An important issue for understanding early cognition is why very young children’s real-world representations do not get confused by pretense events. One possible source of information for children is the pretender’s behaviors. Pretender behaviors may vary systematically across real and pretend scenarios, perhaps signaling to toddlers to interpret certain events as not real. Pretender behaviors were examined in 2 experiments in which mothers were asked both to pretend to have a snack and really to have a snack with their 18-month-olds. Episodes were analyzed for condition differences in verbal and nonverbal behaviors, including smiling, looking, laughter, and functional movements. Reliable differences were found across conditions for several variables. In a 3rd experiment, children’s apparent understanding of pretense in relation to their mothers’ behaviors was examined, and significant associations were found with some of the mothers’ behavioral changes but not others. This work provides a first inroad into the issue of how children learn to interpret pretense acts as pretense.
Participation in imagined worlds is a hallmark of the human species, and yet we know little about the context of its early emergence. The experiments reported here replicated and extended in 2 directions Lillard and Witherington’s (2004) study of how mothers pretend to have snacks, across different ages of children (15- to 24-month-olds, Experiment 1) and to a different scenario (personal grooming, Experiment 2). Mothers’ pretend behaviors changed little as infants aged, but there were some scenario differences. Most striking in this research was the consistency with which particular maternal pretend behaviors were associated with children engaging in pretense behaviors and smiling. The findings are discussed with reference to the child’s emerging skills in joint attention and social referencing.
Do infants understand that intention can be transferred through communication? We answered this question by examining 12-month-olds' looking times in a violation-of-expectation paradigm with two human agents. In familiarization, the non-acting agent spoke, clapped her hands, read aloud a book, or remained silent before the acting agent grasped one (the target) of two objects. During test only the non-actor remained, grasping either the target or distractor. The infants looked longer in the distractor than target condition, suggesting violation of expectation, only if the non-actor had spoken or clapped in familiarization. Because the non-actor never had grasped any of the objects in familiarization, the infants' expectation on her behavior could have developed from the understanding that her intention was transferred to the actor, who executed it by grasping the target in familiarization, via speaking and clapping as acts of communication (but not reading aloud and remaining silent).
This study examined 2- to 3-year-olds’ ability to make a pretend – real distinction in the absence of content cues. Children watched two actors side by side. One was really eating, and the other was pretending to eat, but in neither case was information about content available. Following the displays, children were asked to retrieve the real food (Experiment 1) or point to the container with the real food (Experiments 2 and 3). 3- and 2.5-year-olds distinguished between the real and pretend acts based on behavioral cues alone. Two-year-olds chose the containers at random, but their spontaneous reactions suggested that they discriminated the real acts from pretense to some degree. Possible accounts for the discrepancy between the different behavioral measures are discussed.
This research investigated 3- to 5-year-old’s understanding of the role of intentional states and action in pretense. There are two main perspectives on how children conceptualize pretense. One view is that children understand the mental aspects of pretending (the rich interpretation). The alternative view is that children conceptualize pretense as “acting-like” and do not appreciate that the mind is crucial to pretense (the lean interpretation). The experiments in this article used a novel approach to test these two interpretations. Children were presented with two types of videotaped scenarios. In Experiment 1, children were presented with a scenario in which people wanted to be like something else (e.g., a kangaroo) and either acted like it or did not act like it. Children were asked whether the protagonists were pretending and whether they were thinking about the pretend entity. In Experiment 2, children were presented with the Experiment 1 scenarios and also with a scenario in which a person had the intention to do something else (e.g., look for her keys) but whose actions were similar to those of a pretend entity (e.g., a bear). Children were asked about the pretense, thoughts, and the intentions of the protagonists. Experiment 3 tested for the effect of asking an open-ended versus a forced-choice question on the Experiment 2 tasks. The results of this study suggest that in certain facilitating conditions (e.g., intention information salient, forced-choice question) children have an early understanding of the role of mind in pretense.
