Motor asymmetries in the human infant: Stepping movements

Stepping movements were investigated for evidence of early motor asymmetry in 24 familial right-handed infants and 14 familial left-handed infants at each of five ages: 2–3 days after birth, 14 days, and 1, 2, and 3 months of age. Results indicated a nonsignificant right leg advantage during the newborn period, with few significant lateral preferences evidenced in either direction at later testing ages. These results fail to indicate that a reliable leg preference persists beyond the newborn period, particularly among familial right-handed infants. Thus, it seems unlikely that an asymmetry in stepping movements during early infancy marks the beginning of a direct developmental path that culminates in a motor asymmetry in later childhood.     

On the state-dependent nature of infant head orientation

The relationship between infant state and head orientation after the head is held in a midline or lateral position was investigated longitudinally in infants 2, 4, 8, and 12 weeks of age. Across the four ages, there was a general decrease in the amount of time spent in an active-awake state, whereas the amount of time spent crying remained fairly stable. Overall, infants turned more often to the right than to the left, but this difference was more pronounced when the infants were quietly alert or active-awake than when they were crying. The results thus indicate that state variables influence the expression of headorientation biases in early infancy.     

The Dynamics of Personality Approach (DPA): 20 Tenets for Uncovering the Causal Mechanisms of Personality

Over the last few decades, most personality psychology research has been focused on assessing personality via scores on a few broad traits and investigating how these scores predict various behaviours and outcomes. This approach does not seek to explain the causal mechanisms underlying human personality and thus falls short of explaining the proximal sources of traits as well as the variation of individuals' behaviour over time and across situations. On the basis of the commonalities shared by influential process-oriented personality theories and models, we describe a general dynamics of personality approach (DPA). The DPA relies heavily on theoretical principles applicable to complex adaptive systems that self-regulate via feedback mechanisms, and it parses the sources of personality in terms of various psychological functions relevant in different phases of self-regulation. Thus, we consider personality to be rooted in individual differences in various cognitive, emotional–motivational, and volitional functions, as well as their causal interactions. In this article, we lay out 20 tenets for the DPA that may serve as a guideline for integrative research in personality science. © 2020 The Authors. European Journal of Personality published by John Wiley & Sons Ltd on behalf of European Association of Personality Psychology     

Impact of second-language experience in infancy: brain measures of first- and second-language speech perception

Language experience 'narrows' speech perception by the end of infants' first year, reducing discrimination of non-native phoneme contrasts while improving native-contrast discrimination. Previous research showed that declines in non-native discrimination were reversed by second-language experience provided at 9-10 months, but it is not known whether second-language experience affects first-language speech sound processing. Using event-related potentials (ERPs), we examined learning-related changes in brain activity to Spanish and English phoneme contrasts in monolingual English-learning infants pre- and post-exposure to Spanish from 9.5-10.5 months of age. Infants showed a significant discriminatory ERP response to the Spanish contrast at 11 months (post-exposure), but not at 9 months (pre-exposure). The English contrast elicited an earlier discriminatory response at 11 months than at 9 months, suggesting improvement in native-language processing. The results show that infants rapidly encode new phonetic information, and that improvement in native speech processing can occur during second-language learning in infancy.     

The role of visual information in the processing of place and manner features in speech perception

Visual information provided by a talker's mouth movements can influence the perception of certain speech features. Thus, the "McGurk effect" shows that when the syllable (bi) is presented audibly, in synchrony with the syllable (gi), as it is presented visually, a person perceives the talker as saying (di). Moreover, studies have shown that interactions occur between place and voicing features in phonetic perception, when information is presented audibly. In our first experiment, we asked whether feature interactions occur when place information is specificed by a combination of auditory and visual information. Members of an auditory continuum ranging from (ibi) to (ipi) were paired with a video display of a talker saying (igi). The auditory tokens were heard as ranging from (ibi) to (ipi), but the auditory-visual tokens were perceived as ranging from (idi) to (iti). The results demonstrated that the voicing boundary for the auditory-visual tokens was located at a significantly longer VOT value than the voicing boundary for the auditory continuum presented without the visual information. These results demonstrate that place-voice interactions are not limited to situations in which place information is specified audibly.(ABSTRACT TRUNCATED AT 250 WORDS)     

Motivational determinants of motor performance: The hidden second task

Summary The present study was designed to test facilitating and debilitating effects of motivational processes on motor behavior. It was predicted that motivational processes have a more pronounced effect on motor performance when control is frequently transferred to attentional mechanisms (i. e., early in the acquisition phase). The results were consistent with this expectation. A strong motive to achieve success and pretreatment designed to enhance achievement motivation were associated with an increase in the quality of performance. A strong tendency to engage in state-oriented cognitive activities, by contrast, (e.g., thinking about the potential threat to one's selfesteem resulting from failure) was associated with poorer performance, It is concluded that experiments on motor behavior in which subjects are instructed to perform a single motor task may actually involve dual-task (or even multiple-task) performance if some part of the subjects' attentional capacity is used for task-irrelevant cognitive activities.