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<article xmlns:xlink="http://www.w3.org/1999/xlink">
  <front>
    <journal-meta>
      <journal-title-group>
        <journal-title>Published by CEUR-WS.org</journal-title>
      </journal-title-group>
      <issn pub-type="ppub">1613-0073</issn>
    </journal-meta>
    <article-meta>
      <title-group>
        <article-title>Information Overload and Usage of Recommendations</article-title>
      </title-group>
      <contrib-group>
        <contrib contrib-type="author">
          <string-name>Muhammad Aljukhadar</string-name>
          <email>Muhammad.aljukhadar@hec.ca</email>
          <xref ref-type="aff" rid="aff1">1</xref>
        </contrib>
        <contrib contrib-type="author">
          <string-name>Sylvain Senecal</string-name>
          <email>Sylvain.senecal@hec.ca</email>
          <xref ref-type="aff" rid="aff2">2</xref>
        </contrib>
        <contrib contrib-type="author">
          <string-name>Charles-Etienne Daoust</string-name>
          <email>charles-etienne.daoust@hec.ca</email>
          <xref ref-type="aff" rid="aff0">0</xref>
        </contrib>
        <contrib contrib-type="author">
          <string-name>General Terms</string-name>
          <xref ref-type="aff" rid="aff3">3</xref>
        </contrib>
        <aff id="aff0">
          <label>0</label>
          <institution>Cossette Communication, Canada</institution>
          ,
          <addr-line>1-514-340-6980</addr-line>
        </aff>
        <aff id="aff1">
          <label>1</label>
          <institution>HEC Montreal</institution>
          ,
          <addr-line>3000 Cote-St-Catherine, Montreal</addr-line>
          ,
          <country country="CA">Canada</country>
          <addr-line>H3T2A7, 1-514-340-7012</addr-line>
        </aff>
        <aff id="aff2">
          <label>2</label>
          <institution>HEC Montreal</institution>
          ,
          <addr-line>3000 Cote-St-Catherine, Montreal, CanadaH3T2A7, 1-514-340-6980</addr-line>
        </aff>
        <aff id="aff3">
          <label>3</label>
          <institution>Management</institution>
          ,
          <addr-line>Measurement, Design, Theory.</addr-line>
        </aff>
      </contrib-group>
      <pub-date>
        <year>2010</year>
      </pub-date>
      <volume>612</volume>
      <fpage>26</fpage>
      <lpage>33</lpage>
      <abstract>
        <p>This research examines the antecedents of information overload and recommendation agents' consultation and their effects on reactance and choice quality. We propose that information overload and the user need for cognition affect the tendency to employ decision heuristic (consulting a recommendation agent) and shape the user reactance to recommendations. A fully randomized experiment with different levels of information loads that involved 466 individuals with the task of choosing a laptop and the option to consult a recommendation agent is performed. Results show that users opted to consult the recommendation agent more as information loads and as perceived overload increases and that product recommendations were salient in enhancing choice, particularly when the information was less diagnostic (for choice sets with proportional distribution of attribute levels across alternatives). Results further reveal that as perceived overload increases, people show less reactance to recommendations. Whereas users consulting the recommendations at higher overload levels had generally better choices, they showed higher confidence in their choices only when they conform rather than react to recommendations.</p>
      </abstract>
      <kwd-group>
        <kwd>Factors</kwd>
        <kwd>Performance</kwd>
      </kwd-group>
    </article-meta>
  </front>
  <body>
    <sec id="sec-1">
      <title>-</title>
      <p>Agents,
Information
Overload
Theory,</p>
    </sec>
    <sec id="sec-2">
      <title>1. INTRODUCTION</title>
      <p>
        When making purchase decisions, users typically process large
amounts of information. As people shop online to save time and
effort, retailers are required to effectively manage product
information delivered on their e-stores. The many choice
possibilities associated with large choice sets represents an
opportunity and challenge for consumers and retailers [
        <xref ref-type="bibr" rid="ref7 ref9">7, 9</xref>
        ]. To
help customers reduce the cognitive effort while enhancing their
decision, retailers incorporate on their e-stores agents that filter,
optimize, and organize product information. Product
recommendations are decision-aid tools that support rather than
replace consumer decision-making by suggesting one or more
product that closely matches consumer preferences [
        <xref ref-type="bibr" rid="ref26">26</xref>
        ]. In effect,
decision support systems are heuristics that partly alleviate
processing effort while maintaining an acceptable level of choice
accuracy [
        <xref ref-type="bibr" rid="ref10">10</xref>
        ]. Xiao and Benbasat [28 p. 137] recently provide an
extensive review of the RA literature, and conclude that “by
providing product recommendations based on consumers’
preferences, RAs have the potential to support and improve the
quality of the decisions consumers make when searching for and
selecting products online as well as to reduce the information
overload facing consumers and the complexity of online
searches.” This explains why 40% of retailers plan to integrate
some personalized recommendations on their e-stores [
        <xref ref-type="bibr" rid="ref6">6</xref>
        ].
