gaze bias both reflects and influences preference s. shimojo, c. simion, e. shimojo, and scheier...

Gaze bias both reflects and influences preference

S. Shimojo, C. Simion, E. Shimojo, and Scheier

발표 : 생물심리 전공 설선혜

Introduction

Emotions and attitudes have the function of preparing people to act (i.e. approach or aversion) in such a way that the individual need not have much insight into what causes his or her behavior. (Darwin,1872)

The subjective experience of emotions is following facial expression rather than preceding it. (Zanjonc, 1985)

Implicit somatosensory inputs influence emotional and cognitive processes. (Zajonc/ Neumann and Strack, 1999)

Introduction

Orienting behavior is intrinsically linked to emotionally involved processes.

(Maner et al., 2002)

Introduction

In this study…Orienting behavior gaze directionEmotionally involved processes preference decisions

The hypothesis is…Gazing has and active role in preference formation and decision

makings.

Two experiments1. Two-alternative forced choice task2. Gaze manipulation

Experiment1: Methods

Two-alternative forced-choice task Face attractiveness rating (score 1-7) Eye movement data collection: Video-based eye tracker(30Hz) All trials were aligned at the moment of response, 1.67s before

decision. The likelihood curve was fitted with a sigmoid function

Main tasks

1) Face-attractive easy (>3.25)

2) Face-attractive difficult (<0.25)

Control tasks1) Face-roundness task

2) Face-dislike task

Experiment 1: Results

Figure 1A progressive bias in observers’ gaze toward chosen stimulus

Face attractiveness -difficult

Face-dislike

Face-roundnessFace attractiveness -easy

Fourier-descriptor-attractiveness


1. significant difference between the heights of likelihood curves in the main tasks and the control tasks

2. Curves did not reach a saturation level in the main tasks gaze cascade effect


Face-dislike

MainFace attractiveness -easy

Face-roundnessControl


Gaze cascade effect - The gaze bias is continually reinforced when attractiveness

comparisons are to be made.

Dual-contribution model


A larger cascade effect in the difficult task

When the cognitive biases are weak, gaze would contribute more to the decision making.


Face attractiveness -easy


Is it evolved from social interaction or basic orienting behavior?

Abstract shape attractiveness task

Basic orienting behavior!

Orienting is essential, particularly when the cognitive systems cannot be discriminative in making preference decisions over a rage of stimuli.


Is the effect relying on memory?

Two-session face attractiveness task (one-day inter delay)

1st session 2nd session Decision changed (22.3%)

No!

The cascade effect reflects the process of decision making itself.

Experiment 2: Methods

Gaze manipulation

900ms

300ms

900ms

300ms

Control (central)


Gaze manipulation, preference

1) Horizontal (2, 6, 12 repetitions)

2) Vertical

- to ascertain that saccade size and direction is not important

Gaze Manipulation2 repetition

Gaze Manipulation6 repetitions


Gaze Manipulationvertical

No, Central

No,Peripheral

Gaze Manipulationroundness

Percent preference for longer shown face

51.2 59.0 59.2 60.2 45.8 51.8 49.8

P-valueT-test

0.31 <0.001* <0.005* <0.0001* 0.99 0.30 0.56


Control

1) No gaze shift, central (retinotopically identical)

2) No gaze shift, peripheral

- to distinguish mere exposure effect from gaze bias





No, Central

No,Peripheral



51.2 59.0 59.2 60.2 45.8 51.8 49.8

P-valueT-test

0.31 <0.001* <0.005* <0.0001* 0.99 0.30 0.56

Results: Experiment 2

Control

3) Gaze manipulation, roundness

- to find out whether specific to preference tasks.





No, Central

No,Peripheral



51.2 59.0 59.2 60.2 45.8 51.8 49.8

P-valueT-test

0.31 <0.001* <0.005* <0.0001* 0.99 0.30 0.56

Results: Experiment 2





No, Central

No,Peripheral



51.2 59.0 59.2 60.2 45.8 51.8 49.8

P-valueT-test

0.31 <0.001* <0.005* <0.0001* 0.99 0.30 0.56

Gaze directly influences preference formation

Table 1 Results of Experiment 2 (gaze manipulation)

Conclusion

Dual-contribution model of preference formation

gaze bias both reflects and influences preference s. shimojo, c. simion, e. shimojo, and scheier...

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