Global form and motion processing in healthy ageing
Introduction
Biological motion can be defined as any movement pattern, produced by the body of a human or animal, and is an important visual cue that helps us to perceive the facial and body movements of others so that we can understand and predict their behaviour (e.g., Blake & Shiffrar, 2007). Successful decoding of biological motion information provides us with information about movement direction and intention but also about mental states, personality traits, and emotions (Bonda, E., et al., 1996, Dittrich, W. H., et al., 1996, Heberlein, A. S. and Saxe, R. R., 2005, Insch, P. M., et al., 2012). The ability to perceive biological motion is commonly tested using point-light animations, which were first introduced by Johansson (1973). Point-light animations consist of dots or light points that mimic or represent the joint movements of a moving person. By integrating the motion of those dots, it is possible to recognise a human figure. The perception of biological motion is very robust and from point-light animations it is possible to extract information about gender (Kozlowski, L. T. and Cutting, J. E., 1977, Pollick, F. E., et al., 2005), identity (Kozlowski, L. T. and Cutting, J. E., 1977, Loula, F., et al., 2005, Troje, N. F., et al., 2005), or emotions (Dittrich, W. H., et al., 1996, Roether, C. L., et al., 2008, Spencer et al., 2016), and to identify a wide range of different actions (Fig. 1; Vanrie & Verfaillie, 2004).
Interestingly, recent studies have shown that biological motion perception changes with age (Norman, J. F., et al., 2004, Billino, J., et al., 2008, Pilz, K.S., et al., 2010, Insch, P. M., et al., 2012 Legault, Troje & Faubert, 2012). It has been found that older adults have difficulties detecting point-light walkers in noise (Billino, J., et al., 2008, Pilz, K.S., et al., 2010), need more time to process biological motion than younger adults (Norman, J. F., et al., 2004, Pilz, K.S., et al., 2010) and have difficulties discriminating walkers from short distances (Legault et al., 2012). In a recent study, Pilz et al. (2010) suggested that older and younger adults use different kinds of information present in point-light animations. Point-light animations contain local motion information, the local motion trajectories of the single dots, and global form information, which is revealed when integrating the single dots into a global percept at each point in time. The global motion of the animated figure can be derived from the integration of the local motion trajectories of the single dots or by integrating the global form information over time (e.g., Giese and Poggio, 2003).
Pilz et al. (2010) investigated the contribution of form and motion information to age-related changes in biological motion processing by presenting three different kinds of upright and inverted point-light walkers: normal walkers that contained local motion, and global form information, random-position walkers that contained primarily global form information (adapted from Beintema & Lappe, 2002), and scrambled walkers that contained preserved local motion information, but disrupted global information (e.g. Bertenthal, B. I. and Pinto, J., 1994, Thornton, I. M., et al., 1998, Troje, N. F. and Westhoff, C., 2006). Participants had to discriminate the walking direction of the stimuli. Pilz et al. (2010) found that at longer stimulus durations older adults were as good as younger adults at discriminating the walking direction for upright normal and random-position walkers. Interestingly, older adults had difficulties discriminating the walking direction for inverted normal walkers, but at longer stimulus durations performed as well as younger adults for inverted random-position walkers. These results indicate that older adults are better at discriminating the motion direction for less familiar stimuli when local motion information is absent. Pilz et al. (2010) therefore suggested that older adults have difficulties integrating global form and local motion information as efficiently as younger adults. More recently, Insch et al. (2012) investigated the relationship between global form and biological motion processing by relating performance on a point-light action discrimination task with performance in a Navon type task (Navon, 1977). The Navon task is often used to investigate a visual preference for processing the global information contained within a stimulus, otherwise known as global precedence. Global precedence occurs when the global and local levels of a stimulus are incongruent, and the global stimulus interferes with processing the local stimulus to a greater degree, than the local stimulus interferes with processing the global stimulus (e.g. Insch, P. M., et al., 2012, Navon, D., 1977).
The original Navon task requires the identification of letters. Navon letters consist of many small letters (local stimuli) that are arranged to form a larger letter (global stimulus; Fig. 2). The global and local letters can be the same (consistent) or different (inconsistent). Participants are required to identify either the global or local letters. By relating performance in the Navon task and point-light action discrimination, Insch et al. (2012) found that, across all ages, the ability to decode emotions and actions from point-light displays was positively related to a global-processing bias, i.e., a preference for processing the global letters. More interestingly however, older adults exhibited a local processing bias in the Navon task, i.e., a preference for processing the local letters, which is in accordance with previous studies (Lux, S., et al., 2008, Oken, B. S., et al., 1999, Slavin, M. J., et al., 2002, Staudinger, M. R., et al., 2011). Overall, older adults performed worse on the biological motion task than younger adults. However, as shown by mediation analyses, age-differences in global to local processing did not entirely account for age-related changes in biological motion discrimination.
