Effect of counterfactual and factual thinking on causal judgements

The significance of counterfactual thinking in the causal judgement process has been emphasized for nearly two decades, yet no previous research has directly compared the relative effect of thinking counterfactually versus factually on causal judgement. Three experiments examined this comparison by manipulating the task frame used to focus participants' thinking about a target event. Prior to making judgements about causality, preventability, blame, and control, participants were directed to think about a target actor either in counterfactual terms (what the actor could have done to change the outcome) or in factual terms (what the actor had done that led to the outcome). In each experiment, the effect of counterfactual thinking did not differ reliably from the effect of factual thinking on causal judgement. Implications for research on causal judgement and mental representation are discussed.     

Creating partially deleted objects for perception research

Line drawings are commonly used in perception research. A basic strategy used in such research is to remove portions of the line drawings in order to determine what features of an object are important for recognition. However, it is important to monitor the amount of contour and type of information that are deleted when one is making partially deleted or fragmented objects. With the Image Fragmenting Program, researchers can use random or manual contour deletion strategies to create fragmented objects while controlling for the amount of contour removed from the images.     

The role of edges in object recognition by pigeons

In three experiments, we explored how pigeons use edges, corresponding to orientation and depth discontinuities, in visual recognition tasks. In experiment 1, we compared the pigeon's ability to recognize line drawings of four different geons when trained with shaded images. The birds were trained with either a single view or five different views of each object. Because the five training views had markedly different appearances and locations of shaded surfaces, reflectance edges, etc, the pigeons might have been expected to rely more on the orientation and depth discontinuities that were preserved over rotation and in the line drawings. In neither condition, however, was there any transfer from the rendered images to the outline drawings. In experiment 2, some pigeons were trained with line drawings and shaded images of the same objects associated with the same response (consistent condition), whereas other pigeons were trained with a line drawing and a shaded image of two different objects associated with the same response (inconsistent condition). If the pigeons perceived any correspondence between the stimulus types, then birds in the consistent condition should have learned the discrimination more quickly than birds in the inconsistent condition. But, there was no difference in performance between birds in the consistent and inconsistent conditions. In experiment 3, we explored pigeons' processing of edges by comparing their discrimination of shaded images or line drawings of four objects. Once trained, the pigeons were tested with planar rotations of those objects. The pigeons exhibited different patterns of generalization depending on whether they were trained with line drawings or shaded images. The results of these three experiments suggest that pigeons may place greater importance on surface features indicating materials, such as food or water. Such substances do not have definite boundaries cued by edges which are thought to be central to human recognition.     

Temporal contiguity and the judgement of causality by human subjects

Three experiments examined the role of the degree of temporal contiguity between an action and an outcome in human causality judgement. In all the experiments subjects were required to perform an action—pressing a key on a computer keyboard—and to judge the extent to which the action caused an outcome on the computer screen to occur. The action and outcome occurred on a free-operant schedule. In the first experiment a 2-sec delay between the action and outcome reduced causality judgements relative to a situation in which there was no delay. In the second experiment judgements in conditions with delays of 0, 4, 8, and 16 sec were compared with judgements in conditions in which the same pattern of outcomes occurred non-contingently with respect to the subjects' responding. In both of these experiments the events were controlled by random ratio schedules, following the procedure of Wasserman, Chatlosh, and Neunaber (1983), in which each condition was divided into 1-sec intervals. In the third experiment judgements in conditions with delays of 0, 2, 4, or 8 sec were compared in a continuous procedure rather than one divided into 1-sec intervals. In all experiments the increasing delays led to progressively lower judgements of causality. The results are related to three accounts of the mechanism underlying human causality judgement and are also compared with results from analogous animal conditioning studies.     

Contour deletion as a method for identifying the weights of features underlying object recognition

A prerequisite for comparative work on object recognition is a method for identifying the features actually extracted from the form. The method introduced here with pigeons is discrimination training between two simple line drawings, followed by a generalization test in which contour is deleted from the reinforced drawing. In Condition 1, the line drawings were a square (S+) versus a triangle (S-); for Condition 2, the line drawings were planar projections of a cube (S+) versus a truncated pyramid (S-). The generalization decrement between responses to S+ and responses to test stimuli provides a quantitative index of the weight assigned to each feature. Contour deletion at either vertices or midsegments produced a decrement in the rate of responding, showing that each contour was represented as a feature. The generalization decrement to forms containing vertices with midsegments deleted was larger than the generalization decrement to forms containing midsegments with vertices deleted. Therefore, it appears that midsegments are weighted more strongly as features than vertices. Contour deletion provides a direct method for identifying the visual features underlying object recognition and lays a foundation for the development of comparative theories of object recognition.     

