Picture yourself in a packed lecture hall where the professor is illustrating how to analyze an extensive set of data from a longitudinal study. The analysis involves multiple complex components, and you diligently follow along, taking notes on your computer for later review. The room hums with the dull clatter of keyboards as students diligently take notes, their screens going back and forth between slides containing equations and graphs previously projected onto the board. As you’re jotting down a specific equation and attempting to comprehend your professor’s explanation of its significance to the analysis, you notice the person to your right reading a text message that just appeared on their screen. Believing in their multitasking abilities, they continue copying notes, listening to the lecture, and occasionally responding to the text conversation when a notification appears on their phone. To your left, you notice someone who looks inattentive and is doodling relentlessly in their notebook. Clearly, the person to your left is not paying attention to the lecture and seems to be adrift in their own thoughts. Considering the additional demands of responding to the texts while trying to encode the presented information, one would expect the student attempting to multitask will not perform well on an upcoming examination of the covered material. Similarly, your classmate that is mind wandering, will also likely not perform as well as they could if their attention was focused on the lecture.
Substantial evidence exists that multitasking impairs task performance, especially when one of the tasks is difficult (e.g., Adler & Benbunan-Fich, 2012; 2015), There is also a plethora of evidence that mind wandering (e.g., Randall et al., 2014; Thomson et al., 2014) impairs performance, yet recent evidence suggests that some learning may occur even when one is mind wandering (Brosowsky et al., 2021). Brosowsky et al. (2021) used a serial reaction time task (SRT) with implicit- and explicit-learning conditions to evaluate whether implicit learning occurs even when participants report mind wandering. Their results suggest that the degree of mind wandering was negatively associated with learning in the explicit condition (i.e., greater mind wandering led to poorer performance) but not in the implicit condition.
They interpreted their results as suggesting that mind wandering is associated with impaired explicit learning, but not impaired implicit learning and that that explicit learning is impaired under attentional load, but implicit learning is not. This final claim—implicit learning is not impaired under attentional load—was not directly tested. Brosowsky et al. (2021) did not have participants attempt to complete the SRT while concurrently completing an explicit learning task, but rather participants in the explicit condition were told about the repeating pattern in the SRT and to try to learn the pattern. The aim of the current study was to replicate the finding that implicit learning occurs during mind wandering, and to extend Brosowskyet al.’s findings by evaluating whether implicit learning can occur while a concurrent attention demanding (explicit learning) task is also being performed.
Brosowsky et al. (2021) used the SRT, an implicit task, to assess whether participants exhibited implicit learning when reporting instances of mind wandering. Before delving into the specifics of this implicit learning task, it is crucial to fully understand the distinction between the underpinnings of implicit learning and its counterpart, explicit learning. Implicit learning refers to a type of learning that occurs under the absolute threshold when information is obtained by the individual unconsciously and not intentionally (Kaufman et al., 2010). Several investigations of implicit learning suggest that implicit learning functions automatically when attention is directed towards a stimulus at a relatively low-level perceptually, without the dedication of executive attention resources (Cowan, 1995; Frensch & Miner, 1994). Explicit Learning, on the other hand, can be defined as a type of learning in which the individual deliberately and intentionally obtains information (Stadler, 1997). When explicit learning occurs, information is actively being sought out. Graf and Schacter (1985) state that “explicit memory is revealed by intentional recollection from a specific previous episode, whereas implicit memory is revealed when performance on a task is facilitated without deliberate recollection from a specific learning episode” (pp. 501). Put differently, explicit learning is purposeful acquisition of knowledge, while implicit learning is unintentional or incidental acquisition of information. Regarding the difference between explicit and implicit learning tasks, explicit learning tasks are organized to offer precise instructions and an emphasis on conscious comprehension whereas implicit learning tasks are defined by the indirect and experiential nature, which features minimal explicit guidance and feedback (Heuer et al., 2001).
In the experiment conducted by Brosowsky et al. (2021), participants completed a SRT task during which they were presented with a sequence of visual stimuli in a predetermined sequence on a computer screen and were instructed to respond to the stimuli by pressing corresponding buttons on a response box. Participants were instructed to respond quickly without sacrificing accuracy. Participants were assigned to one of two groups. The “explicit” group were informed that the stimuli were to be presented in a predetermined sequence and instructed to attempt to memorize the sequence. Those in the “implicit” group did not receive any information about the sequence and were simply instructed to respond to the stimuli by pressing the corresponding keys. While completing the SRT, participants were also required to respond to several mind wandering probes during which they indicated the degree to which they were mind wandering during the task. Following the presentation of the sequence in several blocks of trials participants completed two tasks to determine if they had explicitly learned the sequence: one required to participants to attempt to recreate the stimuli sequence and the second required participants to recreate it backward.
