The search scope of Google Scholar and PsycINFO are very different.
As their “About” page says: Google Scholar provides a simple way to broadly search for scholarly
literature. Google Scholar searches across resources from all disciplines/subject areas:
PsycINFO searches a defined set of resources, all focused in the field of psychology. You will find citations and abstracts for journal articles, book chapters, and dissertations from 1879 to the present. Nearly 2500 journals are indexed in PsycINFO, the database is updated weekly, and it contains 4.5 million records.
PsycINFO identifies the citing articles within its scope (i.e., the journals it indexes). Within PsycINFO, this article has been cited 223 times since 2001.
Google Scholar's scope is larger, therefore it can identify that an article has been cited more times across a larger body of literature or types of sources (such as books and reports). Google Scholar reports this article has been cited 344 times since 2001.