[Proposal] Feel & Think: Exploring different sensory modalities and memory as frontlines against infectious disease

Santos, S.M.P.(1,2), Pandeirada, J.N.S.(1,2,3), Fernandes, N.L.(1)

1.William James Center for Research
2.University of Aveiro, Portugal
3.Department of Psychological Sciences, Purdue University, USA

Introduction

Infectious diseases and pandemics have threatened our survival and well-being throughout evolution. Preventative behaviors play a crucial role in managing infectious diseases justifying the urgency to investigate ways to increase them[1].

We are armored with a set of mechanisms developed to avoid pathogens before they enter the body–the Behavioral Immune System (BIS). The BIS is sensitive to perceptual pathogen cues in the environment (e.g.,sneezing); Perceiving them, triggers disgust and activates cognitive resources (e.g.,attention) that facilitate preventive behaviours (e.g.,avoidance of pathogen sources)[2].

Recent research revealed that memory is enhanced for items processed as potential sources of contamination[3–6], suggesting that memory may be a key component of the BIS. Indeed, a preferential remembering of sources of potential contamination (e.g.,infected objects) would be highly adaptive through the promotion of preventive actions towards them.

Studies on this “contamination effect” in memory have used visual stimuli (e.g.,pictures) and free recall as the memory test. However, in our daily lives various sensory-modality pathogen cues are likely to activate the BIS, such as sounds (e.g.,hearing someone coughing) or sounds+images (e.g.,seeing and hearing someone coughing). The effects of different sensory-modality pathogen cues and their coupling on memory is still unknown[7]. An important question then remains: Which type of sensory information best promotes the “contamination effect” on memory?

Also, the effect of contextual framing of the cues – signals framed as potential sources of infection (e.g.,sneezing due to an infectious disease) or not (e.g.,sneezing due to allergies) –needs further exploration. Previous data suggest the importance of fitness-relevance as a promoter of the contamination effect in memory[5], but more evidence is needed to establish such finding.

The main goals of our project are:

All the proposed studies have been pre-registered (AsPredicted#70666,#70671,#70672).

Methodology

Inspired by the “law of contagion”[8], Fernandes et al.(2017) developed a procedure in which everyone remembers the same items; what differs between conditions is their previous association with a potential contamination source or not (sick or healthy person). This solves item-selection problems and resembles more what happens in our daily lives: innocuous objects become sources of contamination after contacting with a sick person. We will implement the same experimental strategy, with pictures of objects being held by clean hands (see[4]), presented alongside cues of different sensory modalities: auditory(A), visual(V) or audio-visual(AV).

Another key component in our proposal is the manipulation of the contextual framing to investigate if the fitness-relevant component (i.e.,the threat for contamination) is the driver of the mnemonic effects for contamination.

Prescreening will ensure that participants are at least 18 years old, only participate in one of our studies, and have an approval rate >=90%.

Study 1

The aim of these study will be to properly validate our database of multisensory-stimuli in several dimensions constructed as depicted in the Figure.

making of stimuli

Three groups of participants will be assigned to each stimuli sensory-modality (A, V, AV). They will be asked to rate the stimuli on the dimensions depicted below.

Our stimuli will feature 30 actors (15 female), each performing four behaviours in three modalities (i.e.,120 stimuli/modality). Each participant will evaluate 20 stimuli; thus, we will need six participants to get one evaluation per stimulus/modality. Having three modalities, we will need 18 participants to get one evaluation per stimulus. A total of 540 participants will be needed to obtain 30 datapoints/stimulus (as is typical in norming studies).

Study 2

This study aims to evaluate how participants’ affective experience on each sensory-modality differ depending on the fitness-relevancy and the health status of the actor/actress. To do so, we will manipulate the contextual framing of the stimuli: to some participants the sickness cues will be described as signs of an infectious disease and to others as signs of an allergy (contamination vs. non-contamination). For the three sensory-modalities (A, V, AV), we will need 6 groups of participants. We expect the contextual framing of the stimuli with different potentials of contamination will influence the participant’s emotional response as previously reported[9]; The main question is whether it will interact with sensory-modality. We will ask participants to evaluate each stimulus on the same dimensions as in Study 1.

We will select the 20 actors (10 females) which proved to be more suitable in Study 1, performing the four behaviours in the three modalities (i.e.,80 stimuli/modality). Each participant will evaluate 20 stimuli in a given modality; thus, considering the two groups with different contextual framings (contamination vs. non-contamination), a total of 720 participants will be required.

Study 3

Following previous procedures (see figure bellow), we aim to investigate which stimuli sensory-modality is more effective in eliciting the mnemonic effect of contamination. Using a between-subjects design, we will manipulate the contextual framing of the stimuli as in Study 2 (contamination vs. non-contamination). The objects will be selected from the Object-on-Hands Picture Database[9]. The cues will be selected from the previous studies and will be V, A, or AV to different groups of participants. With a G-Power calculation based on the hp2=0.065 (effect size of the Contextual FramingXContamination interaction from Fernandes et al.(2017)), we will need 300 participants.

Analysis plan

Descriptive and inferential statistics will be used (e.g.,ANOVAS). Alpha levels will be set at .05 (multiple comparison corrections will be applied whenever necessary).

Potential impact and Open Science

The validated multi-sensory stimuli database from this project will be an asset for researchers. Furthermore, the results from Study 3 will enrich our knowledge on memory and the BIS. Intervention based on the BIS activation may be more effective to prompt preventative behaviours (e.g., hand hygiene), than education-based strategies[10,11]. Thus, we expect that the knowledge acquired by this project will help to inform on the most effective forms of risk-communication, public health strategies, and health-related campaigns.

We aim to publish our findings and interpretations in an open-access modality. Furthermore, our procedures, stimuli and data will be available in OSF, a recurrent practice of our research group (e.g.,OSF | The Objects-on-Hands Picture Database Files) which holds a strong publication track-record.