Current Event The Interpretation of Motion Event perception embeds - - PowerPoint PPT Presentation

Visual Experience and the Current Event

The Interpretation of Motion

• Event perception embeds constraints on motion from

how object move in the world

– Gravity and evolution & experience builds expectation on sort of movement to occur

• People ‘fill in’ missing information when observer

misses part of motion path - Apparent motion: Is a consequence of ‘filling in’ motion based on expectation

• Generates strong motion percept: the strength of which

depends on: Distance between the objects; Percept intensity; The duration of the interval between the first

• bject’s offset and second object’s onset

Apparent motion Display

• Simple Apparent Display -
• ne visual element offsets

and another onsets

Figure 5.4 Apparent Motion display, arrow denotes a brief delay

• Path-guided display – perceive

apparent motion as following a path, geometrically simple

• Display is ambiguous; the

square in the left perceived as moving to the bottom left or to the top right

(c) Ambiguous Apparent display (a) Simple Apparent display (b) Path-guided Apparent display

What affects Apparent motion?

• Affected by: Physics, Recent history and how

things move

• Biological motion constrains the path an

apparently moving body takes.

• Spatiotemporal forms: determined by

underlying dynamics of the system that produced the motion

• Viewers Expectation: Hardwired by evolution

and/or Learned over experience

Apparent Motion

• It is an optical illusion in which stationary objects

viewed in quick succession appear to be in motion; An example of interpolation based expectation

• Representational Momentum – systematic error

in visual working memory {extrapolated motion and distortion}

• Representational momentum and related

memory distortion occur because as we observe an event we simulate aspects beyond what’s seen

Biological Motion Perception

• Biological Motion – movement of person or other

living organism

• Point-light walker stimulus - biological motion

made by placing lights in specific places on a person

• Structure-from-motion takes place with point-

light walkers

• Neurological studies show biological motion is

processed in the superior temporal sulcus (STS)

Biological Motion Demo

• Mood is systematically related to body motion

pattern.

• All these cues allow a perceiver to bootstrap

from peripheral sensory features to conceptually meaningful aspects of an event.

• Humans were discriminated from other

animals; gender and age; weight, arousal state, and mood were animated and distinguished

Biological Motion Demo

• Biological Motion

Biological Motion Perception

• Is associated with Neural processing
• One region in the lateral Occipitotemporal

cortex (extrastriate body area) responds selectively to visual depictions of bodies

• Lateral Superior temporal sulcus responds

selectively to point-light biological motion displays

Biological Motion - Summary

• The perceptual system settles on smooth

forms that are as simple as possible consistent with the sensory information. In synch with the Gestalt principles of visual grouping.

• It does not depend on previous experience.

However, the identification of individuals from motion would seem to require experience.

Causes, Intension and Social Behaviour

• Motion provides clues on intentions: What a

person intends to do {movement to} and when an intentional action has ended {retract}

• Movement conveys information about goals,

intensions and personalities of actors

• Viewers can construct rich representations of

events consisting of intentional social actions from patterns of movement alone.

Causes, Intension and Social Behaviour

• Viewers key in on features of movement that

discriminate intentional animate motions from mechanical movements - wolf & sheep

• Viewers can make fine and accurate

discriminations from motion alone

• If biological motion processing and the

attribution of intentions are coupled, it produces traces in the patterns of neural activity when people view other’s actions

Causes, Intension and Social Behaviour

• Activation in STSp can be obtained without

biological movement patterns.

– Neurons representing intentional actions that keep firing – Woman’s intention incongruent with her action, the right STSp responds more

• The right region of STPp selectively activated

by features of human action that are specific to biological motion /or intentional action

Causes, Intension and Social Behaviour

• Possibility of activations:

(a) The STSp “really” is selective for processing intentions (b) Responses to biological motion cues and to animacy are co-localized because they are tightly coupled computationally (c) Regions responsive to biological motion and to intentional action may be different units that happen to be nearby the cortex

• People use a set of expectations beyond those

that apply to movements of inanimate objects

Vision and Language, Vision and Action

• Perception is tightly coupled to language

understanding, action, planning and problem

• solving. May apply for perception of events
• Visual information can be used to update the

location of objects, integrate with linguistic input and world knowledge for identification and disambiguation {“this” identification}

• Visual information is combined with linguistic

information to construct event representation

– Boy sitting with cake, ball, truck, train; when speak eyes move to object

Vision and Language, Vision and Action

• Conclusion: Listeners integrate information

about possible objects, the action could apply to with their representation of the situation depicted by the picture, they do so rapidly

• Visual and Linguistic information is combined

to form event representation

• Event representations are not just for passive

comprehension and offline thinking, but also guiding action online

Chapter Summary

• Visual motion plays role in event perception
• Features related to entities, causes and goals can

be experienced visually;

• Media as movies and comics, introduce visual

features that do not occur in nature, and how they affect even perception – give insights into how events are perceived and conceived

• Visual perception of events interacts pervasively

with our actions and intentions for actions