Mothers begin to pretend with their children during the second year, when children still have much to learn about the real world. Although it would be easy to confuse what is pretend with what is real, children at this young age often demonstrate comprehension during pretense situations. It is plausible that social referencing, in which the child uses the mother’s emotional expression as a guide to behavior, might facilitate this emerging knowledge by signaling to the child not to take the pretend situation seriously. Data from 32 pairs of mothers and their 18-month-olds who had engaged in pretend and real snack behaviors were subjected to a sequential analysis to investigate a social referencing interpretation. Consistent with our hypothesis, behaviors suggestive of a baby’s understanding pretense were more likely to follow a specific combination of behaviors consistent with social referencing than other combinations of behaviors. These results provide support for the possibility that children use information obtained through social referencing to assist understanding during pretense interactions.
The current study investigated whether 18-months-olds attribute opaque mental states when they solve false belief tests, or simply rely on behavioural cues available in the stimuli. Infants experienced either a trick blindfold that looked opaque but could be seen through, or an opaque blindfold. Then both groups of infants observed an actor wearing the same blindfold that they had themselves experienced, whilst a puppet removed an object from its location. Anticipatory eye movements revealed that infants who experienced the opaque blindfold expected the actor’s action in accord with her having a false belief about the object’s location, but infants who experienced the trick blindfold did not. The results suggest that 18-months-olds used self-experience with the blindfold to assess the actor’s visual access, and updated her knowledge/belief state accordingly. These data constitute compelling evidence that 18-months-olds infer perceptual access and appreciate its causal role in altering epistemic states of others.
Theory of mind; infants; eye-tracking; social cognition
Four-, 6-, and 11-month old infants were presented with movies in which two adult actors conversed about everyday events, either by facing each other or looking in opposite directions. Infants from 6 months of age made more gaze shifts between the actors, in accordance with the flow of conversation, when the actors were facing each other. A second experiment demonstrated that gaze following alone did not cause this difference. Instead the results are consistent with a social cognitive interpretation, suggesting that infants perceive the difference between face-to-face and back-to-back conversations and that they prefer to attend to a typical pattern of social interaction from 6 months of age.
infants; social cognition; gaze following; social interaction; eye tracking
Discriminating what is pretense from what is real is a fundamental problem in development. Research has addressed the proficiency with which adults and children discriminate between play fighting and real fighting, and yet none (to our knowledge) has investigated discrimination of other kinds of pretense and real acts. In addition, little is known about what aspects of pretender behavior (as opposed to pretend content) might cue pretense interpretations. In two experiments, 8–20 s clips showing pretense and real snack behaviors were presented to adult and child participants. All participants distinguished between pretense and real behaviors at better than chance level. Furthermore, certain features (specific looking patterns and mistimed behaviors) were most prominent in the videotapes that were most often correctly identified. This provides empirical support for the suggestion that these cues, as opposed to more commonly cited cues, like smiles, might serve as important indicators of pretense for children and adults.
Pretense; Discrimination; Development; Social cognition; Behavioral cues
The current study examined the integration of non-numerical (featural) and numerical information in 9-, 11-, and 13-month-old infants’ performance on a number discrimination task. Infants were habituated to pictures of objects (e.g., bowl, shoe) either in groups of two or three. In the test phase, infants saw both new and old objects in both groups of two and three. Nine-month-old infants discriminated number independent of the familiarity of the object, 11-month-old infants discriminated between familiar and novel objects (but not the number of objects), and 13-month-old infants discriminated between the familiar and novel objects only in the context of a familiar number of objects. These data suggest that early number representations are dissociated from featural information, and that the integration of these stimulus properties is a developmental process that occurs across the first year.
