spatial perception presentation

Living in Two SpacesEffect of Attention on

Perception of Haptic Space

Rachel Franz & Siyan Zhao

Difference between Haptic Space and Physical SpaceWhat we sense is parallel when we can't see is different from what is physically parallel

Parallel in haptic space

Parallel in physical space

Kappers, A. M. (2007). Haptic space processing–allocentric and egocentric reference frames. Canadian Journal of Experimental Psychology, 61(3), 208-218.

Our Question

How does attention affect what we perceive as parallel by touch alone?

Systematic Deviations

Pattern is always the same

Why do we see this pattern?

First, some definitions:

Egocentric reference frame

Mental representation of space from our own perspective

Why do we see this pattern?

Allocentric reference frame:

Our mental representation of space that is independent of our perspective

...same house, different representations.

Both reference frames contribute to our perception of what is parallel

Why do we see this pattern?

Kappers, A. M. (2004). The contributions of egocentric and allocentric reference frames in haptic spatial tasks. Acta psychologica, 117(3), 333-340.

Why do we see this pattern?

In this task:

Allocentric reference frame-same as physical space, more accurate

Egocentric reference frame-less accurate

Where is the egocentric reference frame located?

For 8 out of 10 participants, the hand centered model was weighted more

The oblique effectInteresting effect occurs at 45 and 135 degrees

90135

Allocentric reference frame

4590

Egocentric

reference

frame

Allocentric reference frame

The oblique effectInteresting effect occurs at 45 and 135 degrees

Participants more accurate for oblique orientations!

4590

Egocentric

reference

frame

Allocentric reference frame

How were reference frames manipulated in other studies?

Zuidhoek et al. (2003)Time delay -> + allocentric

Newport et al. (2002)Vision -> + allocentric

Our study

Attention -> + egocentric

4590

Egocentric

reference

frame

Allocentric reference frame

Based on our question..

How does attention affect what we perceive as parallel by touch alone?

Hypothesis

● Attention causes subjects to place more importance on their egocentric reference frame

Method - IV, DV

● Within-subject design● Independent Variable: Attention● Dependent Variable: Weight of allocentric

and egocentric reference frame

Method - Setup

Target bar (static)Test Bar

Participants sat here

Method - Setup

Target bar (static)Test Bar

Participants sat here

Method - Operationalization

● IV: To focus participants' attention on their hands, we trace the outline of their hands in treatment condition (~20 sec). For control condition, participants sat for 20 seconds

● DV: The degree of deviation of the test bar from the target bar

Target bar Test bar

Method - Participants

19 Carnegie Mellon University Students:12 were from a Research Method class7 outside of the class

ResultThe treatment group performed significantly better (p = 0.02, t(18) = 2.54)

Large variation supports oblique effect

Some people performed better

Treatment

Control

Conclusion● Blindfolded participants who had their

hands traced had a better sense when objects were parallel.

ConclusionParticipants put more weight on their egocentric reference frame after we traced their hands.

4590

Egocentric

reference

frame

Allocentric reference frame

Alternative Explanation

Attention caused increased awareness of hand orientations

Limitations

Who gave more weight to their egocentric reference frame?

Gender?

Directions for future research

Did the allocentric participants also give more weight to egocentric reference frame?

What happens when people don't attend to spatial properties of their hands?

Contribution

The egocentric reference frame can be manipulated

Attention can affect egocentric reference frame