Since the seminal work of Heider and Simmel, and Michotte’s research, many studies have shown tha... more Since the seminal work of Heider and Simmel, and Michotte’s research, many studies have shown that, under appropriate conditions, displays of simple geometric shapes elicit rich and vivid impressions of animacy and intentionality. The main purpose of this review is to emphasize the close relationship between kinematics and perceived animacy by showing which specific motion cues and spatiotemporal patterns automatically trigger visual perceptions of animacy and intentionality. The animacy phenomenon has been demonstrated to be rather fast, automatic, irresistible, and highly stimulus-driven. Moreover, there is growing evidence that animacy attributions, although usually associated with higher-level cognition and long-term memory, may reflect highly specialized visual processes that have evolved to support adaptive behaviors critical for survival. The hypothesis of a life-detector hardwired in the perceptual system is also supported by recent studies in early development and animal co...
In the present study we broadly explored the perception of physical and animated motion in bounci... more In the present study we broadly explored the perception of physical and animated motion in bouncing-like scenarios through four experiments. In the first experiment, participants were asked to categorize bouncing-like displays as physical bounce, animated motion, or other. Several parameters of the animations were manipulated, that is, the simulated coefficient of restitution, the value of simulated gravitational acceleration, the motion pattern (uniform acceleration/deceleration or constant speed) and the number of bouncing cycles. In the second experiment, a variable delay at the moment of the collision between the bouncing object and the bouncing surface was introduced. Main results show that, although observers appear to have realistic representations of physical constraints like energy conservation and gravitational acceleration/deceleration, the amount of visual information available in the scene has a strong modulation effect on the extent to which they rely on these represen...
We ran a pilot experiment to explore, using a new psychophysical method, the hypothesis proposed ... more We ran a pilot experiment to explore, using a new psychophysical method, the hypothesis proposed by Zietz and Werner in the ’30s, that a sound presented simultaneously with an afterimage can change its phenomenal appearance in non-synaesthetes. The method we adopted is able to directly collect and visualise the apparent changes in intensity of the afterimages, by recording observers’ interactions with a physical feedback mechanism (the paths that the observers generated by moving a cursor), without referring to verbal descriptions. These first findings support some of the most meaningful observations reported by Werner (1934) and Zietz (1931), according to which the colours of the afterimages ‘disintegrate’ at the hearing of a low sound and ‘concentrate’ for a high sound. This relationship is particularly evident with the Yellow stimulus, where the perceived colour intensity of its afterimage seems to have a faster negative change with a low-pitched tone sound, and an increase in in...
Causal relation between two movements is evident in the launching paradigm [Michotte, 1946/1963 T... more Causal relation between two movements is evident in the launching paradigm [Michotte, 1946/1963 The Perception of Causality (London: Methuen)], in which the first moving object (S1) appears to cause the motion of the second object (S2). The causal relation requires a short delay between S1 and S2 (40 ms, launching) and fades when it is long (1040 ms, non-launching). We recently showed that in the launching condition the speed of S2 is overestimated by 34% with respect to the non-launching condition (Parovel and Casco Vision Research submitted). Here, we demon- strated the general properties of the spatio-temporal integration mechanism underlying speed overestimation in the causality phenomenon. We manipulated the trajectory-to-trajectory alignment [4 experiments], the spatio-temporal coincidence between S1 and S2 [3 experiments], the duration of the whole event [1 experiment], and the speed ratio [2 experiments]. A two-interval forced-choice task was used to measure the point of sub...
According to Werner's hypothesis (Zietz and Werner, 1928 Zeitschrift fÏr Psychologie 105 226 ... more According to Werner's hypothesis (Zietz and Werner, 1928 Zeitschrift fÏr Psychologie 105 226 ^ 249), the phenomenal concomitance of two dynamic events (visual and auditory) gives rise to an intermodal unitary event. Zietz and Werner showed that a hardly noticeable apparent movement of a visual stimulus became more evident when a sound event was presented simulta- neously. Other authors, for example Staal and Donderi (1983 American Journal of Psychology 1 95 ^ 105), did not always obtain the same results. The purpose of the present work was to investigate the effect of different sounds on a visual bistable event: two different apparent movements can be seen inside a black frame: a `phi' move- ment, ie a small square moving from left to the right, or a `gamma' polarised movement, ie an expansion of the small square toward the centre of the frame from both sides in succession. I used (i) continuous, (ii) increasing and (iii) decreasing in frequency sounds, and (iv) two shor...