In uncertain situations such as descending challenging slopes, social signals from caregivers can provide infants with important information for guiding action. Previous work showed that 18- month-old walking infants use social information selectively, only when risk of falling is uncertain. Experiment 1 was designed to alter infants’ region of uncertainty for walking down slopes. Slippery Teflon-soled shoes drastically impaired 18-month-olds’ ability to walk down slopes compared with walking barefoot or in standard crepe-soled shoes, shifting the region of uncertainty to shallower range of slopes. In Experiment 2, infants wore Teflon-soled shoes while walking down slopes as their mothers encouraged and discouraged them from walking. Infants relied on social information on shallow slopes, even at 0°, where the probability of walking successfully was uncertain in the Teflon-soled shoes. Findings indicate that infants’ use of social information is dynamically attuned to situational factors and the state of their current abilities.
infant locomotion; social cognition; perceptual exploration; walking; communication
The present research investigated whether 13.5-month-old infants would attribute to an actor a disposition to perform a recurring action, and would then use this information to predict which of two new objects—one that could be used to perform the action and one that could not—the actor would grasp next. During familiarization, the infants watched an actor slide various objects forward and backward on an apparatus floor. During test, the infants saw two new identical objects placed side by side: one stood inside a short frame that left little room for sliding; the other stood inside a longer frame that left ample room for sliding. The infants who saw the actor grasp the object inside the short frame looked reliably longer than those who saw the actor grasp the object inside the long frame. This and control results from a lifting condition provide evidence that by 13.5 months, infants can attribute to an actor a disposition to perform a particular action.
There is increasing evidence that infants’ representations of physical events can be enhanced through appropriate experiences in the laboratory. Most of this research has involved administering infants multiple training trials, often with multiple objects. In the present research, 8-month-olds were induced to detect a physical violation in a single trial. The experiments built on previous evidence that for occlusion events, infants encode height information at about age 3.5 months, but for covering events, they encode height information only at about age 12 months. In two experiments, a short cover was first placed in front of a short or a tall object (occlusion event); next, the cover was lowered over the tall object until it became fully hidden (covering event). Exposure to the occlusion event (but not other events in which height information was not encoded) enabled the infants to detect the violation in the covering event, much earlier than they would have otherwise.
Do 18-month-olds understand that an agent’s false belief can be corrected by an appropriate, though not an inappropriate, communication? In Experiment 1, infants watched a series of events involving two agents, a ball, and two containers: a box and a cup. To start, agent1 played with the ball and then hid it in the box, while agent2 looked on. Next, in agent1’s absence, agent2 moved the ball from the box to the cup. When agent1 returned, agent2 told her “The ball is in the cup!” (informative-intervention condition) or “I like the cup!” (uninformative-intervention condition). During test, agent1 reached for either the box (box event) or the cup (cup event). In the informative-intervention condition, infants who saw the box event looked reliably longer than those who saw the cup event; in the uninformative-intervention condition, the reverse pattern was found. These results suggest that infants expected agent1’s false belief about the ball’s location to be corrected when she was told “The ball is in the cup!”, but not “I like the cup!”. In Experiment 2, agent2 simply pointed to the ball’s new location, and infants again expected agent1’s false belief to be corrected. These and control results provide additional evidence that infants in the second year of life can attribute false beliefs to agents. In addition, the results suggest that by 18 months of age infants expect agents’ false beliefs to be corrected by relevant communications involving words or gestures.
Although working memory has a highly constrained capacity limit of 3 to 4 items, both adults and toddlers can increase the total amount of stored information by chunking object representations in memory. To examine the developmental origins of chunking, we used a violation-of-expectation procedure to ask whether 7-month-old infants, whose working memory capacity is still maturing, also can chunk items in memory. In Experiment 1 we found that in the absence of chunking cues, infants failed to remember 3 identical hidden objects. In Experiments 2 and 3 we found that infants successfully remembered 3 hidden objects when provided with overlapping spatial and featural chunking cues. In Experiment 4 we found that infants did not chunk when provided with either spatial or featural chunking cues alone. Finally, in Experiment 5 we found that infants also failed to chunk when spatial and featural cues specified different chunks (i.e., were pitted against each other). Taken together, these results suggest that chunking is available before working memory capacity has matured, but still may undergo important development over the first year of life.
working memory; cognitive development; chunking; infants
As they observe or produce events, infants identify variables that help them predict outcomes in each category of events. How do infants identify a new variable? An explanation-based learning (EBL) account suggests three essential steps: (1) observing contrastive outcomes relevant to the variable; (2) discovering the conditions associated with these outcomes; and (3) generating an explanation for the condition-outcome regularity discovered. In Experiments 1–3, 9-month-old infants watched events designed to “teach” them the variable height in covering events. After watching these events, designed in accord with the EBL account, the infants detected a height violation in a covering event, three months earlier than they ordinarily would have. In Experiments 4–6, the “teaching” events were modified to remove one of the EBL steps, and the infants no longer detected the height violation. The present findings thus support the EBL account and help specify the processes by which infants acquire their physical knowledge.
