Number Versus Contour Length in Infants' Discrimination of Small Visual Sets

This study examined infants' use of contour length in number discrimination tasks. We systematically varied number and contour length in a visual habituation experiment in order to separate these two variables. Sixteen 6- to 8-month-old infants were habituated to displays of either two or three black squares on a page. They were then tested with alternating displays of either a familiar number of squares with a novel contour length or a novel number of squares with a familiar contour length. Infants dishabituated to the display that changed in contour length, but not to the display that changed in number. We conclude that infants base their discriminations on contour length or some other continuous variable that correlates with it, rather than on number.     

Video Versus Reality: Infants' Attention and Affective Responses to Video and Live Presentations

Television viewing by infants has become very common, yet relatively little is known about infants' reactions to video compared to live events. We conducted two experiments in order to compare 9- or 10-month-old infants' behavioral reactions to live events and video presentations of those events. In the first experiment, infants' were shown video and live presentations shown consecutively; their affective reactions were consistent, indicating that video conveys meaning and emotional impact even in infancy. However, infants generally looked longer at, reached more to, showed more interest in, and exhibited more fear to the real stimuli. In a second experiment, infants were shown identical live and video events simultaneously; they looked much longer at the live presentations, further confirming that they distinguished live events from video and preferred to watch real events. Implications for infants' television viewing and the use of video images in infancy research are discussed.     

Comparing Data Sets: Implicit Summaries of the Statistical Properties of Number Sets

Comparing datasets, that is, sets of numbers in context, is a critical skill in higher order cognition. Although much is known about how people compare single numbers, little is known about how number sets are represented and compared. We investigated how subjects compared datasets that varied in their statistical properties, including ratio of means, coefficient of variation, and number of observations, by measuring eye fixations, accuracy, and confidence when assessing differences between number sets. Results indicated that participants implicitly create and compare approximate summary values that include information about mean and variance, with no evidence of explicit calculation. Accuracy and confidence increased, while the number of fixations decreased as sets became more distinct (i.e., as mean ratios increase and variance decreases), demonstrating that the statistical properties of datasets were highly related to comparisons. The discussion includes a model proposing how reasoners summarize and compare datasets within the architecture for approximate number representation.     

Naming and Exclaiming: Infants' Sensitivity to Naming Contexts

In three experiments, we examined 17-month-olds' acquisition of novel symbols (words and gestures) as names for object categories. Experiment 1 compares infants' extension of novel symbols when they are presented within a familiar naming phrase (e.g., "Look at this [symbol]!") versus presented alone (e.g., "Look! ... [symbol]!") Infants mapped novel gestures successfully in both naming contexts. However, infants mapped novel words only within the context of familiar naming phrases. Thus, although infants can learn both words and gestures, they have divergent expectations about the circumstances under which the 2 symbolic forms name objects. Experiments 2 and 3 test the hypothesis that infants' expectations about the circumstances under which words that name objects are acquired by monitoring how adults indicate their intention to name. By employing a training paradigm, these two experiments demonstrated that infants can infer how an experimenter signals his or her intention to name an object on the basis of a very brief training experience.     

Infants' Developing Sensitivity to Object Function: Attention to Features and Feature Correlations

In this research we examine the relation between executive function (EF) and false-belief (FB) understanding in young children. Specifically, we proposed that performance on tasks combining 2 executive demands: (a) working memory and (b) inhibitory control would be most predictive of performance on FB tasks. Forty-eight children between the ages of 3 and 5 years were given a battery of EF and FB measures. As predicted we found that performance on executive tasks that combined demands for memory and inhibitory control were highly predictive of performance on FB tasks. To further test the relation of EF and FB understanding we also introduced an experimental manipulation designed to reduce the working memory demands of FB tasks. This manipulation did not significantly improve performance. The results from this study provide support for the relation between EF and FB understanding, although the exact nature of the relation requires further clarification.     

Ideal Versus Actual Number of Sales Calls: An Application of Disconfirmation Theory

The current study focuses on the relationship that buyers have with their salespeople. Specifically, the study uses disconfirmation theory to evaluate whether a salesperson that meets or exceeds the buyer’s ideal number of sales calls has higher levels of commitment, trust, and satisfaction from the buyer than a salesperson that does not meet expectations. The study also looks at the impact of meeting expectations on the buyer’s evaluation of the salesperson’s commitment and performance versus a salesperson that does not meet expectations. Findings suggest that when a salesperson contacts a buyer with a frequency and consistency that the buyer perceives as ideal, the buyer will have a higher level of satisfaction with and trust of the salesperson as well as a higher level of commitment to the buyer–seller relationship. Managers could take advantage of this by making an effort to align a salesperson’s call frequency with what a buyer perceives as ideal.     

