Executive functioning by 18‐24‐month‐old children: effects of inhibition,working memory demands and narrative in a novel detour‐reaching task

Infants can inhibit a prepotent but wrong action towards a goal in order to perform a causal means‐action. It is not clear, however, whether infants can perform an arbitrary means‐action while inhibiting a prepotent response. In four experiments, we explore this executive functioning in 18–24‐month‐old children. The working memory and inhibition demands in a novel means‐end problem were systematically varied in terms of the type and combination of means‐action(s) (causal or arbitrary) contained within the task, the number of means‐actions (1 or 2), the goal visual availability and whether the task was accompanied by a narrative. Experiments 1 and 2 showed that children performed tasks that contained causal as opposed to arbitrary information more accurately; accuracy was also higher in tasks containing only one step. Experiment 2 also demonstrated that performance in the arbitrary task improved significantly when all sources of prepotency were removed. In Experiment 3, task performance improved when the two means‐actions were intelligibly linked to the task goal. Experiment 4 demonstrated that the use of a narrative that provided a meaningful (non‐causal) link between the two means‐actions also improved children's performance by assisting their working memory in the generation of a rationale. Findings provide an initial account of executive functioning in the months that bring the end of infancy. Copyright © 2006 John Wiley & Sons, Ltd.     

Fourteen-month-old infants copy an action style accompanied by social-emotional cues

Human adults exaggerate their actions and facial expressions when interacting with infants. These infant-directed modifications highlight certain aspects of action sequences and attract infants’ attention. This study investigated whether social-emotional aspects of infant-directed modifications, such as smiling, eye contact, and onomatopoeic vocalization, influence infants’ copying of another's action, especially action style, during the process of achieving an outcome. In Study 1, 14-month-old infants (n = 22) saw an experimenter demonstrate goal-directed actions in an exaggerated manner. Either the style or the end state of the actions was accompanied by social-emotional cues from the experimenter. Infants copied the style of the action more often when social-emotional cues accompanied the style than when they accompanied the end state. In Study 2, a different group of 14-month-old infants (n = 22) watched the same exaggerated actions as in Study 1, except that either the style or the end state was accompanied by a physical sound instead of social-emotional cues. The infants copied the end state consistently more often than the style. Taken together, these two studies showed that accompanying social-emotional cues provided by a demonstrator, but not accompanying physical sound, increased infants’ copying of action style. These findings suggest that social-emotional cues facilitate efficient social learning through the adult–infant interaction.     

Action preferences and the anticipation of action outcomes

Skilled performers of time-constrained motor actions acquire information about the action preferences of their opponents in an effort to better anticipate the outcome of that opponent's actions. However, there is reason to doubt that knowledge of an opponent's action preferences would unequivocally influence anticipatory responses in a positive way. It is possible that overt information about an opponent's actions could distract skilled performers from using the advance kinematic information they would usually rely on to anticipate actions, particularly when the opponent performs an ‘unexpected’ action that is not in accordance with his or her previous behaviour. The aim of this study was to examine how the ability to anticipate the outcome of an opponent's actions can be influenced by exposure to the action preferences of that opponent. Two groups of skilled handball goalkeepers anticipated the direction of penalty throws performed by opponents before and after a training intervention that provided situational probability information in the form of action preferences (AP). During the training phase participants in an AP-training group anticipated the action outcomes of two throwers who had a strong preference to throw in one particular direction, whilst participants in a NP-training group viewed players who threw equally to all directions. Exposure to opponents who did have an action preference during the training phase resulted in improved anticipatory performance if the opponent continued to bias their throws towards their preferred direction, but decreased performance if the opponent did not. These findings highlight that skilled observers use information about action preferences to enhance their anticipatory ability, but that doing so can be disadvantageous when the outcomes are no longer consistent with their generated expectations.     