When a side of a regular geometrical figure is interrupted, an illusory effect of irregularity ca... more When a side of a regular geometrical figure is interrupted, an illusory effect of irregularity can be perceived. The aim of our two experiments was to establish the influence of a spatial gap and of shrinkage by amodal completion on the perceived regularity of triangles. In the first experiment, we used an equilateral triangle with a gap in the base. The length of the sides was 8 deg. We manipulated the length (2, 2.5, 3 deg) and the position (0.6, 1.2, 1.8 deg from the base angles) of the gap. The adjustment method was adopted: ten subjects varied the horizontal position of the top angle until they perceived the shape to be regular. The results demonstrate that length and position of the gap influence the strength of the illusion. In the second experi- ment, we used, instead of a gap, an opaque rectangle. By amodal completion the base of the equilateral triangle was perceived to be complete. The results do not show a significant distortion of the triangle. A possible explanation is...
In launching and triggering effects [Michotte, 1946 La Perception de la Causalite¨ (Louvain: Publ... more In launching and triggering effects [Michotte, 1946 La Perception de la Causalite¨ (Louvain: Publi- cations Universitaires)] object A moves towards object B and, when the two objects make contact, B starts to move. Phenomenally, the movement of A appears to cause the movement of B: either mechanically, in launching, or psychologically, in triggering. Perceived kinetics of these events have been explored in four experiments. We measured P50, the point of subjective equality between experimental stimulus and standard stimulus, of the perceived velocity of B. We found that P50 in control condition, obtained on adding a pause before the motion of B (P50 = -0.005 deg s-1 ), is different from P50 of experimental conditions: in launching (i) the P50 is 0.56 deg s-1; in triggering (ii) the P50 is 0.42 deg s-1. Moreover, in launching para- digm, P50 is also affected by kinetic variations of the objects before and after the collision, related to the impression of `force' of the impact. In...
The distinction cause/effect is often linked to the distinction before/after [Michotte, 1946 La P... more The distinction cause/effect is often linked to the distinction before/after [Michotte, 1946 La Perception de la Causalite ̈ (Louvain: Institut Supe ̈ rieur de Philosophie)]. We run two experi- ments referring to Michotte's launch-effect paradigm, to test the hypothesis that it is possible to perceive a relationship of causation when (I) the second member B of the succession disappears before being touched by the first member A (from 450 ms of anticipation to 366 ms of delay), and when (II), given the simultaneity of the stopping of A and the vanishing of B, B is not in contact with A (from 1 to 70 mm) and it is in different spatial positions. Experimental results show that the perception of causation persists even (i) if B disappears 170 ms before A ceases its motion, and (ii) if the distance between the two squares is about 6 mm. The position of B is not relevant. The conclusions are: (1) an event can be perceived as an effect even when it occurs before the first event, perceived as the cause, finishes; (2) since the event effect is not a motion, there is no room for the Michotte's theory (about perception of causality) of amplification of the movement
In the launch effect studied by Michotte [1963 The Perception of Causality (London: Methuen)] the... more In the launch effect studied by Michotte [1963 The Perception of Causality (London: Methuen)] the radius of action is a critical aspect in the perception of causality: after the contact, the second moving object, from a certain distance on, seems to move autonomously. According to Yela (1952 Quarterly Journal of Experimental Psychology 4 139^154) the radius of action is a function of the time. In the present research, we tested this hypothesis. The experimental para- digm of Michotte (1963) was used. In the experiment, the velocity of the second moving object (50, 75, 100 mm s-1) was varied. Two values (0 ms, 30 ms) of the time interval between the moment of contact of the first object and the moment when the latter begins to move were adopted. Observers indicated where the second moving object lost its passivity and started to move autonomously. The results show that the time duration of the radius of action increases with the velocity of the second moving object, whereas the time interval after the contact is not a significant factor. Our findings suggest that the radius of action is a function of the kinetic properties of the event
Oltre alla forma, al movimento e al colore degli oggetti, le cosiddette qualità ‘primarie’ e ‘sec... more Oltre alla forma, al movimento e al colore degli oggetti, le cosiddette qualità ‘primarie’ e ‘secondarie’, percepiamo anche qualità più sottili di natura sovrasensoriale o psicologico-emozionale, di carattere paradossale: l'arancione di un tulipano è 'gioioso', una voce ‘ruvida’, e un semplice quadratino sullo schermo può saltellare animato come un essere vivente. Questo saggio è una sintesi delle principali teorie e esperimenti realizzati in psicologia della percezione sulle 'qualità espressive', dette anche 'qualità terziarie' o 'qualità fisiognomiche'. Per quanto eterogenee, le ricerche descritte condividono l’obiettivo di esplorare sperimentalmente i parametri percettivi degli oggetti espressivi
