The Relation between Self-Reported Alcohol and Cannabis Use and Prospective Memory in College Students

The aim of this study was to examine the relation between drug use and prospective memory performance. Prospective memory is the ability to remember to do something in the future and is a vital aspect of everyday living. Prospective memory can be broken down into regular, irregular and event-based or time-based components. Most research on prospective memory has primary examined differences between young and old adults (e.g., Einstein & McDaniel, 2005; Rendell & Craik, 2000; Schnitzpahn et al., 2014). The current study examined possible effects of selfreported alcohol and cannabis use on prospective memory performance. A computer based Virtual Week task to assess prospective memory and a questionnaire to assess substance use were administered to college students at a large Midwestern university. It was hypothesized that prospective memory scores would be lower in college students who reported both alcohol and cannabis consumption. DRUG USE AND PROSPECTIVE MEMORY 3 Memory is one of the most important capacities humans possess. Prospective memory is being able to make plans and to remember to execute said plans and intentions at a specific time and place (Arana et al., 2011). Not only is prospective memory vital for personal functioning, it is also important in the area of social, occupational and health domains (Cuttler, McLaughlin, & Graf, 2012; Einstein & McDaniel, 2005). Prospective memory is necessary to take a prescribed medication at a specific time or with a certain task (eating dinner) and is also used when remembering to go to a particular event or to do a precise job at work. Aberle, Rendell, Rose, McDaniel, and Kliegel (2010) described how prospective memory is being able to remember “delayed intentions. ” Having good prospective memory is essential to succeed in life (Rose, Rendell, McDaniel, Aberle, & Kliegel, 2010). If one forgets to do something as important as taking a medication, the results could be fatal. Though most research examined prospective memory ability in older adults, prospective memory is also critical for functioning during other stages of the lifespan including emerging adulthood. The current study explored how substance use (i.e., alcohol and cannabis) in college students may have contributed to prospective memory failure and the implications for their daily functioning. Since drug use may become even more prominent in emerging adulthood, it is important to understand the repercussions these substances have on memory. General Prospective Memory Prospective memory has two main components: event based or time based (Einstein & McDaniel, 2005). Event based tasks include remembering to do a task with a certain activity (e.g., taking a medication with one’s breakfast). Time based tasks require remembering to do something at a certain time (e.g., weighing oneself at exactly nine a.m. every morning or picking up one’s children at 3:15 pm from school). Prospective memory can also be activity based (e.g., DRUG USE AND PROSPECTIVE MEMORY 4 see Griffiths et al., 2012), doing something following the completion of a specific activity. Understanding the differences between types of prospective memory is important to understand the mechanisms that underlie it. Prospective memory is a complex system that involves multiple parts of the brain. Not only is memory used, but cognitive control is also needed. The cognitive mechanisms underlying prospective memory are unclear (Schnitzpahn et al., 2014). Prospective memory relies on the prefrontal and frontal lobes (Heffernan, 2008). The hippocampus also plays an important role in prospective memory functioning. Considering that the hippocampus controls memory, it is reasonable to assume that it also plays a major role in prospective memory. It also is understandable that the prefrontal lobe is involved because it controls executive functioning, which is important to remember when to do tasks. Many aspects of the brain are not fully developed until individuals enter their mid-twenties (Arnett, 2013). It is important to note that prospective memory failures in young adults may in part be due to normal age-related changes in the brain during this early part of the lifespan. Multiple aspects of memory are utilized within prospective memory. Working memory is an important component of prospective memory (Einstein & McDaniel, 2005). Working memory is necessary to plan and remember the task while focusing on alternative tasks (Rose et al., 2010). Therefore, working memory and prospective memory are interrelated specifically when performing a prospective memory task. Einstein and McDaniel (2005) examined the performance of individuals during a lexical-decision task consisting of remembering different words. Those who also had to complete a prospective memory-task were slower at responding during the working memory task. This finding indicates a possible relation between working memory and prospective