Task: Classify the mental state of the tweeter based on the tweet, determining if it is 'neutral or no emotion' or characterized by any of the provided emotions (anger, anticipation, disgust, fear, joy, love, optimism, pessimism, sadness, surprise, trust).
Tweet: It is no coincidence that Lacan recorded infants' jubilant reactions to their mirror images in the noise.
This tweet contains emotions: 
sadness