive test can improve performance to this test. In the present study, we investigated first how the practice of the Trail Making Test (TMT, flexibility test) may influence the age-related deficit to the performance in this test and then how the performance tended to improve, and at which pace, through the practice of this executive test. Two age groups of participants (young and older adults) practiced the TMT and were compared to two control groups (i.e., no practice between pre- and post-test). The practice groups’ scores were obtained at the end of each session. Globally, the results showed an improvement of performance (1) greater in the practice groups than in the control groups and (2) in practice groups, greater in older adults than in younger ones. Both younger and older adults progressed during the early practice sessions but the younger ones reached their optimal level earlier than the older adults who continued to improve over the sessions. These results could have a major impact on adapting cognitive stimulation programs to individual's characteristics such as age.     

Orangutans (Pongo pygmaeus) and bonobos (Pan paniscus) point to inform a human about the location of a tool

Although pointing is not part of great apes’ natural gestural repertoire, they can learn to point to food, in order to request it. To assess the flexibility with which they can use this gesture, one can vary the potential referent of the point. In two previous studies, three orangutans (two of them human-reared) have shown the ability to point to the location of a tool which a human experimenter needed in order to give them food. Here, we tested six orangutans and five bonobos using a set-up in which our subjects had to guide a human experimenter to the hiding place of a fork which was needed in order to retrieve a piece of food for the subject out of a vertical tube. We further examined the potential role of a competitive/deceptive context by varying the identity of the person responsible for hiding the tool. In addition, we implemented three different control conditions in which an object was hidden but it was not necessary to indicate its location to get the food. We found that the majority of subjects spontaneously guided the experimenter to the hiding place of the fork by pointing to it when it was necessary and they did so significantly less in control conditions. We did not find an effect of the person hiding the fork. Our results show that mother-reared orangutans and bonobos are able to point to inform a human about the location of an object that the human needs to procure food for the subject and that they can take into account whether it is relevant or not to do so.

Interpersonal rigidity and complementarity

The relations among behavioral complementarity, interpersonal rigidity, as indicated by the Interpersonal Adjective Checklist (IAS, Wiggins, 1995) vector score, and interpersonal distress, as indicated by the Inventory of Interpersonal Problems (IIP, Horowitz, Rosenberg, Baer, Ureno, & Villasenor, 1988), were examined in two studies. In Study 1, 214 undergraduates viewed videotapes depicting different interactions and then provided their responses. In Study 2, 122 undergraduates interacted in randomly paired dyads on a mutual task. These interactions were videotaped and the interchanges were rated using the Interpersonal Communication Ratings Scale (ICRS, Strong, Hills, & Nelson, 1988). The extent to which each participant demonstrated complementary behavior was determined. Results of the studies demonstrated support for interpersonal rigidity as related to complementarity and as a moderator of the adaptability of behavior. Further complementarity was a mediator in the behavioral rigidity–interpersonal distress relation.     

Gestural communication of the gorilla (Gorilla gorilla): repertoire, intentionality and possible origins

Social groups of gorillas were observed in three captive facilities and one African field site. Cases of potential gesture use, totalling 9,540, were filtered by strict criteria for intentionality, giving a corpus of 5,250 instances of intentional gesture use. This indicated a repertoire of 102 gesture types. Most repertoire differences between individuals and sites were explicable as a consequence of environmental affordances and sampling effects: overall gesture frequency was a good predictor of universality of occurrence. Only one gesture was idiosyncratic to a single individual, and was given only to humans. Indications of cultural learning were few, though not absent. Six gestures appeared to be traditions within single social groups, but overall concordance in repertoires was almost as high between as within social groups. No support was found for the ontogenetic ritualization hypothesis as the chief means of acquisition of gestures. Many gestures whose form ruled out such an origin, i.e. gestures derived from species-typical displays, were used as intentionally and almost as flexibly as gestures whose form was consistent with learning by ritualization. When using both classes of gesture, gorillas paid specific attention to the attentional state of their audience. Thus, it would be unwarranted to divide ape gestural repertoires into ‘innate, species-typical, inflexible reactions’ and ‘individually learned, intentional, flexible communication’. We conclude that gorilla gestural communication is based on a species-typical repertoire, like those of most other mammalian species but very much larger. Gorilla gestures are not, however, inflexible signals but are employed for intentional communication to specific individuals.     

Adjustments of task-set control processes: Effect of task switch frequency on task-mixing and task-switching costs

The present study tested the hypothesis that task-switch frequency triggers adjustments of task-set control processes. A mixed-task condition where task switches are frequent should promote flexibility—thus improving task-switch performance—whereas a condition where task repetitions are more expected should favour stability—thus improving task-repeat performance. In two experiments, participants performed single-task and mixed-task blocks. In mixed-task blocks, tasks varied randomly on a trial-by-trial basis. For half of the mixed-task blocks, the frequency with which the task changed was 25%, for the other half, it was 50%. Overall, depending on the task-switch frequency, performance on both task-repeat and task-switch trials was modified. Switch cost was reduced and task-repeat performance was altered by the increase in switch probability. This study demonstrates context-sensitive adjustments of task-set control processes. These results further support the view that mixing cost reflects sustained and endogenous components of cognitive control.