Quick note for future self: Here’s study that was testing number-of-variables one could compare (here on SciHub, for now).
Abstract (emphasis mine)
The conceptual complexity of problems was manipulated to probe the limits of human information processing capacity. Participants were asked to interpret graphically displayed statistical interactions. In such problems, all independent variables need to be considered together, so that decomposition into smaller subtasks is constrained, and thus the order of the interaction directly determines conceptual complexity.
As the order of the interaction increases, the number of variables increases. Results showed a significant decline in accuracy and speed of solution from three-way to four-way interactions. Furthermore, performance on a five-way interaction was at chance level. These findings suggest that a structure defined on four variables is at the limit of human processing capacity.
Method
Participants
To optimize expertise for the task, we recruited 30 participants who were academic staff and graduate students in psychology and computer science and had experience in interpreting the type of data presented.
Materials
Each problem involved selecting the correct form of a verbal description to match a graphical representation of an interaction based on fictitious data on one of six everyday topics (see Figs. 1 and 2). The verbal descriptions were written so as to suggest that the lowest level of difference between pairs be treated as a single entity, such as a preference or difference (e.g., “People prefer fresh cakes to frozen cakes”). The sentences then described how the other variables in the interaction affected that preference entity (e.g., “The difference between fresh and frozen increases from chocolate cakes to carrot cakes”). Thus, the construction of the sentences encouraged conceptual constructions as described in the representational analysis just presented, in which a difference between two levels of one variable is operated on by further variables. To keep the complexity of the tasks equal at all levels of interaction, we used only binary variables.
The materials were designed to equalize all task characteristics except for complexity. In the crucial comparisons, the input memory load was kept as constant as possible by equalizing the amount of verbal information and the number of bars. Thus, 2 two-way interactions were compared with a three-way interaction using 8 bars (as shown in Figs, la and lb) and 2 three-way interactions were compared with a four-w
Quick note for future self: Here’s study that was testing number-of-variables one could compare (here on SciHub, for now).
Abstract (emphasis mine)
Method