Participants
A total of 132 (91.7% female, mean age 24.4 ± 5.1 s.d.) Italian participants were enrolled in the study. Participants were recruited and provided written informed consent following the ethical standards of the Declaration of Helsinki and IRB approval was obtained by the University G. D’Annunzio institutional ethical committee. The experimental methods were carried out in accordance with the approved guidelines. Participants received no monetary or other forms of compensation for their participation. Since the study was carried out during the lockdown phase in Italy and due to the impossibility to invite participants in the laboratory, the whole procedure was conducted remotely. Participants were instructed to perform the task and answer questionnaires while being alone in a quiet room. For the visual dot-probe task, participants were asked to sit in front of a computer screen while maintaining a distance from the screen of about 60 cm for the entire duration of the task.
Stimuli Selection
A total of 60 pictures of objects, standardized for size and brightness, were selected from the web (for details see Supplementary Table S1 online). The task was administered through the recently released E-prime Go software, which allows remote data collection (pstnet.com). Participants were presented each object (1000ms) in random order. After each object, participants were asked to rate on a scale from 0 (not at all) to 100 (extremely) how much the object just saw was related to the COVID-19. Based on the participants’ ratings, 40 objects were selected and divided into 2 categories. 30 objects, rated as weakly associated to the virus (rating score ranging from 6 to 22.5), were attributed to the neutral stimuli category while the others 10 objects, rated as strongly associated to the virus (rating score ranging from 82.7 to 98.8), were attributed to the virus-related stimuli category.
Visual dot-probe task
Attentional bias was measured by a visual dot-probe task, using the Inquisit Web software’s script (millisecond.com). Based on Miller & Fillmore (2010), the script implemented a visual dot-probe procedure to measure attentional bias with images, [31]. The 10 pairs of virus-related/neutral objects were presented 4 times based on the four possible object/target combinations (the position of the object on the left or the right and the position of the target probe on the left or the right), thus obtaining 40 test trials. Also, there were 40 filler trials, which consisted of 10 pairs of neutral images presented four times each. The filler trials are commonly included in tasks of attentional bias to reduce possible habituation to target stimuli that might occur if all trials contained virus-related images. The 40 filler trials were intermixed randomly among the 40 test trials for a total of 80 trials. The task consisted of two blocks: the first block with 10 practice trials and the second block with the 80 task trials (40 test trials and 40 filler trials), randomly sampled without replacement. After the presentation of a fixation cross (+) in the center of the screen (500 ms), two side by side objects (virus-related and neutral objects for test trials, and both neutral objects for filler trials) were presented. The position of the pictures was randomly chosen to be either on the left or on the right of the fixation cross. After a short interval (1000ms), the two objects disappeared and a probe stimulus (X) appeared in the position of one of the two objects (duration of the probe stimulus was 1000 ms). Participants were asked to press one key (E) if the probe was on the left and another key (I) if the probe was on the right. Attentional bias is determined by the reaction times difference between congruent trials (the probe replaces threatening stimuli) and incongruent trials (the probe replaces neutral stimuli). For individuals whose attention is systematically drawn to the threatening stimulus, reaction times are expected to be shorter (i.e., faster) for trials where the probe replaces threatening virus-related objects compared to trials where the probe that replaces neutral objects.
Fear for COVID-19 Questionnaire
The Fear for COVID-19 questionnaire is a scale specifically created to measure fear and concerning beliefs related to the COVID-19 pandemic. The questionnaire is composed of 8 items, which mainly refer to the perceived possibility of being infected by COVID-19 and to the possible consequences of the contagion. In the Fear for COVID-19 questionnaire, participants are asked to answer on a scale from 0 (“not at all”) to 100 (“extremely”) how much they agree with certain statements about COVID-19. Component structure and questionnaire’s reliability were explored in a larger Italian sample (N = 4121) through principal component analysis (PCA) and Cronbach’s alpha (α). Specifically, an oblique rotation (promax) was used to test the factor structure of the questionnaire. Results revealed a structure with two moderately correlated factors (r = .45). Four items reported good loadings on the first factor, labeled “Belief of contagion”, since these items refer to the idea of being infected (for themselves and significant ones) by COVID-19, either in the past or in the future. Furthermore, four other items showed satisfactory loadings on the second factor. We labeled this second factor “Consequences” since these items refer to the possible consequences of being infected (for themselves and others). The questionnaire’s items and pattern matrix are reported in Table 3. Internal consistency of the 8-items questionnaire was tested with Cronbach’s alpha reporting optimal values for both the “belief of contagion” sub-scale (α = .82) and “consequences of contagion” sub-scale (α = .80). For the present study, scores were computed by averaging participants’ answers on the four items of each sub-scale.
Whiteley-7 Index
The Whiteley-7 Index (WI-7) [32] is a 7-item scale, based on the Whiteley Index (WI-14) [33]. Specifically, WI-7 is composed of 7 of the original 14 items of the WI-14. Each item requires a dichotomous choice (yes or no) with a total test score ranging between 0 and 7. Higher scores indicate higher levels of health anxiety. This short-version scale has been increasingly used to assess health anxiety both in the clinical and general population as well as in the primary care context. WI-7 is a valid screening instrument with high sensitivity and specificity for hypochondriasis [33], DSM-IV somatization disorder [34,35,36], and health anxiety in the general population [37,38].
Table 3. Fear for COVID-19 Questionnaire: item descriptions and pattern matrix of the PCA.
|
Item
|
Factor loading
|
|
|
A
|
B
|
A. Belief of Contagion
|
I often thought I was infected with the virus
|
.734
|
|
I think I could be infected with the virus in the future
|
.802
|
|
I think that a dear or close person to me could potentially be infected with the virus
|
.848
|
|
I think that a dear or close person to me could potentially be infected with the virus in the future
|
.843
|
|
B. Consequences of contagion
|
I think that a person infected with the virus could recover
|
|
.841
|
I think that a person infected with the virus could die
|
|
.800
|
I think it is probable that I would recover after being infected with the virus
|
|
.810
|
I think that being infected with the virus could be lethal for me
|
|
.721
|
Visual dot-probe data preparation
Before data analysis, visual dot-probe data were computed according to the methods described in previous studies [29]. Trials with incorrect responses were not included in the dataset and reaction times shorter than 250ms and longer than 1000ms, were excluded. As a result, 93.48 % of the original data were included in the following analyses. Since attentional bias is indicated by shorter (i.e., faster) reaction times to congruent versus incongruent trials, each participant’s mean per trial reaction time to probes was calculated for trial type (congruent versus incongruent). Finally, attentional bias was computed by subtracting congruent trials’ reaction times to incongruent trials’ reaction times.