Biological motion processing

Question 1

What is biological motion?

Answer 1

is the motion of any human or animate being (human or animal) and is often studied by using point like animations (PLAs). these animations are usually walkers that are made out of dots that represent joints of humans that contain local motion and global form.

Question 2

what is local motion?

Answer 2

is the motion of single dots

Question 3

what is global form

Answer 3

is the integration from all dots at one given point in time

Question 4

what is global motion

Answer 4

can be derived by integrating the local motion of all dots or by integrating the global form over time.

Question 5

Recognizing emotions-1

Answer 5

Spencer et al (2016)

• what emotion does the point like walker show? happy angry or sad?
• participants could do it well for normal walkers, okay for inverted but not very well for scrambled
• were not so good to distinguish angry walkers

Question 6

Recognizing emotions-2

Answer 6

Clarke et al (2005)

• what emotions are walkers portraying?
• could be more than one emotion.
• best at anger

Question 7

Why are we more vulnerable to inversions?

Answer 7

• the global form is disrupted

- not familiar to the stimulus, not used to seeing people walk on the ceiling.

Question 8

Do we have to learn biological motion processing or is it innate/intrinsic?

Answer 8

• babies seem to be good at recognizing biological motion in early months but it develops
• pavlova et al: 3 year olds were bad at discriminating, but developed with age
• Freire et al: thresholds increased with age and could tolerate more dots (noise).

this suggests that biological motion processing is not innate.

Question 9

Gieses model of biological motion processing (2003)

Answer 9

the idea was that there are two different pathways, the dorsal (motion) and the ventral (form).

depending on task and condition both local and global form can be used to detect biological motion.

STS uses information from both pathways integrates it to allow us to recognize motion

Question 10

Autism

Answer 10

• neurodevelopment disorder with deficits in social understanding and behavior.
• repetitive actions, delayed language skills,
• impaired motion perception and biological motion perception
• dorsal pathway seems to be impaired.

Question 11

Blake et al

Answer 11

1. person or not a person?
   - autistic individuals have difficulties discriminating biological from scrambled motion.
   - This result could be due to the fact that autistic individuals use primarily local motion for biological motion perception and therefore, are unable to discriminate the two stimuli.
2. which quadrant shows the target?
   - performed equally well as normal developing children
   - show no deficits in global form tasks

Question 12

Boxtel et al

Answer 12

showed that individuals with high autistic traits are able to use local motion information for biological motion discrimination, which suggests that there is no general deficit in local motion perception.

Question 13

Spencer et al.

Answer 13

was the target left or right of the center?

• autistic children have higher coherence thresholds,
• —> worse at detecting motion perception.

Question 14

Biological motion processing for older adults

Answer 14

older adults are impaired at detecting walking direction in noise

• higher level cognitive mechanisms seem to compensate for age related changes in visual areas that affect motion perception
• older adults rely on global form rather than local motion