Papers by Stephen Kosslyn
Journal of Cognitive …, Jan 1, 1990
1990. Receptive field characteristics that allow parietal lobe neurons to encode spatial properti... more 1990. Receptive field characteristics that allow parietal lobe neurons to encode spatial properties of visual input: A computational analysis. Journal of Cognitive Neuroscience 2(2): 141-155.
Neuroimage, 2007
Although the visual system rapidly categorizes objects seen under optimal viewing conditions, the... more Although the visual system rapidly categorizes objects seen under optimal viewing conditions, the categorization of objects seen under impoverished viewing conditions not only requires more time but may also depend more on top-down processing, as hypothesized by object model verification theory. Two studies, one with functional magnetic resonance imaging (fMRI) and one behavioral with the same stimuli, tested this hypothesis. FMRI data were acquired while people categorized more impoverished (MI) and less impoverished (LI) line drawings of objects. FMRI results revealed stronger activation during the MI than LI condition in brain regions involved in top-down control (inferior and medial prefrontal cortex, intraparietal sulcus), and in posterior, object-sensitive brain regions (ventral and dorsal occipitotemporal, and occipitoparietal cortex). The behavioral study indicated that taxing visuospatial working memory, a key component of topdown control processes during visual tasks, interferes more with the categorization of MI stimuli (but not LI stimuli) than does taxing verbal working memory. Together, these findings provide evidence for object model verification theory and implicate greater prefrontal cortex involvement in top-down control of posterior visual processes during the categorization of more impoverished images of objects.
European Journal of Cognitive Psychology, 2004
The present study was designed to discover whether variations in normalised regional cerebral blo... more The present study was designed to discover whether variations in normalised regional cerebral blood flow (rCBF) in different brain areas predict variations in performance of different imagery tasks. Positron emission tomography (PET) was used to assess brain activity as 16 participants performed four imagery tasks. These tasks were designed so that performance was particularly sensitive to the participant's ability to form images with high resolution, to generate images from distinct segments, to parse imaged forms into parts while inspecting them, or to transform (rotate) images. Response times and error rates were recorded. Multiple regression Correspondence should be addressed to S. M. Kosslyn, Harvard Univ. Psychology
Developmental Psychology, 1975
... The evidence of this study instead shows that low-specificity properties of nouns are retriev... more ... The evidence of this study instead shows that low-specificity properties of nouns are retrieved more quickly than high-specificity properties (eg, a lion's mane) when strength of direct as-sociation between nouns and properties is controlled.1 Previous studies on specificity ...
Memory & Cognition, 2008
The research reported in the present article investigates whether information is represented the ... more The research reported in the present article investigates whether information is represented the same way in both visual mental imagery and the early phases of visual perception. In Experiment 1, the same participants scanned over patterns of dots in a mental image (with images based on a just-seen pattern), during perception, and in an iconic image. The time to scan increasing distances increased at comparable rates in the three tasks. However, in Experiment 2, when mental images were created from information stored in long-term memory, participants scanned more slowly in the mental image condition. Nevertheless, the rates of scanning in the perceptual tasks were highly correlated with the rates of scanning in the imagery tasks in both experiments. The results provide evidence that mental images and perceived stimuli are represented similarly and can be processed in the same way.
