Effects of Visual Anchors in Sequential Presentations of Data
Visualization
Authors: Tang Xinyi , Wang Linlin , Peng Ningyue , Xue Chengqi 
Published: February 2023

Nowadays, people need to process a great deal of complex information,
and make more elaborate estimations or decisions. One particular concern
when handling complex information is that the first piece of information
tends to bias cognition and results in estimation deviation, which is
referred to as the anchoring effect. Currently, some researchers on
information visualization suggest that anchoring effects can not only be
found in classical numerical anchors, but in the form of visual anchors.
Recent research concerning the anchoring effects in visualization
investigated the existence of anchoring effects in a variety of forms and
tasks of data visualization. However, these studies seem to focus only on
evaluating whether users are subject to anchoring biases in a way similar to
previous studies from psychology, and it is still unclear how various
sequential presentations of information affect decision-making. The present
study is aimed to investigate the effects of different presentations of
anchors on the performance of decision-making, thus providing some support
for mitigating this kind of cognitive bias.Methods To investigate, two
within-subjects experiments were performed. In both experiments,
participants were tasked to estimate the value of target stimuli, which
presented after anchoring stimuli. In Experiment 1, A 2 (anchor value:
higher vs. lower) ×2 (anchor source: experimenter-provided vs.
self-generated) experimental design was adopted, to check if these factors
of anchoring stimuli play a role in numerical estimation. Based on the
results of Experiment 1, showing no anchoring effects under the condition of
self-generated anchors, the purpose of Experiment 2 was to evaluate how
different presentations of experimenter-provided anchors (with four
conditions: control, clockwise, counterclockwise, and vertical) facilitate
or hinder visual information processing, thus affecting decision-making.
User behavior and performance in decision-making were assessed through
multiple behavioral metrics, including an estimation value metrics, an
estimation accuracy metric based on the correctness and a time-of-task
metrics.Results Evidence of anchoring effects was presented by analyzing a
variety of presentations of visual anchors. The data of Experiment 1
revealed that when responding to experimenter-provided anchors, the
estimation of the target stimuli was affected by the prior anchoring
stimuli, while the same results were not observed under the condition of
self-generated anchors. It is shown in the Experiment 2 that these four
different types of visual anchors were comparable on most metrics, and there
are significant differences between three experimental groups and the
control group. Then implications of our results on future work was
discussed, such as the need for more physiological and electrophysiological
methods to investigate underlying neural mechanisms, and raise concerns on
how to alleviate anchoring biases through the design of data visualization.
Conclusions To sum up, the existence of anchoring effects in data
visualization was uncovered under two sources of anchors. Moreover, the
effects of anchors of different presentations on decision-making was
evaluated by comparing four types of visual anchors through various
behavioral metrics. Our findings of this study open the potential for
discovering biased visual information processing and judgements, as well as
bring some insights into the design of data visualization, which might be
applied to information visual analytic systems.