Increasing Safety Belt Use: Effects of Modeling and Trip Length1

Effects of modeling on car safety belt use were investigated in a field experiment. Modeling, anticipated trip length, and gender of the model were manipulated in a 2 × 2 × 2 factorial design. Sixty-four female college students were told that they were to participate in an experiment that would take place in another location, requiring a drive either of less than one mile or of several miles. The driver either used or did not use a safety belt. Subjects' belt use was significantly related to the model's behavior. When the driver used a safety belt, 77.4% of the subjects used one; when the driver did not use a safety belt, only 313% of the subjects used one. A significant effect for trip length was also found. In the long trip condition, 71.9% of the subjects used a belt; in the short trip condition, 35.5% used one. Results are interpreted as support for a social learning theory approach to increasing voluntary safety belt use.     

Infants' formation and use of categories to segregate objects

Four- and-a-half-month-old infants' (N = 100) category formation and use was studied in a series of five experiments. For each experiment, the test events featured a display composed of a cylinder and a box. Previous research showed that this display is not clearly parsed as a single unit or as two separate units by infants of this age. Immediately prior to testing, infants were shown a set of category exemplars. Knowledge about this category could help infants disambiguate the test display, which contained a novel exemplar of this category. Clear interpretation of the test display as composed of two separate units (as indicated by infants' longer looking at the move-together than at the move-apart test event) was taken as evidence of category formation and use. In Experiments 1 and 5, infants' prior experience with a set of three different boxes that were similar to the test box facilitated their segregation of the test display. Experiment 2 showed that three different exemplars are necessary: prior experience with any two of the three boxes used in Experiment 1 did not facilitate infants' segregation of the test display. Experiment 3 showed that variability in the exemplar set is necessary: prior experience with three identical boxes did not facilitate infants' segregation of the test display. Experiment 4 showed that under these conditions of very brief prior exposure, similarity between the exemplar set and test box is necessary: prior experience with three different boxes that were not very similar to the test box did not facilitate infants' segregation of the test display. Together, these findings suggest that: (a) number of exemplars, variability, and similarity in the exemplar set are important for infants' category formation, and (b) infants use their category knowledge to determine the boundaries of the objects in a display.     

Limits to Infants' Knowledge of Objects: The Case of MagicalAppearance

Young infants have an impressive knowledge of material objects. They appreciate that distinct objects cannot occupy the same space at the same time, are internally cohesive units that maintain their boundaries, and exist continuously in space and time. We report a surprising limit to this body of understanding: Although 8-month-olds responded to the "magical" disappearance of an object as an unexpected event, they did not so respond to a magical appearance. These results suggest that infants' understanding of objects differs from adult cognition in important respects. We discuss four possible ways in which this finding can be reconciled with evidence that infants appreciate the spatiotemporal continuity of objects.     

Infants' sensitivity to pictorial depth cues: a review and meta-analysis of looking studies

This paper reviews habituation-dishabituation and preferential-looking studies on the emergence of sensitivity to pictorial depth cues in infancy. This research can be subdivided into two groups. While one group of studies has established responsiveness to pictorial depth cues at 3-5 months of age, the other has found that the ability to extract pictorial 3D information emerges at about 6 months. In the former, young infants were tested for their ability to distinguish between displays that differ in spatial information provided by pictorial depth cues. The results of these studies might demonstrate that 3-5-month-old infants perceive spatial layout from pictorial cues. It is possible, however, that the infants in these studies responded primarily to low-level, two-dimensional stimulus differences. In contrast, the second group of studies controlled for the potential influence of lower-level stimulus features on the infants' experimental performance and more unambiguously demonstrated sensitivity to pictorial depth information in infants 6 months of age and older. In sum, the divergent findings of studies in this area may be resolved by assuming substantial developmental progress in infant sensitivity to pictorial depth cues during the first months of life.     

The Verifiability Approach: Countermeasures Facilitate its Ability to Discriminate Between Truths and Lies

According to the verifiability approach, liars tend to provide details that cannot be checked by the investigator and awareness of this increases the investigator's ability to detect lies. In the present experiment, we replicated previous findings in a more realistic paradigm and examined the vulnerability of the verifiability approach to countermeasures. For this purpose, we collected written statements from 44 mock criminals (liars) and 43 innocents (truth tellers), whereas half of them were told before writing the statements that the verifiability of their statements will be checked. Results showed that ‘informing’ encouraged truth tellers but not liars to provide more verifiable details and increased the ability to detect lies. These findings suggest that verifiability approach is less vulnerable to countermeasures than other lie detection tools. On the contrary, in the current experiment, notifying interviewees about the mechanism of the approach benefited lie detection. Copyright © 2013 John Wiley & Sons, Ltd.     