It is widely accepted that the relative height of objects is an important cue of depth perception... more It is widely accepted that the relative height of objects is an important cue of depth perception in pictorial displays. However, this phenomenon has never been investigated experimentally. The present study was designed to systematically test the elevation cue in various pictorial contexts. An experiment was conducted to examine the role of relative elevation of two identical 1.43 deg*1.43 deg squares presented with different orientations to one another (at 45deg and 225deg) and at different separations from one another (1.43 deg and 2.86 deg) in the perception of depth. In addition, the two squares were presented at seven different heights, on the left and on the right of the monitor and within different pictorial contexts (eg a gradient on the floor only; gradients on the floor limited by a wall at a distance; gradients both on the floor and ceiling limited by a wall at a distance; and a single line of the horizon), together with a control con- dition without any background structure. As expected, the results show floor gradient effects in the perception of depth as a function of relative elevation. In addition, the wall and the ceiling gradient significantly change this effect. The depth effect is inverted, with squares in higher positions being perceived closer
In Michotte's paradigm an object A moves toward, and makes contact with, another object B, wh... more In Michotte's paradigm an object A moves toward, and makes contact with, another object B, which then moves away. If B’s motion is faster than A’s, and starts before the arrival of A, B is perceived to intentionally escape from A. Many studies show an association between speed and animacy, in that objects moving faster are judged as more animated. In our study, conversely, we explored how much a square looks faster when intentionally escaping from another square. We used the method of constant stimuli to measure the speed overestimation of the escaping object in comparison to different levels of speed of a single moving object. We also varied the behaviour of the chasing object, allowing it to move either in a linear or in a caterpillar-like way. Paired comparisons data were analysed using generalized linear mixed-effects models to estimate the PSE in the different conditions. We found a significant overestimation of the escaping object in the fast speed condition, both in the caterpillar-like motion and in the linear motion. These results suggest an interesting connection between specific emotional qualities of motion and its apparent speed, supporting the hypothesis that social causality and animacy are deeply rooted in visual processing
Experimental Phenomenology can boast an ample repertoire of discoveries, that is facts which not ... more Experimental Phenomenology can boast an ample repertoire of discoveries, that is facts which not only represent a foundation of incontrovertible empirical knowledge, but also the explanandum on which other scientific disciplines can model new hypotheses in the abstract. Nevertheless, there is still an ambivalent attitude both of deference and diffidence towards Experimental Phenomenology. This attitude is the consequence of at least two factors: on the one hand a mixture of prejudices and misunderstandings and, on the other, a failing of the discipline itself: the lack of a theory
A chromatically homogeneous surface is not always perceived as a single figure. It can sometimes ... more A chromatically homogeneous surface is not always perceived as a single figure. It can sometimes be perceived as the result of superimposing two or more figures; in such a case illusory contours are seen bounding the figure in the foreground (Petter, 1956 Rivista di Psicologia 50 213^227). Local factors, such as relatability, have been proposed in order to explain perception of two or more figures (Kellman and Shipley, 1991 Cognitive Psychology 23 141 ^ 221). However, even when these factors are at work, there are conditions favouring the perception of a single figure which have not been explored so far. Here we propose that one such condition is the mirror symmetry of the surface. We have run three experiments in order to study several aspects of the problem. The main results show that: (a) mirror symmetry enhances perception of a single figure; (b) effectiveness of symmetry increases with the number of axes of symmetry; (c) vertical and horizontal axes are more effective than a 458-oriented axis. We conclude that the global factor of mirror symmetry plays an important role in the perception of chromatically homogeneous surfaces, along with local factors, such as relatability and, more generally, good continuation
Since the seminal work of Heider and Simmel, and Michotte’s research, many studies have shown tha... more Since the seminal work of Heider and Simmel, and Michotte’s research, many studies have shown that, under appropriate conditions, displays of simple geometric shapes elicit rich and vivid impressions of animacy and intentionality. The main purpose of this review is to emphasize the close relationship between kinematics and perceived animacy by showing which specific motion cues and spatiotemporal patterns automatically trigger visual perceptions of animacy and intentionality. The animacy phenomenon has been demonstrated to be rather fast, automatic, irresistible, and highly stimulus-driven. Moreover, there is growing evidence that animacy attributions, although usually associated with higher-level cognition and long-term memory, may reflect highly specialized visual processes that have evolved to support adaptive behaviors critical for survival. The hypothesis of a life-detector hardwired in the perceptual system is also supported by recent studies in early development and animal co...
