Exploring children’s face-space: A multidimensional scaling analysis of the mental representation of facial identity

We explored differences in the mental representation of facial identity between 8-year-olds and adults. The 8-year-olds and adults made similarity judgments of a homogeneous set of faces (individual hair cues removed) using an “odd-man-out” paradigm. Multidimensional scaling (MDS) analyses were performed to represent perceived similarity of faces in a multidimensional space. Five dimensions accounted optimally for the judgments of both children and adults, with similar local clustering of faces. However, the fit of the MDS solutions was better for adults, in part because children’s responses were more variable. More children relied predominantly on a single dimension, namely eye color, whereas adults appeared to use multiple dimensions for each judgment. The pattern of findings suggests that children’s mental representation of faces has a structure similar to that of adults but that children’s judgments are influenced less consistently by that overall structure.     

The relationship between knowing a word and reading it aloud in children’s word reading development

This experiment examined the item-level relationship between 7-year-olds’ ability to read words aloud and their knowledge of the same words in the oral domain. Two types of knowledge were contrasted: familiarity with the phonological form of the word (lexical phonology), measured by auditory lexical decision, and semantic knowledge, measured by a definitions task. Overall, there was a robust relationship between word knowledge and reading aloud success. The association was stronger when words contained irregular spelling-sound correspondences. There was no evidence that a deeper or more semantic knowledge of words was more closely related to reading aloud success beyond the association between reading success and familiarity with the phonological form of the same words. This finding is not compatible with models that see semantics as contributing directly to the reading aloud process, at least during the relatively early stages of reading development. More critical was whether or not a word was considered a lexical item, as indexed by auditory lexical decision performance.     

You do not find your own face faster; you just look at it longer

Previous studies investigating the ability of high priority stimuli to grab attention reached contradictory outcomes. The present study used eye tracking to examine the effect of the presence of the self-face among other faces in a visual search task in which the face identity was task-irrelevant. We assessed whether the self-face (1) received prioritized selection (2) caused a difficulty to disengage attention, and (3) whether its status as target or distractor had a differential effect. We included another highly familiar face to control whether possible effects were self-face specific or could be explained by high familiarity. We found that the self-face interfered with the search task. This was not due to a prioritized processing but rather to a difficulty to disengage attention. Crucially, this effect seemed due to the self-face’s familiarity, as similar results were obtained with the other familiar face, and was modulated by the status of the face since it was stronger for targets than for distractors.     

Beginning readers activate semantics from sub-word orthography

Two experiments assessed whether 7-year-old children activate semantic information from sub-word orthography. Children made category decisions to visually-presented words, some of which contained an embedded word (e.g., hip in ship). In Experiment 1 children were slower and less accurate to classify words if they contained an embedded word related in meaning to the category (e.g., slower to reject ship as a ‘body part’ than an ‘animal’), especially when the embedded word was higher in frequency than the carrier word. This demonstrates that young children activate semantic information from sub-word orthographic representations, and that they do so from the relatively early stages of learning to read. Experiment 2 replicated this effect. Furthermore, we observed semantic interference regardless of whether the embedded word shared its pronunciation with the carrier (e.g., the hip in ship) or not (e.g., the crow in crown), and regardless of its position within the carrier, suggesting that interference was not dependent on phonological mediation. These findings show that by 7-years-of age, children have begun to establish an orthographic system that is capable of activating sub-word orthographic patterns, strong enough to connect with meaning, when reading words silently.     

Categorical perception of affective and linguistic facial expressions

Two experiments investigated categorical perception (CP) effects for affective facial expressions and linguistic facial expressions from American Sign Language (ASL) for Deaf native signers and hearing non-signers. Facial expressions were presented in isolation (Experiment 1) or in an ASL verb context (Experiment 2). Participants performed ABX discrimination and identification tasks on morphed affective and linguistic facial expression continua. The continua were created by morphing end-point photo exemplars into 11 images, changing linearly from one expression to another in equal steps. For both affective and linguistic expressions, hearing non-signers exhibited better discrimination across category boundaries than within categories for both experiments, thus replicating previous results with affective expressions and demonstrating CP effects for non-canonical facial expressions. Deaf signers, however, showed significant CP effects only for linguistic facial expressions. Subsequent analyses indicated that order of presentation influenced signers’ response time performance for affective facial expressions: viewing linguistic facial expressions first slowed response time for affective facial expressions. We conclude that CP effects for affective facial expressions can be influenced by language experience.     

