When and how less is more: reply to Tharp and Pickering

In DeCaro et al. [DeCaro, M. S., Thomas, R. D., & Beilock, S. L. (2008). Individual differences in category learning: Sometimes less working memory capacity is better than more. Cognition, 107, 284-294] we demonstrated that sometimes less working memory (WM) has its advantages. The lower individuals’ WM, the faster they achieved success on an information-integration (II) category learning task adopted from Waldron and Ashby [Waldron, E. M., & Ashby, F. G. (2001). The effects of concurrent task interference on category learning: Evidence for multiple category learning systems. Psychonomic Bulletin & Review, 8, 168-176]. We attributed this success to the inability of lower WM individuals to employ explicit learning strategies heavily reliant on executive control. This in turn, we hypothesized, might push lower WM individuals to readily adopt procedural-based strategies thought to lead to success on the II task. Tharp and Pickering [Tharp, I. J., & Pickering, A. D. (2009). A note on DeCaro, Thomas, and Beilock (2008): Further data demonstrate complexities in the assessment of information-integration category learning. Cognition] recently questioned whether the II category learning task DeCaro et al. used really reflects procedural learning. In an effort to investigate Tharp and Pickering’s assertions with respect to individual differences in WM, we replicate and extend our previous work, in part by modeling participants’ response strategies during learning. We once again reveal that lower WM individuals demonstrate earlier II learning than their higher WM counterparts. However, we also show that low WM individuals’ initial success is not because of procedural-based responding. Instead, individuals lower in WM capacity perseverate in using simple rule-based strategies that circumvent heavy demands on WM while producing above-chance accuracy.     

Individual differences in the acquisition of second language phonology

Perceptual training was employed to characterize individual differences in non-native speech sound learning. Fifty-nine adult English speakers were trained to distinguish the Hindi dental–retroflex contrast, as well as a tonal pitch contrast. Training resulted in overall group improvement in the ability to identify and to discriminate the phonetic and the tonal contrasts, but there were considerable individual differences in performance. A category boundary effect during the post-training discrimination of the Hindi but not of the tonal contrast suggests different learning mechanisms for these two stimulus types. Specifically, our results suggest that successful learning of the speech sounds involves the formation of a long-term memory category representation for the new speech sound.     

Responses on a lateralized lexical decision task relate to both reading times and comprehension

Research over the last few years has shown that the dominance of the left hemisphere in language processing is less complete than previously thought [Beeman, M. (1993). Semantic processing in the right hemisphere may contribute to drawing inferences from discourse. Brain and Language, 44, 80–120; Faust, M., & Chiarello, C. (1998). Sentence context and lexical ambiguity resolution by the two hemispheres. Neuropsychologia, 36(9), 827–835; Weems, S. A., & Zaidel, E. (2004). The relationship between reading ability and lateralized lexical decision. Brain and Cognition, 55(3), 507–515]. Engaging the right brain in language processing is required for processing speaker/writer intention, particularly in those subtle interpretive processes that help in deciphering humor, irony, and emotional inference. In two experiments employing a divided field or lateralized lexical decision task (LLDT), accuracy and reaction times (RTs) were related to reading times and comprehension on sentence reading. Differences seen in RTs and error rates by visual fields were found to relate to performance. Smaller differences in performance between fields tended to be related to better performance on the LLDT in both experiments and, in Experiment 1, to reading measures. Readers who can exploit both hemispheres for language processing equally appear to be at an advantage in lexical access and possibly also in reading performance.     

The effect of development and individual differences in pointing comprehension of dogs

In spite of the rather different procedures actually used in comparative studies to test the ability of different species to rely on the human pointing gesture, there is no debate on the high performance of dogs in such tasks. Very little is known, however, on the course through which they acquire this ability or the probable factors influencing the process. Important developmental questions have remained unsolved and also some methodological concerns should be addressed before we can convincingly argue for one interpretation or another. In this study we tested 180 dogs of different age (from 2 months to adults) to investigate their performance in the human distal momentary pointing gesture. The results, analyzed at both the group and the individual levels, showed no difference in the performance according to age, indicating that in dogs the comprehension of the human pointing may require only very limited and rapid early learning to fully develop. Interestingly, neither the keeping conditions nor the time spent in active interaction with the owner, and not even some special (agility) training for using human visual cues, had significant effect on the success and explained individual differences. The performance of the dogs was rather stable over time: during the 20 trials within a session and even when subsamples of different age were repeatedly tested. Considering that in spite of the general success at the group level, more than half of the dogs were not successful at the individual level, we revealed alternative “decision-making rules” other than following the pointing gesture of the experimenter. Electronic supplementary material  The online version of this article (doi:) contains supplementary material, which is available to authorized users.

Crossing at a red light: Behaviour of individuals and groups

The present study examines the road behaviour of individual pedestrians at an intersection with a traffic signal compared to groups of pedestrians at the same intersection.In total, 1392 pedestrians were unobtrusively observed in an urban setting at a pedestrian street crossing of undivided streets; 842 were female (60.5%) and 550 were male (39.5%). The observations took place between 7:30 and 8:30 in the morning. Chi-square test revealed the males crossed on red more frequently than females. Logistic regression predicting red-light crossing for pedestrians arriving during a red-light phase indicated that, apart from gender, the tendency to cross on red was greater when there were fewer people waiting at the curb, either when a pedestrian arrived, or joining after arrival. The discussion refers to the theoretical explanations concerning the theory of ‘social control’ and to some practical implications of the results, such as using the positive value of social control in media campaigns and adjusting the red light duration in order to encourage people to obey the traffic light.     

