If you study a single neuron it's neuroscience. If you study 2; that's psychology.
Now, laboratories are mostly (if not exclusively) linked to natural sciences like Physics or Biology. Psychology also fashions itself to be formally defined as a natural science which studies mental processes, experiences and human behavior via scientific methods
Social science is the scientific study of human society and social relationships. Whereas natural science deals with the physical world. By these definitions then psychology would fall under the category of a natural science.
The formal beginnings of Psychology as a discipline date back to when Wilhelm Wundt started a dedicated laboratory for the study of psychology in Leipzig, Germany in 1879.
Laboratories are mostly linked to natural sciences like Physics or Biology. Psychology studies mental processes, experiences and human behavior via the scientific method through experimentation, hypothesis testing, and observation. Psychology encompasses fields such as memory, cognitive processes, attention and perception, language acquisition, linguistics, human development, autism, mental illness. These examples all deal with the physical world.
Research psychologists are using scientific methods right from data collection to interpretation and are using objectivity in their researchrather than subjective interpretation of data or formulation of theories; which are key characteristics of natural science.
However, it cannot be denied that a decent amount of psychological research also involves impacts socio-cultural and physical settings where some amount of subjectivity exists