Journal of Experimental Psychology-human Perception and Performance, 1995
Cognition, 2002
The debate about whether objects in mental images can be ambiguous has produced ambiguous results... more The debate about whether objects in mental images can be ambiguous has produced ambiguous results. In some studies, participants could not reinterpret objects in images, but even in the studies where participants could reinterpret visualized patterns, the results are not conclusive. The present study used a novel task to investigate the reinterpretation of ambiguous figures in imagery, which required the participants to mentally rotate a figure 180 degrees before attempting to "see" an alternate interpretation. In addition, the participants did not know the purpose of the study in advance, nor did they see alternate interpretations of the stimuli; moreover, we explicitly measured individual differences in key mental imagery abilities. Eight of the 44 participants discovered the alternate version while they were memorizing the figure; 16 reported it after mentally rotating an image; and 20 were not able to "see" the alternate version. The ability to rotate images, assessed with an independent task, was highly associated with reports of image reversals, whereas measures of other imagery abilities were not. q
Cognitive Brain Research, 2003
We recorded the paths of subjects who walked along a memorized hexagonal route without vision, an... more We recorded the paths of subjects who walked along a memorized hexagonal route without vision, and studied the impact of previous mental simulation of this activity on how well the path could be reproduced from memory. We compared two kinds of mental simulation to actual physical practice, rest, or simple memorization of the path. The results indicated that mental simulation led to better reproduction of the global shape of a path than rest, and in fact mental simulation was as effective as actual physical practice. However, this result occurred only for ‘simple shapes’ when the lengths of the sides of the path were kept constant. Nevertheless, this level of performance was not reached when the complexity of the shape was increased by altering the lengths of sides, even when keeping constant the angles between consecutive sides. This finding indicates that the internal representation of space depends on geometric properties of the environment in which the subjects operate. Mental simulation appears to affect both a map-like and route-like representation of the environment.
Experimental Aging Research, 1998
T wenty-four young (mean age 21.8 years) and 24 old (mean age 65.2 years) participants were asked... more T wenty-four young (mean age 21.8 years) and 24 old (mean age 65.2 years) participants were asked to determine whether spoken words correctly named pictures of objects. Half of the objects were portrayed from noncanonical (unusual) viewpoints, and half were portrayed from canonical viewpoints. T he older participants required more time and made more errors when they evaluated the noncanonical pictures (relative to the canonical pictures) than the younger participants. T his nding is consistent with previous evidence that frontal lobe function degrades with aging and with results from a positron emission tomography study (S. M. that showed that the frontal lobes (among other areas) are activated more in the noncanonical condition than in the canonical condition.
Cognitive Science, 1999
simulation models of spatial relations encoding in part because the absolute position of a stimul... more simulation models of spatial relations encoding in part because the absolute position of a stimulus in the input array was correlated with its spatial relation to a landmark; thus, on at least some trials, the networks did not need to compute spatial relations. The network models reported here include larger input arrays, which allow stimuli to appear in a large range of locations with an equal probability of being above or below a "bar," thus eliminating the confound present in earlier models, The results confirm the original hypothesis that as the size of the network's receptive fields increases, performance on a coordinate spatial relations task (which requires computing precise, metric distance) will be relatively better than on a categorical spatial relations task (which requires computing above/below relative to a landmark). 33 34 BAKER, CHABRIS, AND KOSSLYN 1995). This article presents new simulation results in response to perhaps the most fundamental issue, whether our previous simulations actually provide evidence that the size of receptive fields selectively influences one type of spatial relations encoding. This is important because the issue centers on whether there actually is more than one way to encode spatial information, and selective effects in the simulation models are one source of evidence for this distinction. postulated the existence of two distinct subsystems within the visual-spatial processing pathway (the dorsal system described by . One subsystem encodes caregorical spatial relations, which describe the location, orientation, or other spatial characteristics of one object relative to another in terms of a broad equivalence class (e.g., A is above/or below B). The other subsystem encodes coordinate spatial relations, which specify an object's spatial attributes with respect to another object in terms of precise metric coordinates (see . Categorical spatial relations are useful for recognizing and identifying natural objects that can be seen in many distinct configurations, because categorical spatial relations tend to remain constant under natural flexion and movement: although an arm can be in many specific places relative to the trunk of a body, it is always attached, and this information helps one to distinguish human bodies from other objects. As such, categorical relations tend not to discriminate finely on the basis of metric spatial location but are instead defined on somewhat broad regions of space; for example, there are many distinct spatial locations above a given object. In contrast, knowing that someone's hand is attached to her arm is not enough to be able to shake it; you need to know exactly where in space to direct your hand. Coordinate spatial relations need to refer to specific spatial locations and distances, and thus do not group different points in space into one equivalence class. reviewed neuropsychological and behavioral data suggesting that the left hemisphere is specialized to encode categorical spatial relations more readily than the right, but that the right hemisphere is specialized to encode coordinate spatial relations more readily than the left-although each hemisphere is able to process both kinds of information. He proposed that a small initial imbalance in the processing characteristics of the two hemispheres' computational systems, perhaps related to innate left-hemisphere competence for language and right-hemisphere superiority in mapping space, may cause a "snowball effect" of increasing divergence of neural systems during development, leading ultimately to the dissociation between these two types of spatial relations encoding (for a simulation, see . further refined this thesis, suggesting that categorical and coordinate spatial relations processing may occur differentially in the two hemispheres because the two kinds of computations are incompatible: in order to compute the categorical relations among visual objects, the visual system needs to ignore precise spatial information, whereas exactly that information is required for coordinate spatial relations computation.