High in the hierarchy: How vertical location and judgments of leaders’ power are interrelated

Leadership implies power. We argue, from a social embodiment perspective, that thinking about power involves mental simulation of vertical location. Three studies tested whether judgments of leaders’ power and information on a vertical location are interrelated. In Studies 1a–1c, participants judged a leader’s power after being presented with, among other information, an organization chart containing either a long or a short vertical line. A longer vertical line increased judged power. Study 2 showed that this effect persists when longer (vs. shorter) vertical lines are presented in an independent priming task and not in an organization chart, and that horizontal lines do not have the same effect. Finally, Studies 3a and 3b showed the reverse causal effect: information about a leader’s power influenced participants’ vertical positioning of a leader’s box in an organization chart and of a leader picture into a team picture. Implications for leadership communication are discussed.     

Children's imitation of causal action sequences is influenced by statistical and pedagogical evidence

Children are ubiquitous imitators, but how do they decide which actions to imitate? One possibility is that children rationally combine multiple sources of information about which actions are necessary to cause a particular outcome. For instance, children might learn from contingencies between action sequences and outcomes across repeated demonstrations, and they might also use information about the actor’s knowledge state and pedagogical intentions. We define a Bayesian model that predicts children will decide whether to imitate part or all of an action sequence based on both the pattern of statistical evidence and the demonstrator’s pedagogical stance. To test this prediction, we conducted an experiment in which preschool children watched an experimenter repeatedly perform sequences of varying actions followed by an outcome. Children’s imitation of sequences that produced the outcome increased, in some cases resulting in production of shorter sequences of actions that the children had never seen performed in isolation. A second experiment established that children interpret the same statistical evidence differently when it comes from a knowledgeable teacher versus a naïve demonstrator. In particular, in the pedagogical case children are more likely to “overimitate” by reproducing the entire demonstrated sequence. This behavior is consistent with our model’s predictions, and suggests that children attend to both statistical and pedagogical evidence in deciding which actions to imitate, rather than obligately imitating successful action sequences.     

Causal learning from probabilistic events in 24‐month‐olds: an action measure

How do young children learn about causal structure in an uncertain and variable world? We tested whether they can use observed probabilistic information to solve causal learning problems. In two experiments, 24‐month‐olds observed an adult produce a probabilistic pattern of causal evidence. The toddlers then were given an opportunity to design their own intervention. In Experiment 1, toddlers saw one object bring about an effect with a higher probability than a second object. In Experiment 2, the frequency of the effect was held constant, though its probability differed. After observing the probabilistic evidence, toddlers in both experiments chose to act on the object that was more likely to produce the effect. The results demonstrate that toddlers can learn about cause and effect without trial‐and‐error or linguistic instruction on the task, simply by observing the probabilistic patterns of evidence resulting from the imperfect actions of other social agents. Such observational causal learning from probabilistic displays supports human children's rapid cultural learning.     

Two‐year‐old children preferentially transmit simple actions but not pedagogically demonstrated actions

Children are sensitive to both social and non‐social aspects of the learning environment. Among social cues, pedagogical communication has been shown to not only play a role in children's learning, but also in their own active transmission of knowledge. Vredenburgh, Kushnir and Casasola, Developmental Science, 2015, 18, 645 showed that 2‐year‐olds are more likely to demonstrate an action to a naive adult after learning it in a pedagogical than in a non‐pedagogical context. This finding was interpreted as evidence that pedagogically transmitted information has a special status as culturally relevant. Here we test the limits of this claim by setting it in contrast with an explanation in which the relevance of information is the outcome of multiple interacting social (e.g., pedagogical demonstration) and non‐social properties (e.g., action complexity). To test these competing hypotheses, we varied both pedagogical cues and action complexity in an information transmission paradigm with 2‐year‐old children. In Experiment 1, children preferentially transmitted simple non‐pedagogically demonstrated actions over pedagogically demonstrated more complex actions. In Experiment 2, when both actions were matched for complexity, we found no evidence of preferential transmission of pedagogically demonstrated actions. We discuss possible reasons for the discrepancy between our results and previous literature showing an effect of pedagogical cues on cultural transmission, and conclude that our results are compatible with the view that pedagogical and other cues interact, but incompatible with the theory of a privileged role for pedagogical cues.     