Outline shape is a mediator of object recognition that is particularly important for living things

We assess the importance of outline shape in mediating the recognition of living and nonliving things. Natural objects were presented as shaded line drawings or silhouettes, and were living and nonliving things. For object decision (deciding whether an object may be encountered in real life) there were longer response times to nonliving than to living things. Importantly, this category difference was greater for silhouettes than for shaded line drawings. For naming, similar category and stimulus differences were evident, but were not as pronounced. We also examined effects of prior naming on subsequent object decision performance. Repetition priming was equivalent for nonliving and living things. However, prior presentation of silhouettes (but not shaded line drawings) reduced the longer RT to nonliving things relative to living things in silhouette object decision. We propose that outline contour benefits recognition of living things more than nonliving things: For nonliving things, there may be greater 2-D/3-D interpretational ambiguity, and/or they may possess fewer salient features.     

Distortions and fluctuations in topographic memory

Two experiments dealing with, the learning of a space by map or by navigation approached the questions of equivalency of the cognitive processes involved in spatial information and of response fluctuation. In the first experiment, 11 subjects were asked to situate, six times, 18 lo-cations on a blank map. In the second experiment, the subjects were first given 3 min to learn a map with 12 locations marked, and then asked to reproduce it. The task was repeated six times, using three different maps. This gave us several trials per subject, so that distortion could be distinguished from response fluctuation. In Experiment 1, the range of values was the same for response inaccuracy and response, fluctuation; in Experiment 2, the range was greater for response inaccuracy than for response fluctuation. The results showed that space learning by navigation and space learning by map involve different cognitive processes.     

17,000 years of depicting the junction of two smooth shapes

Competent realistic drawings preserve viewpoint-invariant shape characteristics of simple parts, such that a contour in the object that is straight or curved, for example, is depicted that way in the drawing. A more subtle invariant--a V-shaped singularity of the occluding boundary, containing a T-junction and a contour termination--is produced at the junction between articulated smooth surfaces, as with the leg joining the body of a horse. 45% of the drawings made in 2007 by individuals with only minimal art education correctly depicted such junctions, a proportion that is not reliably different from the incidence (42%) of correct depictions in a large sample of cave art made 17000 years ago. Whether a person did or did not include the invariant in their drawing, all agreed that it made for a better depiction.     

Change detection in complex scenes: hemispheric contribution and the role of perceptual and semantic factors

The perceptual salience and semantic relevance of objects for the meaning of a scene were evaluated with multiple criteria and then manipulated in a change-detection experiment that used an original combination of one-shot and tachistoscopic divided-visual-field paradigms to study behavioural hemispheric asymmetry. Coloured drawings that depicted meaningful situations were presented centrally and very briefly (120 ms) and only the changes were lateralised by adding an object in the right or in the left visual hemifield. High salience and high relevance improved both response times (RTs) and accuracy, although the overall contribution of salience was greater than that of relevance. Moreover, only for low-salience changes did relevance affect speed. RTs were shorter when a change occurred in the left visual hemifield, suggesting a right-hemisphere advantage for detection of visual change. Also, men responded faster than women. The theoretical and methodological implications are discussed.     

Core geometry in perspective

Research on animals, infants, children, and adults provides evidence that distinct cognitive systems underlie navigation and object recognition. Here we examine whether and how these systems interact when children interpret 2D edge‐based perspectival line drawings of scenes and objects. Such drawings serve as symbols early in development, and they preserve scene and object geometry from canonical points of view. Young children show limits when using geometry both in non‐symbolic tasks and in symbolic map tasks that present 3D contexts from unusual, unfamiliar points of view. When presented with the familiar viewpoints in perspectival line drawings, however, do children engage more integrated geometric representations? In three experiments, children successfully interpreted line drawings with respect to their depicted scene or object. Nevertheless, children recruited distinct processes when navigating based on the information in these drawings, and these processes depended on the context in which the drawings were presented. These results suggest that children are flexible but limited in using geometric information to form integrated representations of scenes and objects, even when interpreting spatial symbols that are highly familiar and faithful renditions of the visual world.     

