Elsevier

Acta Psychologica

Volume 166, May 2016, Pages 12-20
Acta Psychologica

Global form and motion processing in healthy ageing

https://doi.org/10.1016/j.actpsy.2016.03.005Get rights and content

Highlights

  • This study investigates global form and motion processing in healthy ageing.

  • We use a point-light action matching task and the Navon task.

  • Older adults were significantly worse at using only form information to match point-light actions, compared to younger adults.

  • There were no overall age differences for the Navon task.

  • Performance in both tasks was not correlated indicating that processing biases in form- and motion-based tasks are unrelated.

Abstract

The ability to perceive biological motion has been shown to deteriorate with age, and it is assumed that older adults rely more on the global form than local motion information when processing point-light walkers. Further, it has been suggested that biological motion processing in ageing is related to a form-based global processing bias. Here, we investigated the relationship between older adults' preference for form information when processing point-light actions and an age-related form-based global processing bias. In a first task, we asked older (> 60 years) and younger adults (19–23 years) to sequentially match three different point-light actions; normal actions that contained local motion and global form information, scrambled actions that contained primarily local motion information, and random-position actions that contained primarily global form information. Both age groups overall performed above chance in all three conditions, and were more accurate for actions that contained global form information. For random-position actions, older adults were less accurate than younger adults but there was no age-difference for normal or scrambled actions. These results indicate that both age groups rely more on global form than local motion to match point-light actions, but can use local motion on its own to match point-light actions. In a second task, we investigated form-based global processing biases using the Navon task. In general, participants were better at discriminating the local letters but faster at discriminating global letters. Correlations showed that there was no significant linear relationship between performance in the Navon task and biological motion processing, which suggests that processing biases in form- and motion-based tasks are unrelated.

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)

  • J. Beintema et al.

    Perception of biological motion without local image motion

    Proceedings of the National Academy of Science USA

    (2002)
  • Y. Benjamini et al.

    Controlling the false discovery rate: A practical and powerful approach to multiple testing

    Journal of the Royal Statistical Society. Series B (Methodological)

    (1995)
  • B.I. Bertenthal et al.

    Global processing of biological motions

    Psychological Science

    (1994)
  • R. Blake et al.

    Perception of Human Motion

    Annual Review of Psychology

    (2007)
  • E. Bonda et al.

    Specific involvement of human parietal systems and the amygdala in the perception of biological motion

    Journal of Neuroscience

    (1996)
  • D.H. Brainard

    The psychophysics toolbox

    Spatial Vision

    (1997)
  • R. Bruyer et al.

    Aging and the locus of the global precedence effect: A short review and new empirical data

    Experimental Aging Research

    (2003)
  • C. Cappe et al.

    Is there a common factor for vision?

    Journal of Vision

    (2014)
  • J.E. Cutting

    A program to generate synthetic walkers as dynamic point-light displays

    Behavior Research Methods and Instrumentation

    (1978)
  • G. Dale et al.

    Investigating the stability of and relationships among global/local processing measures

    Attention, Perception, & Psychophysics

    (2013)
  • W.H. Dittrich et al.

    Perception of emotion from dynamic point-light display represented in dance

    Perception

    (1996)
  • G.E. Ennis et al.

    The impact of age and motivation on cognitive effort: Implications for cognitive engagement in older adulthood

    Psychology and Aging

    (2013)
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