Infant cognition; knowledge acquisition; physical reasoning; identification of variables; explanation-based learning; event categories
Novelty seeking is viewed as adaptive, and novelty preferences in infancy predict cognitive performance into adulthood. Yet 7-month-olds prefer familiar stimuli to novel ones when searching for hidden objects, in contrast to their strong novelty preferences with visible objects (Shinskey & Munakata, 2005). According to a graded representations perspective on object knowledge, infants gradually develop stronger object representations through experience, such that representations of familiar objects can be better maintained, supporting greater search than with novel objects. Object representations should strengthen with further development to allow older infants to shift from familiarity to novelty preferences with hidden objects. The current study tested this prediction by presenting 24 11-month-olds with novel and familiar objects that were sometimes visible and sometimes hidden. Unlike 7-month-olds, 11-month-olds showed novelty preferences with both visible and hidden objects. This developmental shift from familiarity to novelty preference with hidden objects parallels one that infants show months earlier with perceptible stimuli, but the two transitions may reflect different underlying mechanisms. The current findings suggest both change and continuity in the adaptive development of object representations and associated cognitive processes.
Recent research on infants’ responses to occlusion and containment events indicates that, although some violations of the continuity principle are detected at an early age e.g. Aguiar, A., & Baillargeon, R. (1999). 2.5-month-old infants’ reasoning about when objects should and should not be occluded. Cognitive Psychology 39, 116–157; Hesposs, S. J., & Baillargeon, R. (2001). Knowledge about containment events in very young infants. Cognition 78, 207–245; Luo, Y., & Baillargeon, R. (in press). When the ordinary seems unexpected: Evidence for rule-based reasoning in young infants. Cognition; Wilcox, T., Nadel, L., & Rosser, R. (1996). Location memory in healthy preterm and full-term infants. Infant Behavior & Development 19, 309–323, others are not detected until much later e.g. Baillargeon, R., & DeVos, J. (1991). Object permanence in young infants: Further evidence. Child Development 62, 1227–1246; Hespos, S. J., & Baillargeon, R. (2001). Infants’ knowledge about occlusion and containment events: A surprising discrepancy. Psychological Science 12, 140–147; Luo, Y., & Baillargeon, R. (2004). Infants’ reasoning about events involving transparent occluders and containers. Manuscript in preparation; Wilcox, T. (1999). Object individuation: Infants’ use of shape, size, pattern, and color. Cognition 72, 125–166. The present research focused on events involving covers or tubes, and brought to light additional examples of early and late successes in infants’ ability to detect continuity violations. In Experiment 1, 2.5- to 3-month-old infants were surprised (1) when a cover was lowered over an object, slid to the right, and lifted to reveal no object; and (2) when a cover was lowered over an object, slid behind the left half of a screen, lifted above the screen, moved to the right, lowered behind the right half of the screen, slid past the screen, and finally lifted to reveal the object. In Experiments 2 and 3, 9- and 11-month-old infants were not surprised when a short cover was lowered over a tall object until it became fully hidden; only 12-month-old infants detected this violation. Finally, in Experiment 4, 9-, 12-, and 13-month-old infants were not surprised when a tall object was lowered inside a short tube until it became fully hidden; only 14-month-old infants detected this violation. A new account of infants’ physical reasoning attempts to make sense of all of these results. New research directions suggested by the account are also discussed.
