Development of infants' use of continuity cues in their perception of causality.

Two experiments investigated the role of continuity cues in infants' perception of launching events as causal. Exp 1 showed that 7-mo-old infants can use spatial and temporal contiguity to perceive causality: Infants who were habituated to a causal event dishabituated to novel noncausal events, in which either spatial or temporal contiguity was violated, and those who were habituated to a noncausal event dishabituated to a novel causal but not a novel noncausal event. Experiment 2 showed that 10-mo-olds, but not 7-mo-olds, perceived the causality of launching events in which the objects moved along dissimilar paths. Thus, younger infants do not appear to attend to causality when the objects move along different paths. Results are discussed in terms of the development of the use of continuity cues in causal judgments. (PsycINFO Database Record (c) 2010 APA, all rights reserved)     

Peer imitation by toddlers in laboratory, home, and day-care contexts: Implications for social learning and memory.

Three experiments examined peer imitation with 14- to 18-mo-old infants. In Exp 1, infants saw a trained 14-mo-old ("expert peer") perform specific actions on 5 objects. Imitation from memory was tested after a 5-min delay. In Exp 2, the infants observed an expert peer in the laboratory, and retention and imitation were tested in the home (change of context) after a 2-day delay. In Exp 3, a peer demonstrated target acts at a day care, and after a 2-day delay infants were tested in their homes. Results from all 3 experiments showed significant imitation compared with controls. The experiments demonstrate social learning from peers during infancy and also provide the first evidence for infant imitation from memory across a change in context. (PsycINFO Database Record (c) 2010 APA, all rights reserved)     

Episodic memory in 16- and 20-month-old children: Specifics are generalized but not forgotten.

Three experiments tested (1) whether 1–2 yr olds generalize their knowledge of events to new instantiations and (2) 1 possible mechanism by which generalization is accomplished. In Exp 1, 12 16- and 12 20-mo-old children enacted 6 event sequences. One week later Ss were tested for delayed recall. At delayed testing the props used to enact half of the events were replaced by novel, functionally equivalent props. Ss in both age groups used the new props to enact the events, thereby demonstrating spontaneous generalization. Exps 2 and 3 tested whether generalization was accomplished through forgetting of the specific details of the original event. At Session 1, 24 16- (Exps 2 and 3) and 16 20-mo-olds (Exp 2) enacted 4 events. After a 1-wk delay, Ss selected props used to enact the events at Session 1. Among the objects from which they selected were functionally equivalent props of the sort used to assess generalization in Exp 1. Ss in both age groups performed reliably on the recognition-memory task. Results show that 16- and 20-mo-old children have at their disposal the capacity to productively generalize their knowledge of events to form specific, episodic event memories. (PsycINFO Database Record (c) 2010 APA, all rights reserved)     

Multicausal inference: Evaluation of evidence in causally complex situations.

Investigated in 2 experiments the types of information that people use in making inferences about causality in uncertain situations in which there are many potentially causal factors. A model previously proposed for unicausal inference by M. W. Schustack and the present 2nd author (see record 1982-02716-001) was found to be appropriate to the multicausal case. In Exp I, 60 abstract causal inference problems were presented to 47 college students. Ss were asked to evaluate the likelihood that the particular set of events described in hypothetical situations would lead to the outcome described. In Exp II, 60 abstract multicausal inference problems were presented to college students, 34 in the abstract condition and 40 in the concrete condition. Findings show that both multicausal and unicausal inference rely primarily on 4 types of evidence concerning the sufficiency and necessity of possible causal events. In multicausal inference, people also consider the representativeness, or resemblance, of the events in a situation to causal models suggested by previous situations. When evaluating multicausal problems presented in either abstract or concrete terms, most people average the unicausal likelihoods of all the events in a situation and adjust for the situation's representativeness. However, when evaluating concrete problems, some people base their multicausal estimates only on the unicausal likelihood for the most likely causal event and the situation's representativeness. (36 ref) (PsycINFO Database Record (c) 2010 APA, all rights reserved)     

Detection of intermodal proprioceptive–visual contingency as a potential basis of self-perception in infancy.