Postliberal Theory

This paper begins with a critical part and concludes with a constructive part. First, with reference to a definition of liberalism and using immanent critique, I show deficiencies in the claims of four selfprofessed postliberals to have articulated non-liberal positions. Then, I argue that postliberal political theory consists in acknowledging that in political contexts some voluntary groups as such can be moral, not merely political, agents. Analysis of what moral autonomy is for persons as empirical (not noumenal) agents reveals that that account can be transposed to some groups. A key common element among the four rejected positions is their emphasis on the normative authority of some practices as over against principles. My proposal congeals that normative emphasis on the social into group-moral authority. Recognition of some voluntary groups’ episodic moral authority over their members is non-liberal but not anti-liberal.

Olfactory self-recognition in a cichlid fish

Animal self-cognizance might be of importance in different contexts like territoriality, self-referent mate-choice or kin recognition. We investigated whether the cichlid fish Pelvicachromis taeniatus is able to recognize own olfactory cues. P. taeniatus is a cave breeding fish with pronounced brood care and social behavior. In the experiments we gave male cave owners the choice between two caves in which we introduced scented water. In a first experiment males preferred caves with their own odor over caves with the odor of an unfamiliar, unrelated male. To examine whether self-recognition is based rather on individual or on family cues we conducted two further experiments in which males could choose between their own odor and the odor of a familiar brother and between the odor of a familiar brother and an unfamiliar, unrelated male, respectively. Males preferred their own odor over that of a familiar brother suggesting individual self-referencing. Interestingly, males (at least outbred ones) preferred the odor of an unfamiliar, unrelated male over that of a familiar brother, maybe to avoid competition with kin. We discuss the results in the context of animal self-cognizance. All experiments were conducted with in- and outbred fish. Inbreeding did not negatively affect self-recognition.     

家庭环境影响青少年人格特质的性别差异

对855名青少年学生用家庭环境量表和中国人人格量表进行测试,结果表明：青少年的家庭环境对其人格特质的影响,存在显著的性剐差异;家庭亲密度和组织性是影响男孩人格特质的重要家庭环境因素,而家庭道德宗教观是影响女孩人格特质的重要家庭环境因素。新的家庭教育模式应充分考虑到家庭环境影响孩子人格特质的性别差异。     

Beyond quantity: Individual differences in working memory and the ordinal understanding of numerical symbols

In two different contexts, we examined the hypothesis that individual differences in working memory (WM) capacity are related to the tendency to infer complex, ordinal relationships between numerical symbols. In Experiment 1, we assessed whether this tendency arises in a learning context that involves mapping novel symbols to quantities by training adult participants to associate dot-quantities with novel symbols, the overall relative order of which had to be inferred. Performance was best for participants who were higher in WM capacity (HWMs). HWMs also learned ordinal information about the symbols that lower WM individuals (LWMs) did not. In Experiment 2, we examined whether WM relates to performance when participants are explicitly instructed to make numerical order judgments about highly enculturated numerical symbols by having participants indicate whether sets of three Arabic numerals were in increasing order. All participants responded faster when sequential sets (3-4-5) were in order than when they were not. However, only HWMs responded faster when non-sequential, patterned sets (1-3-5) were in order, suggesting they were accessing ordinal associations that LWMs were not. Taken together, these experiments indicate that WM capacity plays a key role in extending symbolic number representations beyond their quantity referents to include symbol-symbol ordinal associations, both in a learning context and in terms of explicitly accessing ordinal relationships in highly enculturated stimuli.     

Individual Differences in Learning Abilities Impact Structure Addition: Better Learners Create More Structured Languages

Over the last decade, iterated learning studies have provided compelling evidence for the claim that linguistic structure can emerge from non-structured input, through the process of transmission. However, it is unclear whether individuals differ in their tendency to add structure, an issue with implications for understanding who are the agents of change. Here, we identify and test two contrasting predictions: The first sees learning as a pre-requisite for structure addition, and predicts a positive correlation between learning accuracy and structure addition, whereas the second maintains that it is those learners who struggle with learning and reproducing their input who add structure to it. This prediction is hard to test in standard iterated learning paradigms since each learner is exposed to a different input, and since structure and accuracy are computed using the same test items. Here, we test these contrasting predictions in two experiments using a one-generation artificial language learning paradigm designed to provide independent measures of learning accuracy and structure addition. Adults (N = 48 in each study) were exposed to a semi-regular language (with probabilistic structure) and had to learn it: Learning was assessed using seen items, whereas structure addition was calculated over unseen items. In both studies, we find a strong positive correlation between individuals' ability to learn the language and their tendency to add structure to it: Better learners also produced more structured languages. These findings suggest a strong link between learning and generalization. We discuss the implications of these findings for iterated language models and theories of language change more generally.