The development of infants' preference for motherese

Generally, infants prefer infant-directed (ID) to adult-directed (AD) speech. Mostly, researchers have used unfamiliar female voices in these studies. We investigated preferences for maternal ID speech in 1- and 4-month-olds. Using a procedure in which infants controlled access to voices by fixating a visual display, infants listened to recordings of natural female ID and AD speech. In Experiment 1, 1-month-olds heard recordings of maternal ID and AD speech, but these infants showed no preference for maternal ID speech. In Experiment 2, 1-month-olds heard the same ID and AD speech tapes but were not familiar with the speakers. Contrary to Experiment 1, these infants preferred ID speech. In Experiment 3, 4-month-olds heard recordings of maternal ID and AD speech and showed a significant preference for ID speech. Collectively, these results suggest that infant attention to ID speech depends on both speaker-general and speaker-specific characteristics, with interesting developmental changes occuring during early infancy.     

Dichotic listening ear asymmetry: Patterns of longitudinal development

Dichotic listening research with children has continued to be prevalent although numerous authors have described both theoretical and methodological limitations with traditional dichotic listening free-recall paradigms. The present research adds to this growing skepticism by reanalyzing two major longitudinal studies of children's ear asymmetries. These two studies, based in different countries (United States, Holland), utilized highly similar paradigms (free-recall digits), subjects (males), and age levels (kindergarten and second and fifth grade). The questions of ear advantage development, patterns of ear advantages, and the relationship between dichotic listening performance and reading skills are addressed from the multiple statistical methodologies represented in the literature. From these analyses, support for all of the major hypotheses regarding the developmental patterns of dichotic listening performances could be obtained from the same data samples. The use of traditional free-recall dichotic listening paradigms are not recommended for use with children. The implications for future research are discussed.     

Intraindividual consistencies in cross-modal matching across several continua

To determine the relationship between individual exponents for cross-modal stimulus matches for both directions of matching, and to assess the transitivity of individual exponents, subjects were asked to adjust both the judgment and criterion stimuli. Experiment 1 involved four continua paired in 12 ordered combinations; Experiment 2 involved five continua and 20 ordered combinations. Two subjects served in each experiment. The individual exponent of the power function for matches of A to B was close to the inverse of the exponent for matches of B to A, but there was systematic deviation, indicating the presence of a small regression effect. Transitivity of individual exponents was determined by forming ratios of exponents from matches involving other continuum pairs to predict obtained exponents; the means of the distribution of deviations of obtained from predicted values was ?.02 log units, and the standard deviation was .15 log units, indicating that, on the average, predicted values were close to obtained exponents—that is, transitivity of exponents holds for individuals.     

Environmental determinants of altruism: The effects of stimulus overload and perceived control on helping

In an experiment designed to measure the effects of stimulus overload on altruism, 60 female subjects were randomly assigned to three stimulus conditions of 20 subjects each: (1) overload, (2) overload with perceived control, and (3) no overload. Subjects performed simultaneous proofreading and number attention tasks while at the same time listening to distracting or nondistracting background sound, and one group believed they could have the sound turned off if they desired. Following task performance, all subjects received a request for a favor from an ostensibly unrelated confederate. Although all subjects performed the tasks about equally well regardless of stimulus condition, altruism increased significantly across the three conditions. Results were discussed in terms of stimulus overload associated with the urban environment.     

Mothers' responses to infants' facial expressions of sadness,anger, and physical distress

It was hypothesized the mothers' predictions of their caregiving interventions would be differentially influenced by infants' facial expressions of sadness, anger, and physical distress. Mothers viewed slides of infants whose facial displays had first been objectively classified with the Maximally Discriminative Facial Movement Coding System (Izard, 1979). Mothers imagined their infants showing similar expressions while scaling their own tendencies to respond with a number of specific caregiving and socializing interventions and affective reactions. Multivariate ANOVAs showed that the mothers' predictions differed for the three types of negative display. In an emotion decoding task, mothers' responses did not differ as a function of the infants' sex. The patterns of decoded emotions were most similar between physical distress and anger expressions, and least similar between physical distress and sadness expressions. Generally, the findings supported the hypothesis that the negative facial displayes signaled different affective states and had differential motivational effects on the mothers.     

On the partitioning of squared Euclidean distance and its applications in cluster analysis

The partitioning of squared Eucliean distance between two vectors in M-dimensional space into the sum of squared lengths of vectors in mutually orthogonal subspaces is discussed and applications given to specific cluster analysis problems. Examples of how the partitioning idea can be used to help describe and interpret derived clusters, derive similarity measures for use in cluster analysis, and to design Monte Carlo studies with carefully specified types and magnitudes of differences between the underlying population mean vectors are presented. Most of the example applications presented in this paper involve the clustering of longitudinal data, but their use in cluster analysis need not be limited to this arena.     

Semantic processing in aphasia: Evidence from an auditory lexical decision task

W. Milberg and S. E. Blumstein (1981, Brain and Language 14, 371–385) demonstrated semantic facilitation effects in a visual lexical decision task administered to Wernicke and other aphasics with severe comprehension deficits. In an attempt to explore the generalizability of these findings in a task where the acoustic-phonetic system could not be bypassed to access meaning, Wernicke's, Global, Broca's, and Conduction aphasics were administered a lexical decision task in the auditory modality. The patients were also given a simple semantic judgment task using the word pairs from the lexical decision task. The aphasic patients showed evidence of semantic facilitation whether they were categorized by diagnostic group or comprehension level. Performance of the semantic judgment task correlated with the severity of auditory comprehension deficits, whereas the consistency of the semantic facilitation effect did not. Even patients with severe comprehension deficits showed semantic facilitation. These results decrease the likelihood that auditory comprehension deficits are due to semantic organization per se and increase the likelihood that the deficits lie in one of the many processes involved in access to that information.     

A study of the relationship between individual differences in nonverbal expressiveness and factors of personality and social interaction

Some theoretical and applied implications of individual differences in nonverbal expressiveness were investigated in a medical setting. In Study I, the abilities of 21 physicians to express different emotions through voice tone were assessed and related to physician personality and to actual patient ratings of the physician. Study II replicated Study I using visual as well as vocal cues (i.e., videotapes) of a new sample of physicians, and added a study of physician greetings. It was found that: (1) Aspects of expressive ability were reliably correlated with a cluster of personality traits, thus supporting the notion that nonverbal affective style may be a window to inner dispositions; and (2) expressive ability was related to patient satisfaction with the interpersonal manner of their physicians and to the judged likeability of the physician's greeting, thus providing evidence for the importance of this ability for social interaction.     

Prediction and judgment as indicators of sensitivity to covariation of continuous variables

The present study used both judgments of strength of relationship and measures of the ability to predict one variable from another to assess subjects’ sensitivity to the covariation of two continuous variables. In addition, one group of subjects judged strength of relationship after merely observing the presentation of 60 pairs of two-digit numbers, and a second group made strength judgments after being actively engaged in predicting one member of a pair when given the other. The prediction and judgment data provide different pictures of subjects’ sensitivity to covariation. The subjects were quite poor at estimating strength of relationship but, by some measures, good at predicting one variable from another. Judgments were not strongly influenced by whether subjects had previously engaged in overt prediction. The implications of these results for the literature on covariation estimation are discussed.