An age-related local processing bias as found by Insch et al. (2012) seems to be in contrast to the global form advantage for biological motion stimuli that was found by Pilz et al. (2010). Therefore, to assess the exact relationship between the age-related form-based local processing bias (Insch et al., 2012) and a potential form-based global processing advantage for point-light walkers in ageing (Pilz et al., 2010), this study combined the recent findings and stimuli by Insch et al. (2012) and those of Pilz et al. (2010). Rather than using a single computer-generated so called Cutting point-light walker as was used in Pilz et al. (2010), this study used complex motion captured actions (Vanrie & Verfaillie, 2004). It has been suggested that motion-captured walkers provide stronger local motion signals than Cutting walkers (Saunders, Suchan, & Troje, 2009), allowing us to better differentiate between the contributions of local motion and global form information for point-light walker processing. To assess the importance of form and motion information in biological motion perception, a matching task was employed, in which the first stimulus contained either local motion information, global form information, or both, and the second stimulus always contained local motion and global form information. Participants simply had to indicate whether the first and second stimulus showed the same action or not. Using this task, we were able to assess which kind of information older and younger adults preferentially utilise for biological motion processing. Based on the findings from Pilz et al. (2010), we anticipated that older adults would be worse at matching scrambled actions that primarily contain local motion compared to random-position actions that primarily contain global form information. In addition, we used the Navon task to investigate perceptual processing styles for both age groups. We expected that, similar to previous studies, both age groups would be faster at responding to the global than the local Navon letters, therefore exhibiting global precedence. In addition, we wanted to assess how the increased accuracy for local compared to global letters in older adults found by Insch et al. (2012) relates to the form-based processing advantage suggested by Pilz et al. (2010). We therefore correlated performance in the biological motion task with performance in the Navon task to investigate whether age-related differences in perceptual processing styles in the form-based Navon task accounted for the advantage of form over local motion information in biological motion processing.
Section snippets
Participants
18 younger participants (M = 19.9 years; SD = 1.2; Range = 19–23; 3 males) and 20 older participants (M = 65.4 years; SD = 3.9; Range = 61–78; 4 males) took part in the experiment. 1 younger and 5 older participants were excluded from the participant sample due to poor visual acuity so that the analysis was based on 17 younger and 15 older adults. The exclusion of these participants did not change the age ranges of the remainder younger and older participants. Participants were recruited from the student
Visual acuity
An independent samples t-test showed that there was no significant difference in visual acuity between older (M = 19.5, SD = 2.2) and younger (M = 19.1, SD = 1.75) adults (t(30) = − 0.673, p = .506).
Sequential action matching task
In the sequential action-matching task, observers had to match two actions. The first action contained primarily form information (random-position), primarily local motion information (scrambled) or both (normal). The second action was always normal. To summarise the results of the matching task (details below),
Discussion
The current study investigated age-related changes in the ability to process local motion and global form information in more complex biological motion stimuli using a sequential action matching task. In addition, we assessed age-differences in perceptual processing styles, i.e., local and global form-based processing, and whether differences in perceptual processing styles account for an advantage of form over local motion information in biological motion perception.
In the sequential
References (44)
- et al.
Motion processing at low light levels: Differential effects on the perception of specific motion types
Visual Research
(2008) - et al.
Age-related differences in cognitive function using a global local hierarchical paradigm
Brain Research
(2006) - et al.
Dissociation between emotion and personality judgements: Convergent evidence from functional neuroimageing
NeuroImage
(2005) - et al.
Differential processing of hierarchical visual stimuli in young and older healthy adults: Implications for pathology
Cortex
(2008) Forest before trees: The precedence of global features in visual perception
Cognitive Psychology
(1977)- et al.
Effects of ageing on biological motion discrimination
Vision Research
(2010) - et al.
Does aging affect the allocation of visual attention in global and local information processing?
Brain and Cognition
(2001) - et al.
Local–global processing in Alzheimer's disease: An examination of interference, inhibition and priming
Neuropsychologia
(2002) - et al.
Gestalt perception and the decline of global precedence in older subjects
Cortex
(2011) - et al.
The inversion effect in biological motion perception: Evidence for a “life detector.”
Current Biology
(2006)
Perception of biological motion without local image motion
Proceedings of the National Academy of Science USA
Controlling the false discovery rate: A practical and powerful approach to multiple testing
Journal of the Royal Statistical Society. Series B (Methodological)
Global processing of biological motions
Psychological Science
Perception of Human Motion
Annual Review of Psychology
Specific involvement of human parietal systems and the amygdala in the perception of biological motion
Journal of Neuroscience
The psychophysics toolbox
Spatial Vision
Aging and the locus of the global precedence effect: A short review and new empirical data
Experimental Aging Research
Is there a common factor for vision?
Journal of Vision
A program to generate synthetic walkers as dynamic point-light displays
Behavior Research Methods and Instrumentation
Investigating the stability of and relationships among global/local processing measures
Attention, Perception, & Psychophysics
Perception of emotion from dynamic point-light display represented in dance
Perception
The impact of age and motivation on cognitive effort: Implications for cognitive engagement in older adulthood
Psychology and Aging
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