Development of manipulatory skills and the deployment of attention

Two independent tasks, object manipulation and auditory-visual matching, were used to examine the relationship between developing manual action skills and attention to intermodal object properties in 3.5- and 5.5-month-olds. Although handling skills improved with age, with older infants demonstrating more varied manipulation, there were no age differences for the matching task. When grouped by handling skills, a significant interaction between skill and event type was found for the two age groups combined and for 5.5-month-olds alone. Auditory-visual matching of social events did not vary with handling skills, whereas auditory-visualmatching of object events did. Infants at higher skill levels responded similarly to social and object events, whereas less skilled infants' matching preferences were weaker for object events. These findings indicate that infants increase their attention to auditory and visual properties of objects as this information becomes useful for guiding new actions. This effect is independent of age due to considerable individual variability in the development of object handling skills.     

PyHab: Open-source real time infant gaze coding and stimulus presentation software

Infant looking-time paradigms often use specialized software for real time manual coding of infant gaze. Here, I introduce PyHab, the first open-source looking-time coding and stimulus presentation solution designed specifically with open science in mind. PyHab is built on the libraries of PsychoPy (Peirce, 2007). PyHab has its own graphical interface for building studies and requires no programming experience to use. When creating a study, PyHab saves a folder that contains all of the code required to run the study and all of the stimuli, making each experiment a self-contained, easily shared package. This feature guarantees the ability to replicate a PyHab experiment exactly as it was run. PyHab also has several features designed to support rigorous methodology, such as experimenter blinding and automatic stimulus control. In addition, because it is open-source, PyHab can be modified and improved not only by its developer but by anyone who knows Python.     

A generalized distance function for preferential choices

Many cognitive theories of judgement and decision making assume that choice options are evaluated relative to other available options. The extent to which the preference for one option is influenced by other available options will often depend on how similar the options are to each other, where similarity is assumed to be a decreasing function of the distance between options. We examine how the distance between preferential options that are described on multiple attributes can be determined. Previous distance functions do not take into account that attributes differ in their subjective importance, are limited to two attributes, or neglect the preferential relationship between the options. To measure the distance between preferential options it is necessary to take the subjective preferences of the decision maker into account. Accordingly, the multi‐attribute space that defines the relationship between options can be stretched or shrunk relative to the attention or importance that a person gives to different attributes describing the options. Here, we propose a generalized distance function for preferential choices that takes subjective attribute importance into account and allows for individual differences according to such subjective preferences. Using a hands‐on example, we illustrate the application of the function and compare it to previous distance measures. We conclude with a discussion of the suitability and limitations of the proposed distance function.     

How Information Availability Interacts with Visual Attention during Judgment and Decision Tasks

Decisions in front of a supermarket shelf probably involve a mix of visually available information and associated memories—and interactions between those two. Several cognitive processes, such as decision making, search, and various judgments, are therefore likely to co‐occur, and each process will influence visual attention. We conducted two eye‐tracking experiments capturing parts of these features by having participants make either judgments or decisions concerning products that had been previously encoded. Half the time, participants made their choices with full information about the available products and half the time with crucial task‐relevant information removed. By comparing participants' use of visual attention during decisions and search‐based and memory‐based judgments, we can better understand how visual attention is differently employed between tasks and how it depends on the visual environment. We found that participants' visual attention during decisions is sensitive to evaluations already made during encoding and strongly characterized by preferential looking to the options later to be chosen. When the task environment is rich enough, participants engage in advanced integrative visual behavior and improve their decision quality. In contrast, visual attention during judgments made on the same products reflects a search‐like behavior when all information is available and a more focused type of visual behavior when information is removed. Our findings contribute not only to the literature on how visual attention is used during decision making but also to methodological questions concerning how to measure and identify task‐specific features of visual attention in ecologically valid ways. Copyright © 2015 John Wiley & Sons, Ltd.     

