A distraction task as an assessment of object permanence

Object permanence, as expressed on a task which involves distracting the infant, was tested with infants ranging between 8 and 16 months of age. For this task, the attention of an infant who was playing with one toy was diverted to another. While the infant examined the second toy, the first was covered. Finally, the second toy was removed and the infant was allowed to search for the first. A comparison with performance on multiple visible-displacement, single invisible-displacement, and multiple invisible-displacement tasks showed that the distraction task fell between the two invisible-displacement tasks in difficulty. This distraction task appears to have heuristic value, since it facilitates separation of search strategies from the infant's understanding of the adult's role as an active agent in an object's disappearance.     

Infant intentionality as object directedness: A method for observation*

It is argued that a definition of intentionality in terms of object directedness is more adequate than the traditional definition in terms of goal directedness. Inconsistencies in the use of “intentionality” among infant researchers are pointed out. A method of observation is explored, based on the definition in terms of behavioral object directedness, that takes into account precursors to fully-fledged intentional actions by approaching intentionality as a matter of degree rather than as an all or none issue. The method, when used on longitudinal video recordings of parent-infant interaction, produced results that substantiated Tre-varthen's observations of infant intentionality before the age of six months. Furthermore, the results suggest that the parent's attribution of intentions to the infant is based on the perception of the infant's intentionality, whether in social interaction or in interaction with “physical” objects.     

A formal cognitive model of the go/no-go discrimination task: evaluation and implications

This article proposes and tests a formal cognitive model for the go/no-go discrimination task. In this task, the performer chooses whether to respond to stimuli and receives rewards for responding to certain stimuli and punishments for responding to others. Three cognitive models were evaluated on the basis of data from a longitudinal study involving 400 adolescents. The results show that a cue-dependent model presupposing that participants can differentiate between cues was the most accurate and parsimonious. This model has 3 parameters denoting the relative impact of rewards and punishments on evaluations, the rate that contingent payoffs are learned, and the consistency between learning and responding. Commission errors were associated with increased attention to rewards; omission errors were associated with increased attention to punishments. Both error types were associated with low choice consistency. The parameters were also shown to have external validity: Attention to rewards was associated with externalizing behavior problems on the Achenbach scale, and choice consistency was associated with low Welsh anxiety. The present model can thus potentially improve the sensitivity of the task to differences between clinical populations.     

Two types of perseveration in the Dimension Change Card Sort task

In the Dimension Change Card Sort (DCCS) task, 3-year-olds can sort cards well by one dimension but have difficulty in switching to sort the same cards by another dimension when asked; that is, they perseverate on the first relevant information. What is the information that children perseverate on? Using a new version of the DCCS, the experiments in this article reveal that there are two types of perseverators: those who perseverate at the level of dimensions and those who perseverate at the level of values (stimulus features). This novel finding has implications for theories of perseveration.     

Factors affecting infants' manual search for occluded objects and the genesis of object permanence

Two experiments systematically examined factors that influence infants’ manual search for hidden objects (N = 96). Experiment 1 used a new procedure to assess infants’ search for partially versus totally occluded objects. Results showed that 8.75-month-old infants solved partial occlusions by removing the occluder and uncovering the object, but these same infants failed to use this skill on total occlusions. Experiment 2 used sound-producing objects to provide a perceptual clue to the objects’ hidden location. Sound clues significantly increased the success rate on total occlusions for 10-month-olds, but not for 8.75-month-olds. An identity development account is offered for why infants succeed on partial occlusions earlier than total occlusions and why sound helps only the older infants. We propose a mechanism for how infants use object identity as a basis for developing a notion of permanence. Implications are drawn for understanding the dissociation between looking time and search assessments of object permanence.     