While research studied various designs of recommendation
agents, it has not investigated the factors triggering consumers to
consult the recommendations nor the cases where product
recommendations are vital to choice enhancement [
        <xref ref-type="bibr" rid="ref10 ref27 ref28">10, 27, 28</xref>
        ].
Indeed, research is yet to assess the factors that lessen the user
reactance to recommendations [
        <xref ref-type="bibr" rid="ref7">7</xref>
        ]. Lurie [18 p. 484] indicates that
“… in the age of the Internet, developing an understanding of how
information-rich environments affect consumer decision making
is of crucial importance. Given the disparate ways in which
product information can be presented to consumers and the high
potential for information overload in online environments, it is
important to use measures that capture the multiple dimensions of
information.”
The contribution of this article is four-fold. First, the article
examines the relation between the delivered information load in
the choice set and perceived overload by simultaneously
manipulating the number of alternatives, number of attributes, and
the distribution of attribute levels across the alternatives. Second,
it assesses the role of information overload on employing decision
heuristics (the tendency to consult the recommendation agent)
while considering the role of need for cognition. Third, it
investigates how information overload and need for cognition
shape users’ reactance to recommendations. Fourth, it examines
the impact on choice quality and confidence. We next briefly
review the literature and present the study conceptual framework.
The methodology section reports the details of the pretest and the
experiment. Results are then presented. The paper concludes with
a summary of findings and implications on theory and practice.
      </p>
    </sec>
    <sec id="sec-3">
      <title>2. CONCEPTUAL FRAMEWORK</title>
      <p>
        Research showed the effects of information overload on the
choice and purchase of different products: Laundry detergent [
        <xref ref-type="bibr" rid="ref13">13</xref>
        ],
rice and prepared dinner [
        <xref ref-type="bibr" rid="ref14">14</xref>
        ], peanut butter [
        <xref ref-type="bibr" rid="ref25">25</xref>
        ], houses [
        <xref ref-type="bibr" rid="ref19">19</xref>
        ],
calculators [
        <xref ref-type="bibr" rid="ref18">18</xref>
        ], and CD players [
        <xref ref-type="bibr" rid="ref17">17</xref>
        ]. Research indicates that
variations in the amount of information impact the decision
processes, which affects decision quality. Information overload
Copyright © 2010 for the individual papers by the papers' authors. Copying permitted only for private and academic purposes.
      </p>
      <p>
        This volume is published and copyrighted by its editors: Knijnenburg, B.P., Schmidt-Thieme, L., Bollen, D.
happens because of humans’ limits in assimilating and processing
information within any timeframe [
        <xref ref-type="bibr" rid="ref13 ref19">13, 19</xref>
        ]. When consumers are
faced with high levels of information, their limited capacity to
process information becomes overloaded, which results in
dysfunctional consequences such as cognitive fatigue and
confusion [
        <xref ref-type="bibr" rid="ref16 ref20 ref21 ref25 ref8">8, 16, 20, 21, 25</xref>
        ].
      </p>
      <p>
        Several measures were used to capture the amount of product
information. Researchers have traditionally manipulated the
alternative and attribute levels in product choice sets [
        <xref ref-type="bibr" rid="ref13 ref19">13, 19</xref>
        ].
