Controlling the Anchoring Effect through Transcranial Direct Current Stimulation (tDCS) to the Right Dorsolateral Prefrontal Cortex

Abstract

Selective accessibility mechanisms indicate that anchoring effects are results of selective retrieval of working memory. Neuroimaging studies have revealed that the right dorsolateral prefrontal cortex (DLPFC) is closely related to memory retrieval and performance. However, no research has investigated the effect of changing the cortical excitability in right DLPFC on anchoring effects. Transcranial direct current stimulation (tDCS) can modulate the excitability of the human cerebral cortex, while anodal and cathodal tDCS are postulated to increase or decrease cortical activity, respectively. In this study, we used tDCS to investigate whether effects of increased or decreased right DLPFC excitability influence anchoring effects in willingness to pay (WTP) experiments. Ninety participants were first randomly assigned to receive either anodal, cathodal, or sham stimulation of 15 min, then they performed a valuation task regarding WTP. The results showed that anchoring effects were negatively related to activities of right DLPFC: the anodal stimulation diminished anchoring effects while the cathodal stimulation increased anchoring effects. These outcomes provide one of the first instances of neural evidence for the role of the right DLPFC in anchoring effects and support psychological explanations of the selective accessibility mechanisms and cognitive sets.

Transcranial Direct Current Stimulation of the Right Lateral Prefrontal Cortex Changes a priori Normative Beliefs in Voluntary Cooperation

“…All participants received tDCS delivered by a battery-driven stimulator (Neuro Conn, Germany) in our experiment. tDCS was applied using a set of standard 5 cm × 7 cm electrodes fixed with rubber straps, which is the most commonly used approach in tDCS ( Fusco et al, 2013 ; Li et al, 2017 ). For subjects receiving tDCS, the anodal/cathodal electrode was placed over the rLPFC according to the international EEG 10–20 electrode system, and the reference electrode (cathode for anodal tDCS and anode for cathodal tDCS) was positioned over the vertex, which was consistent with the design of Ruff et al (2013) .…”

“…They were requested to complete a self-report on a priori normative beliefs. (Schematic representation of the experimental design, see Figure 1 ) The procedures were the same for the sham group, except that the current was stopped after the first 30 s. The 30-s stimulation in the sham condition can mimic the itching sensation of real stimulation without producing any significant neural-altering effects on the cortex ( Civai et al, 2015 ; Willis et al, 2015 ; Li et al, 2017 ). The protocol was approved by the Ethics Committee of Business of Nankai University, and all participants gave written informed consent.…”

Transcranial Direct Current Stimulation Altered Voluntary Cooperative Norms Compliance Under Equal Decision-Making Power

“…In the sham treatment, the neural excitability in rDLPFC was left unaltered as control for possible non-neural effects of the other two treatments. The current was constant (1.0 mA) with 15 s of ramp up and down (Ambrus et al, 2012 ; Meesen et al, 2014 ; Li et al, 2017 ; Wang et al, 2017 ). The tDCS, delivered by a battery-driven stimulator (Neuro Conn, Germany), was applied using a set of standard 5 × 7 cm electrodes fixed by rubber straps.…”

I am physically and personality-wise warmer when wearing round eyeglasses: Shape priming influences personality judgments and estimated temperature

“…First, the temperature was estimated to be higher in the round than in the square condition, although it was estimated to be lower than the actual temperature under both conditions, suggesting that the "anchoring effect" (Tversky & Kahneman, 1974) might have influenced the estimate. The anchoring effect is the phenomenon in which an individual's decision tends to be biased towards previously presented information (Li et al, 2017). It was not expected that the participants would be able to estimate the room temperature without any cues, and therefore, they were informed about the temperature of the room in the morning.…”