In the present study we broadly explored the perception of physical and animated motion in bounci... more In the present study we broadly explored the perception of physical and animated motion in bouncing-like scenarios through four experiments. In the first experiment, participants were asked to categorize bouncing-like displays as physical bounce, animated motion, or other. Several parameters of the animations were manipulated, that is, the simulated coefficient of restitution, the value of simulated gravitational acceleration, the motion pattern (uniform acceleration/deceleration or constant speed) and the number of bouncing cycles. In the second experiment, a variable delay at the moment of the collision between the bouncing object and the bouncing surface was introduced. Main results show that, although observers appear to have realistic representations of physical constraints like energy conservation and gravitational acceleration/deceleration, the amount of visual information available in the scene has a strong modulation effect on the extent to which they rely on these represen...
We ran a pilot experiment to explore, using a new psychophysical method, the hypothesis proposed ... more We ran a pilot experiment to explore, using a new psychophysical method, the hypothesis proposed by Zietz and Werner in the ’30s, that a sound presented simultaneously with an afterimage can change its phenomenal appearance in non-synaesthetes. The method we adopted is able to directly collect and visualise the apparent changes in intensity of the afterimages, by recording observers’ interactions with a physical feedback mechanism (the paths that the observers generated by moving a cursor), without referring to verbal descriptions. These first findings support some of the most meaningful observations reported by Werner (1934) and Zietz (1931), according to which the colours of the afterimages ‘disintegrate’ at the hearing of a low sound and ‘concentrate’ for a high sound. This relationship is particularly evident with the Yellow stimulus, where the perceived colour intensity of its afterimage seems to have a faster negative change with a low-pitched tone sound, and an increase in in...
Causal relation between two movements is evident in the launching paradigm [Michotte, 1946/1963 T... more Causal relation between two movements is evident in the launching paradigm [Michotte, 1946/1963 The Perception of Causality (London: Methuen)], in which the first moving object (S1) appears to cause the motion of the second object (S2). The causal relation requires a short delay between S1 and S2 (40 ms, launching) and fades when it is long (1040 ms, non-launching). We recently showed that in the launching condition the speed of S2 is overestimated by 34% with respect to the non-launching condition (Parovel and Casco Vision Research submitted). Here, we demon- strated the general properties of the spatio-temporal integration mechanism underlying speed overestimation in the causality phenomenon. We manipulated the trajectory-to-trajectory alignment [4 experiments], the spatio-temporal coincidence between S1 and S2 [3 experiments], the duration of the whole event [1 experiment], and the speed ratio [2 experiments]. A two-interval forced-choice task was used to measure the point of sub...
According to Werner's hypothesis (Zietz and Werner, 1928 Zeitschrift fÏr Psychologie 105 226 ... more According to Werner's hypothesis (Zietz and Werner, 1928 Zeitschrift fÏr Psychologie 105 226 ^ 249), the phenomenal concomitance of two dynamic events (visual and auditory) gives rise to an intermodal unitary event. Zietz and Werner showed that a hardly noticeable apparent movement of a visual stimulus became more evident when a sound event was presented simulta- neously. Other authors, for example Staal and Donderi (1983 American Journal of Psychology 1 95 ^ 105), did not always obtain the same results. The purpose of the present work was to investigate the effect of different sounds on a visual bistable event: two different apparent movements can be seen inside a black frame: a `phi' move- ment, ie a small square moving from left to the right, or a `gamma' polarised movement, ie an expansion of the small square toward the centre of the frame from both sides in succession. I used (i) continuous, (ii) increasing and (iii) decreasing in frequency sounds, and (iv) two shor...