Lines that induce phenomenal transparency

Three neighbouring opaque surfaces may appear split into two layers, one transparent and one opaque beneath, if an outline contour is drawn that encompasses two of them. The phenomenon was originally observed by Kanizsa [1955 Rivista di Psicologia 69 3-19; 1979 Organization in Vision: Essays on Gestalt Psychology (New York: Praeger)], for the case where an outline contour is drawn to encompass one of the two parts of a bicoloured figure and a portion of a background of lightest (or darkest) luminance. Preliminary observations revealed that the outline contour yields different effects: in addition to the stratification into layers described by Kanizsa, a second split, opposite in depth order, may occur when the outline contour is close in luminance to one of the three surfaces. An initial experiment was designed to investigate what conditions give rise to the two phenomenal transparencies: this led to the conclusion that an outline contour superimposed on an opaque surface causes this surface to emerge as a transparent layer when the luminances of the contour and the surface differ, in absolute value, by no more than 13.2 cd m(-2). We have named this phenomenon 'transparency of the intercepted surface', to distinguish it from the phenomenal transparency arising when the contour and surface are very different in luminance. When such a difference exists, the contour acts as a factor of surface definition and grouping: the portion of the homogeneous surface it bounds emerges as a fourth surface and groups with a nearby surface if there is one close in luminance. The transparency phenomena ('transparency of the contoured surface') perceived in this context conform to the constraints of Metelli's model, as demonstrated by a second experiment, designed to gather 'opacity' ratings of stimuli. The observer judgments conformed to the values predicted by Metelli's formula for perceived degree of transparency, alpha. The role of the outline contour in conveying figural and intensity information is discussed.     

Spatial coherence does not affect contrast discrimination for multiple Gabor stimuli

Gestalt grouping rules imply a process or mechanism for grouping together local features of an object into a perceptual whole. Several psychophysical experiments have been interpreted as evidence for constrained interactions between nearby spatial filter elements and this has led to the hypothesis that element linking might be mediated by these interactions. A common tacit assumption is that these interactions result in response modulation which disturbs a local contrast code. We addressed this possibility by performing contrast discrimination experiments using two-dimensional arrays of multiple Gabor patches arranged either (i) vertically, (ii) in circles (coherent conditions), or (iii) randomly (incoherent condition), as well as for a single Gabor patch. In each condition, contrast increments were applied to either the entire test stimulus (experiment 1) or a single patch whose position was cued (experiment 2). In experiment 3, the texture stimuli were reduced to a single contour by displaying only the central vertical strip. Performance was better for the multiple-patch conditions than for the single-patch condition, but whether the multiple-patch stimulus was coherent or not had no systematic effect on the results in any of the experiments. We conclude that constrained local interactions do not interfere with a local contrast code for our suprathreshold stimuli, suggesting that, in general, this is not the way in which element linking is achieved. The possibility that interactions are involved in enhancing the detectability of contour elements at threshold remains unchallenged by our experiments.     

Quality of Drawing as a Factor in the Interpretation of Figure Drawings

Examined the drawings of 32 poliomyelitis patients and their matched controls to see whether figure drawings primarily reflect the subject's projection of psychological state, ability to draw, or some combination of these two factors. An overview of the literature is also given. Drawings from disabled and nondisabled subjects were reliably rated for quality, with no significant quality difference found between groups. Analyses of variance were then used to compare the drawings on several different measures of drawing size, completion and movement that might be assumed on the basis of the literature, to reflect the subjects' projection of disability status. Results showed that quality of drawing was a significant factor in 13 of the 17 comparisons while disability status proved to be a significant factor in only one of the 17 comparisons. There were no significant interactions. Therefore, the overall findings are consistent with the hypothesis that quality of drawing—rather than projective mechanisms—may at times be the overwhelming determinant of clinical and research findings with figure drawings.     

Factors that affect action possibility judgements: recent experience with the action and the current body state

It has been suggested that action possibility judgements are formed through a covert simulation of the to-be-executed action. We sought to determine whether the motor system (via a common coding mechanism) influences this simulation, by investigating whether action possibility judgements are influenced by experience with the movement task (Experiments 1 and 2) and current body states (Experiment 3). The judgement task in each experiment involved judging whether it was possible for a person's hand to accurately move between two targets at presented speeds. In Experiment 1, participants completed the action judgements before and after executing the movement they were required to judge. Results were that judged movement times after execution were closer to the actual execution time than those prior to execution. The results of Experiment 2 suggest that the effects of execution on judgements were not due to motor activation or perceptual task experience-alternative explanations of the execution-mediated judgement effects. Experiment 3 examined how judged movement times were influenced by participants wearing weights. Results revealed that wearing weights increased judged movement times. These results suggest that the simulation underlying the judgement process is connected to the motor system, and that simulations are dynamically generated, taking into account recent experience and current body state.     

