<prompt> unaweza kugeuza matini haya ya swahilikwa kiingereza?wanasaikolojia wamefanya kidogo kuelezea hili: kwa miaka, wamesisitiza kuwa biolojia yetu inaweka kikomo kikubwa cha juu - kuhusu watu wa 150 - kwa ukubwa wa makundi yetu ya kijamii.  <response>: psychologists have done little to explain this: for years, they have held that our biology puts a hard upper limit of about 150 people on the size of our social groups. 