Spontaneous and directed attention to number and proportion.

Although difficulties processing both symbolic and nonsymbolic proportion compared with absolute number are well established, the mechanisms involved remain unclear. We investigate four potential explanations to account for better number processing in adulthood: (a) number is more salient than proportion, (b) number is encoded more automatically than proportion, (c) proportion is more effortfully processed than number, and (d) number competes with proportion during decision making. Across three experiments, we used a delayed match-to-sample paradigm in which adults were asked which of two alternatives matched a sample set of red and blue dots.

The temporal dynamics of infants' joint attention: Effects of others' gaze cues and manual actions.

Infants' development of joint attention shows significant advances between 9 and 12 months of age, but we still need to learn much more about how infants coordinate their attention with others during this process. The objective of this study was to use eye tracking to systematically investigate how 8- and 12-month-old infants as well as adults dynamically select their focus of attention while observing a social partner demonstrate infant-directed actions. Participants were presented with 16 videos of actors performing simple infant-directed actions from a first-person perspective.

Author Correction: A consensus-based transparency checklist.

An amendment to this paper has been published and can be accessed via a link at the top of the paper.

A consensus-based transparency checklist.

We present a consensus-based checklist to improve and document the transparency of research reports in social and behavioural research. An accompanying online application allows users to complete the form and generate a report that they can submit with their manuscript or post to a public repository.

Direct gaze, eye movements, and covert and overt social attention processes.

The present study is a replication and extension of previous research examining the effects of others' gaze direction and gaze shifts on both participants' (N = 32) manual responses, as an indicator of covert processes, and their visual attention, as an indicator of overt processes, within an experimental response time (RT) paradigm, under both fixed- and free-viewing instructions. Participants viewed arrays of faces displaying direct or averted gaze, which shifted or held their gaze, concurrent with the presentation of a target letter that participants had to identify overlaid on one face, all while their gaze was recorded with an eye-tracking system. Participants' RTs and eye movements both revealed faster responses when the target face displayed either direct or shifted gaze, and especially when its gaze had shifted from averted to direct, though these effects were modulated by the viewing instructions.

Infants' motor simulation of observed actions is modulated by the visibility of the actor's body.

Previous research suggests that 9-month-old infants will develop a response bias in the A-not-B search paradigm after only observing an experimenter search for a hidden object on A-trials. In the current experiment, we tested whether infants would persist in making errors when only the hands-and-arms of the experimenter were visible. Three different conditions were included: (1) the experimenter was silent while hiding and finding the object, (2) the experimenter communicated with the infant via infant-directed speech, or (3) the body of the experimenter was visible during the training phase before his head and body were occluded during the test phase.

Attention to body-parts varies with visual preference and verb-effector associations.

Theories of embodied conceptual meaning suggest fundamental relations between others' actions, language, and our own actions and visual attention processes. Prior studies have found that when people view an image of a neutral body in a scene they first look toward, in order, the head, torso, hands, and legs. Other studies show associations between action verbs and the body-effectors used in performing the action (e.

Isolated processing of geometric shapes and their corresponding shape words: Evidence from a delayed match-to-sample task.

Some theorists propose a domain-specific cognitive system dedicated to processing geometric information, but existence of this system remains debatable because of challenges in isolating geometric from linguistic and semantic processing. Recently, Sturz, Edwards, and Boyer (2014) developed a delayed match-to-sample task that presented a sample of a shape, shape word, or bidimensional stimulus composed of a shape and shape word. After a delay, participants identified the sample shape or the sample word by selecting between 2 shapes or 2 shape words.

Infants' observation of others' actions: Brief movement-specific visual experience primes motor representations.

Recent research suggests that infants' observation of others' reaching actions activates corresponding motor representations which develop with their motor experience. Contralateral reaching develops a few months later than ipsilateral reaching, and 9-month-old infants are less likely to map the observation of these reaches to their motor representations. The goal of the current study was to test whether a brief familiarization with contralateral reaching is sufficient to prime this less developed motor representation to increase the likelihood of its activation.

Disfluent fonts don't help people solve math problems.

Prior research suggests that reducing font clarity can cause people to consider printed information more carefully. The most famous demonstration showed that participants were more likely to solve counterintuitive math problems when they were printed in hard-to-read font. However, after pooling data from that experiment with 16 attempts to replicate it, we find no effect on solution rates.

Prompting children to reason proportionally: Processing discrete units as continuous amounts.

Recent studies reveal that children can solve proportional reasoning problems presented with continuous amounts that enable intuitive strategies by around 6 years of age but have difficulties with problems presented with discrete units that tend to elicit explicit count-and-match strategies until at least 10 years of age. The current study tests whether performance on discrete unit problems might be improved by prompting intuitive reasoning with continuous-format problems. Participants were kindergarten, second-grade, and fourth-grade students (N = 194) assigned to either an experimental condition, where they were given continuous amount proportion problems before discrete unit proportion problems, or a control condition, where they were given all discrete unit problems.

Signal clarity: an account of the variability in infant quantity discrimination tasks.