Infants' responses to arm restraint at 2 and 6 months: a longitudinal study

This study examined the continuity, stability, and change of infants' responses to a frustrating event (i.e., arm restraint) between 2 and 6 months in terms of both negative reactivity and its regulation. Fifty-two healthy, full-term infants and their mothers participated in an arm restraint procedure. Infant behaviors were observed and coded at 3-s intervals. The results showed that infants' reactivity to frustration and their ability to regulate such reactivity significantly changed in level over time. Individual differences in frustration reactivity were stable across the two ages; two regulatory behaviors (i.e., orientation to mother and avoidance) could be observed in the same percentage of babies at both 2 and 6 months. At 6 months, several significant associations between frustration reactivity and infant regulatory behaviors emerged. These findings suggest that the arm restraint procedure may be usefully employed to study individual differences in infants as young as 2 months of age.     

Word Length and Vowel Duration in Apraxia of Speech: The Use of Relative Measures

Previous research has established that the duration of stressed word stem vowels is shorter in polysyllabic words than in monosyllabic words for normal speakers and for speakers with aphasia and apraxia of speech (AOS). However, the results are inconsistent across studies with regard to the magnitude and pattern of the duration reduction for apraxic speakers. We hypothesized that this inconsistency may be explained based on different relative measures of duration reduction. A speech sample was obtained from 10 aphasic speakers with AOS, 10 aphasic speakers without AOS, and 10 normal controls. As predicted, the use of two different relative measures resulted in different vowel reduction patterns, both of which were consistent with previous reports. The results further indicate that the production of polysyllabic words is particularly taxing in AOS and is associated with a substantial reduction of speaking rate compared to other aphasic and normal speakers.     

语义信息在大小数量表征中的作用

本研究采用注意瞬脱实验范式探讨了语义信息在数量表征中的作用。结果发现：（1）在双任务方式中,字母辨认任务对大数（5及以上）的辨认产生干扰,但不影响小数（4及以下）的辨认绩效;（2）数量表征在视野上出现差异性,表现为在小数辨认时,左侧视野呈现绩效高于右侧;大数辨认正好相反,即右侧视野呈现高于左侧。结果表明,语义信息在表征小数和大数中的作用不同：小数的表征无需语言参与;而大数则更多地涉及语义信息,可能需语音回路中无声复述机制的参与。     

Infants' enumeration of actions: numerical discrimination and its signature limits

Are abstract representations of number – representations that are independent of the particular type of entities that are enumerated – a product of human language or culture, or do they trace back to human infancy? To address this question, four experiments investigated whether human infants discriminate between sequences of actions (jumps of a puppet) on the basis of numerosity. At 6 months, infants successfully discriminated four‐ versus eight‐jump sequences, when the continuous variables of sequence duration, jump duration, jump rate, jump interval and duration, and extent of motion were controlled, and rhythm was eliminated. In contrast, infants failed to discriminate two‐ versus four‐jump sequences, suggesting that infants fail to form cardinal number representations of small numbers of actions. Infants also failed to discriminate between sequences of four versus six jumps at 6 months, and succeeded at 9 months, suggesting that infants’ number representations are imprecise and increase in precision with age. All of these findings agree with those of studies using visual–spatial arrays and auditory sequences, providing evidence that a single, abstract system of number representation is present and functional in infancy.     

Mapping Words to the World in Infancy: Infants' Expectations for Count Nouns and Adjectives

Three experimentsdocumentthat 14-month-old infants'construal of objects (e.g., purple animals) is influenced by naming, that they can distinguish between the grammatical form noun and adjective, and that they treat this distinction as relevant to meaning. In each experiment, infants extended novel nouns (e.g., "This one is a blicket") specifically to object categories (e.g., animal), and not to object properties (e.g., purple things). This robust noun-category link is related to grammatical form and not to surface differences in the presentation of novelwords (Experiment 3). Infants'extensions of novel adjectives (e.g., "This one is blickish") were more fragile: They extended adjectives specifically to object properties when the property was color (Experiment 1), but revealed a less precise mapping when the property was texture (Experiment 2). These results reveal that by 14 months, infants distinguish between grammatical forms and utilize these distinctions in determining the meaning of novel words.