When a side of a regular geometrical figure is interrupted, an illusory effect of irregularity ca... more When a side of a regular geometrical figure is interrupted, an illusory effect of irregularity can be perceived. The aim of our two experiments was to establish the influence of a spatial gap and of shrinkage by amodal completion on the perceived regularity of triangles. In the first experiment, we used an equilateral triangle with a gap in the base. The length of the sides was 8 deg. We manipulated the length (2, 2.5, 3 deg) and the position (0.6, 1.2, 1.8 deg from the base angles) of the gap. The adjustment method was adopted: ten subjects varied the horizontal position of the top angle until they perceived the shape to be regular. The results demonstrate that length and position of the gap influence the strength of the illusion. In the second experi- ment, we used, instead of a gap, an opaque rectangle. By amodal completion the base of the equilateral triangle was perceived to be complete. The results do not show a significant distortion of the triangle. A possible explanation is...
In launching and triggering effects [Michotte, 1946 La Perception de la Causalite¨ (Louvain: Publ... more In launching and triggering effects [Michotte, 1946 La Perception de la Causalite¨ (Louvain: Publi- cations Universitaires)] object A moves towards object B and, when the two objects make contact, B starts to move. Phenomenally, the movement of A appears to cause the movement of B: either mechanically, in launching, or psychologically, in triggering. Perceived kinetics of these events have been explored in four experiments. We measured P50, the point of subjective equality between experimental stimulus and standard stimulus, of the perceived velocity of B. We found that P50 in control condition, obtained on adding a pause before the motion of B (P50 = -0.005 deg s-1 ), is different from P50 of experimental conditions: in launching (i) the P50 is 0.56 deg s-1; in triggering (ii) the P50 is 0.42 deg s-1. Moreover, in launching para- digm, P50 is also affected by kinetic variations of the objects before and after the collision, related to the impression of `force' of the impact. In...
The distinction cause/effect is often linked to the distinction before/after [Michotte, 1946 La P... more The distinction cause/effect is often linked to the distinction before/after [Michotte, 1946 La Perception de la Causalite ̈ (Louvain: Institut Supe ̈ rieur de Philosophie)]. We run two experi- ments referring to Michotte's launch-effect paradigm, to test the hypothesis that it is possible to perceive a relationship of causation when (I) the second member B of the succession disappears before being touched by the first member A (from 450 ms of anticipation to 366 ms of delay), and when (II), given the simultaneity of the stopping of A and the vanishing of B, B is not in contact with A (from 1 to 70 mm) and it is in different spatial positions. Experimental results show that the perception of causation persists even (i) if B disappears 170 ms before A ceases its motion, and (ii) if the distance between the two squares is about 6 mm. The position of B is not relevant. The conclusions are: (1) an event can be perceived as an effect even when it occurs before the first event, perceived as the cause, finishes; (2) since the event effect is not a motion, there is no room for the Michotte's theory (about perception of causality) of amplification of the movement
In the launch effect studied by Michotte [1963 The Perception of Causality (London: Methuen)] the... more In the launch effect studied by Michotte [1963 The Perception of Causality (London: Methuen)] the radius of action is a critical aspect in the perception of causality: after the contact, the second moving object, from a certain distance on, seems to move autonomously. According to Yela (1952 Quarterly Journal of Experimental Psychology 4 139^154) the radius of action is a function of the time. In the present research, we tested this hypothesis. The experimental para- digm of Michotte (1963) was used. In the experiment, the velocity of the second moving object (50, 75, 100 mm s-1) was varied. Two values (0 ms, 30 ms) of the time interval between the moment of contact of the first object and the moment when the latter begins to move were adopted. Observers indicated where the second moving object lost its passivity and started to move autonomously. The results show that the time duration of the radius of action increases with the velocity of the second moving object, whereas the time interval after the contact is not a significant factor. Our findings suggest that the radius of action is a function of the kinetic properties of the event
Oltre alla forma, al movimento e al colore degli oggetti, le cosiddette qualità ‘primarie’ e ‘sec... more Oltre alla forma, al movimento e al colore degli oggetti, le cosiddette qualità ‘primarie’ e ‘secondarie’, percepiamo anche qualità più sottili di natura sovrasensoriale o psicologico-emozionale, di carattere paradossale: l'arancione di un tulipano è 'gioioso', una voce ‘ruvida’, e un semplice quadratino sullo schermo può saltellare animato come un essere vivente. Questo saggio è una sintesi delle principali teorie e esperimenti realizzati in psicologia della percezione sulle 'qualità espressive', dette anche 'qualità terziarie' o 'qualità fisiognomiche'. Per quanto eterogenee, le ricerche descritte condividono l’obiettivo di esplorare sperimentalmente i parametri percettivi degli oggetti espressivi