Four studies investigated 29 3-mo-old (Exp IV) and 60 5-mo-old (Exps I–III) infants' capacity to detect proprioceptive–visual relations uniting self-motion with a visual display of that motion. Previous research has shown that 5-mo-old infants can detect the invariant relationship between their own leg motion and a video display of that motion. The 1st 3 experiments showed that the 5-mo-olds discriminated between a perfectly contingent live display of their own leg motion and a noncontingent display of self or a peer. They showed this discrimination by preferential fixation of the noncontingent display. This effect was evident even when an S's direct view of his/her own body was occluded, eliminating video image discrimination on the basis of an intramodal visual comparison between the sight of self-motion and the video display of that motion. These results suggest that the contingency provided by a live display of one's body motion is perceived by detecting the invariant intermodal relationship between proprioceptive information for motion and the visual display of that motion. The detection of these relations may be fundamental to the development of self-perception in infancy. Although 3-mo-olds did not show significant discrimination of the contingent and noncontingent displays in Exp IV, they did show significantly more extreme looking proportions to the 2 displays than did the 5-mo-olds. This may reflect the infant's progression from a self- to a social orientation. (32 ref) (PsycINFO Database Record (c) 2010 APA, all rights reserved)     

Infants' manipulative exploration of objects: Effects of age and object characteristics.

Examined the ways that infants acquire information about the haptic and visual properties of objects. The 1st study was a cross-sectional investigation of exploratory behavior in 60 6-, 9-, and 12-mo-old infants. Each S was presented with 2 series of objects having some common characteristic. Several general behaviors—looking, handling, mouthing, and banging—were considered along with more specific measures—turning the object while looking, alternating between looking and mouthing, transferring the object from hand to hand, and fingering. Duration of mouthing and particular types of mouthing decreased with age, whereas fingering and other more precise forms of manipulation increased. There were significant stimulus effects showing that the Ss adjusted their behavior to the particular characteristics of the objects. Decrements with increasing familiarization were also observed in most behaviors. The 2nd study addressed the issue of whether the different behaviors are actually used to pick up information about object characteristics. 48 9- and 12-mo-old infants were presented with 3 problems that involved a period of familiarization followed by a trial in which the object was changed along 1 dimension: shape, texture, or weight. Ss' behavior in the change trials suggests that different types of manipulation are used to explore the different changes. (28 ref) (PsycINFO Database Record (c) 2010 APA, all rights reserved)     

Development of visual size constancy during the 1st year of human infancy.

Visual size constancy for distances up to 70 cm was studied in 3 experiments with 96 4-, 6-, and 8-mo-old infants and up to 200 cm with 32 6-mo-old Ss in Exp IV. A habituation–test procedure was used throughout. At each age Ss were repeatedly shown a 3-dimensional model of a human head until a criterion of habituation of looking was reached. Relative to the habituation condition, the standard test condition was either the same (control) or different in distance, size, or both size and distance. Appropriate comparisons between the recovery scores for the test conditions showed that at 6 and 8 mo, size constancy occurred for the head model up to a distance of 70 cm. This was not so for 100 and 200 cm. At 4 mo, size constancy measured in the same way as for older Ss was not apparent in the range 30–60 cm, but there was a suggestion that it is present at this age among those infants with lower variance of responding. (10 ref) (PsycINFO Database Record (c) 2010 APA, all rights reserved)     

Knowing who dunnit: Infants identify the causal agent in an unseen causal interaction.

Preverbal infants can represent the causal structure of events, including distinguishing the agentive and receptive roles and categorizing entities according to stable causal dispositions. This study investigated how infants combine these 2 kinds of causal inference. In Experiments 1 and 2, 9.5-month-olds used the position of a human hand or a novel puppet (causal agents), but not a toy train (an inert object), to predict the subsequent motion of a beanbag. Conversely, in Experiment 3, 10- and 7-month-olds used the motion of the beanbag to infer the position of a hand but not of a toy block. These data suggest that preverbal infants expect a causal agent as the source of motion of an inert object. (PsycINFO Database Record (c) 2010 APA, all rights reserved)     

Infants' expectations about object label reference.