Based on the results of the experiment, Brosowsky et al. (2021) reported that implicit learning does in fact occur while mind wandering is occurring. Put differently, in the implicit condition, participants’ responses in the during the SRT became faster over the course of the experiment no matter the degree to which they reported mind wandering whereas performance of those in the explicit condition suffered as the degree of mind wandering increased.
Mind Wandering
While the relationship between mind wandering and implicit learning may be complex, there are theoretical explanations of the Brosowsky et al. (2021) results. Mind wandering is defined as a shift from an ongoing activity to task-unrelated thoughts (TUTs). These TUTs are extremely common. Extant research suggests that we mind wander 30%–50% of the time (Levinson et al., 2012; McVay & Kane, 2012). It is also clear from the extant literature that TUTs typically lead to decrements in performance in the ongoing activity (McVay & Kane, 2012; Unsworth & McMillan, 2013). Smallwood and Schooler (2006) stated that mind wandering demands attentional (executive control) resources. This demand on executive control draws resources away from the task at hand without proper metacognitive monitoring. However, the extant literature has focused on how TUTs impair performance on explicit learning and other tasks in which attentional resources are required. Little to no research has focused on the impact of mind wandering on performance on implicit learning tasks prior to Brosowsky et al. (2021). Extant literature suggests that implicit learning, specifically implicit sequence learning, is not working memory or attention resource demanding (Janacsek & Nemeth, 2013) and thus allows for mind wandering to occur during the implicit task. Put differently, there are more working memory resources allowed for mind wandering because implicit learning is not resource demanding.
In summary, participants can implicitly encode information when their cognitive resources aren’t exclusively focused on memorizing the pattern. Based on Brosowsky et al. (2021)’s findings, it can be inferred that there are available cognitive resources during instances of implicit learning. This surplus capacity may allow for mind wandering during implicit learning, thus the potential for success in implicit sequence learning tasks even if mind wandering is occurring, as evidenced by the Brosowsky et al.’s findings in the data. The question that remains unanswered is whether the cognitive resources that are not called upon for the successful completion of an implicit sequence learning task can be recruited for the successful completion of a concurrent explicit learning task. Put differently, can an individual successfully multitask if one task is an implicit learning task and the other an explicit learning task?
Multitasking
Multitasking is defined as a shift in attention to perform several independent but concurrent tasks (Adler & Benbunan-Fich, 2012). Multitasking is considered to have two key components: task independence and performance concurrency (Benbunan-Fich et al., 2011). Independence requires that ongoing tasks are self-contained, and the notion of concurrency requires that multiple tasks are carried out with some temporal overlap. At the personal level, multitasking involves one dividing their mental resources among various tasks. The effectiveness of managing multiple tasks is influenced by the nature of the tasks and the available mental resources (Spink et al., 2008; Waller, 1997). To understand how multitasking affects an individual, it is also important to consider an individual’s environment when they are multitasking. Multitasking is a phenomenon that occurs in various settings: at the workplace, in classrooms, while performing household chores at home, and even during focused study sessions. In an investigation of multitasking in college students, Calderwood et al. (2014) measured how often and for how long college students engage in media multitasking while doing schoolwork outside of class. Calderwood established that on average, students faced 35 distractions in a 3-hour independent study session, spending roughly 26 minutes (around 14% of the study time) on these distractions. The results of Calderwood et al. highlight the significance of multitasking in students’ lives and underscores the expectation for students to engage in multitasking for academic success. Based on the findings from Calderwood et al.’s research, when students multitask at elevated levels, it is foreseeable that errors may occur while attempting to complete various tasks simultaneously. Regarding the connection between accuracy and multitasking, Junco (2012) investigated the impact of non-academic social media use in a classroom setting on students’ overall semester GPA. Junco found that “indeed, frequency of multitasking with certain information and communication technologies (Facebook and text messaging) were negatively predictive of overall semester GPA” (Junco, 2012). Junco’s results suggest that students who multitask during classroom study are less likely to achieve academic success. This is likely attributed to the challenge students face in dividing their attention among various stimuli, often giving excessive focus to unrelated and unimportant activities like texting and Facebook messaging. The results also suggest that students are better served by concentrating on a single attentional demand, as multitasking tends to result in poorer performance.
If we consider multitasking from a cognitive resource perspective (e.g., attention, working memory), attempting to complete more than one task at the same time should require more executive control resources, if the tasks are explicit in nature. However, if Brosowsky et al.’s (2021) conclusions that implicit learning is not resource demanding are correct, then one might hypothesize that it is possible to implicit learn while one is engaged in completing a concurrent explicit task.
