Constructing a past in infancy: a neuro-developmental account

The ability to recall the past is fundamental yet until relatively recently, infants were assumed to lack the capacity. Contrary to this perspective, non-verbal tests indicate that developments in recall are well underway by late in the first year of life; by the end of the second year, long-term recall is reliable and robust. New research combining electrophysiological and behavioral measures is identifying the loci of age-related changes: they are attributed to more effective and efficient encoding, consolidation and storage processes associated with developments in the temporal-cortical network that subserves recall. The emerging framework, which applies to episodic and autobiographical memory, highlights the essential developmental continuities in memory from infancy onwards and sheds new light on the phenomenon of childhood amnesia.     

Discrimination of possible and impossible objects in infancy

Adults can use pictorial depth cues to infer three-dimensional structure in two-dimensional depictions of objects. The age at which infants respond to the same kinds of visual information has not been determined, and theories about the underlying developmental mechanisms remain controversial. In this study, we used a visual habituation/novelty-preference procedure to assess the ability of 4-month-old infants to discriminate between two-dimensional depictions of structurally possible and impossible objects. Results indicate that young infants are sensitive to junction structures and interposition cues associated with pictorial depth and can detect inconsistent relationships among these cues that render an object impossible. Our results provide important insights into the development of mechanisms for processing pictorial depth cues that allow adults to extract three-dimensional structure from pictures of objects.     

Increased visual interest and affective responses to impossible figures in early infancy

This research evaluated infants’ facial expressions as they viewed pictures of possible and impossible objects on a TV screen. Previous studies in our lab demonstrated that four-month-old infants looked longer at the impossible figures and fixated to a greater extent within the problematic region of the impossible shape, suggesting they were sensitive to novel or unusual object geometry. Our work takes studies of looking time data a step further, determining if increased looking co-occurs with facial expressions associated with increased visual interest and curiosity, or even puzzlement and surprise. We predicted that infants would display more facial expressions consistent with either “interest” or “surprise” when viewing the impossible objects relative to possible ones, which would provide further evidence of increased perceptual processing due to incompatible spatial information. Our results showed that the impossible cubes evoked both longer looking times and more reactive expressions in the majority of infants. Specifically, the data revealed significantly greater frequency of raised eyebrows, widened eyes and returns to looking when viewing impossible figures with the most robust effects occurring after a period of habituation. The pattern of facial expressions were consistent with the “interest” family of facial expressions and appears to reflect infants’ ability to perceive systematic differences between matched pairs of possible and impossible objects as well as recognize novel geometry found in impossible objects. Therefore, as young infants are beginning to register perceptual discrepancies in visual displays, their facial expressions may reflect heightened attention and increased information processing associated with identifying irreconcilable contours in line drawings of objects. This work further clarifies the ongoing formation and development of early mental representations of coherent 3D objects.     

A connectionist account of asymmetric category learning in early infancy

Young infants show unexplained asymmetries in the exclusivity of categories formed on the basis of visually presented stimuli. A connectionist model is described that shows similar exclusivity asymmetries when categorizing the same stimuli presented to infants. The asymmetries can be explained in terms of an associative learning mechanism, distributed internal representations, and the statistics of the feature distributions in the stimuli. The model was used to explore the robustness of this asymmetry. The model predicts that the asymmetry will persist when a category is acquired in the presence of mixed category exemplars. An experiment with 3-4-month-olds showed that asymmetric exclusivity persisted in the presence of mixed-exemplar familiarization, thereby confirming the model's prediction.     

A computational and neuropsychological account of object-oriented behaviours in infancy

Infants under 7 months of age fail to reach behind an occluding screen to retrieve a desired toy even though they possess sufficient motor skills to do so. However, even by 3.5 months of age they show surprise if the solidity of the hidden toy is violated, suggesting that they know that the hidden toy still exists. We describe a connectionist model that learns to predict the position of objects and to initiate a response towards these objects. The model embodies the dual-route principle of object information processing characteristic of the cortex. One route develops a spatially invariant surface feature representation of the object whereas the other route develops a feature blind spatial–temporal representation of the object. The model provides an account of the developmental lag between infants’ knowledge of hidden objects and their ability to demonstrate that knowledge in an active retrieval task, in terms of the need to integrate information across multiple object representations using (associative) connectionist learning algorithms. Finally, the model predicts the presence of an early dissociation between infants’ ability to use surface features (e.g. colour) and spatial–temporal features (e.g. position) when reasoning about hidden objects. Evidence supporting this prediction has now been reported.     