      </p>
      <p>
        While this line of research has made substantial contribution,
discrepancies were noted [
        <xref ref-type="bibr" rid="ref12 ref19 ref20 ref21">12, 19, 20, 21</xref>
        ]. More recently, the
concept of information structure was introduced and shown to
have a role in determining overload; this concept asserts that when
measuring information loads, both the number and probability of
outcomes should be considered (for a discussion, see [
        <xref ref-type="bibr" rid="ref18">18</xref>
        ]). When
the distribution of attribute levels for instance is proportional
across the alternatives (e.g., half the laptops in a given choice set
are equipped with Intel and half with AMD processors),
information load will be higher than for a disproportional
distribution (e.g., 3/4 with Intel and 1/4 with AMD processors).
      </p>
      <p>
        This is because a disproportional distribution increases
information diagnosticity [
        <xref ref-type="bibr" rid="ref18">18</xref>
        ]. Information load in a choice set
can hence be affected by the number of alternatives, number of
attributes, as well as the distribution of attribute levels across the
alternatives (attribute distribution hereafter) [
        <xref ref-type="bibr" rid="ref17 ref18">17, 18</xref>
        ]. One purpose
of this research is to manipulate these three dimensions over a
range that is wider than prior work and to assess the impact on
perceived overload and choice. After information-processing
capacity is surpassed, information increments were found to lead
to modest or insignificant reductions in decision quality [
        <xref ref-type="bibr" rid="ref18 ref8">8, 18</xref>
        ].
      </p>
      <p>
        As research stipulates a complex rather than a linear relation
between information load and perceived overload [
        <xref ref-type="bibr" rid="ref14 ref8">8, 14</xref>
        ], we
expect a nonlinear relation to better describe the relation between
these two factors (P1).
      </p>
      <p>
        It is plausible to assume that under high overload levels,
consumers do use heuristics to maintain the cognitive effort at
acceptable levels. Indeed, consumers adapt decision strategy
according to product information, task, and environment [
        <xref ref-type="bibr" rid="ref23 ref5">5, 23</xref>
        ].
      </p>
      <p>
        In complex choice situations, consumers for instance become
more selective in acquiring and processing information [
        <xref ref-type="bibr" rid="ref23">23</xref>
        ].
      </p>
      <p>
        Because consulting product recommendations can be seen as
information-processing heuristic [
        <xref ref-type="bibr" rid="ref10 ref27 ref28">10, 27, 28</xref>
        ], we theorize that the
utility of consulting product recommendations increases with
information overload. Under high overload levels, consumers
behave as satisficers (vs. optimizers) and thus use more an
information-processing reduction strategy [
        <xref ref-type="bibr" rid="ref19">19</xref>
        ]. Therefore, we
expect that (P2) consumers will tend to consult the
recommendations more as (a) information load increases and as
(b) perceived overload increases. Figure 1 depicts the study
conceptual framework.
      </p>
      <p>
        Consumers have divergent needs for information. Need for
cognition (the consumer tendency to engage in effortful thinking)
was cited as an important factor of attitudinal and behavioral
change [
        <xref ref-type="bibr" rid="ref4">4</xref>
        ]. Consumers low on the need for cognition tend to
avoid activities requiring high cognitive effort and to engage in
heuristic strategies [
        <xref ref-type="bibr" rid="ref11">11</xref>
        ]. We thus expect need for cognition to
attenuate the tendency to consult the recommendations such that
as information overload increases, the lower the need for
cognition is, the more the consumer will consult product
recommendations (P3).
      </p>
      <p>
        Consumers do react to product recommendations because they
limit their choice freedom [
        <xref ref-type="bibr" rid="ref7">7</xref>
        ]. Under high overload levels,
consumers behave as satisficers as opposed to optimizers [
        <xref ref-type="bibr" rid="ref19">19</xref>
        ].
      </p>
      <p>
        Because consumers are adaptive decision makers [
        <xref ref-type="bibr" rid="ref3">3</xref>
        ], we propose
that the higher the information overload becomes, the more the
consumer will conform to recommendations (P4). This
proposition finds support in the self-regulation research;
information overload can be seen as a resource depletion
mechanism that “enhances the role of intuitive reasoning by
impairing deliberate, careful processing” of information [24, p.