Physical reasoning in infancy; Continuity violations; Event categories
The current study tested the hypothesis that women pretend orgasm as part of a broader strategy of mate retention. We obtained self-report data from 453 heterosexual women (M age, 21.8 years) in a long-term relationship (M length, 32.8 months) drawn from universities and surrounding communities in the southeastern United States. The results indicated that (1) women who perceived higher risk of partner infidelity were more likely to report pretending orgasm, (2) women who reported greater likelihood of pretending orgasm also reported performing more mate retention behaviors, and (3) women’s perceptions of partner infidelity risk mediated the relationship between pretending orgasm and the performance of cost-inflicting mate retention behaviors, such as Intersexual Negative Inducements (“Flirted with some one infront of my partner”) and Intrasexual Negative Inducements (“Yelled at a woman who looked at my partner”). Thus, pretending orgasm may be part of a broader strategy of mate retention performed by women who perceive higher risk of partner infidelity.
Female orgasm; Infidelity risk; Mate retention; Evolutionary psychology; Sexuality
Infants rapidly learn novel phonotactic constraints from brief listening experience. Four experiments explored the nature of the representations underlying this learning. 16.5- and 10.5-month-old infants heard training syllables in which particular consonants were restricted to particular syllable positions (first-order constraints) or to syllable positions depending on the identity of the adjacent vowel (second-order constraints). Later, in a headturn listening-preference task, infants were presented with new syllables that either followed the experimental constraints or violated them. Infants at both ages learned first- and second-order constraints on consonant position (Experiments 1 and 2) but found second-order constraints more difficult to learn (Experiment 2). Infants also spontaneously generalized first-order constraints to syllables containing a new, transfer vowel; they did so whether the transfer vowel was similar to the familiarization vowels (Experiment 3), or dissimilar from them (Experiment 4). These findings suggest that infants recruit representations of individuated segments during phonological learning. Furthermore, like adults, they represent phonological sequences in a flexible manner that allows them to detect patterns at multiple levels of phonological analysis.
speech perception; phonological development; statistical learning; phonotactic learning; infancy
To examine key parameters of the initial conditions in early category learning, two studies compared 5-month-olds’ object categorization between tasks involving previously unseen novel objects, and between measures within tasks. Infants in Experiment 1 participated in a visual familiarization / novelty preference (VFNP) task with 2D stimulus images. Infants provided no evidence of categorization by either their looking or their examining even though infants in previous research systematically categorized the same objects by examining when they handled them in 3D. Infants in Experiment 2 participated in a VFNP task with 3D stimulus objects that allowed visual examination of objects’ 3D instantiation while denying manual contact with the objects. Under these conditions, infants demonstrated categorization by examining but not by looking. Focused examination appears to be a key component of young infants’ ability to form category representations of novel objects, and 3D instantiation appears to better engage such examining.
Two experiments provide evidence for an age-related deficit in the binding of actors with actions that is distinct from binding deficits associated with distraction or response pressure. Young and older adults viewed a series of actors performing different actions. Participants returned one week later for a recognition test. Older adults were more likely than young adults to falsely recognize novel conjunctions of familiar actors and actions. This age-related binding deficit occurred even when older adults could discriminate old items from new items just as well as could younger adults. Younger adults who experienced distraction or time pressure also had difficulty discriminating old items from conjunction items, but this deficit was accompanied by a deficit at discriminating old and new items. These results suggest that distraction and response pressure lead to deficits in memory for stimulus components, with any deficits in binding ability commensurate with these deficits in component memory. Aging, in turn, may lead to binding difficulties that are independent of attention-demanding executive processes involved in maintaining individual stimulus components in working memory, likely reflecting declines in hippocampally-mediated associative processes.
event memory; binding; associative deficit; conjunction memory error; hippocampus
Objective: To estimate the prevalence of violations of the international code of marketing of substitutes for breast milk in one city in each of Bangladesh, Poland, South Africa, and Thailand.