Developmental changes in word recognition: An information-processing account

Two experiments examining developmental changes in the use of context in single word reading are reported. The first experiment investigated how effectively children can access conceptual knowledge and use this to help their word recognition. The results indicated that young readers can on demand direct their attention to semantic information, and this allows them to reap a relatively greater benefit from context than older more skilful readers. The second experiment attempted to clarify the way such use of contextual information might help in the specific case when a child attempts to decode a new word for the first time. Skilled and unskilled readers pronounced pseudohomophonic nonwords faster when they were primed by a semantic context, and the context effect was greater for unskilled readers. The nonword's graphemic similarity to a lexical item was also important.

In general, the results were consistent with Stanovich's (1980) interactive-compensatory model of reading, and they suggest that in learning to read, several already existing stores of information (e.g. auditory, visual and conceptual) are integrated in order to achieve a solution to the word recognition problem.     

How infants relate looker and object: evidence for a perceptual learning account of gaze following in infancy

In two experiments, it was investigated how preverbal infants perceive the relationship between a person and an object she is looking at. More specifically, it was examined whether infants interpret an adult's object-directed gaze as a marker of an intention to act or whether they relate the person and the object via a mechanism of associative learning. Fourteen-month-old infants observed an adult gazing repeatedly at one of two objects. When the adult reached out to grasp this object in the test trials, infants showed no systematic visual anticipations to it (i.e. first visual anticipatory gaze shifts) but only displayed longer looking times for this object than for another before her hand reached the object. However, they showed visual anticipatory gaze shifts to the correct action target when only the grasping action was presented. The second experiment shows that infants also look longer at the object a person has been gazing at when the person is still present, but is not performing any action during the test trials. Looking preferences for the objects were reversed, however, when the person was absent during the test trials. This study provides evidence for the claim that infants around 1 year of age do not employ other people's object-directed gaze to anticipate future actions, but to establish person-object associations. The implications of this finding for theoretical conceptions of infants' social-cognitive development are discussed.     

Detecting and predicting changes

When required to predict sequential events, such as random coin tosses or basketball free throws, people reliably use inappropriate strategies, such as inferring temporal structure when none is present. We investigate the ability of observers to predict sequential events in dynamically changing environments, where there is an opportunity to detect true temporal structure. In two experiments we demonstrate that participants often make correct statistical decisions when asked to infer the hidden state of the data generating process. However, when asked to make predictions about future outcomes, accuracy decreased even though normatively correct responses in the two tasks were identical. A particle filter model accounts for all data, describing performance in terms of a plausible psychological process. By varying the number of particles, and the prior belief about the probability of a change occurring in the data generating process, we were able to model most of the observed individual differences.     

Detecting surface changes in a familiar tune: exploring pitch,tempo and timbre

Animal Cognition - Humans recognize a melody independently of whether it is played on a piano or a violin, faster or slower, or at higher or lower frequencies. Much of the way in which we engage...     

Disability: a justice-based account

Philosophical Studies - Most people have a clear sense of what they mean by disability, and have little trouble identifying conditions they consider disabling. Yet providing a clear and consistent...     

Classifying emotion: a developmental account

The aim of this paper is to propose a systematic classification of emotions which can also characterize their nature. The first challenge we address is the submission of clear criteria for a theory of emotions that determine which mental phenomena are emotions and which are not. We suggest that emotions as a subclass of mental states are determined by their functional roles. The second and main challenge is the presentation of a classification and theory of emotions that can account for all existing varieties. We argue that we must classify emotions according to four developmental stages: 1. pre-emotions as unfocussed expressive emotion states, 2. basic emotions, 3. primary cognitive emotions, and 4. secondary cognitive emotions. We suggest four types of basic emotions (fear, anger, joy and sadness) which are systematically differentiated into a diversity of more complex emotions during emotional development. The classification distinguishes between basic and non-basic emotions and our multi-factorial account considers cognitive, experiential, physiological and behavioral parameters as relevant for constituting an emotion. However, each emotion type is constituted by a typical pattern according to which some features may be more significant than others. Emotions differ strongly where these patterns of features are concerned, while their essential functional roles are the same. We argue that emotions form a unified ontological category that is coherent and can be well defined by their characteristic functional roles. Our account of emotions is supported by data from developmental psychology, neurobiology, evolutionary biology and sociology.     

