Predictive models of implicit–explicit attitudes and their utility in stock investment
Three main predictive models were derived from the literature: an additive model that occurs when the two types of attitudes predict a unique portion of the variance in the criterion [9,10], a double-dissociation model corresponding to situations where implicit and explicit attitudes are often considered particularly successful in the prediction of spontaneous and deliberate behaviors [30,31], and a multiplicative model, whereby implicit and explicit attitudes interact synergistically to affect behavior. Compared with the former two, the third model is the least tested, given its relatively frequent occurrence. However, since the mid-2000s, there have been several attempts to directly test the predictive power of the implicit–explicit attitude interplay for a range of behaviors. In his pioneering work on health-related behavior, Perugini [32] provided empirical insights into the interactive relationship between self-reported and implicitly assessed attitudes toward smoking by demonstrating how predictions about whether someone was a smoker were more accurate when respondents had positive attitudes, both explicitly and implicitly, toward smoking. Subsequently, the multiplicative effect of implicit and explicit attitudes has been replicated across different domains such as aggression [33] and bullying [34].
Although the multiplicative model seems to be relatively uncommon, we conjecture that it might be useful for the prediction of behavioral outcomes in the domain of stock investment; that is, stock return performance would be better predicted by combining self-reported (explicit) and indirectly assessed (implicit) evaluations of one’s own investment in stocks in a multiplicative fashion. A theoretical framework of financial decision-making proposed by Cheng [35] reinforces our expectation. His framework goes one step further by emphasizing the synergetic interplay between conscious thought, characterized by explicit reasoning processes that require conscious attention, and unconscious thought, conceived as implicit associative mechanisms that operate automatically or with limited conscious accessibility. Given the relatively small capacity of conscious thought (i.e., 40 to 60 bits per second) [36] compared to that of the entire human thought system, Cheng [35] proposed that unconscious thought can help reduce some of the judgmental heuristics (e.g., availability and representativeness) and behavioral biases (e.g., overconfidence and attraction effect) that people are subject to when making complex decisions on financial matters. This is due to its enormous processing capacity, which improves the quality of financial and investment decisions in general. Nordgren, Bos, and Dijksterhuis [37] provided indirect evidence for this view by examining whether a sequential combination of conscious and unconscious thoughts helps make better decisions on complex problems. The authors followed the same procedures and research design (i.e., immediate, conscious, and unconscious thought conditions[4]) as in the standard unconscious thought paradigm [38], except for including a newly created condition; in this case, participants deliberated on which apartments they would be willing to rent for a given time and were then distracted in the same interval, allowing conscious and unconscious thought to occur sequentially. Results showed that participants were more likely to choose the best apartment when they engaged in periods of both conscious and unconscious thought, compared to the other three conditions.
These facts suggest that unconscious thought is of particular value when one is faced with complex decisions that require a substantial amount of information to be processed simultaneously [39], such as stock investment decisions. We argue that measuring one’s automatic evaluations of stock investment with the IAT would help more accurately reflect unconscious[5] features of indirectly assessed attitudes, which cannot be controlled by motivation and ability [40]; as such, when considered simultaneously with implicitly assessed attitudes toward stock investment, their interplay with self-reported attitudes would provide a valid basis for making better decisions and improving performance in stock investment.
Implicit–explicit attitudes toward investment
Similarly, other studies have attempted to apply the IAT to explore the attitude–behavior relationship in risk-related domains such as risky flight behavior [41], gambling [42], and engagement in extreme sports [12]. Another example is Park, Kim, and Oh [43], who adapted the IAT to provide a measure of implicit attitudes toward how aggressively or conservatively valued one’s own investments in stocks were—namely, the Implicit Stock Investment (ISI), in which the strength of automatic associations between the target (i.e., My stock investment and BLANK) and aggressive- and conservative-related attributes (e.g., AGGRESSIVE and CONSERVATIVE) are measured as reaction times. Using a sample of students majoring in financial engineering (FE), they found that the ISI captures unique incremental variance beyond existing self-report measures of financial risk attitudes, while predicting risk-taking in a laboratory-based behavioral task (i.e., BART). Next, to understand the influence of implicit attitudes on real-life risky behavior, we sought to explore a potential link between FE major students’ attitudes toward their investments in stocks and their stock return performance. We expected these two variables to be negatively related, indicating that the FE major group’s overall rate of return on stocks would decrease, as they would respond more quickly when associating “My stock investment” with “Aggressive” than with “Conservative.” There is a growing body of evidence for this idea, suggesting that investors who report being more aggressive and tolerant of risk are more likely to make risky investments such as equities and options [44]; thus, they hold relatively fewer diversified stock portfolios [45]. Indeed, investors who allocate investments to specific industries and stock characteristics perform worse in their annual rates of return than investors with well-diversified portfolios [46]. Hence, implicitly assessed attitudes toward stock investments in the form of the bipolar IAT are expected to negatively affect the overall rate of return in the FE major group.