Optimal scaling of paired comparison and rank order data: An alternative to guttman's formulation

A formulation, which is different from Guttman's is presented. The two formulations are both called the optimal scaling approach, and are proven to provide identical scale values. The proposed formulation has at least two advantages over Guttman's. Namely, (i) the former serves to clarify close relations of the optimal scaling approach to those of Slater and the vector model of preferential choice, and (ii) in addition to the stimulus scale values, it provides scores for the subjects, which indicate the degrees of response consistency (transitivity), relative to the optimum solution. The method is assumption-free and capable of multidimensional analysis.This study was partly supported by the National Research Council Grant (No. A4581) to S. Nishisato. The author is indebted to Dr. Bert F. Green, Jr., Mr. Tomoichi Ishizuka, and anonymous reviewers for their valuable comments on an earlier draft.     

Infant’s gaze in a teasing task with an experimenter or parent: A naturalistic approach

We assessed infant’s gaze in a teasing task in New York City public spaces. The task was administered to two different groups of 5- to 13-month-old infants. We used a between participants design across two studies. In Study 1 an experimenter administered the task to these infants (n = 79), whereas a parent did so in Study 2 (n = 79). The adult engaged the infant with a toy and then pulled it away to one side by counting to 7. A second trial to the other side was repeated. Infants passed the teasing task if they looked to the adult’s face within the first 5 seconds after removing the toy in at least one trial. In Study 1, we found that infants looked to the experimenter’s face after teasing by 7 months of age. In Study 2, infants did not show any significant gazes to the parent’s face after teasing at any age. Most trained parents successfully administered the teasing task to their infant. A teasing game played by an adult stranger (e.g., experimenter) may be optimal to elicit infant’s gaze in a naturalistic setting. Implications for developing cost-effective social-cognitive milestone measures in non-laboratory settings are discussed.     

Infants’ ability to respond to depth from the retinal size of human faces: Comparing monocular and binocular preferential-looking

To examine sensitivity to pictorial depth cues in young infants (4 and 5 months-of-age), we compared monocular and binocular preferential looking to a display on which two faces were equidistantly presented and one was larger than the other, depicting depth from the size of human faces. Because human faces vary little in size, the correlation between retinal size and distance can provide depth information. As a result, adults perceive a larger face as closer than a smaller one. Although binocular information for depth provided information that the faces in our display were equidistant, under monocular viewing, no such information was provided. Rather, the size of the faces indicated that one was closer than the other. Infants are known to look longer at apparently closer objects. Therefore, we hypothesized that infants would look longer at a larger face in the monocular than in the binocular condition if they perceived depth from the size of human faces. Because the displays were identical in the two conditions, any difference in looking-behavior between monocular and binocular viewing indicated sensitivity to depth information. Results showed that 5-month-old infants preferred the larger, apparently closer, face in the monocular condition compared to the binocular condition when static displays were presented. In addition, when presented with a dynamic display, 4-month-old infants showed a stronger ‘closer’ preference in the monocular condition compared to the binocular condition. This was not the case when the faces were inverted. These results suggest that even 4-month-old infants respond to depth information from a depth cue that may require learning, the size of faces.     

Dropout in looking time studies: The role of infants’ temperament and cognitive developmental status

Dropout of infants in looking time studies sometimes occurs at high rates, raising concerns that the representativeness of the final sample might be reduced in comparison to the originally obtained sample. The current study investigated which infant characteristics play a role in dropout. Infants were presented with a preferential looking task at 6 and 9 months of age. At 9 months of age, an additional habituation task and a subsequent novelty preference task were conducted. In addition, temperament was assessed via the Infant Behavior Questionnaire – Revised (IBQ-R, Gartstein & Rothbart, 2003), and cognitive developmental status was assessed via the Cognitive Scale of the Bayley Scale of Infant and Toddler Development (BSID-III, Bayley, 2006). Dropout was positively related to the IBQ-R temperament scales Distress to Limitations and Approach, and negatively related to the scales Falling Reactivity and Cuddliness. The representativeness of the final sample regarding situation-specific temperament dimensions is affected by dropout. Dropout was not related to cognitive developmental status as measured via the BSID-III, habituation speed and novelty preference. Dropout at 6 months of age was associated with dropout at 9 months of age. We concluded that in looking time studies, the representativeness of the final sample regarding performance-relevant temperament dimensions or cognitive developmental status is not affected by dropout.