Examined whether infants at the early stages of lexical development were sensitive to the word-category linkage. In Exp 1, 39 16- to 19-mo-old infants were requested to match a target with either a basic-level or a thematic match, with or without a novel label. Stimuli were presented using the preferential looking paradigm. Infants in the Novel Label condition looked significantly longer at the basic-level match than infants in the No Label condition. In Exp 2, Ss were presented with a target, followed by a basic-level match and a superordinate-level match with or without a novel label. Again, infants in the Novel Label condition looked significantly longer at the basic-level match than infants in the No Label condition. Taken together, these findings indicate that infants initially assume that novel words label basic-level categories and thereby do honor the word-category linkage. (PsycINFO Database Record (c) 2010 APA, all rights reserved)     

The question of decalage between object permanence and person permanence.

In 2 studies of the sources of decalage between person and object permanence, task demands, not the nature of what was searched for, accounted for the decalage. In Exp I, 48 6-mo-old infants were tested with different stimuli (familiar and unfamiliar objects and persons) but with equated task demands, and the effects of practice were also assessed. A longitudinal group tested between 6 and 8.25 mo showed a strong practice effect and generally no decalage between stimuli. Two cross-sectional groups showed some decalage between stimuli, but not simply person before object. In Exp II, 16 8–9 mo old infants tested with the same stimulus but with different task demands showed a large decalage similar to that previously attributed to differences between persons and objects. Decalage can thus be produced by a number of environmental factors, including task demands and practice, as well as stimulus content. Such environmental factors ensure that precise correspondences should not be expected across stages of development in different cognitive domains. (31 ref) (PsycINFO Database Record (c) 2010 APA, all rights reserved)     

Learning a theory of causality.

The very early appearance of abstract knowledge is often taken as evidence for innateness. We explore the relative learning speeds of abstract and specific knowledge within a Bayesian framework and the role for innate structure. We focus on knowledge about causality, seen as a domain-general intuitive theory, and ask whether this knowledge can be learned from co-occurrence of events. We begin by phrasing the causal Bayes nets theory of causality and a range of alternatives in a logical language for relational theories. This allows us to explore simultaneous inductive learning of an abstract theory of causality and a causal model for each of several causal systems. We find that the correct theory of causality can be learned relatively quickly, often becoming available before specific causal theories have been learned—an effect we term the blessing of abstraction. We then explore the effect of providing a variety of auxiliary evidence and find that a collection of simple perceptual input analyzers can help to bootstrap abstract knowledge. Together, these results suggest that the most efficient route to causal knowledge may be to build in not an abstract notion of causality but a powerful inductive learning mechanism and a variety of perceptual supports. While these results are purely computational, they have implications for cognitive development, which we explore in the conclusion. (PsycINFO Database Record (c) 2010 APA, all rights reserved)     

Infants' understanding of visible displacements.

Two studies examined 54 9-mo-old and 54 12-mo-old infants' understanding of visible displacements and whether infants understand that the object has been deleted from its initial hiding place as part of its displacement to a new location. Displacement problems were compared with 2-object problems on which separate objects were hidden at the 1st and 2nd hiding place so that the initial object was not deleted from the 1st displacement location. Nondisplacement problems, on which the object remained at the 1st hiding place while the experimenter moved her visibly empty hand to the 2nd place, were also included in the 1-object condition. Although Exp I showed equivocal results, Exp II provided clear evidence that even 9-mo-olds have at least a limited sensitivity to the deletion component of displacements. In that experiment, the 9-mo-olds searched significantly more at the 2nd than at the 1st hiding place on displacement problems, and the distribution of their searches across the 2 visited locations on those problems was significantly different than on 2-object problems. Although their performance was less consistent than that of 12-mo-olds, there was no evidence that they suffered from any systematic misunderstanding that separated them from the older Ss. (12 ref) (PsycINFO Database Record (c) 2010 APA, all rights reserved)     

How do 4-day-old infants categorize multisyllabic utterances?

Three experiments, using the high-amplitude sucking procedure, tested whether 4-day-old infants discriminate multisyllabic utterances on the basis of number of syllables or number of phonemes. Exp 1 showed that infants discriminate 2 large sets of phonetically variable utterances composed of 2- vs 3-CV (consonant–vowel) syllables. Exp 2 was run to assess whether infants discriminated the 2 sets on the basis of duration differences between the 2- and 3-CV stimuli. Results indicate that reducing the duration differences does not affect infants' discrimination. Finally, Exp 3 investigated whether infants discriminate 4- vs 6-phoneme bisyllabic utterances. The results provide no evidence that infants are sensitive to such a change in number of phonemic constituents. Although not decisive, these results appear to be congruent with the hypothesis that infants perceptually structure complex speech inputs. (PsycINFO Database Record (c) 2010 APA, all rights reserved)     

Effect of reinforcement on infants' performance in an auditory detection task.