In line with the multiplicative model of implicit–explicit attitudes, the influence of the evaluative stock investment associations measured by the ISI on the rate of return is assumed to be conditional: we expect that the influence of implicit evaluations of one’s investment in stocks on the rate of return depends on their explicit evaluations of the level of control they are willing to exert over financial risk. Lampenius and Zickar [47] provided supporting evidence that risk control played a crucial role in predicting investment portfolio selection. In their first study, the authors provided a newly developed, self-report measure of attitudes toward financial risk, Financial Risk-Taking (FRT), that was elicited from two major factors: speculative risk (SR) and risk control (RC). Whereas SR is an internal force that causes individuals to accept greater risks for maximizing returns on investment, RC refers to a driving force that leads them to prioritize the predictability of future expected returns, cash flows, and monetary status when making investment decisions; thus, people prone to high levels of RC are more likely to prefer low-yield but relatively safe investment options, as they want to control their returns. Lampenius and Zickar [47] further investigated the predictive power of these two factors on portfolio selection in their second study examining students who majored in finance. They found that when asked to choose the preferred one from four pairs of portfolios formed by a combination of multiple assets (e.g., cash, stocks, options, and bonds), participants who scored highly in SR and RC preferred a portfolio comprised of a balanced (i.e., diversified) mix of high, medium, and low risk/return on assets.
Hence, by modelling RC as the moderator, we can expect implicit attitudes toward stock investment to positively impact the rate of return when associated with high RC. For instance, an individual harboring strong, aggressive associations with stock investment may perform better in the rate of return on stocks provided he/she becomes more explicit in controlling returns.
Method
In this study, we used a convenience sample of Korean students majoring in FE by recruiting them in collaboration with a Korean university, which established the FE department with student quotas of 40 every year. This is because the number of FE major students in the research participant pool was largely limited for reasons such as the FE department in existence less than four years and a leave of absence for mandatory military service.
Participants and procedure
Fifty-three students majoring in FE (43 males, age M = 20.53, SD = 0.64) participated in the study. Each participant received course credits for completing explicit (the FRT) and implicit (the ISI) measures of financial risk attitudes. One week after completing the surveys, they were asked to join a four-week simulated real-world stock trading competition organized by a large securities company. To encourage active participation, students were paid $5 each. At the end of the competition, participants who ranked first through sixth in the overall rate of return on their investments received additional monetary rewards ($100 for first place, $50 for second place, $30 for third and fourth place, and $20 for fifth and sixth place).
Measures
Financial risk-taking
The FRT measure has two 5-item subscales assessing speculative risk (FRT-SR) and risk control (FRT-RC) (see additional file 6) [47]. This study rates FRT-SR and FRT-RC on a Likert scale ranging from 1 (strongly disagree) to 5 (strongly agree). The Cronbach’s α were 0.65 and 0.57[6], respectively.
Implicit stock investment
We used the ISI to assess implicit attitudes toward stock investment by estimating the relative strength of automatic associations between the attributes, “AGGRESSIVE” and “CONSERVATIVE,” and the target concepts of “My STOCK INVESTMENT” and “[ ]” [43].
As with the IRT task, the ISI procedure also included a sequence of five blocks, each of which involved a categorization task where the participants were instructed to sort the target stimuli (i.e., MY STOCK INVESTMENT and open square bracket, [ ]) while simultaneously discriminating between AGGRESSIVE- and CONSERVATIVE-related words (i.e., attribute stimuli) (see Figure 3). In Block 1, the participants practiced attribute discrimination by sorting the items into the “AGGRESSIVE” and “CONSERVATIVE” categories. In Block 2, the same was done for discrimination by sorting the stimuli into “MY STOCK INVESTMENT” and “[ ]” categories.