Inferring action structure and causal relationships in continuous sequences of human action

In the real world, causal variables do not come pre-identified or occur in isolation, but instead are embedded within a continuous temporal stream of events. A challenge faced by both human learners and machine learning algorithms is identifying subsequences that correspond to the appropriate variables for causal inference. A specific instance of this problem is action segmentation: dividing a sequence of observed behavior into meaningful actions, and determining which of those actions lead to effects in the world. Here we present a Bayesian analysis of how statistical and causal cues to segmentation should optimally be combined, as well as four experiments investigating human action segmentation and causal inference. We find that both people and our model are sensitive to statistical regularities and causal structure in continuous action, and are able to combine these sources of information in order to correctly infer both causal relationships and segmentation boundaries.     

Further evidence for the role of inferential reasoning in forward blocking

Previous studies on human causal learning (De Houwer & Beckers, 2003; De Houwer, Beckers, & Glautier, 2002) showed that secondary task difficulty (performing an easy vs. a difficult secondary task during the main causal learning task) and ceiling information (outcome occurs with a maximal vs. submaximal intensity) had an influence on forward blocking (i.e., lower causal ratings for cue T when AT+ trials are preceded by A+ trials than when no A+ trials are presented). We extended these studies by also examining self-reports of participants about the reasons behind their causal ratings. Blocking was found only for participants who reported an appropriate blocking inference. Furthermore, secondary task difficulty and ceiling information influenced the number of participants who reported an appropriate blocking inference. These findings point to a major impact of inferential reasoning in human causal learning.     

Where science starts: spontaneous experiments in preschoolers' exploratory play

Probabilistic models of expected information gain require integrating prior knowledge about causal hypotheses with knowledge about possible actions that might generate data relevant to those hypotheses. Here we looked at whether preschoolers (mean: 54 months) recognize “action possibilities” (affordances) in the environment that allow them to isolate variables when there is information to be gained. By manipulating the physical properties of the stimuli, we were able to affect the degree to which candidate variables could be isolated; by manipulating the base rate of candidate causes, we were able to affect the potential for information gain. Children’s exploratory play was sensitive to both manipulations: given unambiguous evidence children played indiscriminately and rarely tried to isolate candidate causes; given ambiguous evidence, children both selected (Experiment 1) and designed (Experiment 2) informative interventions.     

The 28th Bartlett Memorial Lecture Causal learning: An associative analysis

The concordance between performance and judgements of the causal effectiveness of an instrumental action suggests that such actions are mediated by causal knowledge. Although causal learning exhibits many associative phenomena—blocking, inhibitory or preventative learning, and super-learning—judgements of the causal status of a cue can be changed retrospectively as a result of learning episodes that do not directly involve the cue. In order to explain retrospective revaluation, a modified associative theory is described in which the learning processes for retrieved cue representations are the opposite to those for presented cues, and this theory is evaluated by studies of the role of within-compound associations in retrospective revaluation and blocking. However, this modified theory only applies when the within-compound association represents a contiguous rather than a causal cue relationship.     

Relations between 18-month-olds’ gaze pattern and target action performance: A deferred imitation study with eye tracking

Deferred imitation studies are used to assess infants’ declarative memory performance. These studies have found that deferred imitation performance improves with age, which is usually attributed to advancing memory capabilities. Imitation studies, however, are also used to assess infants’ action understanding. In this second research program it has been observed that infants around the age of one year imitate selectively, i.e., they imitate certain kinds of target actions and omit others. In contrast to this, two-year-olds usually imitate the model's exact actions. 18-month-olds imitate more exactly than one-year-olds, but more selectively than two-year-olds, a fact which makes this age group especially interesting, since the processes underlying selective vs. exact imitation are largely debated. The question, for example, if selective attention to certain kinds of target actions accounts for preferential imitation of these actions in young infants is still open. Additionally, relations between memory capabilities and selective imitation processes, as well as their role in shaping 18-month-olds’ neither completely selective, nor completely exact imitation have not been thoroughly investigated yet. The present study, therefore, assessed 18-month-olds’ gaze toward two types of actions (functional vs. arbitrary target actions) and the model's face during target action demonstration, as well as infants’ deferred imitation performance. Although infants’ fixation times to functional target actions were not longer than to arbitrary target actions, they imitated the functional target actions more frequently than the arbitrary ones. This suggests that selective imitation does not rely on selective gaze toward functional target actions during the demonstration phase. In addition, a post hoc analysis of interindividual differences suggested that infants’ attention to the model's social-communicative cues might play an important role in exact imitation, meaning the imitation of both functional and arbitrary target actions.     