Dissociation in Italian conjugations: a single-route account

Say and Clahsen (S and C) report an experiment involving assignment of past participle suffixes to nonce words in Italian. Their evidence suggests a dual-route model that assigns the theme vowel of the 1st conjugation, while storing it lexically in other conjugations. However, these nonce words were assigned suffixes by a computer algorithm that determined the past participle of the nonce items on the basis of phonological similarity to existing inflected forms. The outcome of the simulation mirrors that of the subjects closely, suggesting that the dissociations found by S and C are not adequate evidence for a dual-route model of Italian stem formation.     

Sequential effects in naming: a time-criterion account

S. J. Lupker, P. Brown, and L. Colombo (1997) reported that target naming latencies are strongly affected by the difficulty of the other stimuli in a trial block, an effect they attributed to readers' strategic use of a time criterion to guide responding. In the present research, the authors asked whether there are also trial-by-trial ("sequential") effects by examining naming latency as a function of the difficulty of the preceding stimulus. In Experiment 1, both nonwords and high-frequency regular words were named more rapidly following a word than a nonword. Experiments 2, 3, and 4 were parallel experiments involving a variety of stimulus types (e.g., high- and low-frequency inconsistent words, easy and hard nonwords). In all cases, similar sequential effects were observed (i.e., all stimulus types had shorter latencies following an easier-to-name than a harder-to-name stimulus). In terms of the time-criterion account, criterion placement appears to be affected by the relative difficulty of the preceding stimulus in a way that is independent of stimulus type.     

Spectrum inversion without a difference in representation is impossible

Even if spectrum inversion of various sorts is possible, spectrum inversion without a difference in representation is not. So spectrum inversion does not pose a challenge for the intentionalist thesis that, necessarily, within a given sense modality, if two experiences are alike with respect to content, they are also alike with respect to their phenomenal character. On the contrary, reflection on variants of standard cases of spectrum inversion provides a strong argument for intentionalism. Depending on one’s views about the possibility of spectrum inversion, the impossibility of spectrum inversion without a difference in representation can also be used as an argument against a variety of reductive theories of mental representation.     

False belief in infancy: a fresh look

Can infants appreciate that others have false beliefs? Do they have a theory of mind? In this article I provide a detailed review of more than 20 experiments that have addressed these questions, and offered an affirmative answer, using nonverbal ‘violation of expectation’ and ‘anticipatory looking’ procedures. Although many of these experiments are both elegant and ingenious, I argue that their results can be explained by the operation of domain‐general processes and in terms of ‘low‐level novelty’. This hypothesis suggests that the infants' looking behaviour is a function of the degree to which the observed (perceptual novelty) and remembered or expected (imaginal novelty) low‐level properties of the test stimuli – their colours, shapes and movements – are novel with respect to events encoded by the infants earlier in the experiment. If the low‐level novelty hypothesis is correct, research on false belief in infancy currently falls short of demonstrating that infants have even an implicit theory of mind. However, I suggest that the use of two experimental strategies – inanimate control procedures, and self‐informed belief induction – could be used in combination with existing methods to bring us much closer to understanding the evolutionary and developmental origins of theory of mind.     

The rising fastball: baseball's impossible pitch

Batters in professional baseball are confronted with pitches that appear to curve, dip, wobble, or rise. The rising fastball is a pitch where the ball appears to hop up as much as a third of a meter with a sudden increase in speed. Physics experiments confirm that many reported trajectories are possible, but not the rising fastball. The present paper shows how the apparent rise may be explained as a perceptual illusion due to the hitter underestimating original speed of the pitch.