Can horses discriminate human body odors from joy and fear contexts?

2022

Animals are commonly believed to detect human emotions through smell, in link with the primitive and ubiquitous characteristics of chemoreception. Indeed, the brain areas dedicated to odor processing are among the oldest structures in mammalian evolution, and chemosignals may play a role in interspecific communication. However, few studies have conclusively demonstrated that animals can perceive human emotions through smell. To determine whether horses can discriminate between human odors of fear and joy, a habituation-discrimination protocol was used. Horses were exposed to sweat odors from humans who declared they had experienced fear or joy while viewing a comedy or a horror film, respec…

A neural marker of rapid discrimination of facial expression in 3.5 and 7-month-old infants

2020

Little is known about infants' ability to rapidly discriminate a facial expression against many others. Here, we investigated the development of facial expression discrimination in infancy with fast periodic visual stimulation coupled with scalp electroencephalography (EEG). EEG was recorded in 3.5- and 7-month-old infants (n=18 per group) displayed with an expressive (disgust or happy) or neutral female face at a base stimulation frequency of 6 Hz. Pictures of the same individual randomly expressing other expressions (either anger, disgust, fear, happiness, sadness, or neutrality) were introduced every 6 stimuli (i.e., at 6/6 = 1 Hz) to directly isolate a discrimination response between th…

Maternal odor selectively enhances rapid face categorization from natural images in the 4-month-old infant brain

2019

Maternal odor selectively enhances the categorization of face(like) stimuli in the 4 month-old infant brain

2020

Présentation Poster; International audience; In the 4-month-old infant brain, the visual categorization of natural face images is enhanced by concomitant maternal odor (Leleu et al., 2019), providing support for the early perception of congruent associations between co-occurring inputs from multiple senses. Here, we further explore whether this maternal odor effect is selective to faces or if it can be explained by a more general influence of salient odor cues on the perception of any visual object category. In Experiment 1, scalp electroencephalogram was recorded during a fast periodic visual stimulation (FPVS-EEG) while 4-month-old infants were exposed to the maternal vs. a control odor. …

Development of face pareidolia in objects in 3- to 6-month-old infants

2020

Human neonates prefer colostrum to mature milk: Evidence for an olfactory bias toward the "initial milk"?

2021

International audience; OBJECTIVES: Colostrum is the initial milk secretion which ingestion by neonates warrants their adaptive start in life. Colostrum is accordingly expected to be attractive to newborns. The present study aims to assess whether colostrum is olfactorily attractive for 2-day-old newborns when presented against mature milk or a control. METHODS: The head-orientation of waking newborns was videotaped in three experiments pairing the odors of: (a) colostrum (sampled on postpartum day 2, not from own mother) and mature milk (sampled on average on postpartum day 32, not from own mother) (n tested newborns = 15); (b) Colostrum and control (water; n = 9); and (c) Mature milk and …

Maternal odor selectively enhances the categorization of face(like) stimuli in the 4-month-old infant brain

2020

In the 4-month-old infant brain, the visual categorization of natural face images is enhanced by concomitant maternal odor (Leleu et al., 2019), providing support for the early perception of congruent associations between co-occurring inputs from multiple senses. Here, we further explore whether this maternal odor effect is selective to faces or if it can be explained by a more general influence of salient odor cues on the perception of any visual object category. In Experiment 1, scalp electroencephalogram was recorded during a fast periodic visual stimulation (FPVS-EEG) while 4-month-old infants were exposed to the maternal vs. a control odor. In rapid 6-Hz streams of natural images (i.e.…