Are goals or preconditions better explanations? It depends on the question

Recent research on causal inference suggests that common actions tend to be attributed to goals, whereas difficult actions, if obstructed, are attributed primarily to preconditions. The present studies examine the way that the framing of causal questions influences ratings of goals and preconditions for common actions. The studies test the view that ‘why’ questions favour goal explanations, by presenting causal questions framed as ‘why’ questions or ‘explain’ questions. Structured and free-response measures were used. They show that when the question is expressed as asking why an action occurs, goals are rated better than preconditions, regardless of the presence of obstacles, whereas if the question is framed as requesting an explanation of the action, preconditions are deemed better explanations than goals for obstructed actions. Goals remain better explanations when the action is unobstructed. These findings confirm the importance of the framing of causal questions for research on causal explanation, and suggest that the phrasing of causal questions influences the focus of explanations. Copyright © 1998 John Wiley & Sons, Ltd.     

Emulation and “overemulation” in the social learning of causally opaque versus causally transparent tool use by 23- and 30-month-olds

We explored whether a rising trend to blindly “overcopy” a model’s causally irrelevant actions between 3 and 5 years of age, found in previous studies, predicts a more circumspect disposition in much younger children. Children between 23 and 30 months of age observed a model use a tool to retrieve a reward from either a transparent or opaque puzzle box. Some of the tool actions were irrelevant to reward retrieval, whereas others were causally necessary. The causal relevance of the tool actions was highly visible in the transparent box condition, allowing the participants to potentially discriminate which actions were necessary. In contrast, the causal efficacy of the tool was hidden in the opaque box condition. When both the 23- and 30-month-olds were presented with either the transparent or opaque box, they were most commonly emulative rather than imitative, performing only the causally necessary actions. This strategy contrasts with the blanket imitation of both causally irrelevant and causally relevant actions witnessed at 3 and 5 years of age in our previous studies. The results challenge a current view of 1- and 2-year-olds as largely “blind imitators”; instead, they show that these young children have a variety of social learning processes available to them. More broadly the emerging patterns of results suggest, rather counterintuitively, that the human species becomes more imitative rather than less imitative with age, in some ways “mindlessly” so.     

Reasons and psychological causes

The causal theory of reasons holds that acting for a reason entails that the agents action was caused by his or her beliefs and desires. While Donald Davidson (1963) and others effectively silenced the first objections to the theory, a new round has emerged. The most important recent attack is presented by Jonathan Dancy in Practical Reality (2000) and subsequent work. This paper will defend the causal theory against Dancy and others, including Schueler (1995), Stoutland (1999, 2001), and Ginet (2002).Dancy observes that our reasons are neither psychological states nor causes, and that our reasons can be both motivating and normative. I argue that these observations are fully compatible with the causal theory. According to the reductive version I develop for both cognitive and optative reasons, what it is for an action to be done for a reason is for certain beliefs and desires to cause the action in a particular way. Our reasons for action are the objects of some of those beliefs and desires. The causal process has two stages. This theory explains not only Dancys observations, but also many other facts about reasons that alternative theories leave unexplained. I argue against Schueler and others that the non-appetitive desires entailed by acting for reasons are no less distinct and independent causal factors than the beliefs entailed. I go on to rebut arguments that the relation between psychological states and actions cannot be causal because it is non-empirical, rational, normative, or non-deterministic, and that explanations in terms of psychological causes are incompatible with explanations in terms of reasons.I make no claim here about the precise adequacy of the theoretical definitions I present. My goal is to show that a systematic theory along these lines is the most promising and fruitful approach to understanding an important aspect of human nature.     

