| 1. |
- von Hofsten, Claes, et al.
(författare)
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Predictive action in infancy : tracking and reaching for moving objects
- 1998
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Ingår i: Cognition. - : Elsevier. - 0010-0277 .- 1873-7838. ; 67:3, s. 255-285
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Tidskriftsartikel (refereegranskat)abstract
- Because action plans must anticipate the states of the world which will be obtained when the actions take place, effective actions depend on predictions. The present experiments begin to explore the principles underlying early-developing predictions of object motion, by focusing on 6-month-old infants' head tracking and reaching for moving objects. Infants were presented with an object that moved into reaching space on four trajectories: two linear trajectories that intersected at the center of a display and two trajectories containing a sudden turn at the point of intersection. In two studies, infants' tracking and reaching provided evidence for an extrapolation of the object motion on linear paths, in accord with the principle of inertia. This tendency was remarkably resistant to counter-evidence, for it was observed even after repeated presentations of an object that violated the principle of inertia by spontaneously stopping and then moving in a new direction. In contrast to the present findings, infants fail to extrapolate linear object motion in preferential looking experiments, suggesting that early-developing knowledge of object motion, like mature knowledge, is embedded in multiple systems of representation.
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| 2. |
- Jonsson, Bert, 1961-, et al.
(författare)
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Predictive head movements in 6-month old infants
- 1998
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Ingår i: Infant Behavior and Development. - : Elsevier. - 0163-6383 .- 1879-0453. ; 21:Supplement, s. 491-491
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Tidskriftsartikel (refereegranskat)abstract
- The purpose of this study was to investigate infant’s predictive head-tracking relatively to a linearly moving object. Object’s motion was produced by a large computer controlled plotter, tilted 15 degrees forward from vertical position. The objects moved on a white ainted aluminum sheet (98x 130 cm). Objects were presented in three different conditions. It was either visible all the time, occluded during part of its motion, or the room lights were extinguished during part of the object’s motion. Infant’s head movements were recorded by two infrared cameras and mixed onto a single video screen. Each infant was shown 6 initial and 6 final visible trials, and 6 times 2 occlusion trials in between, occlusion either by occluder or extinguished light. Sticky paper was placed on the infant’s head and by a touch-screen technology the markers were coded every 100 msec.
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| 3. |
- Munakata, Yuko, et al.
(författare)
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When it helps to occlude and obscure : 6-month-olds' predictive tracking of moving toys
- 1996
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Ingår i: Infant Behavior and Development. - 0163-6383 .- 1879-0453. ; 19:Suppl. 1, s. 639-639
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Tidskriftsartikel (refereegranskat)abstract
- What do infants know about hidden objects’? Previous research suggests that the answer depends on how the objects are hidden. For instance, infants appear to reach for toys in the dark (Clifton, Rochat, Litovsky, & Penis, 1991; Hood & Willatts, 1986) before they reach for toys occluded in the light. However, these experiments have not compared directly toys occluded in the light and by darkness. The current experiment tests infants under both conditions in the same paradigm. In addition, the experiment introduces a combined ccluderdarkness condition to test two distinct explanations for a possible advantage in the dark. First, infants may have knowledge about hidden objects but cannot act on it for occluder-specific reasons (e.g., means-ends deficits, beliefs about the whether the object is accessible). Second, infants may have graded representations of occluded objects that can be more easily maintained in the face of global darkness than with the direct visual interference of an occluder. Counterintuitive results from the current experiment provide evidence for both representational and occluder-specific effects.
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| 4. |
- Savelsbergh, Geert, et al.
(författare)
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The coupling of head, reach and grasp movement in ninemonths old infant prehension
- 1997
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Ingår i: Scandinavian Journal of Psychology. - Wiley : Wiley. - 0036-5564 .- 1467-9450. ; 38:4, s. 325-333
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Tidskriftsartikel (refereegranskat)abstract
- In 9-month-old-infants adjustments in the reaching pattern to sudden changes in object location were examined. An attractive ball was presented to the infants at their midline and on some trials (perturbation trials) the ball suddenly changed position 15 cm to the right or left during the reach. For the perturbed trials the movement times approximately doubled compared to the control trials and significantly fewer balls were grasped. The results indicate that infants need to finish the first movement before being able to redirect the reach to a new destination. The correlation between the latency of the head and hand adjustment to the perturbation were 0.85 and 0.78 for movements to the left and to the right, respectively, indicating a tight coupling. The time between the start of the perturbation and peak velocity(TPPV) was significantly shorter for the head movement than for the hand movement, indicating that the head is leading the hand.
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| 5. |
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| 6. |
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| 7. |
- Andersson, Patrik, et al.
(författare)
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Readability of vertically vibrating aircraft displays
- 1999
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Ingår i: Displays (Guildford). - 0141-9382 .- 1872-7387. ; 20:1, s. 23-30
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Tidskriftsartikel (refereegranskat)abstract
- Vibrations pose a problem to the visual system. The vibrations in aircraft are mainly vertical and cause reading errors when the pilots read the instruments. In three experiments, reading capability was tested during vertical vibration of modern military aircraft, using symbols presented on a computer monitor. The results showed that complexity of symbols have a significant effect on the performance. The orientations of symbols were also of importance for their readability. Indexes made up of horizontally oriented lines were found to be especially difficult to read during vertical vibration. Orienting them 45° up or down improved readability in a significant way. The size of the symbols was found to be of importance especially when they were horizontally oriented.
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| 8. |
- Lee, David N., et al.
(författare)
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Perception action approach to cerebral palsy
- 1997
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Ingår i: Neurophysiology and Psychology of Motor Development. - : Mac Keith Press. - 9781898683100 ; , s. 257-285
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Bokkapitel (refereegranskat)
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