Neuroimage, 2001
Some, but not all, previous neuroimaging studies of visual mental imagery have found that Area 17... more Some, but not all, previous neuroimaging studies of visual mental imagery have found that Area 17 (primary visual cortex) is activated when people visualize objects. The present study was designed to test the hypothesis that the necessary degree of resolution of the mental image is a determining factor in whether Area 17 is activated during imagery. Eight male subjects visualized and compared sets of stripes that required high or low resolution to resolve, while their brains were scanned using 15 O CO2 positron emission tomography (PET). When imagery in general (visualization of high-and low-resolution gratings stimuli combined) was compared to an auditory baseline condition where subjects did not visualize, Area 17 was activated. However, region of interest (ROI) and statistical parametric mapping (SPM) analyses revealed no difference between imagery conditions using highand low-resolution stimuli. These results indicate that the resolution of the stimuli alone does not necessarily determine whether Area 17 will be activated during visual mental imagery.
Cognitive Brain Research, 2003
We investigated the role of body position on performance in four distinct types of mental imagery... more We investigated the role of body position on performance in four distinct types of mental imagery processing. Previous studies used the upright body position as standard procedure and therefore do not address the issue of whether mental imagery tasks are processed in accordance with ego-centered or gravitational coordinates. In the present study, the subjects were brought into one of three different body positions: upright, horizontal, or supine. In each of these body positions, we measured performance in four imagery tasks, which assessed (1) the ability to generate vivid, high-resolution mental images; (2) the ability to compose mental images from separate parts; (3) the ability to inspect patterns in mental images; and, (4) the ability to mentally rotate patterns in images. Not all processes were affected in the same way when subjects performed them in different body positions. Performance in the image composition and detection tasks depended on body position, whereas there was no such effect for the transformation and resolution tasks.
Journal of Psychosomatic Research, 1999
Problematic health concerns characteristic of hypochondriasis may be better understood with the a... more Problematic health concerns characteristic of hypochondriasis may be better understood with the aid of cognitive, information processing theories. We investigated whether hypochondriacal individuals show perceptual and explicit memory biases favoring health-related information. A clinical sample of hypochondriacs (nϭ18) and healthy controls (nϭ22), and a sample of hypochondriacal (nϭ22) and nonhypochondriacal (nϭ67) patients referred for Holter monitoring, completed a computerized test of perceiving difficult-to-read words and then an encoding task followed by recall of those words. Contrary to our prediction, hypochondriacal individuals in the clinical sample did not perceive more healthrelated words than words not related to health. Hypochondriacal individuals in the Holter-monitoring sample showed an unexpected bias against reporting health-related words. Social class may account for some of the group differences in this sample. Hypochondriacal individuals in both samples showed better memory for health-related than nonhealth words.
Neuropsychologia, 1994
A patient with unilateral visual neglect indicated whether a dot was or was not present in a disp... more A patient with unilateral visual neglect indicated whether a dot was or was not present in a display. When present, the dot appeared equally often in the left and right visual fields. Although he typically denied having seen dots in his left visual field, he was able to make this judgement much more quickly than when no dot was in fact present. The mean response times when the dot was present (1135 and 1004 msec, for left and right) were almost twice as fast as the response times when no dot was present (2025 msec). This result suggests that the patient searched the visual fields individually, and in fact generated a “No” response based on detecting the dot in his neglected field. Thus, the mechanisms used to detect stimuli apparently are not rigidly linked to those used to classify them or to produce a response.
