My experiment is a reflection of the study by Peterson and Peterson in 1959. This published study’s aim was to investigate the effect of decreasing rehearsal, by controlling the time interval, on items recalled in STM. The aim was fulfilled by controlling the time intervals and measuring the trigrams correctly recalled. The Psychologists found that decreasing rehearsal time leads to information loss from the STM (Peterson & Peterson, 1959). My study supported their findings as seen through the decreasing exponential trend of percent trigrams recalled correctly as the interval increases. Although at 3 second interval, Peterson calculated 80% correct trigrams recall (Peterson & Peterson, 1959) and my experiment had a 30%, the overall results collected through the experiment I conducted, supported the published study as the intervals increased the trigrams recalled trend decreased. The differences between the two studies are due to the sample of my study being high school students rather than psychology students in college. The difference in the sample size was minor although the environment was very different. The Hawthorne effect states that participants react differently under watchful observation (McCambridge, Witton, & Elbourne, 2014), and the studies in a lab setting reduces the number of variables affecting the results but also decreases the ecological validity as people behave differently when being observed in a controlled environment. The experiment conducted by me was not in a lab setting which increases the ecological validity and the chances for environmental variables affecting the results.. Each participant received the same instructions for consistency (Brown-Peterson Technique), which increases the reliability of the study (McLeod, 2008). On the other hand limitations included the decrease in ecological validity due to memorizing trigrams not being a everyday task and use of opportunistic sampling which increases sampling bias. To further improve this study, use of larger sample size would better represent wider population. Increased number of time intervals would also provide stronger results. Trigrams are not memorized by the students regularly therefore memorizing small worlds would help decrease ecological validity. lastly to avoid participant destruction, a quiet room could be used for testing rather than busy hallway. In conclusion, information in the STM will be lost if rehearsal is not maintained. As seen through the results, the control group whose rehearsal was not decreased had memorized about 35% of trigrams while the participants in condition 4 with the interval of 12 seconds were only able to recall 15% of the trigrams (see table 1). These results proved that as the time intervals increased the average percent of trigrams memorized decreased rapidly and supported the study published by Peterson & Peterson.