Factors that affect action possibility judgements: Recent experience with the action and the current body state

It has been suggested that action possibility judgements are formed through a covert simulation of the to-be-executed action. We sought to determine whether the motor system (via a common coding mechanism) influences this simulation, by investigating whether action possibility judgements are influenced by experience with the movement task (Experiments 1 and 2) and current body states (Experiment 3). The judgement task in each experiment involved judging whether it was possible for a person's hand to accurately move between two targets at presented speeds. In Experiment 1, participants completed the action judgements before and after executing the movement they were required to judge. Results were that judged movement times after execution were closer to the actual execution time than those prior to execution. The results of Experiment 2 suggest that the effects of execution on judgements were not due to motor activation or perceptual task experience—alternative explanations of the execution-mediated judgement effects. Experiment 3 examined how judged movement times were influenced by participants wearing weights. Results revealed that wearing weights increased judged movement times. These results suggest that the simulation underlying the judgement process is connected to the motor system, and that simulations are dynamically generated, taking into account recent experience and current body state.     

Picture and pattern perception in the sighted and the blind: the advantage of the late blind

Two experiments are reported on the contribution of visual experience to tactile perception. In the first experiment, sighted, congenitally blind, and late blind individuals made tactual matches to tangible embossed shapes. In the second experiment, the same subjects attempted tactile identification of raised-line drawings. The three groups did not differ in the accuracy of shape matching, but both groups of blind subjects were much faster than the sighted. Late blind observers were far better than the sighted or congenitally blind at tactile picture identification. Four of the twelve pictures were correctly identified by most of the late blind subjects. The sighted and congenitally blind performed at comparable levels in picture naming. There was no evidence that visual experience alone aided the sighted in the tactile task under investigation, since they performed no better than did the early blind. The superiority of the late blind suggests that visual exposure to drawings and the rules of pictorial representation may help tactile picture identification when combined with a history of tactual experience.     

Reasons for the attribution of intent in 7- and 9-year-old children

Seven- and 9-year-old children were presented with drawings which depicted two ambiguous action-outcome sequences and asked to make judgements about the intention of an actor towards another, and then to provide an explanation for the judgement. The design incorporated two levels of actor valence (nice, bad) with two types of outcome quality (good, bad). Judgements were influenced by both valence and outcome factors, but no age effect emerged. Content analysis of the explanations did reveal an age difference in reasoning about social judgements which was associated with the bad outcome. Nine-year-olds used more inference-based explanations which reflected a more objective appraisal of the incident. The explanations of the younger children tended to be dominated by the immediacy of the situation. The findings further highlighted the importance of consistency between actor valence and outcome information relative to the direction of the child's judgement. Inconsistency arising in the context of a bad outcome situation elicited more rigorous explanations from the 9-year-olds.     

An experimental approach to the design of cartographic symbols

Graphic designers and an experimental psychologist worked together to improve the design of two map symbols which are frequently confused: the symbols for cuttings and embankments on topographic maps. The problem was analysed in terms of the function of the symbols and their likely cognitive representations. Tests were developed to evaluate alternative designs, including an intervisibility task which requirred users to visualize the landform from the symbols viewed in the context of a map. Tests were given to schoolchildren and to experienced map users in order to compare the standard symbols with five alternative designs. Children's performance was strongly affected by the symbols they used, but experienced users were much less affected. After some refinement of the symbols a further experiment demonstrated the superiority of a number of alternative designs over the existing symbols on a range of test: scores were almost double on the intervisibility task. The paper makes recommendations to cartographers and argues for greater consideration of the inexperienced map user in the design process.     

The importance of alignment in blind subjects' use of tactual maps

An experiment was conducted to test for the presence of alignment effects (previously found in sighted map users) in blind and visually impaired subjects using tactual maps. The term 'alignment effects' refers to the fact that when points represented as further up on a map do not correspond to points forward from the user in the environment, errors in the directional judgments made by subjects are greatly increased. The results show that alignment effects do exist in blind and visually impaired map users. Blind subjects encoded maps using the 'up equals forward' rule, and demonstrated some similarity to sighted subjects in the types of errors made. There was also some indication of improved performance over repeated trials. Differences between blind and sighted subjects were also found and were tentatively attributed to visual experience with object transformations and/or representational variables. Subject background variables were also investigated and some relationships between background of the subject and performance were drawn.