Design: Multistage random sampling was used to select pregnant women and mothers of infants ⩽6 months old to interview at health facilities. Women were asked whether they had received free samples of substitutes for breast milk (including infant formula designed to meet the nutritional needs of infants from birth to 4 to 6 months of age, follow on formula designed to replace infant formula at the age of 4 to 6 months, and complementary foods for infants aged ⩽6 months), bottles, or teats. The source of the free sample and when it had been given to the women was also determined. 3 health workers were interviewed at each facility to assess whether the facility had received free samples, to determine how they had been used, and to determine whether gifts had been given to health workers by companies that manufactured or distributed breast milk substitutes. Compliance with the marketing code for information given to health workers was evaluated using a checklist.
Setting: Health facilities in Dhaka, Bangladesh; Warsaw, Poland; Durban, South Africa; and Bangkok, Thailand.
Subjects: 1468 pregnant women, 1582 mothers of infants aged ⩽6 months, and 466 health workers at 165 health facilities.
Main outcome measures: Number of free samples received by pregnant women, mothers, and health workers; number of gifts given to health workers; and availability of information that violated the code in health facilities.
Results: 97 out of 370 (26%) mothers in Bangkok reported receiving free samples of breast milk substitutes, infant formula, bottles, or teats compared with only 1 out of 385 mothers in Dhaka. Across the four cities from 3 out of 40 (8%) to 20 out of 40 (50%) health facilities had received free samples which were not being used for research or professional evaluation; from 2 out of 123 (2%) to 21 out of 119 (18%) health workers had received gifts from companies involved in the manufacturing or distribution of breast milk substitutes. From 6 out of 40 (15%) to 22 out of 39 (56%) health facilities information that violated the code had been provided by companies and was available to staff.
Conclusion: Violations of the code were detected with a simple survey instrument in all of the four countries studied. Governmental and non-governmental agencies should monitor the prevalence of code violations using the simple methodology developed for this study.
Key messages A simple multistage random sampling procedure can be used to interview women and health professionals to assess whether violations of the international code of marketing of substitutes for breast milk are occurring 3050 women and 466 health professionals were interviewed at 165 health facilities in Bangladesh, Poland, South Africa, and Thailand 97 out of 370 mothers in Bangkok reported receiving free samples of breast milk substitutes, infant formula, bottles, or teats compared with only 1 out of 385 mothers in Dhaka. In Bangkok health workers reported that 20 out of 40 health facilities had also received free samples. Most free samples were distributed by health facilities In Warsaw 56% of facilities surveyed were found to have information available for health workers that had been provided by manufacturers or distributors of breast milk substitutes in contravention of the code; 18% of health workers in Warsaw had received free gifts from manufacturers
Most of us are poor at faking actions. Kinematic studies have shown that when pretending to pick up imagined objects (pantomimed actions), we move and shape our hands quite differently from when grasping real ones. These differences between real and pantomimed actions have been linked to separate brain pathways specialized for different kinds of visuomotor guidance. Yet professional magicians regularly use pantomimed actions to deceive audiences.
Methodology and Principal Findings
In this study, we tested whether, despite their skill, magicians might still show kinematic differences between grasping actions made toward real versus imagined objects. We found that their pantomimed actions in fact closely resembled real grasps when the object was visible (but displaced) (Experiment 1), but failed to do so when the object was absent (Experiment 2).
Conclusions and Significance
We suggest that although the occipito-parietal visuomotor system in the dorsal stream is designed to guide goal-directed actions, prolonged practice may enable it to calibrate actions based on visual inputs displaced from the action.
The present study asks when infants are able to selectively anticipate the goals of observed actions, and how this ability relates to infants’ own abilities to produce those specific actions. Using eye-tracking technology to measure on-line anticipation, 6-, 8- and 10-month-old infants and a control group of adults were tested while observing an adult reach with a whole hand grasp, a precision grasp or a closed fist towards one of two different sized objects. The same infants were also given a comparable action production task. All infants showed proactive gaze to the whole hand grasps, with increased degrees of proactivity in the older groups. Gaze proactivity to the precision grasps, however, was present from 8 months of age. Moreover, the infants’ ability in performing precision grasping strongly predicted their ability in using the actor’s hand shape cues to differentially anticipate the goal of the observed action, even when age was partialled out. The results are discussed in terms of the specificity of action anticipation, and the fine-grained relationship between action production and action perception.