344]. Need for cognition is also expected to shape reactance so
that under higher levels of overload, the lower the need for
cognition is, the less the consumer will react to product
recommendations (P5).
      </p>
      <p>
        We finally study the impact of information overload and product
recommendations on choice quality and confidence. Theory posits
a salient role for recommendations on choice quality in complex
choice situations [
        <xref ref-type="bibr" rid="ref27">27</xref>
        ]. In effect, choice quality suffers when the
processing effort exceeds processing limits [
        <xref ref-type="bibr" rid="ref23">23</xref>
        ]. As product
recommendations help consumers improve choice by
concentrating on the alternatives that best match their preferences
[
        <xref ref-type="bibr" rid="ref10">10</xref>
        ], product recommendations should uphold choice quality as
information overload increases (P6) [
        <xref ref-type="bibr" rid="ref10 ref15 ref19 ref28 ref3">3, 10, 15, 19, 28</xref>
        ]. Because
the negative role of information overload on choice is prominent
in the case of a proportional versus disproportional attribute
distribution [
        <xref ref-type="bibr" rid="ref18">18</xref>
        ], we theorize that the impact of product
recommendations on choice quality will be particularly salient for
choice sets with proportional attribute distribution (P7).
      </p>
      <p>
        According to Fitzsimon and Lehmann [
        <xref ref-type="bibr" rid="ref7">7</xref>
        ], recommendations
reduce uncertainty for consumers who do not react to
recommendations. We hence expect that consumers who consult
and conform to product recommendations will have higher choice
confidence than consumers who consult but react to
recommendations (P8).
      </p>
    </sec>
    <sec id="sec-4">
      <title>3. METHODOLOGY</title>
    </sec>
    <sec id="sec-5">
      <title>3.1 The Experimental Site and the</title>
    </sec>
    <sec id="sec-6">
      <title>Recommender System</title>
      <p>
        An e-store was created for “Portable Direct” using professional
Web design service; a fictitious retailer name was used to control
for retailer preferences [
        <xref ref-type="bibr" rid="ref1">1</xref>
        ]. The computer laptop was chosen as
product category because (a) it is a complex product thus
consumers are expected to be attentive during choice, (b) it has
many known attributes, which allows a meaningful manipulation
at high number of attributes, (c) it is a search product (attributes
can be communicated using the Web), and (d) it is a product that
consumers shop for online, which improve the ecological validity.
Though pretested (see the Appendix), manipulation levels were
adapted from the literature. Three levels of alternatives (6, 18, and
30) were chosen because research investigating this factor along
with attribute distribution considers only two alternative levels (18
and 27 in [
        <xref ref-type="bibr" rid="ref17 ref18">17, 18</xref>
        ]) and because little research manipulated for
choice sets with low alternative level [
        <xref ref-type="bibr" rid="ref19">19</xref>
        ]. Three levels of
attributes (15, 25, and 35) were chosen because research
investigating this factor along with attribute distribution considers
only two attribute levels (9 and 18 in [
        <xref ref-type="bibr" rid="ref17">17</xref>
        ]). Whereas few studies
manipulated for 20 attributes or more [
        <xref ref-type="bibr" rid="ref19 ref8">8, 19</xref>
        ], including higher
number of attributes is necessary as consumers consider many
attributes when shopping for complex products. Akin to prior
work [
        <xref ref-type="bibr" rid="ref17 ref18">17, 18</xref>
        ], the distribution of attribute levels across the
alternatives had two levels (proportional vs. disproportional
distribution); the attributes provided in a choice set were
manipulated according to one of these levels.
      </p>
      <p>The participant rates the importance (weight; 1-7) of each of the
35 attributes (this step is performed before the participant is
randomly assigned to one of the eighteen experimental
conditions). Then, the score of each potential choice (each laptop
in the choice set provided under a particular condition) can be
determined by the following formula (Weighted Additive Rule;
Payne, Bettman, and Johnson 1993):
Where: S = Global score of alternative j for consumer k.
i = Attribute;
j = Alternative (laptop);
k = Consumer;
P = Weight of attribute i for consumer k;
V = A priori value of attribute i applied by system and associated
with alternative j.</p>
      <p>That is, the WADD determines the score of a given alternative j
(for consumer k) by multiplying the weight of each attribute
(provided by consumer k) by its a priori value, and then adding
the obtained values of all attributes. The alternative with the
highest score (i.e. the one that optimizes consumer k’s utility
function) is then suggested by the recommendation agent (should
consumer k choose to consult the agent by clicking the link
provided).</p>
    </sec>
    <sec id="sec-7">
      <title>3.2 Pretest and Measure</title>
      <p>
        Each participant had to choose a laptop with the option to consult
the recommendations (between-subject design).