In Block 3, they sorted the items into two combined categories, each including the target concept and attribute that shared the same response key in the preceding two blocks (e.g., “MY STOCK INVESTMENT” + “AGGRESSIVE” for the right (“5”) key and “[ ]” + “CONSERVATIVE” for the left (“a”) key). In Block 4, stimulus items for the target dimension used in Block 2 were illustrated again but their assignment key was switched. In Block 5, the participants repeated Block 3 actions with switched pairings (e.g., “[ ]” + “AGGRESSIVE” for the right key and “MY STOCK INVESTMENT” + “CONSERVATIVE” for the left key). An overall ISI score (D) was generated by subtracting the mean reaction time in test trials of the combined task (i.e., Block 3) from that in the test trials of the reversed combined task (i.e., Block 5); higher ISI scores indicate faster associations of stock investment with aggressive rather than with conservative behavior. The Cronbach’s α was 0.78.
Control variables
A brief survey was conducted to gather participants’ demographic information and their perception of external factors that could affect trading decisions, such as the investment information, stock market forecasting, international and domestic economic fluctuations, and time spent on stock trading. These factors were rated on a five-point scale from “not at all influential” (1) to “extremely influential” (5) to reflect their perceived influence on participants’ trading decisions during the competition. Along with year of study (ranging from 1 to 3 years), gender (coded female = 0; male = 1), and the average number of stocks in their portfolios as control variables, these factors were included in the analysis.
Results
Enhanced interaction of ISI with FRT-RC
Table 2 presents the correlations between the study variables. As expected, the ISI was negatively correlated with the overall rate of stock return, r = -0.24, p = .079, although it was marginally significant. However, this pattern was not reliable for FRT-RC, r = -0.16, p = .26, and FRT‑SR, r = -0.11, p = .43.
To explain the additional variance due to the interaction between ISI and FRT-RC, we employed a moderated multiple regression analysis, entering control variables in step 1, a set of predictors (i.e., FRT-RC, FRT-SR, and ISI) in step 2, the other two interactions (i.e., ISI × FRT-SR and FRT-RC × FRT-SR) in step 3, and the ISI–FRT-RC interaction in step 4.
Table 2. Correlation coefficients among the main variables for Study 2 (n = 53)
Measure
|
1
|
2
|
3
|
4
|
5
|
6
|
7
|
8
|
9
|
10
|
Individual demographics
|
|
|
|
|
|
|
|
|
|
|
1. Gender
|
-
|
|
|
|
|
|
|
|
|
|
2. Year of study
|
-.21
|
-
|
|
|
|
|
|
|
|
|
3. Investment information
|
-.10
|
.05
|
-
|
|
|
|
|
|
|
|
4. Market forecasting
|
-.40**
|
.05
|
.17
|
-
|
|
|
|
|
|
|
5. Economic condition
|
-.20
|
.002
|
.27†
|
.16
|
-
|
|
|
|
|
|
6. Time spent investing in stocks
|
.12
|
.05
|
.47**
|
.07
|
.15
|
-
|
|
|
|
|
7. Number of stocks in portfolio
|
.29*
|
.02
|
.19
|
-.21
|
-.28†
|
.25
|
-
|
|
|
|
Explicit risk
|
|
|
|
|
|
|
|
|
|
|
8. FRT-RC
|
-.04
|
-.03
|
-.15
|
.06
|
-.07
|
-.32*
|
.14
|
-
|
|
|
9. FRT-SR
|
-.05
|
.09
|
-.01
|
-.07
|
.11
|
.24
|
-.01
|
-.24†
|
-
|
|
Implicit risk
|
|
|
|
|
|
|
|
|
|
|
10. ISI
|
-.15
|
.14
|
-.21
|
-.004
|
-.05
|
-.25
|
-.26†
|
-.16
|
-.11
|
-
|
Performance
|
|
|
|
|
|
|
|
|
|
|
11. Rate of return
|
-.18
|
.05
|
-.13
|
-.04
|
.04
|
.13
|
.14
|
.15
|
-.03
|
-.24†
|
†p < .10, * p < .05, ** p < .0
As shown in Table 3 (Model 2), the three main predictors were found to be non-significant: b = 0.58, se = 0.65, p = 0.38 for FRT-RC; b = -0.15, se = 0.57, p = 0.80 for FRT-SR; b = -6.15, se = 4.04, p = 0.14 for ISI. However, critically and as theoretically expected, a significant two-way interaction effect was found only for ISI × FRT-RC (Model 4), β = 0.53, t = 2.63, p = 0.01. In addition, we conducted a bias-corrected bootstrap test with 5,000 samples to verify the moderating effect, resulting in a significantly positive interaction effect of ISI and FRT-RC on the rate of return (b = 4.17, se = 2.31, 95% CI [0.16, 8.82]).
