Wundt recognised mental processes were difficult to study using his procedures.
Methods were not always scientific
Due to them being subjective and his results not being easily replicable.
Other explanations
Any behaviour outside of conscious awareness could not be tested and other approaches made greater contributions to psychology becoming a science e.g the work of Skinner and Bandura.
Paved the way for other techniques
Introspective techniques could be considered a precursor of methods used in the cognitive approach.