Recommendations consultation and if consulted whether the
recommended product was chosen are observed variables.
Perceived overload was measured using two seven-point items
(There was too much information to make a choice; I wanted to
receive more information about the different products before
making my choice). Similar to [
        <xref ref-type="bibr" rid="ref13 ref19">13, 19</xref>
        ], choice confidence was
measured using three items (I am confident that I made the best
possible choice based on my needs; I am satisfied with the choice
I made; I am certain that I made a good choice; α=0.93). Need for
cognition was measured using the 18-item scale ([
        <xref ref-type="bibr" rid="ref4">4</xref>
        ], α=0.82). As
decision makers draw on their experience and knowledge of
product category, product experience (three-item from [
        <xref ref-type="bibr" rid="ref22">22</xref>
        ],
α=0.95) and product category involvement (four items adapted
from [
        <xref ref-type="bibr" rid="ref2">2</xref>
        ], α=0.92) were measured and controlled for. See the
Appendix for details of the pretest and manipulation checks.
      </p>
    </sec>
    <sec id="sec-8">
      <title>3.3 Stimuli</title>
      <p>
        Participants were informed that their task consisted of choosing a
laptop as they would in an actual purchasing situation. The task
page described “Portable Direct” as a well-established online
retailer of product category and asked the participants to navigate
its e-store (made available through a link provided after the
participants entered personal attribute preferences) to choose the
“The laptop you would seriously consider buying”. Participants
were told to take as much time as needed and to freely consult the
information available on the website. A time constraint was not
imposed because this would be inconsistent with real-life
situations and because this would result in eliminating a portion of
participants based on some cut-off value. In effect, time pressure
was shown to influence information overload [
        <xref ref-type="bibr" rid="ref8">8</xref>
        ]. Before a
participant was randomly assigned to one of the eighteen
conditions, a second page asked the participant to rate the
importance of each attribute (to estimate the participant utility
function so that the recommendation agent could suggest the
optimal choice; Weighted Additive Rule WADD as in [
        <xref ref-type="bibr" rid="ref23">23</xref>
        ]).
Depending on the assigned condition, the e-store provided the
participant with a finite choice set (e.g., six alternatives each with
fifteen attributes for conditions one and two in the Appendix).
Similar to factual e-stores, each alternative appeared in a tabular
format with the attributes headed by the laptop photograph. The
alternatives that made the choice set were presented on the same
page. To avoid presentation bias, the order of alternatives was
randomized for each participant in a given condition. Brand was
concealed to reduce the possibility of following a brand heuristic
and to entice participants to make choice using the information
provided. This is akin to prior work [
        <xref ref-type="bibr" rid="ref17">17</xref>
        ]. Participants had the
option to consult the recommendations by clicking on a hyper link
labeled “Click here for our recommendation according to your
preferences” located at top of the choice set provided. After
making their choice, participants were presented with the measure
items.
      </p>
    </sec>
    <sec id="sec-9">
      <title>3.4 Sample</title>
      <p>An invitation to participate in a “Study on e-commerce” was sent
to consumers randomly chosen from a large consumer panel
belonging to a North American market research company. Of the
472 responses received, 466 were complete and retained. Sample
demographics distribution (see the Appendix) shows that the
sample was well distributed across consumer population with no
important bias toward a particular segment.</p>
    </sec>
    <sec id="sec-10">
      <title>4. RESULTS</title>
      <p>
        A comprehensive analysis of the data with a path model was not
performed because it was not feasible (i.e., central variables in the
model such as RA consultation and reactance to recommendation
were binary; in addition, an important exogenous
variableinformation load-is ordinal and reflected by one item). As such,
ANOVA and regression analysis were used in testing the
propositions (except for P2 through P5 where logistical regression
were used because the dependent variable was binary).
