Tuesday, February 19, 2013

The consequences of our wandering minds


           
          Our minds wander-it's an unavoidable truth.  Studying how and why we enter these periods of unintended thought is therefore crucial to understand how our minds function.  Giambra (1995) found that the propensity of task-unrelated images and thoughts (TUITs) is a reliable measure over a variety of vigilance tasks. In these studies he used a probe-TUIT method to measure TUIT propensity, which was found to be both sensitive to conditions of a concurrent task and also able to maintain individual differences over different tasks and task conditions, as well as over short and long time-intervals. 
Consistent with past vigilance research, Giambra found that target response time was faster for the condition with a larger percentage of target stimuli. However, the reported interaction between response time and event rate was atypical, with response time progressively increasing as event rate increased.  This finding contradicts past literature, in which it has been found that an event rate of 15/min has a faster response time than that of 30/min.  In order to account for both findings, Giambra suggests that the relationship between target response time and event rate may be u-shaped (see graph below for a rough depiction). This explanation definitely raises some flags as this u-shaped curve is unsupported by past research and seems to be a forced way to make both results fit together. However, there was also no association found between response time and P-TUIT frequency, so it remains unclear what caused these unique results.
           The work of Reichle, Reineberg, & Schooler (2010) examines readers’ eye-movements in normal reading, mindless reading, and during meta-awareness, in order to assess the degree that cognition influences eye movements during normal reading. Just as Giambra used the probe- method to measure TUIT frequency, here a probe-caught mind wandering method is used to measure eye movements when participants are in the middle of mind-wandering (i.e. they have not entered meta-awareness, which occurs when mind wandering is self-caught).  Results indicate that longer text fixations are indicative of mindless reading and that the mind wanders for a considerably long time before self-caught (2-4 minutes), during which eye movements become increasingly decoupled from text processing.  This study provides evidence for the use of tracking eye movements as on-line indicators of mind wandering.  However, it is important to note the small sample size, 75% of which was female (3 females and 1 male).
            This being said, it is crucial to note the significant implications gender effect had in many of the mentioned studies. This is specifically noteworthy in the work of Antrobus, Singer, & Greenberg (1966) when testing the interaction between task significance (i.e. payoff) on responding to stimuli and amount of TUITs generated.  Researchers hypothesized that increasing the payoff of signal detection would cause a decrease in the reported occurrence of TUITs. With a starting value of $3.00, participants in three experimental conditions were told there would be a penalty for detection error (1/5, 2/5, or 4/5 cents per error). When analyzing the findings across all subjects (Figure 1), the expected increase in penalty associated with a decrease in TUITs was not as strong as predicted. However, this relationship drastically changed when gender was accounted for (Figure 2). 

             By comparing this difference between male and female subjects, researchers concluded that the predicted payoff effect was exclusively and strongly characteristic of male subjects.  They suggested that this difference might indicate that the reward of mastering the task and performing well for these “high-achieving college girls” was more important than the monetary payoff. Studies, such as that of   Vallerand & Bissonnette (1992), have found that compared to males, females tend to be more intrinsically motivated, less externally regulated, and display higher levels of behavioral persistence. Even further, this is not specific to “high-achieving college girls,” as this gender difference has been found as early as kindergarten.  These findings therefore support the proposed explanation provided by Antrobus et al. when trying to account for the reported gender effect. However, in order to measure this more accurately, researchers should have used a self-report measure to assess the importance each participant placed on monetary value and task performance.
           Further, when analyzing the probability of missing a signal (P(Miss)) as a function of penalty, increasing penalty was associated with a decrease in TUITs (P(Report)), which resulted in the predicted decrease in P(Miss) for the male subjects. A point that the authors should have addressed was the lack of gender effect in the interaction of P(Miss) and penalty (see Figure 3).  Given the significant gender effect in the interaction of P(Report) and penalty (Figure 2), would mean that, for these female subjects, P(Miss) was not inversely related to P(Report).  This suggests that the same cognitive resources were actually not being used for both TUIT and signal detection for these females. Whether this is a result of the undemanding task or the weak relation between payoff and detection accuracy, it highlights the impact that gender may play in mind wandering research.

In a study by Teasdale et al. (1995) task practice reduced the extent that task performance interfered with TUIT frequency.  Supporting past research that TUIT production and task performance both demand central resources of control and coordination, this finding suggests that practice reduces the resources demanded for the task, thus increasing resource availability for TUIT production. However, it is important to note that only female subjects were tested in these studies. After observing the gender effect in the study by Antrobus et al., I would refrain from generalizing Teasdale’s findings to male subjects.  This previously observed gender effect suggests the possibility that task practice might only mediate the central resource demands of females, as a result of their higher levels of intrinsic motivation, which may increase their likelihood to learn from practice and perform well on a task, compared to males.

            So far in this post, research has focused on the negative effects of TUITs, however, a subsequent experiment by Antrobus et al. addresses the importance of cognitive spontaneous thought, especially when incompatible with one’s existing conception of his/her projected environment.  A significant effect of pretask condition on TUIT frequency during a subsequent task was found, such that subjects exposed to a radio broadcast announcing that the US had declared war reported a significant increase in TUITs compared to the control group.
          Based on these findings, when conducting his study, Giambra acknowledged that prior events could influence subsequent TUIT frequency, and therefore manipulated whether participants played an uninteresting video game (control condition) or solved a mental puzzle (experimental condition), with the puzzle expected to produce more TUITs, as subjects would still be thinking about it during the relatively boring subsequent vigilance task. However, I do not believe that Giambra’s pretask conditions were comparable to those of Antrobus et al. While Giambra’s mental puzzle condition might engage and frustrate subjects, I would expect emotions evoked from the broadcast in Antrobus’ experiment to be much stronger with more of a lasting impression, as it presented life-changing news with serious implications directly affecting the subjects.  In addition, to me, the “condition group” of the video game sounded just as frustrating as the puzzle (if not more so) as it provided no instructions, made no logical sense, and therefore could have made subjects upset and frustrated after realizing they lacked any control in the outcome, which could have equally carried over as much distraction as the thoughts from the puzzle pretask condition.  The fact that thoughts reported by the experimental condition in the study by Antrobus et al. were related to the war and its potential effects on the subjects' lives, suggests an increase in payoff for this planful spontaneous thinking.  This is an interesting extension from Antrobus’ previous experiment (mentioned earlier) which had involved a monetary penalty for wrong detection. While in the previous experiment the payoff was within the task itself, in this later study the payoff actually came from the production of TUITs related to information provided in the broadcast.  





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