Lying about the valence of affective pictures: an fMRI study

Abstract

The neural correlates of lying about affective information were studied using a functional magnetic resonance imaging (fMRI) methodology. Specifically, 13 healthy right-handed Chinese men were instructed to lie about the valence, positive or negative, of pictures selected from the International Affective Picture System (IAPS) while their brain activity was scanned by a 3T Philip Achieva scanner. The key finding is that the neural activity associated with deception is valence-related. Comparing to telling the truth, deception about the valence of the affectively positive pictures was associated with activity in the inferior frontal, cingulate, inferior parietal, precuneus, and middle temporal regions. Lying about the valence of the affectively negative pictures, on the other hand, was associated with activity in the orbital and medial frontal regions. While a clear valence-related effect on deception was observed, common neural regions were also recruited for the process of deception about the valence of the affective pictures. These regions included the lateral prefrontal and inferior parietal regions. Activity in these regions has been widely reported in fMRI studies on deception using affectively-neutral stimuli. The findings of this study reveal the effect of valence on the neural activity associated with deception. Furthermore, the data also help to illustrate the complexity of the neural mechanisms underlying deception.

Figure 1. Brain activation map contrasting Positive versus Negative valence in the True condition.

1a: True: Positive>Negative. 1b: True: Negative>Positive. Notes: A = Anterior view; P = Posterior view; R = Right hemisphere; L = Left hemisphere; V = Ventral view; D = Dorsal view’. “True” represents the “True condition”. “Negative” represents the “Negative valence condition”; “Positive” represents the “Positive valence condition”.

Figure 2. Brain activation map contrasting Lie versus True in Positive and Negative valence.

2a: Lie>True for Positive valence. 2b: Lie>True for Negative valence. Notes: A = Anterior view; P = Posterior view; R = Right hemisphere; L = Left hemisphere; V = Ventral view; D = Dorsal view.

Figure 3. Brain activation map for the contrast of Positive versus Negative valence in the Lie condition.

3a: Lie: Positive>Negative. 3b: Lie: Negative>Positive. Notes: A = Anterior view; P = Posterior view; R = Right hemisphere; L = Left hemisphere; V = Ventral view; D = Dorsal view. “Negative” represents “Negative valence condition”. “Positive” represents the “Positive valence condition”. “Lie” represents the “Lie condition”. “Negative” represents the “Negative valence condition”. “Positive” represents the “Positive valence condition”.

Figure 4. Brain activation map: conjunction analysis of contrast of Lie versus True in the Positive and the Negative valence conditions.

Notes: A = Anterior view; P = Posterior view; R = Right hemisphere; L = Left hemisphere; V = Ventral view; D = Dorsal view.

Figure 5. The experiment included randomized truthful and deceptive conditions.

There were 20 trials in each of the four conditions: (1) True - Positive valence, (2) Lie – Positive valence, (3) True – Negative valence, and (4) Lie – Negative valence. Each trial consisted of a randomized cue, either “Truth” or “Lie”, for the True and the Lie condition, respectively. The cue appeared on the screen for 1500 ms. The participants then looked at the picture for as long as 600 ms. A fixation cross appeared for 800 ms to allow the participants to prepare to make the correct response in accordance with the cue. Then, the question “How do you feel about this picture?” was shown to prompt the participants to make either a truthful or a deceptive response according to the cue. At the end of the trial, there was a randomized jittering (average 2500 ms) to separate the trials.