The main effect for information load (called interchangeably
information bits; [
        <xref ref-type="bibr" rid="ref17 ref18">17, 18</xref>
        ], see the Appendix section) on perceived
overload was significant (F=23.88, p&lt;0.001); this result stays
reliable when controlling for product involvement and experience
(only product experience was significant covariate; B= -0.085,
F=5.34, p=0.021). A curvilinear quadratic curve solution
explained more variance (R²=0.264) in the relationship between
information load and perceived overload than a linear (R²=0.224)
or a logarithmic (R²=0.248) solution (Figure 2).
      </p>
      <p>Binary logistical regression was performed to test the impact of
information load on recommendations consultation as well as the
attenuating role of need for cognition. Information loads
increment led to more recommendation consultation by means of
main effect (B=0.164, Wald=6.00, p&lt;0.05). In addition, the
interaction between information loads and need for cognition was
significant in the predicted direction (B=-0.031, Wald=5.587,
p&lt;0.05). Similarly, logistical regression was performed to test the
impact of perceived overload on recommendations consultation
and the attenuating role of need for cognition. Perceived overload
did lead to more consultation of recommendations (B=0.344,
Wald=4.06, p=0.044) and the interaction between perceived
overload and need for cognition was significant in the predicted
direction (B=-0.077, Wald=5.71, p=0.017). The direct effects of
the alternative, attribute, and attribute distribution levels and their
interactions on recommendations consultation were examined and
showed insignificance (all p’s&gt;0.10 NS).
To test the impact of perceived overload and need for cognition
on reactance, we applied binary logistical regression on the
observations that consulted the recommendations (n=178). As
expected, perceived overload was significant factor in predicting
the conformation (vs. reactance) to recommendations (B=0.91,
Wald=8.10, p=0.004). In addition, the interaction between
perceived overload and need for cognition was significant (B=
0.131, Wald=4.52, p=0.034), which shows that as perceived
overload increases, the lower the consumer was on need for
cognition, the less reactance to recommendations the consumer
would exhibit. Alternatively, neither information load nor its
interaction with need for cognition were significant in predicting
reactance (all p’s&gt;.34 NS). We further tested the direct impact of
the levels of alternatives, attributes, and attribute distribution on
reactance and found no significant effects (all p’s&gt;.31). These
results collectively show that perceived overload, rather than
information loads, was the determinant factor in predicting
reactance to recommendations.</p>
      <p>
        Choice quality was measured by the distance between the
participant actual and optimal choice (Weighted Additive Rule
WADD; [
        <xref ref-type="bibr" rid="ref23">23</xref>
        ]). This is akin to past work [
        <xref ref-type="bibr" rid="ref13 ref16 ref19">13, 16, 19</xref>
        ]. The
expected interaction between information load and
recommendations consultation was significant (F=1.68, p=0.012;
Figure 3 Up). Similarly, we found support to the proposition that
recommendations consultation upholds choice quality as
perceived overload increases because the interaction between
perceived overload and recommendations consultation was
significant (F=1.61, p=0.036; Figure 3 down).
      </p>
      <p>Figure 3a. Recommendations effect on choice quality
(upper line: RA consulted).
Figure 3b. Recommendations effect on choice quality
(upper line: RA consulted).</p>
      <p>We then tested the proposition that product recommendations
effect on choice quality is salient for choice sets with proportional
attribute distribution (P7). We found support to this proposition by
means of a three way interaction (Number of Attributes x attribute
distribution x recommendations consultation; F=2.47, p&lt;0.05;
Figure 4). This interaction shows the recommendations to enhance
choice quality for choice sets with proportional distribution of
attribute levels across the alternatives at all attribute levels
(Appendix for means). The interaction also highlights that
recommendations consultation improved choice for all choice sets
only when the number of attributes became high. We finally
tested and found support to the proposition that consumers
consulting and conforming to recommendations will have higher
choice confidence than consumers consulting and reacting to
recommendations (5.13 vs. 4.41, F=8.55, p=.004).</p>
    </sec>
    <sec id="sec-11">
      <title>5. DISCUSSION</title>
      <p>The experimental results lend support to research propositions.
