Pedestrian　social　groups　are　an　essential　part　of　a　crowd.　In　emergency　situations,　they　may　become　principal　victims　during　evacuation　from　buildings,　such　as　bottlenecks　in　corridors.　However,　empirical　data　on　the　dynamics　of　social　groups　through　bottlenecks　are　limited.　In　this　paper,　a　controlled　experiment　was　performed　to　study　movement　features　of　social　groups　through　a　bottleneck　with　different　widths　(i.e.,　0.8,　1.4　and　2.4　m).　There　were　60　participants　in　the　experiment,　forming　four　crowd　compositions　(i.e.,　60　groups　of　singles,　30　groups　of　dyads,　20　groups　of　triads　and　15　groups　of　four-person　groups).　After　extracting　their　movement　trajectories　in　the　video　recordings,　offset　angles,　passing　performance,　interpersonal　distances　and　angles　in　group　walking,　relative　positions　in　social　groups,　etc.　were　analyzed.　The　results　highlight　that　the　negative　effect　of　bottleneck　width　on　instantaneous　speed　for　larger　groups　is　more　significant　than　for　smaller　groups.　The　cooperative　behavior　of　large　groups　is　beneficial　to　the　instantaneous　speed　of　pedestrians　under　wide　bottlenecks.　The　size　of　the　groups　has　no　evident　influence　on　lane　formation.　Singles　adjust　their　movement　directions　more　flexibly,　and　the　offset　angles　of　large　groups　are　smaller.　Good　passing　performance　can　be　reflected　in　large　groups　through　wide　bottlenecks.　It　is　proved　that　interpersonal　distances　and　angles　between　group　members　depend　on　the　group　size,　bottleneck　width　and　pedestrian　flow　state　(free　and　congested　flow).　Under　the　limitation　of　narrow　bottlenecks,　the　walking　structures　of　large　groups　can　lead　to　diverse　walking　structures.　The　phenomenon　of　recurring　splitting　and　rejoining　of　pedestrian　social　groups　can　be　observed.　These　findings　are　helpful　for　crowd　management　in　buildings.　(C)　2022　Elsevier　B.V.　All　rights　reserved.