In this study, we showed that there were different task performances between
positive and negative words in the condition of two competitive words. In the 2AFC
task that we used here, participants had to choose one word that had appeared before.
In Experiment 1, we replicated Zeelenberg et al. (2006) ’s study that both positive and
negative emotional words had better performance than neutral words under the
single-word condition. Namely, the effect of enhanced perceptual encoding of
emotional words can also be observed with Chinese words. In Experiment 2a and 2b,
we used positive words and negative words to pair with neutral words respectively. In
Experiment 3, we used all emotional types of words in the same task. In Experiment 2
and Experiment 3, we found different performances for positive and negative
emotional words. Negative target words had higher accuracy than neutral target words.
Although both positive and neutral target words had higher accuracy in the
positive-neutral pairs, paradoxically, the negative-negative pairs led to the best but
positive-positive pairs led to the worse performance. In Experiment 4 by using the
dot-probe task, we found a shorter detection time of the probe that appeared at the
position that negative emotional words just appeared before.
These results suggest that when there were multiple words competing for limited
attentional resources, different processing mechanisms are revealed for positive and
negative emotional words. Many previous studies showed that emotional stimuli
could be processed more quickly (Calvo & Nummenmaa, 2008; Macleod, et al., 1986;
Mogg, et al., 2000; Ohman, Flykt, et al., 2001). Theoretically speaking, the rapid
processing was influenced by attention, and such effect may disappear under the
situation that lacks attentional resources (Pessoa, et al., 2005; Tomasik, et al., 2009).
These results can also be found in our Experiment 4. After we added a dot-probe
detection task, the emotional effects no longer existed. However, the emotional effects
were still there with limited attentional resources as in our Experiments 2 and 3. We
can observe that the motional words compete for limited attentional resources with the
adjacent word, resulting in a different performance between words of positive and
negative emotional type.
Negative words have the advantage in capturing attention. In Experiments 2b and
Experiment 3, the results indicated that negative emotional words showed a better
performance than positive and neutral words when the attentional resources were
limited or scarce. Many studies have also found that negative emotional words had
better processing efficiency and it was inferred that the results may be caused by its
advantage of attracting attention (Hansen & Hansen, 1988; Macleod, et al., 1986;
Mogg, et al., 2000). This advantage should be related to the specificity of negative
stimuli, such as in the phenomenon of weapon-focus (Loftus, Loftus, & Messo, 1987).
Negative emotional stimuli are often related to dangerous and negative experiences.
In order to avoid the risk of danger, people are inclined to allocate more attentional
resources to the negative emotional stimuli and therefore cause the exclusion of other
peripheral information. Some researchers also argued that negative emotions narrow
the scope of attention (Fredrickson & Branigan, 2005). Our results in Experiment 4
also support the argument that emotional words had the advantage of attentional
capture, and enjoyed a faster response to the position of the negative emotional word.
On the contrary, positive emotional words can expand attentional span and facilitate
the processing of the whole context. It was found that positive emotion could broaden
the scope of attention and the amount of cognitive strategies (Fredrickson & Branigan,
2005; Rowe, Hirsh, & Anderson, 2007). Fredrickson and Branigan (2005) used video
films to trigger people's emotion states and found that positive emotion states can
increase the scope of attention span and cognitive strategies. Rowe et al.(2007) used music to trigger subjects’ emotion states and found similar results. Note that these
increases of attentional span were caused by changing participants’ emotional states.
In our Experiment 2a and 3, the only use of positive words could immediately
increase the attentional span. When there were positive emotional words appearing on
the screen, the neutral target words’ performance was as good as that of positive
emotional target words.
The processing of positive word could also be influenced by the adjacent word:
Two positive effects counteract each other. In Experiments 2a and 3, the participants
had a relatively poor task performance for positive emotional target words when two
positive words were presented simultaneously. Why the advantage caused by positive
emotional words that can broaden attentional span and strengthen the peripheral
stimuli processing disappeared under the positive-positive pairs? Kanske and Kotz
(2011) presented multiple positive emotional words simultaneously and participants
were asked to judge the color of the central word. Their result showed that even in the
condition that the colors of the flanker words and target words were inconsistent; the
effect of positive words would moderate the conflicting processing of different colors
and led to correct identification of the colors of target words. The facilitation effect of
the positive emotional words should not disappear even under the multiple positive
words pairs like Kanske and Kotz’s study, therefore the worse performance of double
positive words can not just attributed to the two-words condition we used here.