Results suggest a curvilinear relation between information load
and perceived overload, which indicates that the impact of
additional increments in product information after some levels
(condition 7 shown in the Appendix) are not as influential in
driving overload perceptions. The consumer use of decision
heuristics at high levels of information overload helps explaining
this finding. Findings lend support to the notion that the utility of
consulting product recommendations increases as the information
load and as perceived overload increases. Consumers did use an
information-processing heuristic by consulting product
recommendations more as information overload increases.
Moreover, this tendency was higher for consumers low on the
need for cognition. Importantly, consumers appear to conform (vs.
react) to recommendations more at high levels of perceived
overload. Further, the lower the need for cognition was, the less
the consumer reacted to recommendations at higher levels of
information overload.</p>
      <p>
        The findings show the positive effects of product
recommendations on choice quality at high levels of information
loads and overload perceptions. The positive impact of
recommendations on choice quality was particularly salient for
choice sets with proportional distribution of attribute levels across
the alternatives. Finally, choice confidence improved for
consumers who consulted and conformed (vs. reacted) to
recommendations. In effect, the recommendations might have
made the accuracy feedback as immediate and tangible as the
effort feedback by signaling to consumers that a product in the
choice set is more optimal than the initially considered one [
        <xref ref-type="bibr" rid="ref5">5</xref>
        ],
which might have triggered consumers to have lower levels of
confidence in their choice if they reacted to the recommendations.
This research contributes to theory by studying the relation
between information loads and overload perceptions over a wide
range for three factors deemed to determine the information load
and by showing that consumers indeed do employ decision
heuristics in response to information overload. People appear to
regard the use of product recommendation agent as
informationprocessing reduction heuristic. This research further established a
link between information overload and reactance to
recommendations and underlined the role of need for cognition. It
contributes to the recommendation agents’ literature by showing
the impact of recommendations on choice at different information
overload levels and by showing the salient effect of
recommendations on choice quality for sets with proportional
distribution of attribute levels across the alternatives.
      </p>
      <p>Several practical implications emerge. Integrating a
recommendation agent based on consumer preferences appears to
be beneficial for consumers and retailers (by helping consumers
make quality choices at high levels of information overload).
Recommendations enhance choice, particularly as information
load and perceived overload increases. In addition,
recommendation agents appear to have particular influence on
choice when product information is less diagnostic (attribute
levels are proportionally distributed across the alternatives in the
choice set). Finally, the outcome of recommendation agents can
be optimized as consumers in general show less reactance to
recommendations at higher levels of information overload.
This work has limitations. Although the study sample comprised
actual consumers randomly selected from large consumer panel,
the sample was self-selected. Nonetheless, the sample distribution
across the consumer population was satisfactory. The research
considered only one product category and did not examine
whether similar effects are obtainable for less complex and for
experience products. Further, this research did not investigate the
effects of information overload and product recommendations on
shopping enjoyment and long term performance measures such as
consumer loyalty and retention. These topics are potential
extensions to this line of research.</p>
    </sec>
    <sec id="sec-12">
      <title>6. APPENDIX</title>
    </sec>
    <sec id="sec-13">
      <title>6.1 Experimental conditions (Information</title>
    </sec>
    <sec id="sec-14">
      <title>Load*)</title>
    </sec>
    <sec id="sec-15">
      <title>6.2 Pretest and Manipulation Checks</title>
      <p>
        A pretest was performed to ensure task and measure
comprehensibility [
        <xref ref-type="bibr" rid="ref8">8</xref>
        ], to check the manipulation of independent
variables and to inspect the distribution of control variables. The
pretest ensured that an increment from six (and eighteen) to thirty
alternatives resulted in a noticeable change in information load.
The pretest included three sections: The first contained the
manipulation checks, the second examined product experience
level and where the product category was relevant for the
participant pool (e.g., manipulating the attributes level would be
realistic and meaningful). The third section helped determining
the 35 most important attributes (of 45 attributes identified using
two retailing websites) to be included in experiment (each
attribute was evaluated using a Very Important/Not Important at
All seven-point item).
