Adult-Child Touching Hands Dataset (AC-THD)

This is the Adult–Child Touching Hands Dataset (AC-THD): a dataset of 59 image stimuli depicting hand-to-hand touch between an adult and a child, systematically categorized into three emotional valence classes: negative (n = 15), neutral (n = 29), and positive (n = 15). The tool emphasizes the central role of the hands in conveying emotional information within an adult–childinterpersonal context.The images and the hand-to-hand positions were developed by four trained psychologists, and were first assigned into three emotional valence categories: negative (e.g., one person tightly pinching or forcefully gripping the other person’s hand); neutral (e.g., the two individuals’ fingers lightly overlapping or their wrists touching), and positive (e.g., one person gently stroking the back of the other person’s hand or the two individuals interlocking their hands). Images were initially assigned provisional alphabetical labels, which were subsequently refined through a percentile-based procedure in accordance with validation data. The AC-THD acquisition phase involved a mother (Caucasian, aged 48, right-handed) and her child (Caucasian male, aged 10, right-handed). Images were acquired by a professional photographer using a Canon EOS 1100D digital SLR camera with a 12.2 megapixel APS-C CMOS sensor and a resolution of 4272 × 2848 pixels, equipped with an EF-S 18–55 mm f/3.5–5.6 lens. The built-in flash (Guide Number 9.2 at ISO 100) was manually triggered for each shot to standardize illumination and minimize shadows. The camera was positioned on a tripod to maintain a fixed 90° angle. All images were captured in color in sRGB mode, with framing restricted to the hands and forearms. In the validation study, images were rated by 321 participants on valence, using a numeric rating scale ranging from 0 to 10, where 0 indicates a strongly negative image, 5 a neutral image, and 10 a strongly positive image, with anchors at 0 (“strongly negative”) and 10 (“strongly positive”). Mean emotional valence ratings were calculated for each image, along with standard deviations (SDs), mode, minimum and maximum values, and percentiles. Stimuli were finally classified as negative, neutral, or positive based on the 25th and 75th percentiles of the distribution of mean valence ratings. Accordingly, images with mean valence scores ≤ 4.25 were classified as negative, those with mean valence scores > 4.25 and < 7.23 as neutral, and those with mean valence scores ≥ 7.23 as positive. Therefore, the final dataset is comprised of: N = 15 images in the negative category; N = 29 images in the neutral category; N = 15 images in the positive category. Study validation of the dataset also examined potential differences in emotional valence ratings as a function of participants’ socioeconomic status (SES) and gender, which are reported as Supplementary Materials. These images can be used across a range of research fields, including emotion elicitation, neuroscience, and psychophysiological studies, as well as for assessing affective responses in individuals with histories of supportive or adverse tactile caregiving, given their potential to evoke autobiographical memories.