Study of the duration of the decision-making process

A significant increase in the efficiency of the human-computer interface can be achieved by taking into account the parameters of the human decision-making process. We have developed and tested an algorithm for estimating the duration of this process (Soghoyan et al., 2022). The algorithm consists of tuning the optimal duration of the preparatory period, during which a response decision is made, based on the variation in the duration of the response period (Figure 1).

Figure 1: Sequence of events in the experimental sample.A. Sequence of events in the sample. B. Ratio of cue to response in the easy and difficult conditions. C. Illustration of the adaptive method. Data from ten consecutive samples were taken from one subject. The red arrows show the sequence of calculating the parameters of the adaptive method for the two samples. First, the difference (RTdiff) between the reaction time (RT) and the history of smoothed reaction times (RTh) is calculated. The Foreperiod (FP) is then increased as a linear function of this difference, resulting in a lower reaction time in the next sample.

We found that complex response choices required a longer decision period compared to easier choices. Importantly, the duration of response execution did not differ between the difficult and easy response choice tasks (Figure 2).

Figure 2: Mean values and standard errors of reaction times for stimulus presentation conditions with no preparation period (RTFP0), with a constant long preparation period (1.2 seconds) (RTFP1.2), as well as preparation period duration (FPad) and reaction time (RTad) in the condition with the adaptive algorithm for estimating the optimal duration of the preparation period.

In this way, we can estimate the duration of the decision making process independently of the duration of its realization.In the following study (Aksiotis et al., 2023), we applied this algorithm to investigate the motor response inhibition process in a Stop-Signal Task. It was found that the duration of the Stop-Signal Delay (SSD) reflects the process of deciding on the response category (left or right button press). The result of this choice is then translated into the next period, which includes both the activation of the motor response program and the possibility of its inhibition.The algorithm we developed to estimate the duration of the decision process shows predictable results and provides new insights into the mechanisms of response selection and execution. The use of the adaptive algorithm provides some additional possibilities in comparison with the previously used methods. In particular, the parameters of the algorithm are adjusted to the individual characteristics of the subject and the requirements of the task online in the course of task performance, which gives the researcher the opportunity to influence the process of reaction selection and execution, as well as to develop training and rehabilitation programs for patients with cognitive and motor impairments. The algorithm also allows explicit and objective assessment of the duration of the decision-making process, in contrast to approaches of mathematical modeling of decision-making or subjective assessment of its duration. 

1. Soghoyan G, Aksiotis V, Rusinova A, Myachykov A, Tumyalis A (2022) An adaptive paradigm for detecting the individual duration of the preparatory period in the choice reaction time task. PLoS ONE 17(9): e0273234.https://doi.org/10.1371/journal.pone.0273234
2. Aksiotis, V., Myachykov, A. & Tumyalis, A. Stop-signal delay reflects response selection duration in stop-signal task.  Atten Percept Psychophys  (2023).https://doi.org/10.3758/s13414-023-02752-y