Cognitive Psychology, 1977
This paper has four major sections: First, we review the basic arguments offered by Pylyshyn (Psy... more This paper has four major sections: First, we review the basic arguments offered by Pylyshyn (Psychological Bulletin, 1973, 80, 1–24) and others against using imagery as an explanatory construct in psychology. Second, we consider each of these points and find none that speak against any but the most primitive notions of imagery. Third, we review the results of various experiments on imagery. In each case, we compare two explanations of the findings: one which assumes the existence of a surface image manifesting emergent properties, and one which assumes that all internal representations are coded in terms of “abstract propositions.” We find imagery hypotheses to be at least as adequate as those based on propositional representation. Finally, we conclude that debate about the ultimate foundations of internal representation is fruitless; the empirical question is whether images have properties that cannot be derived directly from more abstract propositional structures.
International Journal of Eating Disorders, 2001
ObjectiveThis study tested the hypothesis that women with anorexia nervosa (AN) have an inappropr... more ObjectiveThis study tested the hypothesis that women with anorexia nervosa (AN) have an inappropriately fatter body image in the left cerebral hemisphere (LH) than in the right cerebral hemisphere (RH).This study tested the hypothesis that women with anorexia nervosa (AN) have an inappropriately fatter body image in the left cerebral hemisphere (LH) than in the right cerebral hemisphere (RH).MethodWomen with AN symptomatology were compared with thin controls in a divided visual field experiment. Distorted and undistorted pictures of their own and someone else's body were flashed briefly in the left and right visual fields. Participants judged the pictures as thinner than, equal to, or fatter than the actual body size.Women with AN symptomatology were compared with thin controls in a divided visual field experiment. Distorted and undistorted pictures of their own and someone else's body were flashed briefly in the left and right visual fields. Participants judged the pictures as thinner than, equal to, or fatter than the actual body size.ResultsThe AN participants judged a higher proportion of fatter distortions as equal to their own size. They responded faster when stimuli were presented initially to the LH than when they were presented initially to the RH. In contrast, fewer thinner distortions were judged as equal to their own body size, and were judged more slowly, on LH trials than on RH trials. Controls did not show hemispheric differences when judging their own body and AN participants did not show hemispheric differences when judging pictures of somebody else. Additional analyses revealed that these findings were carried entirely by a subgroup who had AN in the past, not by the subgroup who currently had AN.The AN participants judged a higher proportion of fatter distortions as equal to their own size. They responded faster when stimuli were presented initially to the LH than when they were presented initially to the RH. In contrast, fewer thinner distortions were judged as equal to their own body size, and were judged more slowly, on LH trials than on RH trials. Controls did not show hemispheric differences when judging their own body and AN participants did not show hemispheric differences when judging pictures of somebody else. Additional analyses revealed that these findings were carried entirely by a subgroup who had AN in the past, not by the subgroup who currently had AN.DiscussionThe brain lateralization paradigm may prove useful in understanding body image disturbance in AN patients. © 2001 by John Wiley & Sons, Inc. Int J Eat Disord 29: 409–416, 2001.The brain lateralization paradigm may prove useful in understanding body image disturbance in AN patients. © 2001 by John Wiley & Sons, Inc. Int J Eat Disord 29: 409–416, 2001.
Applied Cognitive Psychology, 2003
Early in a scientific debate, before much evidence has accumulated, why are some scientists incli... more Early in a scientific debate, before much evidence has accumulated, why are some scientists inclined toward one position and other scientists toward the opposite position? We explore this issue with a focus on scientists' views of the 'imagery debate' that unfolded in Cognitive Science during the late 1970s and early 1980s. We examine the possibility that, during the early years of this debate, researchers' views were shaped by their own conscious experiences with imagery. Consistent with this suggestion, a survey of 150 psychologists, philosophers, and neuroscientists showed that those who experienced their own visual imagery as vivid and picture-like recall being more sympathetic in 1980 to the view that, in general, images are picture-like. Similarly, those who have vivid images and who regularly use their images in cognition were more inclined to believe that issues of image vividness deserve more research.
Uploads
Papers by Stephen Kosslyn