Residual Information of Previous Decision Affects Evidence Accumulation in Current Decision.

Farzaneh Olianezhad,Sajjad Zabbah,Reza Ebrahimpour,Maryam Tohidi-Moghaddam

doi:10.3389/fnbeh.2019.00009

Abstract

Bias in perceptual decisions can be generally defined as an effect which is controlled by factors other than the decision-relevant information (e.g., perceptual information in a perceptual task, when trials are independent). The literature on decision-making suggests two main hypotheses to account for this kind of bias: internal bias signals are derived from (a) the residual of motor signals generated to report a decision in the past, and (b) the residual of sensory information extracted from the stimulus in the past. Beside these hypotheses, this study suggests that making a decision in the past per se may bias the next decision. We demonstrate the validity of this assumption, first, by performing behavioral experiments based on the two-alternative forced-choice (TAFC) discrimination of motion direction paradigms and, then, we modified the pure drift-diffusion model (DDM) based on the accumulation-to-bound mechanism to account for the sequential effect. In both cases, the trace of the previous trial influences the current decision. Results indicate that the probability of being correct in the current decision increases if it is in line with the previously made decision even in the presence of feedback. Moreover, a modified model that keeps the previous decision information in the starting point of evidence accumulation provides a better fit to the behavioral data. Our findings suggest that the accumulated evidence in the decision-making process after crossing the bound in the previous decision can affect the parameters of information accumulation for the current decision in consecutive trials.

Highlights

Perceptual decisions and their outcomes can be related to each other as a sequence (Hanks et al, 2011; Akaishi et al, 2014; Purcell and Kiani, 2016; Bornstein et al, 2017; Miller et al, 2017)
The probability of being correct in the current decision increases if it is in line with the previous decision, showing a trace from the previous trial on the current one
Many studies suggested that sequential effects (Falmagne, 1965, 1968; Remington, 1969; Gold et al, 2008; Goldfarb et al, 2012) on decision processes are due to the motor response bias or sensory bias (Gold et al, 2008; Pearson and Brascamp, 2008; Albright, 2012; Carnevale et al, 2012; Marcos et al, 2013), Akaishi et al showed that this decision history effect cannot be defined through these biases, as well as it can be explained by an autonomous learning rule to estimate the likelihood of a choice to be made (Akaishi et al, 2014)

Summary

Introduction

Perceptual decisions and their outcomes can be related to each other as a sequence (Hanks et al, 2011; Akaishi et al, 2014; Purcell and Kiani, 2016; Bornstein et al, 2017; Miller et al, 2017). There is a preference in humans to repeat their decision, especially when it was made about an ambiguous stimulus (Brehm, 1956; Izuma and Murayama, 2013; Akaishi et al, 2014), on the subsequent trial in the absence of response feedback This interaction between the history of choices and sensory context, respectively called internal and external signals, is thought to cause the biased decisions about the sensory events (Albright, 2012; Awh et al, 2012; Carnevale et al, 2012; Akaishi et al, 2014). Akaishi et al suggest that, in the absence of response feedback, this bias is a mechanism to update the likelihood of a choice to be made (Akaishi et al, 2014)

Methods

Results

Conclusion