text: Molecular recognition takes place in a noisy, crowded biological environment and the recognizer often has to cope with the task of selecting its target among a variety of similar competitors. For example, the ribosome has to select the correct tRNA that matches the mRNA codon among many structurally similar tRNAs. If the recognizer and its correct target match perfectly like a lock and a key, then the binding probability will be high since no deformation is required upon binding. At the same time, the recognizer might also bind to a competitor with a similar structure with high probability. Introducing an energy barrier, in particular, structural mismatch between the recognizer (lock) and the key, reduces the binding probability to the correct target but reduces even more the binding probability to a similar wrong target and thus improves the specificity.  Yet, introducing too much deformation drastically reduces binding probability to the correct target. Therefore, the optimal balance between maximizing the correct binding probability and minimizing the incorrect binding probability is achieved when the recognizer is slightly off target. This suggests that conformational changes during molecular recognition processes, such as the induced fit mechanism, are advantageous for enhancing the specificity of recognition. Such conformational changes may be fine-tuned by mutations that affect the mechanical response of the recognizer, also at positions far from the binding site.