Compulsive perseveration: empirical criticism on the mood-as-input model

It has been proposed that the "Mood as Input" model provides an explanation of the perseverative nature of Obsessive Compulsive (OC) behaviour (MacDonald, B. C., & Davey, G. C. L. (2005). A mood-as-input account of perseverative checking: The relationship between stop rules, mood and confidence in having checked successfully. Behaviour Research and Therapy, 43, 69-91). The model implies that task perseveration occurs when individuals (a) experience a bad mood and (b) ask themselves "did I do as much as I can?" In two earlier experiments with healthy participants (MacDonald, B. C., & Davey, G. C. L. (2005). A mood-as-input account of perseverative checking: The relationship between stop rules, mood and confidence in having checked successfully. Behaviour Research and Therapy, 43, 69-91) it was found that when the allegedly critical conditions were met (negative mood and "did I as much as I can?" stop rule) perseveration occurred on a complex text-correction task. This finding was held to support a "mood as input" explanation of compulsive perseveration. It is important to note, however, that perseveration in clinical samples occurs for very simple "tasks" (e.g. closing a door or washing ones hands) and perseveration does not increase efficacy of performance. In the present study we compared the effects of the original task to effects of text correction tasks that were simpler and more OCD-like. The original effects were replicated: the combination of negative mood and the "did I do as much as I can" stop rule provoked perseveration. Meanwhile, "perseveration" was highly functional: the more "perseveration" the more text-errors were detected. Secondly, to the degree that tasks became simpler and more OCD-like, less checking occurred and the effects of the "did I do as much as I can?" stop rule on detection of errors became smaller. The findings raise questions about the validity of the paradigm as a model of OC perseveration.     

Using automated controlled rearing to explore the origins of object permanence

What are the origins of object permanence? Despite widespread interest in this question, methodological barriers have prevented detailed analysis of how experience shapes the development of object permanence in newborn organisms. Here, we introduce an automated controlled‐rearing method for studying the emergence of object permanence in strictly controlled virtual environments. We used newborn chicks as an animal model and recorded their behavior continuously (24/7) from the onset of vision. Across four experiments, we found that object permanence can develop rapidly, within the first few days of life. This ability developed even when chicks were reared in impoverished visual environments containing no object occlusion events. Object permanence failed to develop, however, when chicks were reared in environments containing temporally non‐smooth objects (objects moving on discontinuous spatiotemporal paths). These results suggest that experience with temporally smooth objects facilitates the development of object permanence, confirming a key prediction of temporal learning models in computational neuroscience.     

An assessment of response bias for the same-different task: implications for the single-interval task

Two auditory amplitude discrimination experiments were conducted using the same-different experimental design. Observer bias was manipulated, in the first experiment, by varying payoff matrices and, in the second, by varying prior probabilities of signal presentation. Five levels of bias manipulation and four levels of difficulty were employed in each experiment. Each observer received all combinations of bias manipulation and difficulty, but with only one of these combinations within each block of trials. Nine indices of bias were assessed by simultaneously fitting isosensitivity and isobias functions to the data and by fitting isobias functions only. Although none of the indices tested provided an exceptionally good fit to the data, two indices stood out from the rest. These were c*sd and ci, indices with isobias contours similar in shape to those for the c index derived from the yes-no task.     

The effect of spatial cues on infants’ responses in the AB task,with and without a hidden object

The errors made by infants in the AB task were taken by Piaget as an indication of an inability to update their representations of the spatial location of a hidden object. This paper presents an experiment designed to further investigate the role of spatial representations in the production of the error. The introduction of strong visual cues to spatial location was found to reduce the traditional A‐not‐B search error. However, it also increased perseveration when a ‘lids‐only’ analogue of the AB task was used, in which infants are simply cued to pick up lids rather than encouraged to search for a hidden object. These results present a challenge to the dynamic systems account of the error given by Smith, Thelen, Titzer and McLin (Psychological Review, 106 (1999), 235–260), and indicate that the traditional A‐not‐B search error arises from a difficulty in updating representations of the spatial location of hidden objects. The relation of these results to Munakata’s PDP model (Developmental Science, 1 (1998), 161–211) and Thelen, Schöner, Scheier and Smith’s (Behavioural and Brain Sciences, 24 (2001), 1‐‐86) most recent dynamic systems model of the A‐not‐B error is also discussed.     

Imaging episodic memory: implications for cognitive theories and phenomena

Functional neuroimaging studies are beginning to identify neuroanatomical correlates of various cognitive functions. This paper presents results relevant to several theories and phenomena of episodic memory, including component processes of episodic retrieval, encoding specificity, inhibition, item versus source memory, encoding-retrieval overlap, and the picture-superiority effect. Overall, by revealing specific activation patterns, the results provide support for existing theoretical views and they add some unique information which may be important to consider in future attempts to develop cognitive theories of episodic memory.     

