Does Infant-Directed Speech Help Phonetic Learning? A Machine Learning Investigation

A prominent hypothesis holds that by speaking to infants in infant-directed speech (IDS) as opposed to adult-directed speech (ADS), parents help them learn phonetic categories. Specifically, two characteristics of IDS have been claimed to facilitate learning: hyperarticulation, which makes the categories more separable, and variability, which makes the generalization more robust. Here, we test the separability and robustness of vowel category learning on acoustic representations of speech uttered by Japanese adults in ADS, IDS (addressed to 18- to 24-month olds), or read speech (RS). Separability is determined by means of a distance measure computed between the five short vowel categories of Japanese, while robustness is assessed by testing the ability of six different machine learning algorithms trained to classify vowels to generalize on stimuli spoken by a novel speaker in ADS. Using two different speech representations, we find that hyperarticulated speech, in the case of RS, can yield better separability, and that increased between-speaker variability in ADS can yield, for some algorithms, more robust categories. However, these conclusions do not apply to IDS, which turned out to yield neither more separable nor more robust categories compared to ADS inputs. We discuss the usefulness of machine learning algorithms run on real data to test hypotheses about the functional role of IDS.     

How older adults use cognition in sentence-final word recognition

This study examined the effects of executive control and working memory on older adults’ sentence-final word recognition. The question we addressed was the importance of executive functions to this process and how it is modulated by the predictability of the speech material. To this end, we tested 173 neurologically intact adult native English speakers aged 55–84 years. Participants were given a sentence-final word recognition test in which sentential context was manipulated and sentences were presented in different levels of babble, and multiple tests of executive functioning assessing inhibition, shifting, and efficient access to long-term memory, as well as working memory. Using a generalized linear mixed model, we found that better inhibition was associated with higher accuracy in word recognition, while increased age and greater hearing loss were associated with poorer performance. Findings are discussed in the framework of semantic control and are interpreted as supporting a theoretical view of executive control which emphasizes functional diversity among executive components.     

Psychological distress and quality of life of people living with HIV/AIDS in a Nigerian teaching hospital

Presence of psychological distress and poor quality of life (QoL) may affect the outcome of HIV/AIDS. One hundred and seventeen consecutive and consenting participants were interviewed using a Socio-demographic questionnaire, Kessler Psychological Distress Scale (K10) and World Health Organization Quality of Life-HIV Bref. Fifty-six (47.9%) participants scored 20 and above on K10 Scale. QoL was significantly higher in married participants, those who perceived their state of health as being good, asymptomatic participants and those who scored well–mild on K10. The older age group scored higher on QoL Scale than the younger age group in the physical health domain while the married participants scored higher in the domains of physical health, psychological health, environment and spiritual/religion. The participants who perceived their state of health as being good scored higher than those who perceived their health as poor in all domains. There is a high level of psychological distress and poor QoL in people living with HIV/AIDS.     

Caregivers’ perspective of the child support grant in South Africa: An exploratory study

This study explored caregivers’ perceptions of the South African Child Support Grant as a poverty alleviation instrument. Informants consisted of 72 caregivers who were purposively selected through the snowball method (female = 99%; single parent = 71%, blacks = 100%). They completed a survey based on their perceptions of the Child Support Grant. Thematic analysis applying the happiness or wellbeing approach to poverty revealed that caregivers find the Child Support Grant to be a family stress reliever by providing basic essentials for living. In addition, caregivers indicated the presence of inefficiencies in the administration of the grant. Findings suggest that the Child Support Grant has a buffering effect on poverty-stricken households in South Africa.     

Shu and zhong as the virtue of the Golden Rule: a Confucian contribution to contemporary virtue ethics

I aim to show how Confucian philosophy can contribute to the contemporary resurgence of virtue ethics education by arguing that it has the resource to address a lacuna in Aristotelian ethics. Aristotelian ethics, which is arguably the main resource of contemporary virtue ethics, lacks a virtue that corresponds to the notion of loving each person as one’s self or the Golden Rule. To be more precise, Aristotelian ethics has no virtue about loving all people as one’s self, although philia comes close but is precisely limited because it lacks universality. However, I believe that Dai Zhen’s interpretation of the Confucian virtues of shu and zhong does have this universal scope which philia lacks. For Dai, the ground for loving another is not any characteristic that a particular group of people have in common, such as, in the case of philia, being virtuous. Rather, the ground is universal human nature itself.     

Bridging novelty and familiarity-based recognition memory: A matter of timing

Novelty detection is essential to adapt to changes. However, the relationship between novelty detection and visual recognition memory remains unclear. To characterize the temporal dynamics of novelty and its connection to familiarity, we probed early behavioural performance of novelty and familiarity in 31 participants using a speeded go/no-go recognition task with a 600-ms response deadline. Responses to familiarity and novelty produced symmetrical biases and correlated accuracies and biases, but novelty decisions were less accurate and had slower minimal reaction times (410?ms). These processes thus appear to be independent, as suggested by a more efficient system in the case of familiarity, but with common factors bringing overlapping contributions to both processes. This may possibly be explained by the more fluent processing of repeated stimuli, but with familiarity and novelty potentially relying on one decision criterion, as suggested by the correlated and remarkably symmetrical biases. This study supports models that conceptualize novelty and familiarity decisions as two partly overlapping processes.     

One or two dimensions in spontaneous classification: a simplicity approach

When participants are asked to spontaneously categorize a set of items, they typically produce unidimensional classifications, i.e., categorize the items on the basis of only one of their dimensions of variation. We examine whether it is possible to predict unidimensional vs. two-dimensional classification on the basis of the abstract stimulus structure, by employing Pothos and Chater's simplicity model of spontaneous categorization [Pothos, E. M., & Chater, N. (2002). A simplicity principle in unsupervised human categorization. Cognitive Science, 26, 303-343]. The simplicity model provides a quantitative measure of how intuitive a particular classification is. With objects represented in two dimensions, we propose that a unidimensional classification will be preferred if it is more intuitive than all possible two-dimensional ones, and vice versa. Empirical results supporting this proposal are reported. Implications for Goodman's paradox are discussed.     

Foraging and associative learning of visual signals in a parasitic wasp

To cope with environmental variability, animals should gather and use information to reduce uncertainty. In insect parasitoids, associative learning has been widely documented in the context of host foraging. However, despite its potential adaptive value, the insect food searching strategy and cues used to search are poorly understood. In this study, we examined the ability of hymenopteran Venturia canescens females to associate food to a visual cue. To broaden the scope of our results, experiments were performed with both arrhenotokous (sexual) and thelytokous (asexual) individuals. The wasps showed innate attraction for yellow and orange stimuli when presented versus blue stimuli. When trained to associate a food reward with one of the attractive colours (orange), they significantly moved from a distance towards the colour previously associated with food. The choice of the innately preferred colour (yellow) was not modified by associative learning. In the context of food foraging, this study is the first to show associative learning using visual stimuli in a parasitoid and active choice of this colour. This ability gives new insights concerning potential food sources for V. canescens in the field, since flowers are sugar sources, which emit colour signals.