The percentage of distorted items.

The distorted items (%) were calculated as the distorted items divided by all the items. “Total,” “Toward” and “Reversed” in the figure indicates the total percentage of distortions, the percentage of distorted items for correct information, and the percentage of distorted items against correct information, respectively.</p

Original data of the hindsight bias index.

Our recollections tend to become more similar to the correct information when we recollect an initial response using the correct information, known as the hindsight bias. This study investigated the effect of memory load of information encoded on the hindsight bias’s magnitude. We assigned participants (N = 63) to either LOW or HIGH conditions, in which they answered 20 or 50 questions, which were their initial responses. Then, they memorized and remembered the correct information. They finally recollected the initial responses. Twenty of the fifty questions in the HIGH condition were identical to those in the LOW condition. We used the answers to these 20 common questions in LOW and HIGH conditions to examine the effect of the memory load of information encoded, defined as the number of correct answers to remember (i.e., 20 or 50) on the hindsight bias. Results indicated that the magnitude of the hindsight bias was more prominent in the HIGH than the LOW condition, suggesting that the memory load amplifies the hindsight bias’s magnitude. This finding also implies that controlling the memory load of information encoded when learning correct information could mitigate the hindsight bias. We expect these findings to have practical implications in occupational settings where hindsight bias could lead to critical errors such as financial losses or medical problems.</div

Japanese Hindsight Bias Test (HBT) items.

Our recollections tend to become more similar to the correct information when we recollect an initial response using the correct information, known as the hindsight bias. This study investigated the effect of memory load of information encoded on the hindsight bias’s magnitude. We assigned participants (N = 63) to either LOW or HIGH conditions, in which they answered 20 or 50 questions, which were their initial responses. Then, they memorized and remembered the correct information. They finally recollected the initial responses. Twenty of the fifty questions in the HIGH condition were identical to those in the LOW condition. We used the answers to these 20 common questions in LOW and HIGH conditions to examine the effect of the memory load of information encoded, defined as the number of correct answers to remember (i.e., 20 or 50) on the hindsight bias. Results indicated that the magnitude of the hindsight bias was more prominent in the HIGH than the LOW condition, suggesting that the memory load amplifies the hindsight bias’s magnitude. This finding also implies that controlling the memory load of information encoded when learning correct information could mitigate the hindsight bias. We expect these findings to have practical implications in occupational settings where hindsight bias could lead to critical errors such as financial losses or medical problems.</div

Percentage of hindsight bias index.

The hindsight bias index (%) was defined as 100 (initial responses-recollection values) / (initial responses—correct information), in which initial responses = numerical value of the initial responses, recollection values = numerical value of the recollection values, and correct information = numerical value of the correct information. “Total,” “Toward” and “Reversed” in the figure indicates the total percentage of distortions, percentage of distorted items for correct information, and the percentage of distorted items against correct information, respectively.</p

English Hindsight Bias Test (HBT) items.

Our recollections tend to become more similar to the correct information when we recollect an initial response using the correct information, known as the hindsight bias. This study investigated the effect of memory load of information encoded on the hindsight bias’s magnitude. We assigned participants (N = 63) to either LOW or HIGH conditions, in which they answered 20 or 50 questions, which were their initial responses. Then, they memorized and remembered the correct information. They finally recollected the initial responses. Twenty of the fifty questions in the HIGH condition were identical to those in the LOW condition. We used the answers to these 20 common questions in LOW and HIGH conditions to examine the effect of the memory load of information encoded, defined as the number of correct answers to remember (i.e., 20 or 50) on the hindsight bias. Results indicated that the magnitude of the hindsight bias was more prominent in the HIGH than the LOW condition, suggesting that the memory load amplifies the hindsight bias’s magnitude. This finding also implies that controlling the memory load of information encoded when learning correct information could mitigate the hindsight bias. We expect these findings to have practical implications in occupational settings where hindsight bias could lead to critical errors such as financial losses or medical problems.</div

Spectral power densities in alpha (left) and theta (right) band frequencies.

Name = name condition, Other-name = other’s name condition, and Cont = control condition (no sound).</p

Results of ANOVA.

Results of ANOVA.</p

Reaction time (left), coefficients of variation (middle) and lapses (right) in the Psychomotor Vigilance Test.

Name = name condition, Other-name = other’s name condition, and Cont = control condition (no sound), PVT: Psychomotor Vigilance Test, CV: coefficient of variation.</p

Time schedule of the experiment.

Name = name condition, Other-name = other’s name condition, and Cont = control condition (no sound). The order of the conditions was counterbalanced among the participants.</p

Sample of test session.

KSS = Karolinska Sleepiness Scale, PVT = Psychomotor Vigilance Test. Visual stimuli for PVT were presented with random inter-stimulus intervals between 2–10 sec, while a sound was presented every 20 sec in the stimuli epochs. The order of the conditions was counterbalanced among the participants.</p