One possibility is that positive emotional words have expanded the breadth of the
attentional scope; they might be influenced by the peripheral words and therefore
resulted in a different task performance. We infer that the worse performance of
positive-positive word pairs was caused by the overlapping use of the attentional
resource, which led to the competition of the limited attentional resource shared by
the two positive emotional words, and such competition caused the relatively low
recognition rate in Experiments 2a and 3. That is, the negative effect due to the double
positive words we report here is caused by the positive target word competing with
adjacent positive word and offset each other. When both adjacent words are neutral or
negative, because of their different valences relative to positive emotional target
words and therefore will not offset the processing of effect of emotional words.
Kanske and Kotz’s (2011) results may also be attributed to the different cognitive
resource of word and color, thus the positive emotion effect did not disappear. In
addition, the results may also be due to the slack of attention caused by the positive
words. Positive emotional words make people seeing things in a more relaxed way, so
when the positive words are presented on the screen, they may make people feel
relaxed and induce the poor processing of semantic information (Brosch, et al., 2008).
Our results indicate that negative and positive emotional words can influence the
allocation of attentional resources, thus causing the different performances under
multiple-word situation. Because of the narrowing of attention scope, the negative
emotional effect would not be influenced by the peripheral words. The narrow scope
of attention also causes the narrow area of attentional resources that do not overlap
with the area of attentional resources of other words. Therefore, even the
negative-negative words pair will not have to compete with each other for the same limited attentional resources and this could enhance both words’ perceptual encoding
and lead to the best performance among the other word pairs. The positive emotional
words have broadened the scope of attention that may also expand the area of
attentional resource. As a whole, the words presented on the screen will acquire an
enhancement of perceptual encoding. However, the extended region will let positive
words be influenced by adjacent words that the results showed the positive words
have to compete for the limited resources with the other positive words. It thus leads
to a worse performance.
The difference between positive and negative words can also be illustrated by the
extent to which attentional resources is concentrated That is, the negative words may
highly concentrate attentional focus. Thus, the two negative words in the current study
may be processed more efficiently. On the other hand, the positive words may diffuse
attentional resources spatially; consequently these words are processed less efficiently.
The emotional stimuli induce different performances under the no-competitive and
competitive condition. Zeelenberg et al. (2006) argued that the emotional effects were
caused by the enhanced perceptual encoding of emotional stimuli, and this argument
is also supported in our Experiment 1. That is, both the positive and negative
emotional words were enhanced similarly when only one word was presented where
there was no any competition. However, in our Experiments 2 and 3, the effect of
emotional words were not only influenced by enhanced perceptual encoding of
emotional stimuli but also affected by the limited attentional resource. We believe that
this is due to the competitive condition and induce the difference between positive and
negative stimuli.
The amount of emotion category can also be the interpretation of the results in this
study. The category of negative stimuli were more numerous and complicated than the
category of positive stimuli. We believe that under these conditions, thus the
negative-negative pair’s similarity was lower than positive stimuli, so the
discrimination and recognition of negative stimuli were easier. In contrast,
positive-positive pair’s similarity was relatively higher, leading to relatively poor
identification performance. Future experiments should try to manipulate the number
of emotional stimulus category and the semantic similarity between them and to see
whether recognition of positive and negative stimuli will differ when these factors are
equated.
Many recent studies have found the emotional effect was mostly induced by the
arousal of emotional intensity but less affected by emotional valence (Kissler, et al.,
2007). Our finding indicates that the effect of emotional valence could generate a
difference between positive and negative emotional words under the condition with
limited attentional resources. We did not explore the arousal of emotional intensity.
We predict that the different arousal levels of emotional intensity may lead to different
processing efficiency of emotional words. The stronger the stimulus intensity, the
more powerful results we will find in this experiment. It is a direction for future
research.
The current findings have important implications for in the field of reading and
emotion studies. Past studies adopting the priming, lexical decision task (LDT) and
recognition tasks used a single word (Kissler, et al., 2007; Tomasik, et al., 2009;
Zeelenberg, et al., 2006). Our study used multiple words that would be closer to daily
life and gained better ecological validity. By bearing the discovered processing
mechanism for the positive and negative words in mind, people can understand the
meaning of one sentence or an article efficiently by making the best use of the
different advantage of emotional words under various demanding situations. This may
improve the efficiency during reading. Moreover, the different processing
mechanisms of positive and negative emotion stimuli we suggested here can lead to
further testing in future work.
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Figures
Figure 1. The procedure of the 2AFC task in Experiment 1.
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Negative Neutral Positive
A cc u ra cy ( %)
Figure 2. Mean accuracy of target recognition in Experiment 1. Error bars represent standard errors from the mean.
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Figure 3. The procedure of the 2AFC task in Experiment 2.
Experiment 2a
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Positive Neutral