Testing a dose-response effect of the visuospatial game Tetris on intrusive memories.

Tetris has been shown to reduce intrusions following exposure to experimentally induced and actual traumatic events. However, no study has systematically investigated whether multiple sessions of Tetris produce greater reductions in intrusions than a single session. In this study, 94 participants (58.5% female) watched a trauma film in the laboratory and were then randomly assigned to one of three groups: no Tetris (inactive control), a single session of Tetris (15 min on Day 1), or multiple sessions of Tetris (15 min per day on Days 1, 2, and 3). Participants recorded film-related intrusions in a daily diary over 1 week. The results showed that the trauma film effectively induced intrusions. In terms of group differences, a single Tetris session was associated with a 22.0% reduction in intrusions compared to the control group, Exp(B) = 0.78; and multiple Tetris sessions were associated with a 13.3% increase in intrusions compared to the control group, Exp(B) = 1.13, and a 45.4% increase compared to the single-session group, Exp(B) = 1.45. However, none of these differences were statistically significant, p = .380. These findings may be partially explained by methodological factors, such as administering Tetris remotely via smartphones without researcher supervision and the repeated use of reminder cues. Alternatively, Tetris may not effectively reduce intrusions when played unsupervised in uncontrolled settings.