The influence of negligence, intention, and outcome on children’s moral judgments

Piaget (1932) and subsequent researchers have reported that young children’s moral judgments are based more on the outcomes of actions than on the agents’ intentions. The current study investigated whether negligence might also influence these judgments and explain children’s apparent focus on outcome. Children (3–8 years of age) and adults (N = 139) rated accidental actions in which the valences of intention, negligence, and outcome were varied systematically. Participants of all ages were influenced primarily by intention, and well-intentioned actions were also evaluated according to negligence and outcome. Only two young children based their judgments solely on outcome. It is suggested that previous studies have underestimated children’s use of intention because outcome and negligence have been confounded. Negative consequences are considered to be important because children assume that they are caused by negligence. The findings indicate that young children can show sophisticated understanding of the roles of intention and negligence in moral judgments.     

Parallels Between Action‐Object Mapping and Word‐Object Mapping in Young Children

Across a series of four experiments with 3‐ to 4‐year‐olds we demonstrate how cognitive mechanisms supporting noun learning extend to the mapping of actions to objects. In Experiment 1 (n = 61) the demonstration of a novel action led children to select a novel, rather than a familiar object. In Experiment 2 (n = 78) children exhibited long‐term retention of novel action‐object mappings and extended these actions to other category members. In Experiment 3 (n = 60) we showed that children formed an accurate sensorimotor record of the novel action. In Experiment 4 (n = 54) we demonstrate limits on the types of actions mapped to novel objects. Overall these data suggest that certain aspects of noun mapping share common processing with action mapping and support a domain‐general account of word learning.     

Selective copying of the majority suggests children are broadly “optimal‐” rather than “over‐” imitators

Human children, in contrast to other species, are frequently cast as prolific “over‐imitators”. However, previous studies of “over‐imitation” have overlooked many important real‐world social dynamics, and may thus provide an inaccurate account of this seemingly puzzling and potentially maladaptive phenomenon. Here we investigate this topic using a cultural evolutionary approach, focusing particularly on the key adaptive learning strategy of majority‐biased copying. Most “over‐imitation” research has been conducted using consistent demonstrations to the observer, but we systematically varied the frequency of demonstrators that 4‐ to 6‐year‐old children observed performing a causally irrelevant action. Children who “over‐imitate” inflexibly should copy the majority regardless of whether the majority solution omits or includes a causally irrelevant action. However, we found that children calibrated their tendency to acquire the majority behavior, such that copying did not extend to majorities that performed irrelevant actions. These results are consistent with a highly functional, adaptive integration of social and causal information, rather than explanations implying unselective copying or causal misunderstanding. This suggests that our species might be better characterized as broadly “optimal‐” rather than “over‐” imitators.     

Children’s causal reasoning: Counterfactual thinking occurs for ‘negative’ outcomes only

Harris, German and Mills (Children’s use of counterfactual thinking in causal reasoning. Cognition, 61 (1996), 223–259), following Mackie, argue that children make explicit use of counterfactual thinking in arriving at causal judgments. They showed that children as young as 3, in explaining simple mishap events, made reference to courses of action that a protagonist had rejected, when that course of action would have prevented the observed outcome. It is hypothesized here that such counterfactual thinking might have been invoked by the ‘negative’ mishaps rather than as part of the causal reasoning process. Although the generation of counterfactuals in explanation was replicated using mishap outcomes such as those used by Harris et al., counterfactual thinking was not evident in children’s explanations of ‘positive’ outcomes. These results undermine the view that a counterfactual thinking process, as indexed by reference to possible actions rejected by a protagonist, is necessary for causal reasoning. Alternative characterizations of the relationship between causals and counterfactuals are discussed.