| something (57) | pleasure (26) | should (26) | increases (35) | activity (27) |
| dopamine (506) | things (115) | different (30) | because (79) | motivation (36) |
| system (30) | activities (36) | levels (48) | people (106) | really (87) |
| increase (71) | important (30) | release (74) | pathway (34) | caffeine (26) |
| baseline (81) | little (32) | experience (47) | reward (38) | actually (57) |