      </p>
      <p>Six questionnaire versions were created for the pretest, all sharing
the items of product experience and involvement, as well as
attribute importance evaluation (the versions differed only in the
first section). The first two versions were developed to check the
manipulation of number of alternatives (6, 18, and 30). The two
versions differed in the order the three levels were presented to
each participant (i.e., while the order was 6-18-30 in the first
version, the order was reversed in second version). This
eliminated the possibility that a respondent rated level one as
having fewer alternatives than levels two and three because it was
displayed first. Similar steps were taken in versions three and
four, which checked the manipulation for number of attributes.
Versions five and six examined the manipulation for attribute
distribution (proportional vs. disproportional). Version five (six)
assessed the manipulation for a proportional (disproportional)
distribution of attribute levels across the alternatives (both for the
price attribute).</p>
      <p>An invitation to participate in the pretest was emailed to 116
consumers (convenience sample). 77 useable responses were
received. Because the measure (for both the alternatives level and
attributes level) was within-subjects, ANOVA with repeated
measures was used to analyze the input. For attribute distribution,
a chi-square test was used. The 32 participants that evaluated
alternatives level had to respond to a seven-point bipolar item
(What do you think of the quantity of laptops offered: Not enough
to make a choice/too much to make a choice) (item repeated for
each of the three levels presented to the respondent).</p>
      <p>The analysis showed that participants perceived significantly
different information loads between each of the three levels
(M6=2.66, M18=4.81, M30=4.94; F6-18 (1, 31)=69.65, F6-30(1,
31)=139.7, F18-30(1, 31) =27.59, all p-values&lt;0.001). Similarly,
the 23 participants evaluating the attributes level had to respond to
the seven-point bipolar item (What do you think of the quantity of
attributes offered: Not enough to make a choice/too much to make
a choice; item was repeated for each of the three levels presented
to the participant). The analysis showed that participants reported
significantly different information loads between each of the three
levels (M15=2.87, M25=4.30, M35=4.87; F15-25(1, 22)=77.85,
F25-35(1, 22)=10.33, F15-35(1, 22)= 97.32, all p-values&lt;0.01).
The 22 participants evaluating the success of attribute distribution
manipulation responded to a binary item (Was the number of
laptops priced at $600 different or similar to the number of
laptops priced at $750 and $900?). For (dis)proportional structure,
the number was (not) equal. Participants in the (dis)proportional
structure condition reported (un)equal distribution of the price
attribute across alternatives ( (1, 22) = 12.32, p &lt; 0.01).
The second section (shared for all participants) showed that the
laptop computer is a product bought and used frequently by
participants (87 percent of participants indicated using or to have
used a laptop regularly; 75 percent of participants have already
bought a laptop). This section also showed the internal
consistency for product experience items (α=0.96) and product
involvement items (α=0.87) and clarified the sample distribution
according to these variables.</p>
      <p>
        Attributes were assigned to experimental conditions using the
pretest input. Attributes that have higher weights appeared more
often in conditions with fewer attributes. This was done because
the inclusion of an attribute in a choice set renders the attribute
more important for the decision maker [
        <xref ref-type="bibr" rid="ref9">9</xref>
        ]. Consequently,
including less important attributes in a choice set made up of few
attributes would inflate the attribute’s importance. In effect,
choice sets containing only less relevant attributes for the
alternative (choice sets that do not provide basic and important
attributes such as price, processing speed, or memory size) are
unrealistic and would reduce ecological validity.
6.3 Sample Demographics (n=466; 56.9%
females)
Age: 11.6% ages 18-24, 26.4% 25-34, 20.0% 35-44, 19.7% 45-54,
9.9% 55-64, 12.4% 65+. Education level: 19.6%
Primary/secondary education level, 70.8% Undergraduate degree,
9.7% Graduate degree. Income: 14.2% less than $15K, 18.9%
1529K, 29.0% 30-44K, 19.7% 45-59K, 9.7% 60-74K, 7.5% 75K or
higher. Marital status: 28.8% single, 57.9% married/common law
partner, 13.3 other status. Employment: 9.5% students, 78.6%
working full-time, 7.1% working part-time, 4% searching.
      </p>
    </sec>
    <sec id="sec-16">
      <title>6.4 Choice Quality Means</title>
    </sec>
  </body>
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