Current Study
In the current investigation, we aimed to replicate the observation that implicit learning may occur during mind wandering. Furthermore, we hope to expand on Brosowsky et al.’s (2021). research by exploring whether implicit sequence learning can occur concurrently with a demanding attention task (explicit learning). In two experiments, participants were presented with a SRT task paired with an unrelated video lecture. The SRT task is a common task used amongst various fields of psychology (Robertson, 2007). A SRT is frequently used to measure implicit sequence learning (Schwarb & Schumacher, 2012) and focuses on overcoming obstacles associated with explicit learning of sequence information (Lashley, 1951). Thus, the SRT is appropriate for the implicit learning demand for this experiment. In our SRT task, there were four response options corresponding to colored keys on a keyboard. On each trial an X in one of four colors (blue, green, red, or yellow) appeared on the screen and participants had to press the corresponding key as quickly as possible. The stimuli occurred in a predetermined sequence about which the participants were not informed. In this replication and extension, we hypothesized that implicit sequence learning (in the SRT) would occur even when participants report mind wandering and a secondary task with explicit attentional demands (video lecture) is administered concurrently with the implicit task. The results of this replication and extension will provide valuable insights into human multitasking capabilities and understanding of implicit sequence learning.
General Discussion
The objectives of the current study were to replicate Brosowsky et al.’s (2021) findings that implicit learning takes place during episodes of mind wandering and to expand upon their findings by examining whether implicit learning can also take place while individuals engage in a concurrent attention-demanding task (explicit learning). In both experiments, it was observed that participants implicitly learned a sequence of 12 items, regardless of their understanding of the concurrent video content. Even those who appeared to more actively engage with the video and performed well on the multiple-choice questions showed improved performance on the implicit learning task (SRT).
We anticipated significant instances of mind wandering among participants. Given the seemingly mundane nature of the SRT task and intentionally uneventful video pairing, we expected participants to report instances of mind wandering. However, upon analyzing the data, only 8 out of 94 participants reported mind wandering in the first experiment, and 11 out of 111 participants in the second experiment. While this might initially appear as accurate reporting, it’s crucial to compare the reported mind wandering instances with participants’ scores on the explicit learning task. In the first experiment, participants averaged 43% on the multiple-choice questions based on the video, and in the second experiment, the average score was 42%. Given these failing scores alongside the meager number of reported instances of mind wandering, it can be inferred that most participants were not truthful in their responses to the probes. If participants were genuinely focused on the video, they should have theoretically performed better on the multiple-choice questions. We suspect that participants may have been apprehensive about potential repercussions, leading them to report paying attention to the video due to a social presentation bias. Since participants were told to pay attention to the video during the instructions they may have been wary of reporting that they were mind wandering. It is also possible that because the instructions were to attend to the video, participants did do their best to attend to the video.
An alternative explanation regarding the lack of mind wandering reported, is that participants did not mind wander as much as we anticipated. Regarding the low scores on the quiz, although low, the scores were indeed above chance suggesting that participant did, at least in part, pay attention to the video. At the same time, participants’ response time to the SRT did in fact decrease indicating implicit learning of the sequence. Therefore, it may well be that participants were engaged in the two concurrent tasks and thus did not mind wander. In either case, we cannot draw any conclusion regarding the replication of Brosowsky’s work, or the influence of mind wandering on implicit learning.
This does not limit our ability to draw conclusions regarding the multitasking aspect of the current study. Again, participants on average performed better that chance in both experiments on the quiz. The correlation between quiz performance and change is reaction time during the SRT was not significant. This indicates that the amount of engagement with the video did not impact implicit learning of the SRT sequence. We conclude that one can implicitly learn a sequence of stimuli while engaged in an attention demanding explicit task.
It is important to note that our findings may not generalize to other implicit learning tasks. The SRT is simple sequence task of which increased performance may be partially due to procedural learning. Other implicit learning tasks, such as artificial grammar learning, may require other processes not captured by the SRT and thus may lead to different results. It may also be difficult to generalize our results to other explicit learning tasks. The video lecture was essentially a passive listening task. Tasks that require greater engagement and cognitive resources may not produce the same results. Future research should vary the implicit learning task and the explicit task to further test these hypotheses.
Conclusion
Two separate experiments were carefully designed and conducted to gather more information on the relationship between implicit and explicit learning. The research conducted also covered the topics of mind wandering and multitasking’s impact on implicit learning. We aimed to measure whether implicit learning occurred when participants reported mind wandering while a secondary task with explicit attentional demands was administered concurrently with the implicit task. We hypothesized that implicit learning would occur, even while the participant was engaged in an explicit learning task, and reporting that they were mind wandering. Overall, our hypothesis was correct, and our data support our conclusion that individuals can implicitly learn while engaged in an explicit task. In our experiment, participants were able to complete the serial reaction time task more quickly and accurately over a time, essentially learning the pattern implicitly even while they were engaged in an explicit task. In the second experiment, when the pattern was abruptly changed, there was a measurable spike in reaction time during the SRT task indicating that any sequence learning was implicit, not explicit or dependent on episodic memory for the sequence. Our results suggest that multitasking is possible if one of the tasks is explicit and one is implicit.