Localization responses to octave-band noises with center frequencies at 400 and 4,000 Hz were obtained from 12-mo-old infants, first without reinforcement and with a 5-sec response interval and then with reinforcement and an unlimited response interval. The percentage of correct responses was substantially greater in the reinforced than in the nonreinforced condition. In Exp II, 12-mo-old Ss were tested in nonreinforced and reinforced sessions, as in Exp I, except that both sessions incorporated the 5-sec response interval. Again, performance was superior in the reinforced session. It is suggested that auditory detection techniques that omit reinforcement may be yielding attentional thresholds rather than thresholds of audibility. (11 ref) (PsycINFO Database Record (c) 2010 APA, all rights reserved)     

Specificity of process, response, and stimulus in behavioral bioassays.

Reported 3 experiments which studied aspects of the behavioral specificity of the "biochemical transfer" phenomenon. In Exp I, using 120 common goldfish, an acquisition extract facilitated acquisition but not extinction, while an extinction extract facilitated extinction but not acquisition. In Exp II, using 60 Ss from Exp I and 20 additional Ss, brain extracts facilitated an avoidance response only if they originated in donors that made that same response; extracts from donors that did not respond, although exposed to identical stimuli, did not modify recipient behavior. In Exp III, the biochemical transfer effect was found to be stimulus specific in 48 large and 111 small Ss. Results suggest that the extracts in question are behavior specific and do not generally affect behavior in a global excitatory or global inhibitory way. (15 ref) (PsycINFO Database Record (c) 2010 APA, all rights reserved)     

Using mother as a spatial landmark: Evidence against egocentric coding in infancy.

30 9-mo-old infants learned to turn one way to view a visual event. In a transfer task, they were rotated 180°. The mothers of half the Ss moved with them as in previous procedures, and the other mothers remained in a fixed position throughout training and testing. Ss made more turns to the same spatial location when their mothers did not move. Thus, Ss used their mother's position as a cue to their spatial response. Results suggest that even in situations in which young infants were judged egocentric, they may have been using objective, nonegocentric information. Thus, even apparent errors do not preclude the presence of objective representation. (14 ref) (PsycINFO Database Record (c) 2010 APA, all rights reserved)     

Relative importance of prior and immediate events: A causal primacy effect.

Two experiments tested the hypothesis that prior causes in a chain of events are attributed greater relative importance than later, more immediate causes. In Exp I, 170 undergraduates judged the relative contributions to success or failure made by members of a team who initiated a problem-solution process vs team members who terminated it. In Exp II, 206 undergraduates rated the importance of prior and immediate causes of 4 life events. In both experiments, prior events in a causal chain were perceived to be more important than were immediate events. In addition, Exp II showed that this primacy effect was due to the causal rather than temporal sequencing of events and that it was limited to situations in which the events were of approximately equal relevance to the final outcome. (27 ref) (PsycINFO Database Record (c) 2010 APA, all rights reserved)     

Cortical motor neuron activity in the cat during classical conditioning with central stimulation as the CS and the US.

Studied the neuronal basis of associative conditioning in the cat by pairing stimulation of thalamocortical pathways as the CS with antidromic activation of pericruciate pyramidal tract (PT) cells as the UCS in a differential classical conditioning paradigm. For the 18 Ss in Exp I, the target thalamic nuclei for stimulation were nucleus ventralis posterolateralis (VPL) and nucleus ventralis lateralis. For the 10 Ss in Exp II, the target thalamic nuclei were VPL and nucleus cetromedian. Results show that thalamic stimulation was not an effective CS. The response of PT cells to thalamic stimulation did not change as a function of reinforcement with PT stimulation. These results do not support the hypothesis that the simple pairing of any 2 neural events is the essential mechanism underlying associative conditioning changes. Instead, they suggest that the combined activation of specific and nonspecific thalamic nuclei may be important in producing increases in responsiveness of PT neurons. (45 ref) (PsycINFO Database Record (c) 2010 APA, all rights reserved)