Table 3. Moderating analysis of ISI on rates of return
Variables
|
Rate of return on stock
|
|
1
|
2
|
3
|
4
|
Step 1: Control variables
|
|
|
|
|
Gender
|
-.30
|
-.30
|
-.29
|
-.33†
|
Year of study
|
.06
|
.07
|
.04
|
.17
|
Investment information
|
-.35†
|
-.37†
|
-.41†
|
-.47*
|
Market forecasting
|
-.08
|
-.12
|
-.12
|
-.26
|
Economic fluctuations
|
.13
|
.10
|
.14
|
.16
|
Time spent investing in stocks
|
.24
|
.29
|
.31
|
.31
|
Number of stocks in portfolio
|
.28
|
.15
|
.17
|
.24
|
Step 2: Main effects
|
|
|
|
|
FRT-RC
|
|
.17
|
.13
|
.22
|
FRT-SR
|
|
-.05
|
-.06
|
.07
|
ISI
|
|
-.25
|
-.16
|
-.12
|
Step 3: Interaction 1
|
|
|
|
|
FRT-RC*FRT-SR
|
|
|
.12
|
.05
|
FRT-SR*ISI
|
|
|
-.14
|
.13
|
Step 4: Interaction 2
|
|
|
|
|
FRT-RC*ISI
|
|
|
|
.53*
|
R2
|
.18
|
.28
|
.30
|
.44
|
DR2
|
|
.10
|
.02
|
.14
|
DF
|
|
1.34
|
.44
|
6.91
|
Standardized coefficients are presented († p < 0.10; * p < 0.05)
To better understand this interaction, we plotted and tested simple slopes using values one standard deviation above and below the mean of FRT-RC.
As Figure 4 shows, a positive relationship is evident between ISI and return performance under a high level of FRT-RC (b = 8.25, se = 3.54, p = 0.03), indicating that FE students who were implicitly more aggressive about stock investments had better rates of return when they were explicitly predisposed to pursuing control over expected future returns. In contrast, the relationship was significantly negative under a low level of FRT-RC (b = -13.81, se = 2.34, p = 10-7), indicating that implicitly aggressive FE students had lower rates of return on stock when they were predisposed less explicitly to pursuing control over expected future returns.
Discussion
Study 2 provided evidence for additional benefits of the combined use of financial risk attitudes, demonstrating a complex link moderated by the FRT-RC between the ISI and stock return performance. The interaction was fully crossed, suggesting that stock return performance hinges on the levels of implicit and explicit attitudes toward financial risk. That is, being implicitly more aggressive about stock investment improved rates of return on stock when participants are more predisposed to exercising conscious control over expected future returns and lowered the return rates when they declare themselves to be less explicit in controlling financial risk. Our findings suggest that self-reported and implicitly assessed attitudes toward financial risk, as measured by the FRT-RC and ISI, complement each other in terms of predicting overall rates of return.
[4] Most studies following the unconscious thought paradigm involved three conditions: immediate, conscious, and unconscious. All participants, regardless of condition, encountered a complex decision problem that required them to make a choice between multiple options (e.g., apartment A-D), each with different combinations of positive (e.g., a very nice area) and negative (e.g., rather noisy) attributes. The participants were then asked either to select one of the apartments immediately (the immediate condition) or think about the decision for a couple of minutes (the conscious thought condition), or perform a distraction task (assumed to elicit unconscious thought while directing their attention away from the decision problem; the unconscious thought condition) and then make a decision.
[5] In their review of studies on attitudes, Gawronski et al. [40] found that people are unaware of how their implicit attitudes can impact psychological/behavioral processes outside of conscious awareness and suggested that such unconscious influences can be interpreted as evidence for unconscious features of indirectly assessed implicit attitudes.
[6] The FRT-RC’s reliability coefficient was re-estimated using McDonald's Omega (ω) index, a newly recommended indicator which is less biased than Cronbach's alpha [48], indicating a ω of 0.62 (ω values above 0.6 indicate adequate internal consistency).