Do Subliminal Hints Facilitate Sequential Planning When Solving a Spatial Insight Problem?
Hiromitsu Miyata1, 2, Hitoshi Otagiri3, Hiroaki Suzuki4*
1Center for Research and Development of Higher Education, The University of Tokyo; 2Human Innovation Research Center, Aoyama Gakuin University;
3Graduate School of Social Informatics, Aoyama Gakuin University; 4College of Education, Psychology and Human Studies, Aoyama Gakuin University
*Correspondence: Hiroaki Suzuki (E-mail: [email protected])
Introduction:
Subliminal information has been suggested to facilitate insight problem solving. Previous studies using the T-puzzle, a spatial insight problem, showed that subliminally presented hint stimuli cause better
solution performance and greater relaxation of constraints when actually solving the problem later (Suzuki & Fukuda, 2013; see also Suzuki et al., 2014). The present study examined whether such presentation of subliminal hints
may influence not only retention of the goals but also planning of sequential steps required to solve the nine-dot problem, another type of spatial insight problem. Using continuous flash suppression (CFS), participants were
subliminally presented with either an image depicting the entire solution of the problem, the three steps to solve the problem in a sequential order, or a simple image of the nine dots that does not involve solution of the problem.
Dynamic Constraint Relaxation Theory of Insight:
◆ Assumes three kinds of constraints (object-level, relational, and goal) and their relaxation mechanism.
◆ Constraint: Humans’ natural tendencies to select appropriate options and exclude inappropriate ones out of
the huge amount of information.
Influence of Subliminal Information on Insight Problem Solving:
◆ The T-puzzle: A spatial insight problem consisting of four
polygonal shapes that have to be put together to form a capital T.
- Object-level constraint: Tendencies to place each piece in a stable
position – Putting the pentagon horizontally or vertically to the
reference line.
- Relational constraint: Tendencies to make a good-looking shape
having fewer convex corners – Filling the concave corner of the
pentagon.
Suzuki and Fukuda (2013) – Adults subliminally presented with the solution of the T-puzzle using continuous
flash suppression (CFS) subsequently solved the problem faster and showed greater relaxation of constraints.
Suzuki et al. (2014) – Adults having a secondary task (tapping) during subliminal hint presentation later
tended to show better solution performance and greater relaxation of constraints when solving the T-puzzle.
→ Activated executive mechanisms involved in working memory later facilitated violation of constraints?
◆ The Nine-dot Problem: A spatial insight problem to connect the
nine dots with no more than four straight lines without lifting your
pencil from the paper.
- Constraints to draw lines within the square-shaped frame defined
by the nine dots have to be violated to attain correct solution.
- Suitable for examining sequential steps required to achieve insight
problem solving.
Hattori et al. (2013) – Adults subliminally presented with the hint as
masking images (33 ms) during a movie (56 s) on an LCD display
projector more frequently attained correct solution while frequently
showing solutions that had the same structure as the hint.
→ Suggests significant effect of subliminal stimulation.
Methods
Participants:
◆ 27 Japanese university students (19 females; Age: 19–23 (mean=20.5) years).
- Assigned to the no-hint (n=10), whole-hint (n=7), or sequential-hint (n=10) groups.
- The other 18 reporting prior experience with the problem or recognizing the hint during CFS were
excluded.
Settings:
◆ A laptop computer (CF-SX3YEABR, Panasonic, Japan; CPU: Intel(R) Core(TM) i5-4200U 2.29 GHz) connected to a 24.1-inches external LCD monitor (RDT242WH, Mitsubishi, Japan).
◆ A stereoscope for creating binocular rivalry (TKK 129, Takei Scientific Instruments, Japan): Located
adjacent to the participant’s eyes.
◆ Program for visual stimuli: Written in Microsoft Visual Basic 2012
Stimuli and Procedure:
Test stimulus
(5-7 degrees in visual angle)
No-hint
Whole-hint
Sequential-hint
Hint stimulus/stimuli (each condition)
Phase 1: Dominant Eye Assessment
Phase 2: Presentation of Subliminal Hints
(1) A small red cross presented to each eye: To adjust the mirrors in the stereoscope so that one cross is visible.
(2) The changing colored geometrical stimuli (refresh rate: 30Hz) (dominant eye) and the instruction stimuli
(colored cross) (non-dominant eye): To explain CFS (10 s).
(3) One of the test stimuli presented (non-dominant eye): To confirm that the test stimulus was not perceived three
times consecutively, and to determine the brightness of the hint (-85, -90, or -95% of the original image).
(4) Hint stimulus/stimuli presented once (non-dominant eye): 9 s for the whole-hint condition; 3 s for each
sequential step for the sequential-hint condition (either clockwise or counterclockwise).
Phase 3: Solution of the Nine-dot Problem
- Solved the problem using a mechanical pencil and sheets of paper on which the nine dots are depicted.
- Verbal advice given after 15 minutes (–18 min.). - Camcorder recording conducted during solution.
Purpose and Hypothesis of the Present Study:
◆ To examine whether subliminal information influence not only retention of the goals but also
planning of each sequential step required to solve an insight problem.
→ Experiment using the nine-dot problem and CFS.
◆ In addition to the facilitatory effect of subliminally presented entire solution of the problem,
subliminally presenting each sequential step to complete the problem may enhance use of solution
strategies that correspond to those that participants had seen unconsciously.
◆ Proportion of solvers for each condition
N
% solvers
% solvers
Condition
Total (No advice) (Advice)
No-hint
10
30.0
40.0
Whole-hint
7
42.9
57.1
Sequential-hint 10
20.0
50.0
Results
◆
Constraint Relaxation: Extensions beyond the Frame
Mean (SD) N extension Mean (SD) % extension
All
Present in hintAll
Present in hint
No-hint
4.0 (6.0) 0.8 (1.3) 3.5 (4.8) 1.0 (1.8)
Whole-hint
5.1 (7.3) ＊ 1.6 (2.0) 5.8 (5.5) + 1.5 (1.5)
Sequential-hint 2.6 (2.8) 0.2 (0.6) 2.8 (3.1) 0.4 (1.1)
Condition
*: U=18.500, p=0.045
(Mann-Whitney U test)
+: U=19.500, p=0.061
(proportions arcsine transformed)
Discussion:
Participants presented with the entire solution of the problem tended to show better solution performance and greater relaxation of constraints than those in the remaining two conditions, even though statistical
support was limited. By contrast, sequential presentation of the solution during CFS neither improved solution performance nor elicited solution strategies corresponding to those that participants had seen unconsciously. These
results indicate that subliminal information may be stored as a global and static visuo-spatial representation to influence solution but may not involve planning of each step to achieve insight problem solving. Comparing the present
data with those from non-insight sequential planning tasks should be one promising way forward so that the present paradigm of subliminal priming could be applied to improve performance and motivation of office workers.
References:
Suzuki, H., & Fukuda, H. (2013). Unconscious nature of insight problem solving: An analysis using subliminal priming by continuous flash suppression. Cognitive Studies, 20, 353-367 (in Japanese).
Suzuki, H., Fukuda, H., Miyata, H., & Tsuchiya, K. (2014). Exploring the unconscious nature of insight using continuous flash suppression and a dual task. Proceedings of the 36th Annual Conference of the Cognitive Science Society, 2955-2960.