Effects of stimulus duration and choice delay on visual categorization in pigeons

We [Lazareva, O. F., Freiburger, K. L., & Wasserman, E. A. (2004). Pigeons concurrently categorize photographs at both basic and superordinate levels. Psychonomic Bulletin and Review, 11, 1111-1117] previously trained four pigeons to classify color photographs into their basic-level categories (cars, chairs, flowers, or people) or into their superordinate-level categories (natural or artificial). Here, we found that brief stimulus durations had the most detrimental effect on the basic-level discrimination of natural stimuli by the same pigeons. Increasing the delay between stimulus presentation and choice responding had greater detrimental effect on the basic-level discrimination than the superordinate-level discrimination. These results suggest that basic-level discriminations required longer stimulus durations and were more subject to forgetting than were superordinate-level discriminations. Additionally, categorization of natural stimuli required longer stimulus durations than categorization of artificial stimuli, but only at the basic level. Together, these findings suggest that basic-level categorization may not always be superior to superordinate-level categorization and provide additional evidence of a dissociation between natural and artificial stimuli in pigeons’ categorization.     

The smart gut: Tracking affective associative learning with measures of “liking”, facial electromyography, and preferential looking

We demonstrate here that initially neutral items can acquire specific value based on their associated outcomes, and that responses of physiological systems to such previously meaningless stimuli can rapidly reflect this associative history. Each participant participated in an associative learning task in which four neutral abstract pictures were each repeatedly paired with one of four foods that varied in valence and magnitude. Over the course of learning, participants’ “liking” ratings of and preferences for each picture came to reflect the value of the food with which it was paired. The abstract pictures also elicited physiological responses characteristic of the foods with which they were paired, including changes in facial electromyography (EMG) and preferential looking. A logistic modeling procedure showed that learning parameters, such as the rate at which participants learned the values associated with the pictures, were similar across food outcomes of different value.     

The use of auditory feedback and edible reinforcement to decrease toe walking among children with autism

We replicated and extended previous research on the use of auditory feedback to decrease toe walking exhibited by 3 children with autism. After pretreatment screening analyses suggested that toe walking occurred independent of social consequences, we attached squeakers to the heels of each participants' shoes. The squeakers provided auditory feedback when participants walked appropriately (i.e., with a heel-to-toe gait). For all participants, the auditory feedback itself produced increases in appropriate walking. For 1 participant, this feedback was sufficient to reduce toe walking to clinically acceptable levels; however, for 2 other participants, delivery of edible items paired with the auditory feedback was necessary. Intervention effects maintained when the schedule for edible delivery was thinned for all participants. In addition, for 2 participants, effects maintained when the intervention was implemented in a different setting and with a different person with no edibles or a thin schedule of edibles.     

Medial Gastrocnemius Muscle Activity during Single-Leg Hopping to Exhaustion

Abstract

This study described changes in leg muscle activation characteristics during exhaustive single-leg hopping. Twenty-seven healthy men performed trials (132 hops/min) to exhaustion, without a target height, to a target height with visual feedback and target height with tactile feedback. Mean muscle activation amplitude of the medial gastrocnemius (MG) decreased during the anticipatory period while duration of MG activity was maintained when hopping to a target height and contrasted the changes during hopping without a target height. Changes to MG activity were specific to whether the hopping height had been maintained or not. Changes during the anticipatory period of MG activity, indicative of adaptation in descending motor pathways, implicate utility of a motor learning strategy to allow completion of an exhaustive task.     

Activating Semantic Knowledge During Spoken Words and Environmental Sounds: Evidence From the Visual World Paradigm

Two visual world experiments investigated the activation of semantically related concepts during the processing of environmental sounds and spoken words. Participants heard environmental sounds such as barking or spoken words such as “puppy” while viewing visual arrays with objects such as a bone (semantically related competitor) and candle (unrelated distractor). In Experiment 1, a puppy (target) was also included in the visual array; in Experiment 2, it was not. During both types of auditory stimuli, competitors were fixated significantly more than distractors, supporting the coactivation of semantically related concepts in both cases; comparisons of the two types of auditory stimuli also revealed significantly larger effects with environmental sounds than spoken words. We discuss implications of these results for theories of semantic knowledge.