Episodic effects on picture identification: implications for theories of concept learning and theories of memory

The effects of differences in study processing on free recall of picture names and on generalization in picture identification were investigated. Experience with degraded pictures produced poorer subsequent free recall of picture names than did naming intact pictures. For the test of picture identification, pictures that were identical to a studied picture, pictures that shared a name with a studied picture (same name), and new test pictures were presented, and the amount of clarification required to identify a picture was measured. Experience with degraded pictures produced better subsequent identification of identical test pictures but poorer later identification of same-name test pictures than did naming intact pictures. The importance of these episodic effects for theories of concept learning and theories of memory is discussed. It is argued that distinctions between memory systems (e.g., episodic-semantic) must be couched in terms of a theory of concept learning and that the data are inconsistent with a simple distinction.     

The lexical constituency model: some implications of research on Chinese for general theories of reading

The authors examine the implications of research on Chinese for theories of reading and propose the lexical constituency model as a general framework for word reading across writing systems. Word identities are defined by 3 interlinked constituents (orthographic, phonological, and semantic). The implemented model simulates the time course of graphic, phonological, and semantic priming effects, including immediate graphic facilitation followed by graphic inhibition with simultaneous phonological facilitation, a pattern unique to the Chinese writing system. Pseudocharacter primes produced only facilitation, supporting the model's assumption that lexical thresholds determine phonological and semantic, but not graphic, effects. More generally, both universal reading processes and writing system constraints exist. Although phonology is universal, its activation process depends on how the writing system structures graphic units.     

On being the object of attention: implications for self-other consciousness

Joint attention to an external object at the end of the first year is typically believed to herald the infant's discovery of other people's attention. I will argue that mutual attention in the first months of life already involves an awareness of the directedness of attention. The self is experienced as the first object of this directedness followed by gradually more distal 'objects'. This view explains early infant affective self-consciousness within mutual attention as emotionally meaningful, rather than as bearing only a spurious similarity to that in the second and third years of life. Such engagements precede and must inform, rather than derive from, conceptual representations of self and other, and can be better described as self-other conscious affects.     

A chain-retrieval model for voluntary task switching

To account for the findings obtained in voluntary task switching, this article describes and tests the chain-retrieval model. This model postulates that voluntary task selection involves retrieval of task information from long-term memory, which is then used to guide task selection and task execution. The model assumes that the retrieved information consists of acquired sequences (or chains) of tasks, that selection may be biased towards chains containing more task repetitions and that bottom-up triggered repetitions may overrule the intended task. To test this model, four experiments are reported. In Studies 1 and 2, sequences of task choices and the corresponding transition sequences (task repetitions or switches) were analyzed with the help of dependency statistics. The free parameters of the chain-retrieval model were estimated on the observed task sequences and these estimates were used to predict autocorrelations of tasks and transitions. In Studies 3 and 4, sequences of hand choices and their transitions were analyzed similarly. In all studies, the chain-retrieval model yielded better fits and predictions than statistical models of event choice. In applications to voluntary task switching (Studies 1 and 2), all three parameters of the model were needed to account for the data. When no task switching was required (Studies 3 and 4), the chain-retrieval model could account for the data with one or two parameters clamped to a neutral value. Implications for our understanding of voluntary task selection and broader theoretical implications are discussed.     

A mixed-effects expectancy-valence model for the Iowa gambling task

The Iowa gambling task (IGT; Bechara, Damasio, Damasio, & Anderson, 1994) was developed to simulate real-life decision making under uncertainty. The task has been widely used to examine possible neurocognitive deficits in normal and clinical populations. Busemeyer and Stout (2002) proposed the expectancy-valence (EV) model to explicitly account for individual participants’ repeated choices in the IGT. Parameters of the EV model presumably measure different psychological processes that underlie performance on the task, and their values may be used to differentiate individuals across different populations. In the present article, the EV model is extended to include both fixed effects and subject-specific random effects. The mixed-effects EV model fits the nested structure of observations in the IGT naturally and provides a unified procedure for parameter estimation and comparisons among groups of populations. We illustrate the utility of the mixed-effects approach with an analysis of gender differences using a real data set. A simulation study was conducted to verify the advantages of this approach.