Infants have shown variable success in quantity comparison tasks, with infants of a given age sometimes successfully discriminating numerical differences at a 2:3 ratio but requiring 1:2 and even 1:4 ratios of change at other times. The current explanations for these variable results include the two-systems proposal - a theoretical framework that suggests that there are multiple systems at play and that these systems do not communicate early in infancy, leading to failure in certain numerical comparisons. An alternative proposal is that infants may be attending to continuous extent dimensions in these tasks rather than number per se.

When do infants begin to follow a point?

Infants' understanding of a pointing gesture represents a major milestone in their communicative development. The current consensus is that infants are not capable of following a pointing gesture until 9-12 months of age. In this article, we present evidence from 4- and 6-month-old infants challenging this conclusion.

Asymmetrical interference effects between two-dimensional geometric shapes and their corresponding shape words.

Nativists have postulated fundamental geometric knowledge that predates linguistic and symbolic thought. Central to these claims is the proposal for an isolated cognitive system dedicated to processing geometric information. Testing such hypotheses presents challenges due to difficulties in eliminating the combination of geometric and non-geometric information through language.

Stroop interference in a delayed match-to-sample task: evidence for semantic competition.

Discussions of the source of the Stroop interference effect continue to pervade the literature. Semantic competition posits that interference results from competing semantic activation of word and color dimensions of the stimulus prior to response selection. Response competition posits that interference results from competing responses for articulating the word dimension vs.

Probabilistic cue combination: less is more.

Learning about the structure of the world requires learning probabilistic relationships: rules in which cues do not predict outcomes with certainty. However, in some cases, the ability to track probabilistic relationships is a handicap, leading adults to perform non-normatively in prediction tasks. For example, in the dilution effect, predictions made from the combination of two cues of different strengths are less accurate than those made from the stronger cue alone.

Differential contributions of development and learning to infants' knowledge of object continuity and discontinuity.

Sixty infants divided evenly between 5 and 7 months of age were tested for their knowledge of object continuity versus discontinuity with a predictive tracking task. The stimulus event consisted of a moving ball that was briefly occluded for 20 trials. Both age groups predictively tracked the ball when it disappeared and reappeared via occlusion, but not when it disappeared and reappeared via implosion.

Is automatic imitation a specialized form of stimulus-response compatibility? Dissociating imitative and spatial compatibilities.

In recent years research on automatic imitation has received considerable attention because it represents an experimental platform for investigating a number of interrelated theories suggesting that the perception of action automatically activates corresponding motor programs. A key debate within this research centers on whether automatic imitation is any different than other long-term S-R associations, such as spatial stimulus-response compatibility. One approach to resolving this issue is to examine whether automatic imitation shows similar response characteristics as other classes of stimulus-response compatibility.

Child proportional scaling: is 1/3=2/6=3/9=4/12?

The current experiments examined the role of scale factor in children's proportional reasoning. Experiment 1 used a choice task and Experiment 2 used a production task to examine the abilities of kindergartners through fourth-graders to match equivalent, visually depicted proportional relations. The findings of both experiments show that accuracy decreased as the scaling magnitude between the equivalent proportions increased.

Infants' understanding of actions performed by mechanical devices.

Recent research suggests that 9-month-old infants tested in a modified version of the A-not-B search task covertly imitate actions performed by the experimenter. The current study examines whether infants also simulate actions performed by mechanical devices, and whether this varies with whether or not they have been familiarized with the devices and their function. In Experiment 1, infants observed hiding and retrieving actions performed by a pair of mechanical claws on the A-trials, and then searched for the hidden toy on the B-trial.

True or false: do 5-year-olds understand belief?

In 3 studies (N = 188) we tested the hypothesis that children use a perceptual access approach to reason about mental states before they understand beliefs. The perceptual access hypothesis predicts a U-shaped developmental pattern of performance in true belief tasks, in which 3-year-olds who reason about reality should succeed, 4- to 5-year-olds who use perceptual access reasoning should fail, and older children who use belief reasoning should succeed. The results of Study 1 revealed the predicted pattern in 2 different true belief tasks.

Development of proportional reasoning: where young children go wrong.

Previous studies have found that children have difficulty solving proportional reasoning problems involving discrete units until 10 to 12 years of age, but can solve parallel problems involving continuous quantities by 6 years of age. The present studies examine where children go wrong in processing proportions that involve discrete quantities. A computerized proportional equivalence choice task was administered to kindergartners through 4th-graders in Study 1, and to 1st- and 3rd-graders in Study 2.

Decision-making processes: sensitivity to sequentially experienced outcome probabilities.

A computerized sequential event sampling decision-making task was administered to 187 5- to 10-year-olds and adults Participants made a series of choices between alternatives that differed in win probability (Study 1) or win and loss probability (Study 2). Intuitive and more explicit measures were used. Study 1 revealed that, across ages, participants demonstrated intuitive sensitivity to probability; however, adult participants evidenced greater sensitivity than did children, and younger children failed to demonstrate more explicit understanding of probability.