It is widely accepted that the relative height of objects is an important cue of depth perception... more It is widely accepted that the relative height of objects is an important cue of depth perception in pictorial displays. However, this phenomenon has never been investigated experimentally. The present study was designed to systematically test the elevation cue in various pictorial contexts. An experiment was conducted to examine the role of relative elevation of two identical 1.43 deg*1.43 deg squares presented with different orientations to one another (at 45deg and 225deg) and at different separations from one another (1.43 deg and 2.86 deg) in the perception of depth. In addition, the two squares were presented at seven different heights, on the left and on the right of the monitor and within different pictorial contexts (eg a gradient on the floor only; gradients on the floor limited by a wall at a distance; gradients both on the floor and ceiling limited by a wall at a distance; and a single line of the horizon), together with a control con- dition without any background structure. As expected, the results show floor gradient effects in the perception of depth as a function of relative elevation. In addition, the wall and the ceiling gradient significantly change this effect. The depth effect is inverted, with squares in higher positions being perceived closer
In Michotte's paradigm an object A moves toward, and makes contact with, another object B, wh... more In Michotte's paradigm an object A moves toward, and makes contact with, another object B, which then moves away. If B’s motion is faster than A’s, and starts before the arrival of A, B is perceived to intentionally escape from A. Many studies show an association between speed and animacy, in that objects moving faster are judged as more animated. In our study, conversely, we explored how much a square looks faster when intentionally escaping from another square. We used the method of constant stimuli to measure the speed overestimation of the escaping object in comparison to different levels of speed of a single moving object. We also varied the behaviour of the chasing object, allowing it to move either in a linear or in a caterpillar-like way. Paired comparisons data were analysed using generalized linear mixed-effects models to estimate the PSE in the different conditions. We found a significant overestimation of the escaping object in the fast speed condition, both in the caterpillar-like motion and in the linear motion. These results suggest an interesting connection between specific emotional qualities of motion and its apparent speed, supporting the hypothesis that social causality and animacy are deeply rooted in visual processing
Experimental Phenomenology can boast an ample repertoire of discoveries, that is facts which not ... more Experimental Phenomenology can boast an ample repertoire of discoveries, that is facts which not only represent a foundation of incontrovertible empirical knowledge, but also the explanandum on which other scientific disciplines can model new hypotheses in the abstract. Nevertheless, there is still an ambivalent attitude both of deference and diffidence towards Experimental Phenomenology. This attitude is the consequence of at least two factors: on the one hand a mixture of prejudices and misunderstandings and, on the other, a failing of the discipline itself: the lack of a theory
A chromatically homogeneous surface is not always perceived as a single figure. It can sometimes ... more A chromatically homogeneous surface is not always perceived as a single figure. It can sometimes be perceived as the result of superimposing two or more figures; in such a case illusory contours are seen bounding the figure in the foreground (Petter, 1956 Rivista di Psicologia 50 213^227). Local factors, such as relatability, have been proposed in order to explain perception of two or more figures (Kellman and Shipley, 1991 Cognitive Psychology 23 141 ^ 221). However, even when these factors are at work, there are conditions favouring the perception of a single figure which have not been explored so far. Here we propose that one such condition is the mirror symmetry of the surface. We have run three experiments in order to study several aspects of the problem. The main results show that: (a) mirror symmetry enhances perception of a single figure; (b) effectiveness of symmetry increases with the number of axes of symmetry; (c) vertical and horizontal axes are more effective than a 458-oriented axis. We conclude that the global factor of mirror symmetry plays an important role in the perception of chromatically homogeneous surfaces, along with local factors, such as relatability and, more generally, good continuation
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