memory. DRUG USE AND PROSPECTIVE MEMORY 5 Retrospective memory is another important aspect of prospective memory. Retrospective memory is the ability to remember information previously taught (Cuttler et al., 2012). Even though prospective memory is similar to retrospective memory, it does not rely on external stimuli for retrieval, but involves other processes that may be internal (Einstein & McDaniel, 2005). On the contrary, Aberle et al., (2010) consider retrospective memory to be the opposite of prospective memory. Bearing in mind one is based on the past while the other is used in the future, this claim is reasonable. Prospective memory has multiple ways of recovering the task needing to be done. There is monitoring as well as spontaneous retrieval (Rose et al., 2010). When monitoring, individuals are in constant retrieval mode when expecting a prospective memory task to occur (Einstein & McDaniel, 2005). This monitoring may require a lot of attentional resources. In fact, retrieval monitoring demands more cognitive resources than spontaneous retrieval mode because one is continually evaluating the environment for cues (Rose et al., 2010). For example, one may need to remember to drop off mail on their way home from work. Instead of constantly reminding oneself (monitoring), it would be more cognitively beneficial to rely on spontaneous retrieval. Monitoring may interfere with other activities and therefore the spontaneous retrieval mode may be more efficient (Einstein & McDaniel, 2005). However, spontaneous retrieval mode may be confounded by individual differences, uniqueness of the event, and processing of the event (Einstein & McDaniel, 2005). Finally, Einstein and McDaniel (2005) consider reflexiveassociate theory. It is necessary for individuals to find a relation between the target cue and the intended task to help remember to perform the task. Using the example from above, it would be remembering to drop off the mail after seeing the mailbox because those two are associated together. More research is needed to explore the role of and form of retrieving modes of DRUG USE AND PROSPECTIVE MEMORY 6 prospective memory to truly understand and find the most effective method. Prospective memory is a fascinating aspect of memory that is still not clearly understood. In fact, the empirical study of prospective memory is a recent phenomenon in comparison to other areas of cognitive psychology (Einstein & McDaniel, 2005). Most research on memory has only been tested in lab settings, not in real-life situations (Ling et al., 2003). This is notable, because lab experiments do not always capture what is really happening in daily living. By finding ways to study prospective memory in natural settings, one may be able to better understand how it really works and if different factors, such as alcohol and cannabis, affect performance. Scientists are beginning to explore prospective memory in a somewhat more realistic manner such as with the Virtual Week Task. Virtual Week is a prospective memory task designed to be representative of everyday life tasks (Rendell & Craik, 2000; Rendell & Henry, 2009). Virtual Week is structured like a board game where participants roll a die and make decisions about daily activities. They are also told to match their choices to options they would likely pick in real life. The task requirement’s personalize the activity and make the experience more unique for each individual. Prospective memory is tested by containing repeated and nonrepeated tasks that individuals have to complete (Rose et al., 2010). The Virtual Week Task is a relatively new method to test prospective memory and a computerized version that became recently available was utilized in the present study (Rendell & Craik, 2000). Age and Prospective Memory Many research studies have focused on age-related differences between younger and older adults on prospective memory tasks. Prospective memory is assumed to decline with age; however other studies have reported no age-related differences (Einstein & McDaniel, 2005). DRUG USE AND PROSPECTIVE MEMORY 7 Schnitzpahn et al., (2014) emphasized that most studies have reported that prospective memory decreases with age. Nevertheless, differences in findings may be due to several factors. One major discrepancy is between natural and lab settings. Little to no age-related differences have been reported in studies conducted in natural settings (Rendell & Craik, 2000) with results of a meta-analysis (Aberle et at., 2010) indicating older adults performed better overall than young adults on real-life prospective memory tasks. Conversely, young adults tend to do better than older adults in lab-based settings (Aberle et al., 2010). Rendell and Craik (2000) proposed that although young adults may do better within the lab-setting, in real-life settings, the results are often reversed (i.e., those skills are not generalized to real life tasks). The difference between natural and lab settings raises some important questions. Are the lab setting