The Valence Experiment challenges the desire to quantify emotion - specifically happiness.

In psychology, “valence” is used to describe and quantify the affective quality of an event, object, or situation on the human psyche, referring to its intrinsic attractiveness/“good”-ness (positive valence) or averseness/“bad”-ness (negative valence). It is also applied to specific emotions in order to characterise and categorise them - i.e. fear has negative valence; happiness has positive valence.

The 'Open Affective Standardised Image Set' (OASIS), is an open-access set of 900 colour images collected in 2015. The images depict a large variety of themes along with normative ratings of both arousal and valence. This work uses the valence rating as described above, as arousal describes our fright or flight reaction. The 900 images used were collated online and are provided as lo-res images that can be download along with a spreadsheet containing all average ratings for each image. It was possible to use a reverse image search to find higher resolution images more suitable for printing that you see here. OASIS acquired the ratings in an online study that uses a Likert scale (Very positive to very negative) and averaged the scores from 822 participants for each individual image. The one advantage to the use of OASIS in scientific practice is that the images are open source and not under copyright, unlike the industry standard, the 'International Affective Picture System' (IAPS).
All of the images included within The Valence Experiment have been selected from OASIS, based on the fact that within it they were scientifically determined to have the highest levels of positive valence. Yet once removed from the scientific experiments and contexts for which they were initially intended, a diverse, seemingly ambiguous and at times absurd array of imagery surfaces, not only questioning the validity of such experimentation, but also the quantifiability of affect and human emotion altogether.