Multiple object tracking and attentional processing.

Used the multiple object tracking methodology of Z. W. Pylyshyn and R. W. Storm (see record 1989-35304-001) to investigate the relation between "visual indexing" and attentional processing. 17 participants visually tracked a subset of a set of identical, independently randomly moving objects in a display (the targets), and made a speeded identification response when they noticed a target or a nontarget (distractor) object undergo a subtle form transformation. The authors found that target form changes were identified more rapidly than nontarget form changes, and that the speed of responding to target form changes was unaffected by the number of nontargets in the display when the form-changing targets were successfully tracked. They also found that this enhanced processing only applied to the targets themselves and not to nearby nontarget distractors, showing that the allocation of a broadened region of visual attention could not account for these findings. These results confirm that visual indexing bestows a processing priority to a number of objects in the visual field. (PsycINFO Database Record (c) 2010 APA, all rights reserved)     

Computer science and the enrichment of psychological research.

An analysis is made of the impact of computer science on research method and theory construction in psychology. The influence is roughly divided into what is described as the Level of Application and the Level of Conceptual Enrichment. At the first level the new discipline is used as a tool to extend the facilities available to the psychologist. In spite of this, it is argued, the simple increase in technical power has led to important differences in the kind of research that can be considered and has been the determining factor in the direction and the extent of the development of various research areas in psychology. At the second level computer science has contributed a wealth of conceptual resources. It has been the source of many theoretical constructs and, even more significantly, has contributed an alternative language for the expression of psychological theory--the language of a computer algorithm which simulates the relevant behaviour. (PsycINFO Database Record (c) 2010 APA, all rights reserved)     

Can subjective experience cause brain activity?

Comments on a central disagreement in a dialog between D. Bindra (see record 1971-03399-001) and R. W. Sperry (1970) as to whether subjective experience (e.g., pain) can have a causal effect of brain activity. Sperry maintains that subjective experience itself directly determines the further course of brain activity. The author's views are that emergent properties are presumably "emergent" to the extent that they are not terms in the physical laws governing more elementary components. (PsycINFO Database Record (c) 2010 APA, all rights reserved)     

Multiple parallel access in visual attention.

Argues that the single focus of attention, generally assumed to represent the allocation of processing resources, does not totally explain how spatially local information is accessed in the visual field (VF). It is suggested that even if attention is unitary and spatially focused, there is also a more primitive mechanism for simultaneously indexing several places in a VF, thus individuating these places and making them directly accessible for further processing. Considerations suggesting the need for a multiple-locus indexing mechanism are discussed. Empirical evidence for particular properties (multiple-object tracking, cued search, subitizing, and illusory line motion) of the indexing mechanism is reviewed. Evidence suggests that there is an early preattentive stage in vision where a small number of salient items in the VF are indexed and thereby made readily accessible for a variety of visual tasks. (French abstract) (PsycINFO Database Record (c) 2010 APA, all rights reserved)     

Erratum.

In the article by Zenon Pylyshyn in the July 1973 issue (see record 1974-00324-001), the last paragraph in the first column on page 15 should read: "Intuitively, it seems clear that at least part of what we know when we have learned a concept includes a set of specific procedures for determining whether a particular token is an instance of the concept as well as a set of rules governing the use of the concept in a variety of specific situations." (PsycINFO Database Record (c) 2010 APA, all rights reserved)     

What enumeration studies can show us about spatial attention: Evidence for limited capacity preattentive processing.

Subitizing, the enumeration of 1–4 items, is rapid (40–220 msec/item) and accurate. Counting, the enumeration of 5 items or more, is slow (250–350 msec/item) and error-prone. Why are small numbers of items enumerated differently from large numbers of items? It is suggested that subitizing relies on a preattentive mechanism. Ss could subitize heterogeneously sized multicontour items but not concentric multicontour items, which require attentional processing because preattentive gestalt processes misgroup contours from different items to form units. Similarly, Ss could subitize target items among distractors but only if the targets and distractors differed by a feature, a property derived through preattentive analysis. Thus, subitizing must rely on a mechanism that can handle a few items at once, which operates before attention but after preattentive operations of feature detection and grouping. (PsycINFO Database Record (c) 2010 APA, all rights reserved)     

The imagery debate: Analogue media versus tacit knowledge.

Argues that the main point of disagreement in the debate over the nature of mental imagery concerns the following: (a) whether certain aspects of the way in which images are transformed should be attributed to intrinsic knowledge-independent properties of the medium in which images are instantiated or the mechanisms by which they are processed; or (b) whether images are typically transformed in certain ways because Ss take their task to be the simulation of the act of witnessing certain real events taking place and therefore use their tacit knowledge of the imaged situation to cause the transformation to proceed as they believe it would have proceeded in reality. The tacit knowledge account is seen as more plausible because empirical results demonstrate that both "mental scanning" and "mental rotation" transformations can be critically influenced by varying the instructions given to Ss and the precise form of the task used and, that the form of the influence is explainable in terms of the semantic content of Ss' beliefs and goals. (40 ref) (PsycINFO Database Record (c) 2010 APA, all rights reserved)