Pauline geneva

Document Sample
Pauline geneva Powered By Docstoc
					                                    Pauline Insch, Louise Phillips, Roy Allen & Rebecca Bull
                    Aging, Cognition and Emotion Laboratory, School of Psychology, University of Aberdeen.

                                  INTRODUCTION                                                                                                                   RESULTS
 The ability to decode body movement, as cues to emotions and                         Age was negatively correlated with the perception of biological motion
 actions, is argued to be a fundamental precursor to inferring the                    for both actions and emotions. Accuracy on both the biological motion
 mental states of others. Biological motion has been used to                          tasks correlated with accuracy at identifying the global incongruent trials
 investigate the capability to decode these movements However, to                     in the global-local recognition task (See table 1 below).
 decode biological motion the figures must be processed holistically                 Table 1: Correlations between age, biological motion & global-local processing conditions.
 by the visual system. In these point-light figures the local aspects
 (point-lights) differ from the global form (a person). Failure to                    Variable                                                       1          2                3          4            5           6        7
 holistically group the local aspects means perception of the figure                                                                                                  **             **           *                               **
 will not be achieved. Typically the visual system preferentially                      1. Age                                                        -        -.471           -.372       -.181        -.111       -.162    -.415
                                                                                                                                                                                    **                                            **
                                                                                       2. BM Action                                                              -             .441        .134         .046         .038    .266
 processes stimuli holistically, although there is some evidence of                    3. BM Emotion                                                                             -         .013       -.004        - .012    .245

 age-related. Local bias has been found in older adults and also in                    4. Local Congruent                                                                                    -          .262
                                                                                                                                                                                                                     .015    .318
 conditions with social difficulties such as Autistic Spectrum                         5. Local Incongruent                                                                                               -        -.031     .336
 Disorder and Alzheimer’s disease.                                                     6. Global Congruent                                                                                                             -     .112
                                                                                       7. Global Incongruent                                                                                                                   -

                                   STUDY AIMS                                         *P<   .05 (2-tailed) **P < .01 (2-tailed) (%age accuracy figures used for BM & G/L processing)
• The principle aim was to investigate if biological motion perception
  was subject to age effects when stimuli showing actions and                         Task 1: Biological Motion Perception
  emotions were presented;                                                            • Significant age effects were found in the ability to perceive biological
• A secondary aim was to investigate if there were age effects                          motion (F(2,119) = 18.13, p < .01);
  apparent in the ability to process global incongruent stimuli;                      • There were no significant group differences between young and older
• Finally this study analysed how biological motion perception may                      adults for either action or emotion recognition;
  be moderated by both age and global-local biases.                                   • The older adults in contrast showed significant decline in perceiving
                                                                                        both actions and emotions when compared to both young and middle-
                                    METHOD                                              aged groups suggesting difficulties start in old age;
Participants (n = 121)                                                                • Stimuli type was significant with emotions being harder to decode than
 52 young, aged 18 – 39 (M = 25.81, SD = 5.45), 38 middle-aged,                         actions for all age categories (F(1,119) = 16.25, p < .01).
 40 – 64 (M = 51.53, SD = 8.73 and 32 older adults, 65 - 88                           • There was no age x stimuli interaction (F (2,119) = 2.12, p = ns).
 (M = 73.16, SD = 4.72) took part in both tasks.
                                                                                      Task 2: Global-Local Processing Biases
Task 1: Biological Motion                                                             • A significant effect of age was found with the older adults showing the
 Twenty four short biological motion films were shown. Twelve of                        poorest performance (F (2,119) = 18.13, p <.01);
 the films depicted actions such as driving, while twelve showed the                  • The type of task was also significant as the global-incongruent
 emotions anger, fear, sadness and happiness. Each of these                              condition was most difficult (F(1.57,115) = 31.41, p < .01);
 emotions were shown at three different levels of intensity                           • There was a significant task x age interaction (F (3.14,115) = 8.75
 (See figure 1 for examples).                                                           p <.01), with the largest age effect on measures of global bias.

                                                                                                                                             Action Stimuli    Emotion Stimuli            Global Incongruent Accuracy
                                                                                                      Percentage Accurate Responses





         Action Stimuli: Driving               Emotion Stimuli: Anger
                                                  Intensity = low                                                                                     Young                      Middle-Aged                      Older
 Figure 1: Example of Action and Emotion Point-Light Stimuli                                                                                                               Participant Age Categories

Task 2: Global-Local Processing                                                             Figure 3: Age effects on biological motion and global-incongruent processing accuracy.
  Images of shapes were presented. These consisted of a global
 shape comprised of local shapes. Both types of shape could be                        • An analysis of co-variance showed that even when shared variance
 either circles, diamonds, squares or triangles. When the shapes                        between biological motion perception and global-incongruent
 were blue participants had to identify the global shape. When the                      processing was removed, the main effect of age was maintained but
 shapes were red participants were required to identify the local                       reduced to F (2,116) = 13.45, p = <.01.
 shape. There were four conditions (see Figure 2), determined by
 colour and global/local shape congruency                                                                                                                     DISCUSSION
                                                           Local (red)
                                                                                      Age differences in identifying biological motions from actions and
          Global (blue)
  Congruent                                        Congruent       Incongruent        emotions were found. This replicates previous findings of decline in
                                                                                      emotion recognition over the lifespan. This study was the first to
                                                                                      highlight how biological motion perception may be moderated by both
                                                                                      age and visual processing style. Research has previously suggested that
                                                                                      difficulty in global processing impacts on social cognition and this may
                                                                                      reflect neuropsychological changes within those middle-aged and older
       Global response = Circle                Local response = Circle,   = Square
                                                                                      adults which causes changes in the bias towards global processing.
  Figure 2: The Global/Local, Congruent/Incongruent conditions

                                                                                                                                                                                           The Leverhulme Trust

Shared By: