The effects of graded occlusion on manual search and visual attention in 5- to 8-month-old infants

Young infants may be limited in searching for hidden objects because they lack the means-end motor skill to lift occluders from objects. This account was investigated by presenting 5- to 8-month-old infants with objects hidden behind transparent, semitransparent, and opaque curtains. If a means-end deficit explains search limitations, then infants should search no more for an object behind a transparent curtain than for objects behind semitransparent or opaque curtains. However, level of occlusion had a significant effect on manual search and visual attention. Infants retrieved and contacted the object more, contacted the curtain more, and looked away less with the transparent curtain than with the semitransparent or opaque curtains. Adding a time delay before allowing search and presenting a distraction after occlusion further depressed infants' behavior. The findings fail to support the means-end deficit hypothesis, but are consistent with the account that young infants lack object permanence

Object permanence in five-and-a-half-month-old infants?

Event Set x Event Set designs were used to study the rotating screen paradigm introduced by Baillargeon, Spelke, and Wasserman (1985). In Experiment 1, 36 5 1/2 month-old infants were habituated to a screen rotating up to 180 degrees up to and seemingly through a block. All infants were then tested on the same 3 events and also a screen rotating 120 degrees with no block. The results indicate that infants are using novelty and familiarity preference to determine their looking times. To confirm this, in Experiment 2, 52 5 1/2-month-old infants were familiarized on either 3 or 7 trials to a screen rotating 180 degrees with no block or a screen rotating 120 degrees with no block. All infants were then tested on the same test events as Experiment 1. Infants with fewer familiarization trials were more likely to prefer the familiar rotation event. The results of these 2 experiments indicate that infants did not use the possibility or impossibility of events but instead used familiarity or novelty relations between the habituation events and the test events to determine their looking times, and suggest that the Baillargeon et al study should not be interpreted as indicating object permanence or solidity knowledge in young infants

Reply to Baillargeon, Aslin and Munakata

Our thematic collection relates to the nature of young infants' representation in specific situations involving occluded objects. Piaget (1954) concluded that the infant has no representations at this age. Most now agree that conclusion was unwarranted, but researchers differ as to what, if any, representations exist of occluded objects (Baillargeon, 1993, 1995; Bogartz, Shinskey & Spencer, 1997; Haith, 1988; Leslie, Xu, Tremoulet, & Scholl, 1998; Meltzoff & Moore, 1998). Obviously, issues concerning the nature of infant representation must be decided experimentally. It is therefore important to know how much confidence can be placed in the existing studies, especially those supporting more extreme positions. This exchange regarding the larger theoretical issues takes place in the context of assessing the nature and importance of evidence from the drawbridge experiments in general and the frequently cited Baillargeon, Spelke, and Wasserman (1985) study in particular. Here, we respond to the remarks made by Baillargeon (this issue), Aslin (this issue, and Munakata (this issue)

Life-Space Foam: a Medium for Motivational and Cognitive Dynamics

General stochastic dynamics, developed in a framework of Feynman path integrals, have been applied to Lewinian field--theoretic psychodynamics, resulting in the development of a new concept of life--space foam (LSF) as a natural medium for motivational and cognitive psychodynamics. According to LSF formalisms, the classic Lewinian life space can be macroscopically represented as a smooth manifold with steady force-fields and behavioral paths, while at the microscopic level it is more realistically represented as a collection of wildly fluctuating force-fields, (loco)motion paths and local geometries (and topologies with holes). A set of least-action principles is used to model the smoothness of global, macro-level LSF paths, fields and geometry. To model the corresponding local, micro-level LSF structures, an adaptive path integral is used, defining a multi-phase and multi-path (multi-field and multi-geometry) transition process from intention to goal-driven action. Application examples of this new approach include (but are not limited to) information processing, motivational fatigue, learning, memory and decision-making.Comment: 25 pages, 2 figures, elsar

On the interpretation of removable interactions: A survey of the field 33 years after Loftus

In a classic 1978 Memory &Cognition article, Geoff Loftus explained why noncrossover interactions are removable. These removable interactions are tied to the scale of measurement for the dependent variable and therefore do not allow unambiguous conclusions about latent psychological processes. In the present article, we present concrete examples of how this insight helps prevent experimental psychologists from drawing incorrect conclusions about the effects of forgetting and aging. In addition, we extend the Loftus classification scheme for interactions to include those on the cusp between removable and nonremovable. Finally, we use various methods (i.e., a study of citation histories, a questionnaire for psychology students and faculty members, an analysis of statistical textbooks, and a review of articles published in the 2008 issue of Psychology andAging) to show that experimental psychologists have remained generally unaware of the concept of removable interactions. We conclude that there is more to interactions in a 2 × 2 design than meets the eye

Fleeting Perceptual Experience and the Possibility of Recalling Without Seeing

We explore an intensely debated problem in neuroscience, psychology and philosophy: the degree to which the “phenomenological consciousness” of the experience of a stimulus is separable from the “access consciousness” of its reportability. Specifically, it has been proposed that these two measures are dissociated from one another in one, or both directions. However, even if it was agreed that reportability and experience were doubly dissociated, the limits of dissociation logic mean we would not be able to conclusively separate the cognitive processes underlying the two. We take advantage of computational modelling and recent advances in state-trace analysis to assess this dissociation in an attentional/experiential blink paradigm. These advances in state-trace analysis make use of Bayesian statistics to quantify the evidence for and against a dissociation. Further evidence is obtained by linking our finding to a prominent model of the attentional blink – the Simultaneous Type/Serial Token model. Our results show evidence for a dissociation between experience and reportability, whereby participants appear able to encode stimuli into working memory with little, if any, conscious experience of them. This raises the possibility of a phenomenon that might be called sight-blind recall, which we discuss in the context of the current experience/reportability debate

Learning with a network of competing synapses

Competition between synapses arises in some forms of correlation-based plasticity. Here we propose a game theory-inspired model of synaptic interactions whose dynamics is driven by competition between synapses in their weak and strong states, which are characterized by different timescales. The learning of inputs and memory are meaningfully definable in an effective description of networked synaptic populations. We study, numerically and analytically, the dynamic responses of the effective system to various signal types, particularly with reference to an existing empirical motor adaptation model. The dependence of the system-level behavior on the synaptic parameters, and the signal strength, is brought out in a clear manner, thus illuminating issues such as those of optimal performance, and the functional role of multiple timescales.Comment: 16 pages, 9 figures; published in PLoS ON